La digitalizzazione nello studio dentistico

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digitalizzazione nello studio dentistico

Nel mondo di oggi, la digitalizzazione è diventata una necessità per uno studio dentistico di successo. La digitalizzazione è il processo di conversione dei dati in forma digitale – come file di testo, immagini, video e suoni – e la loro archiviazione in un formato computerizzato. Questo processo è diventato sempre più importante per i dentisti che devono tenere traccia delle cartelle cliniche dei pazienti e degli orari degli appuntamenti, oltre che per il trattamento dei loro pazienti.

Introduzione alla digitalizzazione nello studio dentistico

In passato, la maggior parte degli studi dentistici utilizzava registri cartacei e sistemi di programmazione manuale per gestire le proprie attività. Con il progredire della tecnologia, questo approccio è stato sostituito da tecnologie digitali che consentono ai dentisti di archiviare e accedere ai dati dei pazienti in modo rapido e sicuro. La digitalizzazione nello studio dentistico è diventata essenziale per i dentisti per stare al passo con gli ultimi progressi nel campo dell’odontoiatria e per fornire la migliore qualità di cura ai loro pazienti.
I vantaggi dell’utilizzo della tecnologia digitale nello studio dentistico sono molteplici. La tecnologia digitale consente ai dentisti di tenere traccia delle cartelle cliniche dei pazienti in modo più semplice, di accedere rapidamente ai dati dei pazienti e di fornire loro cure migliori. La tecnologia digitale rende anche più facile coordinare gli appuntamenti e tenersi al passo con gli ultimi progressi in campo odontoiatrico.

Vantaggi della tecnologia digitale per i dentisti

L’uso della tecnologia digitale nello studio dentistico presenta molti vantaggi per i dentisti. La tecnologia digitale consente ai dentisti di archiviare le cartelle cliniche dei pazienti in modo sicuro e di accedervi rapidamente quando necessario. Inoltre, aiuta a gestire i propri impegni in modo più efficace. La tecnologia digitale rende più facile per i dentisti tenersi al passo con le ultime tendenze in campo odontoiatrico e fornire una migliore qualità delle cure ai loro pazienti.
La tecnologia digitale facilita anche la comunicazione con i pazienti. Con la tecnologia digitale, i dentisti possono inviare promemoria per gli appuntamenti, rispondere alle domande e fornire ai pazienti materiale didattico. Ciò contribuisce a migliorare il coinvolgimento e la soddisfazione dei pazienti. Inoltre, la tecnologia digitale può essere utilizzata per monitorare i progressi del paziente e per tenere traccia dei risultati del trattamento.

Diversi tipi di tecnologia digitale per i dentisti

Esiste una varietà di tecnologie digitali che i dentisti possono utilizzare nei loro studi. Queste tecnologie includono:
Cartelle cliniche elettroniche (EHR): Gli EHR sono cartelle cliniche digitali a cui il dentista può accedere. Consentono ai dentisti di archiviare, accedere e aggiornare i dati dei pazienti in modo rapido e sicuro.
Sistemi di imaging digitale: I sistemi di imaging digitale sono utilizzati per acquisire e archiviare radiografie e altre immagini dei denti e della bocca. Queste immagini aiutano i dentisti a diagnosticare e trattare i pazienti con maggiore precisione.
Software di gestione dello studio: Il software di gestione dello studio viene utilizzato per gestire gli appuntamenti, le cartelle cliniche e le informazioni di fatturazione. Questo software aiuta i dentisti a snellire il flusso di lavoro e a ridurre la documentazione cartacea.
Software per l’educazione del paziente: Il software per l’educazione del paziente aiuta i dentisti a educare i loro pazienti alla salute dentale. Questo software può essere utilizzato per fornire ai pazienti informazioni sulle procedure odontoiatriche, sui trattamenti e sulle cure preventive.

Come la tecnologia digitale può migliorare la cura del paziente

L’uso della tecnologia digitale nello studio dentistico può migliorare la cura del paziente in diversi modi. La tecnologia digitale può aiutare i dentisti a diagnosticare e trattare i pazienti con maggiore precisione. Può anche contribuire a snellire il flusso di lavoro e a ridurre la documentazione cartacea. Inoltre, la tecnologia digitale può essere utilizzata per migliorare la comunicazione tra dentisti e pazienti.
La tecnologia digitale facilita anche il monitoraggio dei progressi del paziente e dei risultati del trattamento. Questo aiuta i dentisti a monitorare i progressi dei loro pazienti e a garantire che ricevano la migliore qualità di cura possibile. La tecnologia digitale rende anche più facile per i dentisti fornire materiale educativo ai loro pazienti.

L’importanza della sicurezza dei dati

La sicurezza dei dati è una preoccupazione importante quando si parla di tecnologia digitale nello studio dentistico. I dentisti devono assicurarsi che tutti i dati dei pazienti siano archiviati in modo sicuro e siano accessibili solo al personale autorizzato. I dentisti devono anche essere consapevoli dei rischi associati all’uso della tecnologia digitale, come il rischio di violazione dei dati o di cyberattacchi.
Per proteggere i dati dei pazienti, i dentisti dovrebbero utilizzare soluzioni di archiviazione dati sicure, come i sistemi basati su cloud. Inoltre, i dentisti dovrebbero utilizzare password forti e l’autenticazione a due fattori per proteggere i loro sistemi da accessi non autorizzati.

Vantaggi del flusso di lavoro digitale nello studio dentistico

L’uso della tecnologia digitale può anche contribuire a migliorare il flusso di lavoro nello studio dentistico. La tecnologia digitale può aiutare i dentisti ad automatizzare i processi e a ridurre le attività manuali. Ciò può contribuire a ridurre il tempo necessario per completare le attività e ad aumentare l’efficienza dello studio.
La tecnologia digitale può anche aiutare i dentisti a gestire i loro orari in modo più efficace. I sistemi di programmazione digitale possono essere utilizzati per coordinare gli appuntamenti e garantire che i pazienti giusti siano visitati al momento giusto. Ciò contribuisce a ridurre i tempi di attesa e a migliorare la soddisfazione dei pazienti.

Soluzioni digitali per il coinvolgimento dei pazienti

La tecnologia digitale può essere utilizzata anche per migliorare il coinvolgimento dei pazienti nello studio dentistico. Gli strumenti digitali, come i siti web e i social media, possono essere utilizzati per comunicare con i pazienti e per fornire loro materiale didattico. Inoltre, gli strumenti digitali possono essere utilizzati per monitorare i progressi del paziente e i risultati del trattamento.
Gli strumenti digitali possono anche essere utilizzati per inviare promemoria per gli appuntamenti e per raccogliere feedback dai pazienti. Ciò contribuisce a migliorare la soddisfazione dei pazienti e a garantire loro la migliore qualità di cura possibile.

Soluzioni digitali per il marketing e la promozione

La tecnologia digitale può essere utilizzata anche per commercializzare e promuovere lo studio dentistico. Gli strumenti digitali, come i siti web e i social media, possono essere utilizzati per raggiungere i potenziali pazienti. Inoltre, gli strumenti digitali possono essere utilizzati per monitorare le campagne di marketing e misurare il successo delle attività promozionali.

Come iniziare con la tecnologia digitale nello studio dentistico

Iniziare a utilizzare la tecnologia digitale nello studio dentistico può essere un compito scoraggiante. Tuttavia, ci sono diversi passi che i dentisti possono compiere per garantire una transizione di successo alla tecnologia digitale.
In primo luogo, i dentisti devono identificare le aree del loro studio in cui la tecnologia digitale può essere più vantaggiosa. Ad esempio, le cartelle cliniche, la programmazione degli appuntamenti e il coinvolgimento dei pazienti.
Una volta identificate le aree in cui la tecnologia digitale può essere più vantaggiosa, i dentisti devono ricercare e selezionare le soluzioni digitali migliori per le loro esigenze. I dentisti devono considerare le caratteristiche, i costi e la sicurezza delle soluzioni prese in considerazione.
Infine, i dentisti devono assicurarsi che il loro personale sia adeguatamente formato all’uso della tecnologia digitale. Ciò contribuirà a garantire che la transizione alla tecnologia digitale abbia successo e che lo studio dentistico sfrutti appieno i vantaggi della tecnologia digitale.

Conclusione

L’uso della tecnologia digitale nello studio odontoiatrico è diventato essenziale per i dentisti per stare al passo con gli ultimi progressi nella cura dei denti e per fornire la migliore qualità di cura ai loro pazienti. La tecnologia digitale può aiutare i dentisti a memorizzare le cartelle cliniche dei pazienti in modo sicuro, ad accedere rapidamente ai dati dei pazienti, a gestire gli orari in modo più efficace e a migliorare il coinvolgimento dei pazienti. Inoltre, la tecnologia digitale può essere utilizzata per monitorare i progressi del paziente e per tenere traccia dei risultati del trattamento.
Per sfruttare appieno i vantaggi della tecnologia digitale, i dentisti devono identificare le aree del loro studio in cui la tecnologia digitale può essere più vantaggiosa, ricercare e selezionare le migliori soluzioni digitali per le loro esigenze e assicurarsi che il loro personale sia adeguatamente formato sull’uso della tecnologia digitale.

Se state cercando ulteriori informazioni sulla tecnologia digitale nello studio dentistico, visitate edentist.it. Con edentist.it è possibile ottenere le ultime notizie e approfondimenti sulle tecnologie digitali per i dentisti e trovare le migliori soluzioni digitali per il proprio studio.

Orthodontic Thesaurus

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Orthodontic Thesaurus

Identifiers
Code  Identificatori
Name
A.010 Nome
Sex
A.020 Sesso
Age
A.030 E
Birth Date
A.040 Data di nascita
Record Date
A.050 Data di registrazione
Journal Code Number
A.060 Codice numerico del giornale
   
Diagnosis
B
Diagnosi
Extraoral
B.010 Extraorale
Face Form
B.010.010 Conformazione Facciale
Brachycephalic Face
B.010.010.010 Brachicefalica
Dolichocephalic Face
B.010.010.020 Dolicocefalica
Mesocephalic Face
B.010.010.030 Mesocefalica
Profile
B.010.020 Profilo
Convex Profile
B.010.020.010 Convesso
Straight Profile
B.010.020.020 Dritto
Concave Profile
B.010.020.030 Concavo
Nose
B.010.030 Naso
Normal Nose
B.010.030.010 Normale
Flat Nose
B.010.030.020 Piatto
Small Nose
B.010.030.030 Piccolo
Big Nose
B.010.030.040        Grosso
Pugshaped Nose
B.010.030.050       Schiacciato
Chin
B.010.040      Mento
Normal Chin
B.010.040.010        Normale
Small Chin
B.010.040.020        Piccolo
Retrusive Chin
B.010.040.030        Retruso
Protrusive Chin
B.010.040.040        Protruso
Upper Jaw
B.010.050      Arcata Superiore
Upper Jaw Macrognathism
B.010.050.010        Macrognatica
Upper Jaw Micrognathism
B.010.050.020        Micrognatica
Normal Upper Jaw
B.010.050.030        Normale
Protrusive Upper Jaw
B.010.050.040        Protrusa
Retrusive Upper Jaw
B.010.050.050        Retrusa
Lower Jaw
B.010.060      Arcata Inferiore
Lower Jaw Macrognathism
B.010.060.010        Macrognatica
Lower Jaw Micrognathism
B.010.060.020        Micrognatica
Normal Lower Jaw
B.010.060.030        Normale
Protrusive Lower Jaw
B.010.060.040        Protrusa
Retrusive Lower Jaw
B.010.060.050        Retrusa
Gonion Angle
B.010.070      Angolo Goniale
Normal Gonion Angle
B.010.070.010        Angolo Goniale Normale
Small Gonion Angle
B.010.070.020        Angolo Goniale Piccolo
Large Gonion Angle
B.010.070.030        Angolo Goniale Grande
En Face
B.010.080      Faccia
Oval Face
B.010.080.010        Ovale
Round Face
B.010.080.020        Rotonda
Square Face
B.010.080.030        Quadrata
Asymmetry
B.010.090      Asimmetria
Facial Asymmetry
B.010.090.010        Asimmetria Facciale
Lip-morphology
B.010.100      Morfologia Labiale
Tense Lip-morphology
B.010.100.010        Ipertonica
Hypotonic Lip-morphology
B.010.100.020        Ipotonica
Thick Lip-morphology
B.010.100.030        Spessa
Thin Lip-morphology
B.010.100.040        Sottile
Lip-posture
B.010.110      Postura labiale
Competent Lip-sealant
B.010.110.010        Labbra Competenti
Incompetent Lip-sealant
B.010.110.020        Labbra Incompetenti
Gummy Smile
B.010.110.030        Sorriso Gengivale
Lower to Upper Lip
B.010.110.040        Inferiore to Superiore Lip
Negative Lower to Upper Lip
B.010.110.040.010          Negative Inferiore to Superiore Lip
Positive Lower to Upper Lip
B.010.110.040.020          Positive Inferiore to Superiore Lip
Straight Lower to Upper Lip
B.010.110.040.030          Straight Inferiore to Superiore Lip
Nasolabial Angle
B.010.120      Angolo Nasolabiale
Normal Nasolabial Angle
B.010.120.010        Normale
Acute Nasolabial Angle
B.010.120.020        Acuto
Obtuse Nasolabial Angle
B.010.120.030        Ottuso
Intraoral
B.020    Intraorale
Intraoral Hard Tissue
B.020.010      Tessuto duro intraorale
Cleft Palate
B.020.010.010        Schisi palatina
Cyst
B.020.010.020        Cisti
Exostosis
B.020.010.030        Esostosi
Fenestration
B.020.010.040        Fenestrazione
Intraoral Soft Tissue
B.020.020      Tessuto molle intraorale
Palatal Impinging
B.020.020.010        Traumatismo della mucosa palatina
Frenum
B.020.020.020        Frenulo
High Frenum
B.020.020.020.010          Alto
Lower Frenum
B.020.020.020.020          Basso
Tongue
B.020.020.030        Lingua
Tongue Size
B.020.020.030.010          Misura
Tongue Impression
B.020.020.030.020          Impronta
Occlusion
B.020.030      Occlusione
Sagittal Relation
B.020.030.010        Relazione Sagittale
Angle Class I
B.020.030.010.010          Classe I di Angle
Angle Class II
B.020.030.010.020          Classe II di Angle
Angle Class II Division 1
B.020.030.010.030          Classe II Divisione 1 di Angle
Angle Class II Division 2
B.020.030.010.040          Classe II Divisione 2 di Angle
Angle Class III
B.020.030.010.050          Classe III di Angle
Overjet
B.020.030.010.060          Overjet
Normal Overjet
B.020.030.010.060.010            Normale
Large Overjet
B.020.030.010.060.020            Ampio
Negative Overjet
B.020.030.010.060.030            Negativo
Partial Anterior Cross Bite
B.020.030.010.060.040            Morso inverso anteriore parziale
Vertical Relations
B.020.030.020        Relazioni Verticali
Frontal Open Bite
B.020.030.020.010          Morso Aperto Frontale
Lateral Open Bite
B.020.030.020.020          Morso Aperto Laterale
Deep Bite
B.020.030.020.030         Morso Profondo (Coperto)
Deep Bite with Palatal Impinging
B020.030.020.040  Morso Profondo con traumatismo della mucosa palatina
Infraocclusion
B.020.030.020.050          Infraocclusione
Supraocclusion
B.020.030.020.060          Supraocclusione
Transverse
B.020.030.030        Transverse
Lateral Cross Bite
B.020.030.030.010          Inversione del combaciamento laterale
Buccal Cross Bite
B.020.030.030.010.010            Morso incrociato vestibolare
Lingual Cross Bite
B.020.030.030.010.020            Morso incrociato linguale
Telescoping Bite
B.020.030.030.010.030            Telescoping Bite
Midline Deviation
B.020.030.030.020          Deviazione della linea mediana
Midline Deviation Maxilla
B.020.030.030.020.010            Mascellare
Midline Deviation Mandible
B.020.030.030.020.020            Mandibolare
Tooth Crowding
B.020.040      Affollamento dentale
Midline Deviation
B.020.040.010     Deviazione della linea interincisiva
Upper Midline Deviation
B.020.040.010.010          Superiore
Lower Midline Deviation
B.020.040.010.020          Inferiore
Frontal Crowding
B.020.040.020        Affollamento anteriore
Upper Frontal Crowding
B.020.040.020.010          Superiore
Lower Frontal Crowding
B.020.040.020.020          Inferiore
Tooth Spacing
B.020.050      Diastema
Lateral Spacing
B.020.050.010        Laterale
Lateral Spacing Upper Teeth
B.020.050.010.010          Laterale Superiore
Lateral Spacing Lower Teeth
B.020.050.010.020          Laterale Inferiore
Frontal Spacing
B.020.050.020        Diastema Frontale
Frontal Spacing Upper Teeth
B.020.050.020.010          Superiore
Frontal Spacing Lower Teeth
B.020.050.020.020          Inferiore
Diastema Mediale
B.020.050.030        Diastema Mediale
Apical Base
B.020.060      Base Ossea
Maxillary Apical Base
B.020.060.010        Mascellare
Broad Maxillary Apical Base
B.020.060.010.010          Ampia
Small Maxillary Apical Base
B.020.060.010.020          Piccola
Mandibular Apical Base
B.020.060.020        Mandibolare
Broad Mandibular Apical Base
B.020.060.020.010          Ampia
Small Mandibular Apical Base
B.020.060.020.020          Piccola
Tooth Eruption
B.020.070      Eruzione dentale
Premature Eruption
B.020.070.010        Prematura
Delayed Eruption
B.020.070.020        Ritardata
Ectopic Eruption
B.020.070.030        Ectopica
Tooth Position
B.020.080      Posizione dentale
Buccal Tooth Position
B.020.080.010        Vestibolare
Lingual Tooth Position
B.020.080.020        Linguale
Palatal Tooth Position
B.020.080.030         Palatale
Flared Tooth Position
B.020.080.040        Flared Tooth Position
Migrated Tooth Position
B.020.080.050        Migrata
Mesial Tooth Position
B.020.080.060        Mesiale
Distal Tooth Position
B.020.080.070        Distale
Transpositioned Tooth
B.020.080.080        Transposizione dentale
Tipped Tooth
B.020.080.090        Inclinazione dentale
Buccally Tipped Tooth
B.020.080.090.010          Vestibolare
Palatinally Tipped Tooth
B.020.080.090.020          Palatale
Mesially Tipped Tooth
B.020.080.090.030          Mesiale
Distally Tipped Tooth
B.020.080.090.040          Distale
Rotated Tooth
B.020.080.100        Rotazione
Mesially Rotated Tooth
B.020.080.100.010          Mesiale
Distally Rotated Tooth
B.020.080.100.020          Distale
Intruded Tooth
B.020.080.110        Intrusione
Infraoccluded Tooth
B.020.080.120        Ipotrusione
Extruded Tooth
B.020.080.130        Estrusione
Tooth Eruption Disturbance
B.020.090      Anomalia di eruzione dentale
Ankylosis
B.020.090.010        Anchilosi
Impacted Tooth
B.020.090.020        Inclusione
Natal Eruption
B.020.090.030        Eruzione natale
Neonatal Eruption
B.020.090.040        Eruzione Neonatale
Primary Tooth Eruption Disturbance
B.020.090.050        Anomalia di eruzione in dentatura decidua
Persistent Deciduous Tooth
B.020.090.050.010          Persistenza protratta deldeciduo
Premature Loss of Deciduous Tooth
B.020.090.050.020          Perdita Prematura
Tooth Eruption
B.020.100      Eruzione dentale
Late Tooth Eruption
B.020.100.010        Eruzione tardiva
Premature Tooth Eruption
B.020.100.020        Eruzione Prematura
Premature Tooth Shedding
B.020.100.030        Esfoliazione dentale prematura     
Tooth Abnormality
B.020.110      Anomalia Dentale
Anodontia
B.020.110.010        Anodonzia
Agenesi
B.020.110.020        Agenesia
Hyperdontia
B.020.110.030        Iperdonzia
Distomolar
B.020.110.030.010          Distomolare
Mesiodens
B.020.110.030.020          Mesiodens
Fourth Molar
B.020.110.030.030          Quarto Molare
Paramolar
B.020.110.030.040          Paramolare
Tooth Malformation
B.020.120      Malformazione dentale
Concrescence of Tooth
B.020.120.010        Concrescenza dentale
Dens Confusi
B.020.120.020        Dens Confusi
Dens Evaginatus
B.020.120.030        Dens Evaginatus
Dens Geminati
B.020.120.040        Dens Geminati
Dens Invaginatus
B.020.120.050        Dens Invaginatus
Enamel Pearl
B.020.120.060        Perla dello smalto
Macrodontia
B.020.120.070        Macrodonzia
Microdontia
B.020.120.080        Microdonzia
Molarization
B.020.120.090        Molarizzazione
Peg-shaped Tooth
B.020.120.100        Conoide
Taurodontism
B.020.120.110        Taurodontismo
Tuberculum Paramolare
B.020.120.120        Tubercolo Paramolare
Mottled Tooth
B.020.130      Discromia
Dental Fluorosis
B.020.130.010        Fluorosi Dentale
Hypomineralization
B.020.130.020        Ipomineralizzazione
Mottling of Enamel
B.020.130.030        Discromia dello smalto
Nonfluoride Enamel Opacity
B.020.130.040        Difetto dello smalto
White Spots
B.020.130.050        White Spots
Disturbances of Tooth Formation
B.020.140      Anomalia di sviluppo dentale
Aplasia of Cementum
B.020.140.010        Aplasia Cementizia
Hypoplasia of Cementum
B.020.140.020        Ipoplasia Cementizia
Dilaceration of Tooth
B.020.140.030        Dilacerazione dentale
Enamel Hypoplasia
B.020.140.040        Ipoplasia dello Smalto
Neonatal Enamel Hypoplasia
B.020.140.040.010          Neonatale
Postnatal Enamel Hypoplasia
B.020.140.040.020          Postnatale
Prenatal Enamel Hypoplasia
B.020.140.040.030          Prenatale
Regional Odontodysplasia
B.020.140.050        Odontodisplasia regionale
Turner Tooth
B.020.140.060        Dente di Turner
Hereditary Disturbances in Tooth Structure
B.020.150      Anomalia di struttura ereditaria
Amelogenesis Imperfecta
B.020.150.010        Amelogenesis Imperfecta
Dentinogenesis Imperfecta
B.020.150.020        Dentinogenesis Imperfecta
Odontogenesis Imperfecta
B.020.150.030        Odontogenesis Imperfecta
Dentinal DysplasiaB
B.020.150.040        Displasia Dentinale
Shell Tooth
B.020.150.050        Shell Tooth
Trauma
B.020.160      Trauma
Root Fracture
B.020.160.010        Frattura Radicolare
Tooth Concussion
B.020.160.020        Concussione Dentale
Traumatic Tooth Intrusion
B.020.160.030        Intrusione Traumatica
Traumatic Tooth Extrusion
B.020.160.040        Estrusione Traumatica
Lateral Tooth Luxation
B.020.160.050        Lussazione Laterale
Total Tooth Luxation
B.020.160.060        Lussazione Totale
Pulp Necrosis
B.020.170      Necrosi Pulpare
Root Resorption
B.020.180      Riasssorbimento Radicolare
Apical Root Resorption
B.020.180.010        Riassorbimento dell’apice radicolare
Lateral Root Resorption
B.020.180.020        Riassorbimento radicolare laterale
Disease of Hard Tissue of Tooth
B.020.190      Patologia del tessuto duro del dente
Caries
B.020.190.010        Carie
Arrested Caries
B.020.190.010.010          Carie Secca
Cementum Caries
B.020.190.010.020          Carie del Cemento
Dentine Caries
B.020.190.010.030          Carie della Dentina
Enamel Caries
B.020.190.010.040          Cariedello Smalto
Excessive Attrition
B.020.190.020        Usura patologica
Approximal Tooth Wear
B.020.190.020.010          Approssimale
Occlusal Tooth Wear
B.020.190.020.020          Occlusale
Abrasion
B.020.190.030        Abrasione
Dentifrice Abrasion
B.020.190.030.010          Da Spazzolamento
Habitual Abrasion
B.020.190.030.020          Abrasione Abituale
Occupational Abrasion
B.020.190.030.030          Occupazionale
Ritual Abrasion
B.020.190.030.040          Rituale
Traditional Abrasion
B.020.190.030.050          Traditionale
Tooth Erosion
B.020.190.040        Erosione
Infraction of Enamel
B.020.190.050        Infrazione dello smalto
Pathological Root Resorption
B.020.190.060        Riassorbimento radicolare patologico
Hypercementosis
B.020.190.070        Ipercementosi
Posteruptive Colour Change
B.020.190.080        Cambiamento di colore posteruttivo
Staining of Teeth
B.020.190.080.010          Staining
Craniofacial Morphology
B.030    Morfologia Craniofacciale
Basal Dysplasia
B.030.010      Displasia Basale
Sagittal Relation
B.030.020      Relazione Sagittale
Class I Skeletal Pattern
B.030.020.010        Modello scheletrico di I Classe
Class II Skeletal Pattern
B.030.020.020        Modello scheletrico di II Classe
Class III Skeletal Pattern
B.030.020.030        Modello scheletrico di III Classe
Orthognathia
B.030.020.040        Ortognazia
Prognathia
B.030.020.050        Prognazia
Retrognathia
B.030.020.060        Retrognazia
Micrognathia
B.030.020.060.010          Micrognazia
Protrusion
B.030.020.070        Protrusione
Bimaxillary Protrusion
B.030.020.070.010          Bimascellare
Bimaxillary Dentoalveolar Protrusion
B.030.020.070.010.010            Dentoalveolare Bimascellare
Maxillary Protrusion
B.030.020.070.020          Mascellare
Mandibulary Protrusion
B.030.020.070.030          Mandibolare
Retrusion
B.030.020.080        Retrusione
Bimaxillary Retrusion
B.030.020.080.010          Bimascellare
Bimaxillary Dentoalveolar Retrusion
B.030.020.080.010.010            Dentoalveolare Bimascellare
Maxillary Retrusion
B.030.020.080.020          Mascellare
Mandibulary Retrusion
B.030.020.080.030          Mandibolare
Vertical Relation
B.030.030      Relazione Verticale
Skeletal Open Bite
B.030.030.010        Morso Aperto Scheletrico
Skeletal Deep Bite
B.030.030.020        Morso Coperto Scheletrico
Transverse Relation
B.030.040      Relazione Trasversale
Lateral Skeletal Cross Bite
B.030.040.010        Inversione del combaciamento laterale
Lingual Cross Bite
B.030.040.010.010          Inversione del combaciamento linguale
Lateral Cross Bite
B.030.040.010.020          Inversione del combaciamento vestibolare
Midline Deviation
B.030.040.010.030          Deviazione della linea mediana
Rotation Pattern
B.030.050      Modello Rotazionale
Anterior Rotation
B.030.050.010        Rotazione Anteriore
Maxillary Anterior Rotation
B.030.050.010.010          Rotazione Mascellare Anteriore
Mandibular Anterior Rotation
B.030.050.010.020          Rotazione Mandibolare Anteriore
Posterior Rotation
B.030.050.020        Rotazione Posteriore
Maxillary Posterior Rotation
B.030.050.020.010          Rotazione Mascellare Posteriore
Mandibular Posterior Rotation
B.030.050.020.020          Rotazione Mandibolare Posteriore
Cranial Base
B.030.060      Base Cranica
Obtuse Cranial Base
B.030.060.010        Ottusa
Acute Cranial Base
B.030.060.020        Acuta
Gonion Angle
B.030.070       Angolo Goniale
Obtuse Gonion Angle
B.030.070.010        Ottuso
Acute Gonion Angle
B.030.070.020        Acuto
Anterior Relation, Incisor
B.030.080      Relazione Incisiva Anteriore
Proclined Incisor
B.030.080.010        Incisivo Proclinato
Protruded Incisor
B.030.080.020        Incisivo Protruso
Retroclined Incisor
B.030.080.030        Incisivo Retroclinato
Retruded Incisor
B.030.080.040        Incisivo Retruso
Oral Function
B.040    Funzione Orale
Swallowing
B.040.010      Deglutizione
Normal Swallowing Pattern
B.040.010.010        Modello Deglutitorio Normale
Infantile Swallowing Pattern
B.040.010.020        Modello Deglutitorio Infantile
Respiration
B.040.020      Respirazione
Nose Breathing
B.040.020.010        Nasale
Mouth Breathing
B.040.020.020        Orale
Temporomandibular Joint Function
B.050    Funzione dell’articolazione Temporomandibolare
Dysfunction
B.060    Disfunzione
Muscle Dysfunction
B.060.010      Muscolare
Muscledystrophy
B.060.010.010        Distrofia Muscolare
Muscle Hypertrophy
B.060.010.020        Ipertrofia Muscolare
Muscular Pain
B.060.010.030        Dolore Muscolare
Myalgia
B.060.010.040        Mialgia
Trismus
B.060.010.050        Trisma
Mentalis Contraction
B.060.010.060        Contrazione del Mentale
Oral Dysfunction
B.060.020      Disfunzione Orale
Abnormal Jaw Closure
B.060.020.010        Chiusura mandibolare anomala
Lip Interference
B.060.020.020        Interferenza Labiale
Habitual Occlusion
B.060.020.030        Occlusione Abituale
Tongue Interference
B.060.020.040        Interferenza Linguale
Sucking Habit
B.060.020.050        Vizio di succhiamento
Speech Deviation
B.060.020.060        Disturbo del linguaggio
Forced Bite
B.060.020.070        Morso costretto
Lateral Forced Bite
B.060.020.070.010          Laterale
Anterior Forced Bite
B.060.020.070.020          Anteriore
Vertical Forced Bite
B.060.020.070.030          Verticale
Balancing Side Interference
B.060.020.070.040          Lato Bilanciante
Temporomandibular Dysfunction
B.060.030      Disfunzione Temporomandibolare
Condylar Displacement
B.060.030.010        Dislocamento Condilare
Deviation in Opening Movement
B.060.030.020        Deviazione nel movimento di apertura
Deviation in Opening Movement to the Right
B.060.030.020.010          A Destra
Deviation in Opening Movement to the Left
B.060.030.020.020          A Sinistra
Impaired Mouth Opening
B.060.030.020.030          Limitata apertura orale
Temporomandibular Joint Sound
B.060.030.030        Rumori dell’articolazione temporomandibolare
Temporomandibular Joint Clicking
B.060.030.030.010          Click articolare
Temporomandibular Joint Crepitation
B.060.030.030.020          Crepitazione
Temporomandibular Joint Pain
B.060.030.040        Dolore temporomandibolare
Bruxism
B.060.030.050        Bruxismo
Tooth Clenching
B.060.030.060        Serramento
Snapping Jaw
B.060.030.070        Lussazione mandibolare
Diseases
C   Patologie
Tooth Abnormality
C.010    Anomalia dentale
Anodontia
C.010.010      Anodonzia
Agenesi
C.010.020      Agenesia
Hyperdontia
C.010.030      Iperdonzia
Distomolar
C.010.030.010        Distomolare
Mesiodens
C.010.030.020        Mesiodens
Fourth Molar
C.010.030.030        Quarto Molare
Paramolar
C.010.030.040        Paramolare
Tooth Malformation
C.020    Malformazione Dentale
Concrescence of Tooth
C.020.010      Concrescenza
Dens Confusi
C.020.020      Dens Confusi
Dens Evaginatus
C.020.030      Dens Evaginatus
Dens Geminati
C.020.040      Dens Geminati
Dens Invaginatus
C.020.050      Dens Invaginatus
Enamel Pearl
C.020.060      Perla dello Smalto
Macrodontia
C.020.070      Macrodonzia
Microdontia
C.020.080      Microdonzia
Molarization
C.020.090      Molarizzazione
Peg-shaped Tooth
C.020.100      Conoide
Taurodontism
C.020.110      Taurodontismo
Tuberculum Paramolare
C.020.120      Tubercolo Paramolare
Mottled Tooth
C.030    Discromie Dentali
Dental Fluorosis
C.030.010      Fluorosi Dentale
Hypomineralization
C.030.020      Ipomineralizzazione
Mottling of Enamel
C.030.030      Discromia dello Smalto
Nonfluoride Enamel Opacity
C.030.040      Difetto dello smalto
White Spots
C.030.050      White Spots
Disturbances of Tooth Formation
C.040    Anomalie di Formazione
Aplasia of Cementum
C.040.010      Aplasia del Cemento
Hypoplasia of Cementum
C.040.020      Ipoplasia del Cemento
Dilaceration of Tooth
C.040.030      Dilacerazione
Enamel Hypoplasia
C.040.040      Ipoplasia dello smalto
Neonatal Enamel Hypoplasia
C.040.040.010        Neonatale
Postnatal Enamel Hypoplasia
C.040.040.020        Postnatale
Prenatal Enamel Hypoplasia
C.040.040.030        Prenatale
Regional Odontodysplasia
C.040.050      Odontodisplasia Regionale
Turner Tooth
C.040.060      Dente di Turner
Hereditary Disturbances in Tooth Structure
C.050    Anomalie ereditarie nella struttura dentale
Amelogenesis Imperfecta C
C.050.010      Amelogenesis Imperfecta
Dentinogenesis Imperfecta C
C.050.020      Dentinogenesis Imperfecta
Odontogenesis Imperfecta C
C.050.030      Odontogenesis Imperfecta
Dentinal Dysplasia C
C.050.040      Dysplasia Dentinale
Shell Tooth C
C.050.050      Dens in dente
Disease of Hard Tissue of Tooth C
C.060    Patologia dei tessuti duri del dente
Caries C
C.060.010      Carie
Arrested Caries C
C.060.010.010        Carie secca
Cementum Caries C
C.060.010.020        Carie del cemento
Dentine Caries C
C.060.010.030        Carie della dentina
Enamel Caries C
C.060.010.040        Carie dello smalto
Disease of Pulp C
C.060.020      Patologia Pulpare
Pulp Necrosis C
C.060.020.010        Necrosi Pulpare
Disease of Periapical Tissue C
C.070    Patologia dei tessuti Periapicali
Gingival Disease C
C.080    Patologia Gengivale
Gingivitis C
C.080.010      Gengivite
Acute Gingivitis C
C.080.010.010        Acuta
Chronic Gingivitis C
C.080.010.020         Cronica
Locally Inflamed Gingiva C
C.080.010.030        Localizzata
Generally Inflamed Gingiva C
C.080.010.040        Diffusa
Periodontal Disease C
C.090    Patologia Parodontale
Periodontitis C
C.090.010      Parodontopatia
Acute Periodontitis C
C.090.010.010        Acuta
Chronic Periodontitis C
C.090.010.020        Cronica
Gingival Recession C
C.090.020      Recessione Gengivale
Gingival Dehiscence C
C.090.030      Deiscenza gengivale
Gingival Pocket C
C.090.040      Tasca Gengivale
Acromegaly C
C.100    Acromegalia
Arthritis C
C.110    Artrite
Rheumatoid Arthritis C
C.110.010      Artrite Reumatoide
Juvenile Chronic Arthritis C
C.110.020      Artrite cronica giovanile
Condylar Lesion C
C.120    Lesione Condilare
Condylar Flattening C
C.120.010      Appiattimento Condilare
Condylar Erosion C
C.120.020      Erosione Condilare
Condylar Sclerosis C
C.120.030      Sclerosi Condilare
Craniofacial Deformity C
C.130    Deformità Craniofaciale
Cleft Lip C
C.130.010      Schisi labiale
Cleft Palate C
C.130.020      Schisi Palatale
Head Deformity C
C.130.030      Deformità della Testa
Neck Deformities C
C.130.040      Deformità del collo
Diabetes C
C.140    Diabete
Dysplasia C
C.150    Displasia
Iatrogenic Effect C
C.160    Effetto Iatrogeno
Allergic Reaction C
C.160.010      Reazione Allergica
Root Resorption C
C.160.020      Riassorbimento Radicolare
Apical Root Resorption C
C.160.020.010        Riassorbimento dell’apice radicolare
Lateral Root Resorption C
C.160.020.020        Riassorbimento Radicolare Laterale
Fenestration of Bone C
C.160.030      Fenestrazione Ossea
Infraction of Enamel C
C.160.040      Infrazione dello smalto
Temporomandibular Joint Dysfunction C
C.160.050      Disfunzione dell’articolazione Temporomandibolare
Pulp Damage C
C.160.060      Danneggiamento Pulpare
Pulp Devitalization C
C.160.060.010        Devitalizzazione Pulpare
Caries C
C.160.070      Carie
Periodontitis C
C.160.080      Parodontite
Gingivitis C
C.160.090      Gengivite
Gingival Retraction C
C.160.100      Retrazione Gengivale
Idiopathic Effects C
C.170    Effetti Idiopatici
Down Syndrome C
C.180    Sindrome di Down
Temporomandibular Dysfunction C
C.190    Disfunzione Temporomandibolare
Tinnitus C
C.200    Tinnito
Etiology D
D     Eziologia
Genetic Etiology D
D.010    Genetica
Enviromental Etiology D
D.020    di sviluppo
Sucking Habit D
D.020.010      Vizi di succhiamento
Pacifier D
D.020.010.010        Pacificatori
Finger Sucking D
D.020.010.020        Succhiamento del dito
Thumb Sucking D
D.020.010.030        Succhiamento del Pollice
Breathing D
D.020.020      Respirazione
Oral Breathing D
D.020.020.010        Orale
Nose Breathing D
D.020.020.020        Nasale
Swallowing Pattern D
D.020.030      Modello Deglutitorio
Normal Swallowing Pattern D
D.020.030.010        Normale
Infantile Swallowing Pattern D
D.020.030.020        Infantile
Tongue Thrust D
D.020.040      Succhiamento della lingua
Tongue Position D
D.020.050      Posizione Linguale
Lip Interference D
D.020.060      Interferenza Labiale
Anatomical Structures
E Strutture Anatomiche
   
Cephalometric Landmark
E.010    Punti di repere Cefalometrici
Anterior Nasal Spine E
E.010.010       Spina Nasale Anteriore
Articulare E
E.010.020      Articolare
Basion E
E.010.030      Basion
Bolton Point E
E.010.040      Bolton
Condylion E
E.010.050      Condylion
Infradentale E
E.010.060      Infradentale
Glabella E
E.010.070      Glabella
Gonion E
E.010.080      Goniale
Gnathion E
E.010.090      Gnathion
Menthon E
E.010.100      Menthon
Nasion E
E.010.110      Nasion
Orbitale E
E.010.120      Orbitale
Pogonion E
E.010.130      Pogonion
Porion E
E.010.140      Porion
Pronasale E
E.010.150      Pronasale
Prostion E
E.010.160      Prostion
Pterygoideus E
E.010.170      Pterygoideo
R-point E
E.010.180      Punto R
Sella Turcica E
E.010.190      Sella Turcica
Spinale E
E.010.200      Spinale
Stomion E
E.010.210      Stomion
Subnasale E
E.010.220      Subnasale
Subspinale E
E.010.230      Subspinale
Supramentale E
E.010.240      Supramentale
Lateral Cephalometric Analysis E
E.020    Analisi Cefalometrica Laterale
Sagittal Relation E
E.020.010      Relazione Sagittale
SNA E
E.020.010.010        SNA
SNB E
E.020.010.020        SNB
ANB E
E.020.010.030        ANB
Wits Appraisal E
E.020.010.040        Wits Appraisal
SNPg E
E.020.010.050        SNPg
NSBa E
E.020.010.060        NSBa
Vertical Relation E
E.020.020      Relazione Verticale
ML-NSL E
E.020.020.010        ML-NSL
NL-NSL E
E.020.020.020        NL-NSL
NSL-FH E
E.020.020.030        NSL-FH
ML-NL E
E.020.020.040        ML-NL
Facial Index E
E.020.020.050         Indice Facciale
Gn-tgo-Ar E
E.020.020.060        Gn-tgo-Ar
Incisors Relation E
E.020.030      Relazione incisiva
Ui-Li E
E.020.030.010        Ui-Li
Ui-NL E
E.020.030.020        Ui-NL
Ui-NA E
E.020.030.030        Ui-NA
Li-ML E
E.020.030.040        Li-ML
Li-NB E
E.020.030.050        Li-NB
Ui-NA mm E
E.020.030.060        Ui-NA mm
Li-NB mm E
E.020.030.070        Li-NB mm
Li-APog mm E
E.020.030.080        Li-APog mm
Pg-NB mm E
E.020.040      Pg-NB mm
Soft Tissue E
E.020.050      Tessuto molle
UL-EL mm E
E.020.050.010        UL-EL mm
LL-EL mm E
E.020.050.020        LL-EL mm
Nasolabial E
E.020.050.030        Nasolabiale
PogSoft E
E.020.050.040        Pogonion molle
Facial Structure E
E.030    Struttura Facciale
Chin E
E.030.010      Mento
Gonial Angle E
E.030.020      Angolo Goniale
Lip E
E.030.030      Labbro
Lip-line E
E.030.030.010        Linea labiale
Esthetic Line E
E.030.030.020        Linea Estetica
Nose E
E.030.040      Naso
Profile E
E.030.050      Profilo
Temporomandibular Joint E
E.030.060      Articolazione Temporomandibolare
Condyle E
E.030.060.010        Condilo
Disc E
E.030.060.020        Disco
Fossa Temporomandibulare E
E.030.060.030        Fossa Temporomandibolare
Gonial Angle E
E.030.070      Angolo Goniale
Mandible E
E.030.080      Mandibola
Maxilla E
E.030.090      Mascellare superiore
Orbit E
E.030.100      Orbita
Ramus E
E.030.110      Ramo
Intraoral Soft Tissue E
E.030.120      Tessuti molli intraorali
Frenum E
E.030.120.010        Frenulo
Labial Frenum E
E.030.120.010.010          Labiale
Lingual Frenum E
E.030.120.010.020          Linguale
Labial Sulcus E
E.030.120.020        Solco Labiale
Mucosa E
E.030.120.030        Mucosa
Cheek E
E.030.120.040        Guancia
Pharynx E
E.030.120.050         Faringe
Palate E
E.030.120.060        Palato
Gingiva E
E.030.120.070        Gengiva
Periodontium E
E.030.120.080        Parodonto
Periodontal Ligament E
E.030.120.080.010          Legamento Parodontale
Tongue E
E.030.120.090        Lingua
Masticatory Muscle E
E.030.120.100        Muscolatura Masticatoria
Temporalis Muscle E
E.030.120.100.010          Muscolo Temporale
Masseter Muscle E
E.030.120.100.020          Muscolo Massetere
Medial Pterygoid Muscle E
E.030.120.100.030          Muscolo Pterigoideo Mediale
Lateral Pterygoid Muscle E
E.030.120.100.040          Muscolo Pterigoideo Laterale
Intraoral Hard Tissue E
E.030.130      Tessuto duro intraorale
Antegonial Notch E
E.030.130.010        Incisura Antegoniale
Basal Arch E
E.030.130.020        Arco Basale
Basal Bone E
E.030.130.030        Osso Basale
Hard Palate E
E.030.130.040        Palato Duro
Cranial Structure E
E.040    Struttura Cranica
Cranial Base E
E.040.010      Base Cranica
Lateral Cranial Base E
E.040.010.010        Laterale
Anterior Cranial Base E
E.040.010.020        Anteriore
Dentoalveolar Structure E
E.050    Struttura Dentoalveolare
Apical Base E
E.050.010      Base Apicale
Alveolar Arch E
E.050.020      Arcata Alveolare
Alveolar Bone E
E.050.030      Osso Alveolare
Alveolar Process E
E.050.040      Processo Alveolare
Dental Arch E
E.050.050      Arcata Dentale
Upper Dental Arch E
E.050.050.010        Superiore
Lower Dental Arch E
E.050.050.020        Inferiore
Dentition E
E.050.060      Dentatura
Deciduous Dentition E
E.050.060.010        Dentatura Decidua
Deciduous Molar E
E.050.060.010.010          Molare Deciduo
1st Deciduous Upper Molar E
E.050.060.010.010.010            1° Molare Deciduo Superiore
1st Deciduous Upper Molar Right E
E.050.060.010.010.010.010              Destro
1st Deciduous Upper Molar Left E
E.050.060.010.010.010.020              Sinistro
1st Deciduous Lower Molar E
E.050.060.010.010.020            1°Molare Deciduo Inferiore
1st Deciduous Lower Molar Left E
E.050.060.010.010.020.010              Sinistro
1st Deciduous Lower Molar Right E
E.050.060.010.010.020.020              Destro
2nd Deciduous Upper Molar E
E.050.060.010.010.030            2° Molare Deciduo Superiore
2nd Deciduous Upper Molar Right E
E.050.060.010.010.030.010              Destro
2nd Deciduous Upper Molar Left E
E.050.060.010.010.030.020              Sinistro
2nd Deciduous Lower Molar E
E.050.060.010.010.040            2°Molare Deciduo Inferiore
2nd Deciduous Lower Molar Left E
E.050.060.010.010.040.010              Sinistro
2nd Deciduous Lower Molar Right E
E.050.060.010.010.040.020              Destro
Deciduous Canine E
E.050.060.010.020          Canino Deciduo Superiore
Upper Deciduous Canine Right E
E.050.060.010.020.010            Destro
Upper Deciduous Canine Left E
E.050.060.010.020.020            Sinistro
Lower Deciduous Canine Left E
E.050.060.010.020.030          Canino Deciduo Inferiore
Lower Deciduous Canine Right E
E.050.060.010.020.040            Destro
Lateral Deciduous Incisor E
E.050.060.010.030          Incisivo Laterale Deciduo
Upper Lateral Deciduous Incisor Right E
E.050.060.010.030.010             Superiore Destro
Upper Lateral Deciduous Incisor Left E
E.050.060.010.030.020            Superiore Sinistro
Lower Lateral Deciduous Incisor Right E
E.050.060.010.030.030            Inferiore Destro
Lower Lateral Deciduous Incisor Left E
E.050.060.010.030.040            Inferiore Sinistro
Central Deciduous Incisor E
E.050.060.010.040          Incisivo Centrale Deciduo
Upper Central Deciduous Incisor Right E
E.050.060.010.040.010            Superiore Destro
Upper Central Deciduous Incisor Left E
E.050.060.010.040.020            Superiore Sinistro
Lower Central Deciduous Incisor Left E
E.050.060.010.040.030            Inferiore Sinistro
Lower Central Deciduous Incisor Right E
E.050.060.010.040.040            Inferiore Destro
Mixed Dentition E
E.050.060.020        Dentatura Mista
Succedaneous Tooth E
E.050.060.030        Dente di sostituzione
Permanent Teeth E
E.050.060.040        Denti Permanenti
Permanent Tooth E
E.050.060.050        Dente Permanente
Molar E
E.050.060.050.010          Molare
1st Upper Molar E
E.050.060.050.010.010            1° Superiore
1st Upper Molar Right E
E.050.060.050.010.010.010              Destro
1st Upper Molar Left E
E.050.060.050.010.010.020              Sinistro
1st Lower Molar E
E.050.060.050.010.020            1° Molare Inferiore
1st Lower Molar Left E
E.050.060.050.010.020.010              Sinistro
1st Lower Molar Right E
E.050.060.050.010.020.020              Destro
2nd Upper Molar E
E.050.060.050.010.030            2° Molare Superiore
2nd Upper Molar Right E
E.050.060.050.010.030.010              Destro
2nd Upper Molar Left E
E.050.060.050.010.030.020              Sinistro
2nd Lower Molar E
E.050.060.050.010.040            2° Molare Inferiore
2nd Lower Molar Left E
E.050.060.050.010.040.010              Sinistro
2nd Lower Molar Right E
E.050.060.050.010.040.020              Destro
3rd Upper Molar E
E.050.060.050.010.050            3° Molare Superiore
3rd Upper Molar Right E
E.050.060.050.010.050.010              Destro
3rd Upper Molar Left E
E.050.060.050.010.050.020              Sinistro
3rd Lower Molar E
E.050.060.050.010.060            3° Molare Inferiore
3rd Lower Molar Left E
E.050.060.050.010.060.010              Sinistro
3rd Lower Molar Right E
E.050.060.050.010.060.020              Destro
Premolar E
E.050.060.050.020          Premolare
1st Upper Premolar E
E.050.060.050.020.010            1° Premolare Superiore
1st Upper Premolar Right E
E.050.060.050.020.010.010              Destro
1st Upper Premolar Left E
E.050.060.050.020.010.020              Sinistro
1st Lower Premolar E
E.050.060.050.020.020            1° Premolare Inferiore
1st Lower Premolar Left E
E.050.060.050.020.020.010              Sinistro
1st Lower Premolar Right E
E.050.060.050.020.020.020              Destro
2nd Upper Premolar E
E.050.060.050.020.030            2° Premolare Superiore
2nd Upper Premolar Right E
E.050.060.050.020.030.010              Destro
2nd Upper Premolar Left E
E.050.060.050.020.030.020              Sinistro
2nd Lower Premolar E
E.050.060.050.020.040            2° Premolare Inferiore
2nd Lower Premolar Left E
E.050.060.050.020.040.010              Sinistro
2nd Lower Premolar Right E
E.050.060.050.020.040.020              Destro
Canine E
E.050.060.050.030          Canino
Upper Canine Right E
E.050.060.050.030.010            Superiore Destro
Upper Canine Left E
E.050.060.050.030.020            Superiore Sinistro
Lower Canine Left E
E.050.060.050.030.030            Inferiore Sinistro
Lower Canine Right E
E.050.060.050.030.040            Inferiore Destro
Lateral Incisor E
E.050.060.050.040          Incisivo Laterale
Upper Lateral Incisor Right E
E.050.060.050.040.010            Superiore Destro
Upper Lateral Incisor Left E
E.050.060.050.040.020            Superiore Sinistro
Lower Lateral Incisor Left E
E.050.060.050.040.030            Inferiore Sinistro
Lower Lateral Incisor Right E
E.050.060.050.040.040            Inferiore Destro
Central Incisor E
E.050.060.050.050          Incisivo Centrale
Upper Central Incisor Right E
E.050.060.050.050.010            Superiore Destro
Upper Central Incisor Left E
E.050.060.050.050.020            Superiore Sinistro
Lower Central Incisor Left E
E.050.060.050.050.030            Inferiore Sinistro
Lower Central Incisor Right E
E.050.060.050.050.040            Inferiore Destro
Tooth Structure E
E.050.060.060        Struttura dentale
Cementum E
E.050.060.060.010          Cemento
Dentin E
E.050.060.060.020          Dentina
Enamel E
E.050.060.060.030           Smalto
Pulp E
E.050.060.060.040          Polpa
Orthodontic Appliance F
F   Apparecchio Ortodontico
Orthodontic Removable Appliance
F.010    Apparecchio Ortodontico Rimovibile
Plate F
F.010.010      Placca
Bite Plane F
F.010.010.010        Piano di Svincolo
Lateral Bite Plane F
F.010.010.010.010          Laterale
Frontal Bite Plane F
F.010.010.010.020          Frontale
Inclined Bite Plane F
F.010.010.010.030          Inclinato
Crib F
F.010.010.020        Griglia
Lateral Crib F
F.010.010.020.010          Laterale
Frontal Crib F
F.010.010.020.020          Frontale
Wirework F
F.010.010.030        Filo ortodontico
Loop F
F.010.010.030.010          Ansa
Retentive Wirework F
F.010.010.030.020          Ritentiva Wirework
Adams Clasp F
F.010.010.030.020.010            Gancio di Adams
Arrow Clasp F
F.010.010.030.020.020            Gancio a freccia
Incisor Clasp F
F.010.010.030.020.030            Gancio Incisivo
Open Clasp F
F.010.010.030.020.040            Gancio Aperto
Labial Wire F
F.010.010.030.020.050            Arco Vestibolare
Passive Wirework F
F.010.010.030.030          Passive Wirework
Stop F
F.010.010.030.030.010            Stop
Active Wirework F
F.010.010.030.040          Active Wirework
Spring F
F.010.010.030.040.010            Molla
Palatal Finger Spring F
F.010.010.030.040.010.010              Molla a dito palatale
Buccal Canine Retractor F
F.010.010.030.040.010.020               Retrattore Canino Vestibolare
Z-spring F
F.010.010.030.040.010.030              molla a Z
T-spring F
F.010.010.030.040.010.040              molla a T
Molar Spring F
F.010.010.030.040.010.050              Molla Molare
Labial Wire F
F.010.010.030.040.010.060              Arco Vestibolare
Apron Spring F
F.010.010.030.040.010.070              Molla a Grembiule
Coffin Spring F
F.010.010.030.040.010.080              Ansa di Coffin
Screw F
F.010.010.030.050          Vite
Expansion Screw F
F.010.010.030.050.010            Vite di Espansione
Contraction Screw F
F.010.010.030.050.020            Vite di Contrazione
Distalisation Screw F
F.010.010.030.050.030            Vite Distalizzante
Expansion Plate F
F.010.010.040        Placca di Espansione
Contraction Plate F
F.010.010.050        Placca di Contrazione
Cetlin Plate F
F.010.010.060        Placca di Cetlin
Retention Plate F
F.010.010.070        Placca di Ritenzione
Space Maintainer F
F.010.010.080        Mantenitore di spazio
Space Regainer F
F.010.010.090        Creatore di Spazio
Hawley Retainer F
F.010.010.100        Retainer di Hawley
Tooth Positioner F
F.010.010.110        Posizionatore dentale
Splint F
F.010.010.120        Splint
Split Palate F
F.010.010.130        Disgiuntore
Functional Appliance F
F.020    Apparecchio funzionale
Activator F
F.020.010      Attivatore
Andresen Activator F
F.020.010.010        di Andresen
Herren Activator F
F.020.010.020        di Herren
Woodside Activator F
F.020.010.030        di Woodside
Harvold Activator F
F.020.010.040        di Harvold
Schwarz Activator F
F.020.010.050        di Schwarz
Elastic Open Activator F
F.020.010.060        Elastico Aperto
Palate Free Activator F
F.020.010.070        senza palato
Bass Activator F
F.020.010.080         di Bass
Kinetor F
F.020.010.090        Kinetor
Headgear Activator F
F.020.010.100        con trazione extraorale
Teucher Activator F
F.020.010.100.010          di Teucher
Van Beek Activator F
F.020.010.100.020          di Van Beek
Bite Block F
F.020.020      Bite Block
Hansaplatte F
F.020.030      Hansaplatte
Bionator F
F.020.040      Bionator
Open Bionator F
F.020.040.010        Bionator (aperto)
Close Bionator F
F.020.040.020        Bionator schermato
Reversed Bionator F
F.020.040.030        Bionator invertito
Headgear Bio F
F.020.040.040        con trazione extraorale
Bimler Appliance F
F.020.050      Apparecchio di Bimler
Fraenkel Appliance F
F.020.060      Apparecchio di Fraenkel
Fraenkel I F
F.020.060.010         Fraenkel I
Fraenkel II F
F.020.060.020        Fraenkel II
Fraenkel III F
F.020.060.030        Fraenkel III
Twin Block F
F.020.070      Twin Block
Bite Jumping Appliance F
F.020.080      Apparecchio saltamorso
Retractor F
F.020.090      Retrattore
Screen F
F.020.100      Schermo
Orthodontic Fixed Appliance F
F.030    Apparecchio ortodontico fisso
Straight Wire Appliance F
F.030.010      Straight Wire
Standard Edgewise Appliance F
F.030.020      Standard Edgewise
Begg Appliance F
F.030.030      di Begg
Sectioned Appliance F
F.030.040      Sezionale
Lingual Technique F
F.030.050      Linguale
Universal Appliance F
F.030.060      Universale
Orthodontic Attachment F
F.030.070      Mezzi ortodontici
Wirematerial F
F.030.070.010        Filo Ortodontico
Stainless Steel Wirematerial F
F.030.070.010.010          In acciaio inossidabile
Australian Wirematerial F
F.030.070.010.020          Australiano
Nitinol Wirematerial F
F.030.070.010.030          Nitinol
Titanium Wirematerial F
F.030.070.010.040          Titanium
Alfa-titanium Wirematerial F
F.030.070.010.050          Alfa-titanio
Betatitanium Wirematerial F
F.030.070.010.060          Betatitanio
Tefloncovered Wirematerial F
F.030.070.010.070          Teflonato
Superelastic Wirematerial F
F.030.070.010.080          Superelastico
Bracket F
F.030.070.020        Attacco diretto
Stainless Steel Bracket F
F.030.070.020.010          in acciaio inossidabile
Titanium Bracket F
F.030.070.020.020          in titanio
Plastic Bracket F
F.030.070.020.030          in plastica
Cheramic Bracket F
F.030.070.020.040          in ceramica
Goldcovered Bracket F
F.030.070.020.050          placcati oro
Brackettype F
F.030.070.030        Tipo di attacco diretto
018-slot Brackettype F
F.030.070.030.050.010 18
022-slot Brackettype F
F.030.070.030.050.020 22
Preangulated Brackettype F
F.030.070.030.050.030            Preangolato
Pretorque Brackettype F
F.030.070.030.050.040            Preinclinato
Band F
F.030.070.030.010          Banda
018-slot Band F
F.030.070.030.010.010 18
022-slot Band F
F.030.070.030.010.020 22
Bandmaterial F
F.030.070.030.020          Tipo di Banda
Stainless Steel Bandmaterial F
F.030.070.030.020.010            In accaio inossidabile
Titanium Bandmaterial F
F.030.070.030.020.020            In Titanio
Arch Wire F
F.030.080      Arco ortodontico
Continuous Arch Wire F
F.030.080.010        Continuo
Sectional Arch Wire F
F.030.080.020        Sezionale
Clip-on Arches F
F.030.080.030        Clip-on Arches
Utility Arch Wire F
F.030.080.040        di Utilità
Ligature F
F.030.090      Legatura
Elastomeric Ligature F
F.030.090.010        Elastomerica
Stainless Steel Ligature F
F.030.090.020        In accaio inossidabile
Bend F
F.030.100      Piega
First Order Bend F
F.030.100.010         Di primo ordine
Second Order Bend F
F.030.100.020        Di secondo ordine
Third Order Bend F
F.030.100.030        Di terzo ordine
Tip-back Bend F
F.030.100.040        Piega di Tip-back
Tip-forward Bend F
F.030.100.050        Piega di Tip-forward
Tip-back Bend F
F.030.100.060        Piega di Tip-back
Gable, Tent Bend F
F.030.100.070        Gable, Tent Bend
V-bend F
F.030.100.080        Piega a V
Aesthetic Bend F
F.030.100.090        Piega Estetica
Loop F
F.030.110      Ansa
Open Loop F
F.030.110.010        Aperta
Closed Loop F
F.030.110.020        Chiusa
Omega Loop F
F.030.110.030        ad Omega
Tie Back Loop F
F.030.110.040        ansa di Tie Back
Elastic Coil F
F.030.120      Legatura elastica
Hook F
F.030.130      Gancio
Jesper Jump F
F.030.140      Jasper Jumper
Elastic F
F.030.150      Elastici
Cross-elastic F
F.030.150.010        di Cross-cross
Class I Elastic F
F.030.150.020        di prima Classe
Class II Elastic F
F.030.150.030        di seconda Classe
Class III Elastic F
F.030.150.040        di terza Classe
Vertical Elastic F
F.030.150.050        Elastici Verticali
Herbst Appliance F
F.040    Apparecchio di Herbst
Moulded Herbst Appliance F
F.040.010      Saldato
Herbst Appliance Integrated with Fixed Appliance F
F.040.020      Integrato con apparecchio fisso
Jasper Jumper F
F.050    Jasper Jumper
Rapid Palatal Expander F
F.060    Espansore Rapido Palatale
Lip Bumper F
F.070    Lip Bumper
Lingual Arch F
F.080    Arco Linguale
Quad Helix F
F.080.010      Quad Helix
Lingual Arch with Frontal Bite Plane F
F.080.020      Arco Linguale con piano di svincolo anteriore
Lingual Arch with Crib F
F.080.030      Arco Linguale con griglia
Nance Holder F
F.080.040      Bottone di Nance
Palatal Bar F
F.080.050      Barra Palatale
Gosh Garian F
F.080.060      Goshgarian
Tongue Crib F
F.080.070      Griglia linguale
W-arch F
F.080.080      W-arch
Lingual Arch Lock F
F.090    Lingual Arch Lock
Vertical Lock F
F.090.010      Vertical Lock
Horizontal Lock F
F.090.020      Horizontal Lock
Soldered Lock F
F.090.030      Soldered Lock
Extraoral Traction F
F.100    Trazione Extraorale
Kloehn Headgear F
F.100.010      Kloehn
Cervical Headgear F
F.100.020      Cervicale
Occipital Headgear F
F.100.030      Occipitale
Combined Headgear F
F.100.040      Combinata
Vertical Headgear F
F.100.050      Verticale
Asymmetrical Headgear F
F.100.060      Asimmetrica
J-hook Headgear F
F.100.070      J-hook Headgear
Reversed Headgear F
F.100.080      Trazione extraorale invertita
Chin Cap F
F.100.090      Mentoniera
Separation F
F.110    Separazione
Elastics Separation F
F.110.010      Elastica
Separation Spring F
F.110.020      Molla di separazione
Separation Brass Wire F
F.110.030      con filo di rame
Bonded Retainer F
F.120    Retainer Incollato
Lingual Bonded Retainer F
F.120.010      Linguale
Buccal Bonded Retainer F
F.120.020      Vestibolare
Force F
F.130    Forza
Intermittent Force F
F.130.010      Intermittente
Continuous Force F
F.130.020      Continua
Interrupted Force F
F.130.030      Interrotta
Intraoral Force F
F.130.040      Intraorale
Extraoral Force F
F.130.050      Extraorale
Magnetic Force F
F.130.060       Magnetica
Treatment
G       Trattamento
Orthodontic Treatment
G.010    Trattamento Ortodontico
Preventive Orthodontics G
G.010.010      Preventivo
Corrective Orthodontics G
G.010.020      Correttivo
Cosmetic Orthodontics G
G.010.030      Cosmetico
Interceptive Orthodontics G
G.010.040      Intercettivo
Prophylactic Orthodontics G
G.010.050      Profilattico
Orthodontic Treatment with Fixed Appliance G
G.010.060      Con apparecchio fisso
Leveling Phase G
G.010.060.010         Fase di Livellamento
Movement Phase G
G.010.060.020        Fase di Movimento
Contraction Phase G
G.010.060.030        Fase di Contrazione
Distalisation Phase G
G.010.060.040        Fase di Distalizzazione
Adjustment Phase G
G.010.060.050        Fase di Rifinitura
Retention Phase G
G.010.060.060        Fase di Ritenzione
Bonding G
G.010.070      Incollaggio
Indirect Bonding G
G.010.070.010        Indiretto
Direct Bonding G
G.010.070.020        Diretto
Banding G
G.010.080      Bandaggio
Debonding G
G.010.090      Debonding
Debanding
G.010.100      Sbandaggio
Orthopedic Treatment G
G.010.110      Trattamento Ortopedico
Sutural Expansion G
G.010.110.010        Espansione Suturale
Habit Therapy G
G.010.120      Terapia delle abitudini viziate
Councelling G
G.010.120.010        Councelling
Appliance Therapy G
G.010.120.020        Appliance Therapy
Functional Treatment G
G.010.130      Trattamento Funzionale
Jaw Excersises G
G.010.130.010        Esercizi mandibolari
Bite Jumping G
G.010.130.020        Bite Jumping
Muscle Strengthening G
G.010.130.030        Rafforzamento Muscolare
Interproximal Stripping of Enamel G
G.010.140      Stripping dello smalto interprossimale
Orthodontic Anchorage G
G.010.150      Ancoraggio Ortodontico
Cervical Anchorage G
G.010.150.010        Cervicale
Cranial Anchorage G
G.010.150.020        Craniale
Extraoral Anchorage G
G.010.150.030        Extraorale
Intraoral Anchorage G
G.010.150.040        Intraorale
Occipital Anchorage G
G.010.150.050        Occipitale
Anchorage Preparation G
G.010.150.060        Preparazione di Ancoraggio
Implant G
G.010.150.070        Impianto
Palatal Implant G
G.010.150.070.010          Impianto Palatale
Tooth Movement G
G.020    Movimento Dentale
Bodily Movement G
G.020.010      Corporeo
Extrusion G
G.020.020      Estrusione
Intrusion G
G.020.030      Intrusione
Rotation G
G.020.040      Rotazione
Derotation G
G.020.050      Derotatione
Tipping Movement G
G.020.060      Movimento di Tipping
Torque Movement G
G.020.070      Movimento di Torque
Crown Movement G
G.020.080      Movimento della Corona
Surgical Treatment G
G.030    Trattamento Chirurgico
Cleft Lip and Palate Surgery G
G.030.010      Labiopalatoschisi e chirurgia palatale
Enucleate G
G.030.020      Enucleare
Extraction of Tooth G
G.030.030      Estrazione dentale
Serial Extraction G
G.030.030.010        Estrazioni Seriali
Fiberotomy G
G.030.040      Fibrotomia
Fixation G
G.030.050      Fissazione
Frenectomy G
G.030.060      Frenulectomia
Genioplasty G
G.030.070      Genioplastica
Gingival Graft G
G.030.080      Innesto Gengivale
Glossotomy G
G.030.090      Glossectomia
Grafting G
G.030.100      Innestare
Orthognatic Surgery G
G.030.110      Chirurgia Ortognatica
Maxillary Osteotomy G
G.030.110.010        Osteotomia Mascellare
Le Fort I G
G.030.110.010.010          Le Fort I
Le Fort II G
G.030.110.010.020          Le Fort II
Segmented Osteotomy G
G.030.110.010.030          Osteotomia Segmentale
Mandibular Osteotomy G
G.030.110.020         Osteotomia Mandibolare
Sagittal Split G
G.030.110.020.010          Sagittale
Oblique Ramusosteotomy G
G.030.110.020.020          Ramosteotomia obliqua
Segmented Osteotomy G
G.030.110.020.030          Osteotomia Segmentata
Replantation G
G.030.120      Reimpianto
Resection G
G.030.130      Resezione
Root Resection G
G.030.130.010        Resezione Radicolare
Surgical Exposure of Impacted Teeth G
G.030.140      Esposizione Chirurgica di denti inclusi
Cariological Treatment G
G.040    Trattamento Conservativo
Periodontal Treatment G
G.050    Trattamento Parodontale
Endodontic Treatment G
G.060    Trattamento Endodontico
Root Filling G
G.060.010      Otturazione canalare
Prosthetic Treatment G
G.070    Trattamento Protesico
Implant G
G.070.010      Impianto
Crown G
G.070.020      Corona
Bridge G
G.070.030      Ponte
Maryland Bridge G
G.070.030.010        Maryland Bridge (ponte incollato)
Treatment Need G
G.080    Necessità di Trattamento
Esthetic Treatment Need G
G.080.010      Estetica
Functional Treatment Need G
G.080.020      Funzionale
Prophylactic Treatment Need G
G.080.030      Profilattica
Psychological Treatment Need G
G.080.040      Psicologica
   
Measurements Procedures
H   Procedure di misurazione
Anthropometric Measurement H
H.010    Misure Antropometriche
Body Height H
H.010.010      Statura
Craniometry H
H.010.020      Craniometria
Bolton Analysis H
H.020    Analisi di Bolton
Cast Analysis H
H.030    Analisi dei modelli
Facial Index H
H.040    Indice Facciale
Helkimo’s Index H
H.050    Indice di Helkimo
Anamnestic Index H
H.050.010      Anamnestico
Dysfunctional Index H
H.050.020      Disfunzionale
Occlusal Index H
H.050.030      Occlusale
Irregularity Index H
H.060    Di irregolarità
IOTN H
H.070    IOTN
Radiographic Measurement H
H.080    Misura Radiografica
Cephalometric Analysis H
H.080.010      Analisi Cefalometrica
Hasund’s Analysis H
H.080.010.010        di Hasund
Ricket’s Analysis H
H.080.010.020        di Ricketts
Downs’ Analysis H
H.080.010.030        di Down
Computer-assisted Tomography H
H.080.020      Tomografia Computerizzata
Computerized Cephalometrics H
H.080.030      Cefalometria Computerizzata
Magnet Resonance Imaging H
H.080.040      Risonanza Magnetica
Panoramic Radiograph H
H.080.050      Radiografia Panoramica
Tomography H
H.080.060      Tomografia
PAAR-index H
H.090    Indice PAAR
   
Materials
I   Materiali
Acrylic I
I.010    Resina Acrilica
Alginate I
I.020    Alginato
Stainless Steel I
I.030    Acciaio Inossidabile
Titanium I
I.040    Titanio
Alfa-titanium I
I.040.010      Alfa-titanio
Betatitanium I
I.040.020      Betatitanio
Plastic I
I.050    Plastica
Cheramic I
I.060    Ceramica
Gold I
I.070    Oro
Guttaperka I
I.080    Guttaperca
Nitinol I
I.090    Nitinol
Teflon I
I.100    Teflon
Superelastic Metal I
I.110    Metallo Superelastico
   
Time Period
J   Epoca
Age Group J
J.010    Gruppo di età
Newborn J
J.010.010      Neonato
Infant J
J.010.020      Lattante
Child, Preschool J
J.010.030      Bambino in età prescolare
Child J
J.010.040      Bambino
Adolescence J
J.010.050      Adolescente
Adult J
J.010.060      Adulto
Middle-age J
J.010.070      di mezza età
Aged J
J.010.080      Anziano
Childhood J
J.020    Età scolare
Growth Spurt J
J.030    Picco di crescita puberale
Natal J
J.040    Neonatale
Prenatal J
J.050    Prenatale
Puberty J
J.060    Pubertà
Youth J
J.070    Età giovanile
Ugly Duckling Stage J
J.080    Stadio del brutto anatroccolo
Dental Development J
J.090    Sviluppo Dentale
Orthodontic Treatment Phase J
J.100    Fase di trattamento ortodontico
Leveling Phase J
J.100.010      di livellamento
Movement Phase J
J.100.020      attiva (di movimento)
Contraction Phase J
J.100.030      di contrazione
Distalisation Phase J
J.100.040      di distalizzazione
Adjustment Phase J
J.100.050      di rifinitura
Retention Phase J
J.100.060      di ritenzione
Orthodontic Treatment J
J.110    Trattamento Ortodontico
Start Orthodontic Treatment J
J.110.010      Inizio
End Orthodontic Treatment J
J.110.020      Fine
Follow Up Orthodontic Treatment J
J.110.030      Follow Up
   
Document Type, Picture Coding
K   Tipologia di documento, Codice immagini
University Code K
K.010    Codice dell’ Università
Bergen K
K.010.010      Bergen
Goeteborg K
K.010.020      Goeteborg
Munich K
K.010.030      Munich
Thessaloniki K
K.010.040      Thessaloniki
Stage K
K.020    Stadio
First Recording K
K.020.010      Prima registrazione
Start Treatment K
K.020.020      Inizio Trattamento
During Treatment K
K.020.030      In corso di trattamento
Leveling Phase K
K.020.030.010        Fase di Livellamento
Movement Phase K
K.020.030.020        Fase di Movemento
Closure Phase K
K.020.030.030        Fase di chiusura
Finishing Phase K
K.020.030.040        Fase di Finitura
Presurgical Orthodontic Phase K
K.020.030.050        Prechirurgica
Postsurgical Orthodontic Phase K
K.020.030.060        Postchirurgica
Appliance Removal K
K.020.040      Apparecchiatura Rimovibile
Retainer Removal K
K.020.050      Retainer Rimovibile
Follow Up K
K.020.060      Controllo a distanza
Type of Image K
K.030    Tipo di immagine
Photo K
K.030.010      Foto
Extraoral Photo K
K.030.010.010        Extraorale
Extraoral Photo En Face K
K.030.010.010.010          Frontale
Other Extraoral Photo En Face K
K.030.010.010.010.010            Altre
Extraoral Photo Smiling K
K.030.010.010.020          Frontale del sorriso
Extraoral Photo Profile K
K.030.010.010.030          Profilo
Extraoral Photo 3/4 K
K.030.010.010.040          di ¾
Intraoral Photo K
K.030.010.020        Foto Intraorale
Intraoral Photo Front K
K.030.010.020.010          Frontale
Intraoral Photo Left K
K.030.010.020.020          Sinistro
Intraoral Photo Right K
K.030.010.020.030          Destro
Intraoral Photo Upper Arch K
K.030.010.020.040          Arcata sueriore
Intraoral Photo Lower Arch K
K.030.010.020.050          Arcata inferiore
Radiographs K
K.030.020      Radiografie
Cephalogram K
K.030.020.010        Cefalogramma
Tracing K
K.030.020.020        Tracciato
Superimposition K
K.030.020.030        Superimposition
Panoramic Radiograph K
K.030.020.040        Radiografia Panoramica
Posterior-anterior Radiograph K
K.030.020.050        Postero-anteriore
Hand Wrist Radiograph K
K.030.020.060        del polso
Intraoral Radiograph K
K.030.020.070        Radiografia Intraorale
Intraoral Radiograph Upper Molar Right K
K.030.020.070.010          Molare Superiore Destro
Intraoral Radiograph Upper Premolar Right K
K.030.020.070.020          Premolare Superiore Destro
Intraoral Radiograph Upper Canine Right K
K.030.020.070.030          Canino Superiore Destro
Intraoral Radiograph Upper Lateral Right K
K.030.020.070.040          Laterale Superiore Destro
Intraoral Radiograph Upper Anteriors K
K.030.020.070.050          Centrali Superiori
Intraoral Radiograph Upper Lateral Left K
K.030.020.070.060          Laterale Superiore Sinistro
Intraoral Radiograph Upper Canine Left K
K.030.020.070.070          Canino Superiore Sinistro
Intraoral Radiograph Upper Premolar Left K
K.030.020.070.080          Premolare Superiore Sinistro
Intraoral Radiograph Upper Molar Left K
K.030.020.070.090          Molare Superiore Sinistro
Intraoral Radiograph Lower Molar Right K
K.030.020.070.100          Molare Inferiore Destro
Intraoral Radiograph Lower Premolar Right K
K.030.020.070.110          Premolare Inferiore Destro
Intraoral Radiograph Lower Canine Right K
K.030.020.070.120          Canino Inferiore Destro
Intraoral Radiograph Lower Lateral Right K
K.030.020.070.130          Laterale Inferiore Destro
Intraoral Radiograph Lower Anteriors K
K.030.020.070.140           Incisivi centrali inferiori
Intraoral Radiograph Lower Lateral Left K
K.030.020.070.150          Incisivo Laterale Sinistro
Intraoral Radiograph Lower Canine Left K
K.030.020.070.160          Canino Inferiore Sinistro
Intraoral Radiograph Lower Premolar Left K
K.030.020.070.170          Premolare Inferiore Sinistro
Intraoral Radiograph Lower Molar Left K
Details/additional Radiographs K
Study Model K
Study Model En Face K
Study Model Left K
Study Model Right K
Study Model Upper Arch K
Study Model Lower Arch K
Study Model From Back K

References

  1. Maag KP et al.Ortho ICON (International Courses in Orthodontists Networking) Final Report Leonardo da Vinci Programme
  2. Floria G. Xenakis D. Vergari A. The first on-line orthodontic journal: an international networking experience. Abstract book 2nd World Congress on Biomedical Communications ACTA University of Amsterdam The Netherlands 08-12/05/99

Glossary of Orthodontic Terms

0

Glossary of Orthodontic Terms

Abrasion

Mechanical wear of tooth structure caused by a foreign abrasive material. Toothbrush abrasion is the most common example, which may sometimes present as a sharp V-shaped notch in the gingival portion of the labial surface of the teeth.
[Compare with Attrition (Dental wear, Occlusal wear)]

Abrasive strips

(Finishing strips, Lightening strips, Coated abrasive strips)
Strips containing abrasive particles on a flexible backing material (heavyweight paper, metal or plastic). Used mainly for interproximal enamel reduction. [See Interproximal stripping (Interproximal reduction of enamel, Reproximation, Slenderizing)]

Anterior guidance

Term used to describe a particular scheme of disclusion of the dental arches during a protrusive mandibular excursion. Contacts between the maxillary incisors and the mandibular anterior teeth guide the mandible downward, to create disarticulation (separation) of all other teeth.

Achondroplasia

An autosomal dominant condition characterized by failure of the primary growth cartilages of the limbs and cranial base to grow properly. Early fusion of the sphenoethmoidal, intersphenoidal and sphenooccipital synchondroses and early closure of the epiphyseal plates of the long bones result in very short arms and legs and a characteristic midface deficiency that is most accentuated at the bridge of the nose. The anterior cranial base appears to be of approximately normal length, whereas the posterior cranial base is extremely short (i.e. the sphenooccipital synchondrosis seems to be affected more than the sphenoethmoidal). Affected patients also exhibit short bodies with thick extremities and stubby fingers, often associated with limited motion of the joints, lumbar lordosis, protruding abdomen, and inability to straighten the elbows. Correction of the midface deficiency and the resulting Class III malocclusion in achondroplasia may require a Le Fort III, or modified Le Fort II, osteotomy to advance the entire midface.

Acid etching

An enamel bonding technique invented by M. G. Buonocore in 1955. During this process a selected area of tooth substance is prepared for bonding via the application of a corrosive agent (most commonly a solution or gel of 37% orthophosphoric acid). The effect is a removal of a small amount of less mineralized, interprismatic enamel and opening of pores between the enamel prisms, substantially enlarging the surface area of the bonded part so the adhesive can penetrate into the enamel, providing micromechanical retention.

Acromegaly

Chronic metabolic disorder caused by hyperfunction of the anterior pituitary gland after maturity, usually due to an adenoma. The resulting overproduction of growth hormone induces an overgrowth of the bones, connective tissue and viscera. Skeletal changes principally involve the skull, with frontal bossing, prominent cheek bones, grossly overdeveloped mandible with a protrusive chin and consequent mandibular prognathism. The small bones of the hands and feet are also affected, and there is associated broadening of the hands, fingers and feet. Enlargement of the soft tissue usually is manifested by large ears and nose, thick lips and macroglossia. The tongue, which exhibits a lobulated margin and papillary hypertrophy, fills the oral cavity and results in associated labial and buccal tipping of the teeth. There is generalized splanchnomegaly and hypertrophy of the target organs for anterior pituitary hormones, including the adrenal cortex, thyroid gland, parathyroid glands and gonads.[See Gigantism]

Acrylic (Methyl methacrylate)

An organic resin commonly used for the construction of dental removable appliances, including appliances used during orthodontic treatment and retention. [Modified from the AAO Glossary of Dentofacial Orthopedic Terms, 1993.]

Activation

The process of storing mechanical energy into an active member of an orthodontic appliance (e.g. stretching an elastic, or compressing an open coil spring) in order for it to produce the desired force system, which will be delivered to the dentition. The force system that must be applied for activation of a spring is the opposite to the force system desired (during deactivation).

Active component

The part of an orthodontic appliance that is involved directly in tooth movement. [Compare with Reactive component]

Adaptability (Adaptive capacity, Adaptive potential)

Relative ability to adjust to the demands of the environment.

Adaptation

1. The progressive adjustive changes in sensitivity that regularly accompany continuous sensory stimulation or lack of stimulation. The process by which an organism responds to the functional demands of its environment.

2. The process by which a dental device is fitted to another structure (e.g. adaptation of a band to a tooth).

“Adenoid facies”

A long-standing descriptive term implying a relationship between mouth breathing (due to enlarged adenoids) and the development of malocclusion through altered function. The classic description of “adenoid facies” consists of narrow nasal and alar width, hypotonic musculature, “dull” or “vacant” facial expression and lips separated at rest. It is important to stress that the presence of “adenoid facies” does not necessarily mean that the patient is an obligatory mouth breather, or in other words, mouth breathing is habitual in certain patients.

Adhesion

1. Attractive force between atoms or molecules of dissimilar materials, when they are in close approximation. The attachment of one substance to another.

2. The abnormal fibrous joining of adjacent structures following an inflammatory process or as a result of injury repair. [See Bonding] [See Cohesion] SUBTERMS:

Adhesion

• Capsular adhesion

Fibrosis of the capsular tissues of a joint.

Adhesion

• Extracapsular adhesion

Fibrosis of pericapsular tissues such as muscles or ligaments.

Adhesion

• Intracapsular adhesion (Fibrous ankylosis, Pseudoankylosis)

Fibrosis between intra-articular surfaces within a joint capsule, resulting in reduced mobility of the affected joint.

Advancement (of the mandible)

An orthognathic surgical procedure aiming at sagittal (anterior) augmentation of the mandible, most often performed through a standard, or modified bilateral sagittal split ramus osteotomy (BSSO).[See Setback (of the mandible)]

[See Osteotomy, Bilateral sagittal split osteotomy (BSSO)]

Advancement (of the maxilla)

Anterior repositioning of the maxilla by orthognathic surgery. It most often involves a Le Fort I osteotomy. [See Osteotomy, Complete maxillary osteotomy]

Aesthetic

[See Cephalometric lines (planes), S-line (Esthetic plane of Steiner)]

[See Bends (Archwire bends), Artistic bends (Esthetic bends)]

[See Cephalometric lines (planes), Rees esthetic plane]

[See Facial esthetics]

[See Bracket, Esthetic bracket (Clear bracket)]

[See Cephalometric lines (planes), E-line (E-plane, Esthetic line of Ricketts)]

Agenesis

Congenital absence of a tooth.

Ala

The lateral rim of the nostril.

Alar cinch

A procedure performed during any orthognathic surgery that includes mobilization of the entire maxilla, in order to prevent excessive widening of the alar bases. It involves passing a permanent suture in a figure-eight fashion through the alar base tissues and through a bur hole placed in the region of the anterior nasal spine. This is repeated on the opposite side. Each suture is tightened independently, taking care to maintain symmetry, until the desired alar base width is attained (as determined from measurements before surgery). A situation in which an alar cinch may not be performed during maxillary orthognathic surgery is when very narrow alar bases exist preoperatively.

Alloy

A material that exhibits metallic properties (high electrical and thermal conductivity) and is composed of two or more elements, at least one of which is a metal (e.g. steel is an alloy of iron and carbon, brass is an alloy of copper and zinc).

Alpha position

The anterior component of an orthodontic spring or the anterior point of attachment of a spring. [Compare with Beta position]

Alveolar crest

The most coronal portion of the alveolar process.

Alveolar process

The U-shaped ridge of maxillary or mandibular alveolar bone that surrounds and supports the roots of the erupted teeth, as well as the unerupted tooth buds.

Anchorage

The sites that provide resistance to the reactive forces generated as a (most commonly, undesirable) consequence of the activation of an orthodontic or orthopedic appliance. [Short definition: resistance to unwanted tooth movement].

SUBTERMS:

• Cervical anchorage

Anchorage provided by the back of the neck when extraoral appliances such as a cervical pull headgear are used.

Extraoral anchorage

Anchorage provided by sites located outside the oral cavity.

Infinite anchorage

The term is commonly used when referring to implants used as anchorage in orthodontics, to indicate that they show no movement (zero anchorage loss) as a consequence of reaction forces. [See Implant, Orthodontic implant]

Intermaxillary anchorage

Anchorage for tooth movement provided by the teeth of the opposing arch.

Intramaxillary anchorage

Anchorage provided by teeth within the same arch as the ones that are to be moved.

Maximum anchorage (Type A anchorage)

A situation in which the treatment objectives require that no or very little anchorage can be lost.

Minimum anchorage (Type C anchorage)

A situation in which, for an optimal result, a considerable movement of the anchorage segment (anchorage “loss”) is desirable, during closure of space.

Moderate anchorage (Type B anchorage)

A situation in which anchorage is not critical and space closure should be performed by reciprocal movement of both the active and the anchorage segment.

Occipital anchorage

Anchorage provided by the superior and posterior portions of the head, when extraoral appliances such as a high-pull headgear are used.

Reciprocal anchorage

A situation in which the movement of one or more dental units is balanced against the movement of another, or more dental units, on which the reaction forces are placed. [The term generally means that the movement of both the active and the reactive component is desirable. ]

Anchorage loss

The undesirable movement of the reactive anchorage segment, which happens as a side effect of the movement of the active segment (e.g. mesial movement of the maxillary molars during retraction of maxillary incisors with intramaxillary mechanics).

Anchorage preparation

A procedure commonly used in the Tweed

technique, during which the molars and

premolars are tipped distally prior to

retraction of the anterior teeth. The theory

behind it is that it increases the anchorage

value of the posterior segments, allowing

further retraction of the canines and incisors

with less anchorage loss.

Anchorage reinforcement

The process of increasing the anchorage value of the reactive segment to resist anchorage loss.

This can be done in a number of ways, e.g. by incorporating more teeth into the reactive segment;

by using additional stabilizing arches such as a lingual arch, a Nance holding arch or a transpalatal

arch; or by using extraoral or intermaxillary traction.

Anchorage value

Relative resistance of a tooth (or a segment of teeth) in comparison to another, which usually is

estimated on the basis of comparison of root surface areas and density of the supporting bone.

Angle classification

• “Subdivisions” (left or right)

are used in asymmetric situations to indicate the side that deviates from a Class I molar

relationship.

Angle of activation

A measure (in degrees) of the activation placed into an orthodontic wire by bending or torsion, with

regard to its initial passive state. When the wire characteristics and the interbracket distance are

known, the clinician can estimate the magnitude of the force produced.

Angulation (Second order, “Tip”)

Angular deviation of the long axis of a tooth from a line perpendicular to the occlusal plane, in the

mesiodistal direction.

[Compare with Inclination (Third order, “Torque”)]

Ankylosis

Abnormal immobility, union or fusion that may occur between two bones at their articulation (e.g.

ankylosis of the TMJ) or between teeth and alveolar bone. In the instance of the TMJ, bony or

fibrous ankylosis can be caused by conditions such as congenital defects, trauma, inflammation,

infections, arthritis or neoplasms.

In the case of an ankylosed tooth, the periodontal ligament is obliterated in one or more localized

areas, and a “bony bridge” is formed by penetration of alveolar bone into the cementum. Dental

ankylosis eliminates the potential for both eruption and orthodontic movement. In a growing

individual, an ankylosed tooth is accompanied by a localized vertical deficiency of the alveolar

ridge, and consequently appears to “submerge” as adjacent, unaffected teeth continue to erupt.

Ankylosis of deciduous teeth (usually molars) is a more common phenomenon than ankylosis of

permanent teeth.

[See Tooth mobility, Reduced mobility (Hypomobility)]

Annealing

A heat treatment and cooling schedule used to reduce the hardness and increase the ductility of a

metal by removing residual stress.

Anomalad

A malformation, together with its subsequently derived structural changes (e.g. the Robin

anomalad).

Anodontia

A rare condition characterized by congenital absence of all teeth (both deciduous and permanent).

Most commonly related to ectodermal dysplasia.

[Compare with Oligodontia]

Antegonial notch

A depression or concavity usually present in

the inferior border of the mandible,

immediately anterior to the angle, near the

insertion of the masseter muscle. A deeper

than normal antegonial notch may be

indicative of a dolichofacial pattern or of

mandibular underdevelopment. Pronounced

antegonial notching also is a common

characteristic of some syndromes with

micrognathia of the lower jaw, such as

Treacher Collins syndrome.

Anterior component of occlusal force

A theory attempting to explain the tendency of posterior teeth to drift mesially with time. Factors

that are considered related to this phenomenon are: morphology and angulation of teeth, occlusal

and muscular forces and transseptal fibers.

Anterior cranial base

The anterior aspect of the floor of the cranial vault, commonly delimited cephalometrically by sella

turcica and nasion.

Anterior guidance

Term used to describe a particular scheme of disclusion of the dental arches during a protrusive

mandibular excursion. Contacts between the maxillary incisors and the mandibular anterior teeth

guide the mandible downward, to create disarticulation (separation) of all other teeth.

Anteroposteriorly

In a direction parallel to the sagittal plane; in radiology it denotes beam direction from front to back.

Antrum

A cavity or chamber. The term usually refers to the maxillary sinus.

Apical area (of the bone)

The apical area in the newborn child and during the

first year of life is the region in which the developing

deciduous and permanent teeth are found. In the

deciduous dentition it comprises the area occupied by

the apices of the deciduous teeth and the developing

permanent teeth. In the mixed dentition, the apical

area is the region in which lie the apices of the

deciduous and erupted permanent teeth, as well as

developing unemerged permanent teeth. In the adult,

the apical area consists of the region in which normally

the apices of the permanent teeth can be located. The

concept of the apical area was introduced by F. P. G.

M. van der Linden in 1979.

Apical base

Maxillary and mandibular bone that

supports and is continuous with the

alveolar processes, as well as with the

maxillary and mandibular bodies.

Although the demarcation between

alveolar and basal bone is not specific, it

generally is thought to lie at or slightly

above the level of the apices of the roots.

The concept of the apical base was

introduced by A. F. Lundstrцm in 1923.

[See Bone, Basal bone]

Appliance

Any device used for a particular functional, diagnostic and/or therapeutic effect.

SUBTERMS:

Appliance

• ACCO appliance

A combination of a modified maxillary removable appliance with a straight-pull J-hook headgear.

The acronym “ACCO” was suggested by H. I. Margolis (1976) and stands for ACrylic-Cervical-

Occipital.

The maxillary removable appliance includes an anterior bite plane, a labial bow, clasps for

retention and finger springs for distalization of the maxillary molars. The J-hook headgear is

attached to loops on the labial bow that are bent between the maxillary central and lateral incisors.

Its purpose is to counteract the reaction force on the maxillary anterior teeth caused by the

distalizing force of the finger springs on the maxillary molars. A cervical headgear also may be

attached on the maxillary molars to complement the action of the ACCO.

In the original design of the appliance by Margolis, molar distalization took place one side at a time.

During distalization on one side, ball clasps or passive finger springs on the other side enhanced

retention of the appliance. Once a Class I molar relationship was achieved on the active side, a

new ACCO was made. The new acrylic configuration and clasps on the completed side would

retain the correction achieved, at the same time providing anchorage to correct the residual Class

II relationship on the contralateral side of the arch.

Appliance

• Activator (Monobloc)

The first removable functional appliance, developed by V. Andresen. Historically, the term

“activator” was introduced to describe the “activation of mandibular growth,” to which the achieved

correction of a Class II malocclusion was attributed. The term currently is used in a generic sense,

referring to a family of functional appliances used to treat Class II malocclusions characterized, at

least in part, by mandibular deficiency. [For activators designed for patients with Class III

malocclusions, see Appliance, Class III functional.] These appliances position the mandible

forward, promoting a new mandibular postural position. The reactive forces from the stretch of the

muscles and soft tissues are transmitted to the maxillary dentition and through that, to the maxilla.

The acrylic body of the Andresen activator covers part of the palate and the lingual aspect of the

mandibular alveolar ridge. (Note: In its original design the appliance contacted the mandibular

anterior teeth only on the lingual side and did not extend over the incisal edges.) A labial bow fits

anterior to the maxillary incisors and carries U-loops for adjustment. On the palatal aspects of the

maxillary incisors, the acrylic is relieved to allow their retraction.

A main feature of the appliance is the faceting of the acrylic on palatal and lingual aspects of the

maxillary and mandibular posterior teeth, respectively, designed to direct their eruption. On the

palatal aspect of the maxillary posterior teeth the facets are cut so as to allow occlusal, distal and

buccal movement of these teeth. This movement is achieved by keeping the acrylic in contact with

only the mesiopalatal surfaces of the premolars and molars. On the lingual aspect of the

mandibular posterior teeth the facets only permit occlusal and mesial movement, with the acrylic

contacting the distolingual surface of these teeth.

[See Appliance, Class Class III functional appliances (Reverse functional appliances)]

[See Appliance, Functional appliance]

Appliance

• Active vertical corrector

An appliance introduced by E. L. Dellinger, attempting to correct anterior open bites by intrusion of

posterior teeth. The appliance consists of maxillary and mandibular posterior biteblocks with

incorporated repelling samarium-cobalt magnets. A commonly reported side effect of treatment

with the appliance is the creation of a posterior crossbite owing to the lateral force components of

the repelling magnets.

[See Orthodontic magnets]

Appliance

• Bass appliance

A removable functional appliance designed by N. M. Bass, consisting of a basic maxillary

expansion plate on which various other parts can be mounted. The expansion plate covers the

occlusal surfaces of all maxillary teeth and has torquing springs for the maxillary central incisors.

The appliance also carries tubes in which buccal shields can be attached, and has mandibular lip

pads extending in the vestibule in a fashion similar to the Frдnkel appliance. On the lingual side

there are specially designed flanges that can be gradually advanced. The Bass appliance also can

be combined with a high-pull headgear.

Appliance

• Begg appliance (Light-wire appliance)

Fixed multi-banded

orthodontic appliance

developed by P. R.

Begg for his light-wire technique. The appliance consists of narrow (single-wing), ribbon-arch

brackets (originally developed by E. H. Angle as the “pin and tube” appliance) and light, round

stainless steel archwires. It allows a series of tipping movements of teeth in conjunction with

intermaxillary elastics. Treatment with the Begg technique is classically divided into three stages:

The first stage includes initial alignment by simple tipping, with the exception of the anchor teeth.

Any spaces present between the anterior teeth are closed and any rotations or crossbites are

corrected. Deep anterior overbites or open bites are eliminated, and the anteroposterior occlusal

relationship between the maxillary and mandibular teeth is overcorrected. Arch forms are

coordinated and extraction spaces are reduced, to some degree, during the first stage.

During the second stage all extraction spaces are closed completely, by allowing significant lingual

tipping of the anterior teeth (incisors and canines), brought upon by a combination of intramaxillary

and intermaxillary elastic traction.

The third and final stage basically includes uprighting of the teeth by movement of the roots. This

root movement is performed by round archwires with bent-in torquing loops, in combination with

root-torquing auxiliaries of various designs. Individual tooth positioning is performed with bends

and root-tipping springs.

[See Appliance, Tip-Edge appliance]

[See Differential force theory]

[See Orthodontic wire, Australian wire]

Appliance

• Bimler appliance (Bite former, Bimler stimulator)

A modification of the activator by H. P. Bimler. There are three main kinds of Bimler appliance: type

A for patients with Class II Division 1 malocclusions, type B for those with Class II Division 2 and

type C for patients with a Class III malocclusion. All of the above appliances are flexible and carry

springs and bows on the labial and lingual side in both arches. The springs and bows are

connected together by two acrylic wings which extend toward the palatal and lingual mucosa. Each

appliance type is subdivided further into two main categories, space creation or space closure; the

space creation variety carries additional active springs.

In the type A appliance the mandible is held in its advanced position by engagement of the

mandibular incisors in a splint. The splint contacts the labial aspect of the mandibular incisors while

special springs engage on their lingual aspect. A mandibular labial wire holds the splint in place,

extending distally to connect with the maxillary part of the appliance. The maxillary part of the

appliance carries a labial arch and palatal springs for the maxillary incisors.

In the type B appliance the palate is covered by acrylic, with an incorporated midline screw. No

labial arch exists for the maxillary incisors.

In the type C appliance occlusal wires covered with plastic tubing are used to achieve bite opening.

There is no labial splint, but the mandibular incisors are retracted by a labial bow originating from

the maxillary part of the appliance.

Appliance

• Bionator

A modification of the activator, developed by W. Balters in the 1950s. Its design is significantly less

bulky compared to the activator, thus reducing interference with speech. The bionator consists of a

lingual horseshoe of acrylic, with a palatal spring shaped like a (reversed) Coffin spring. Facets are

created in the acrylic to guide the maxillary and mandibular posterior teeth and hold them in the

postured relationship. A labial bow exists anterior to the maxillary incisors that extends distally to

keep the buccal musculature away from the teeth. In the original design of the appliance, the

mandibular incisors were not capped with acrylic.

Appliance

• Crefcoeur appliance

A removable appliance designed by J. Crefcoeur, most often used to increase space at a specific

location in the dental arch. The appliance is in essence a Hawley-type acrylic plate, sectioned

(split) at the point where space creation is necessary. A heavy-gauge stainless steel wire

(Crefcoeur spring) is embedded in the acrylic at the posterior aspects of the appliance bilaterally.

This wire runs parallel to the edges of the acrylic on the lingual aspect and can be activated

appropriately to increase the separation between the two sectioned parts of the appliance. After

sufficient space has been created, the two parts of the appliance can be reconnected with rapidcuring

acrylic. The appliance also can be used to reduce a localized space in the dental arch and

to expand or constrict the dental arches. Good retention and adequate clasps are very important

for the Crefcoeur appliance, particularly in the area of the separation. The retention of the

appliance can be enhanced by creating artificial undercuts with composite on certain teeth.

Appliance

• Chin cap (Chin cup)

Extraoral orthopedic appliance that consists of a cap that fits on the patient’s chin and a headstrap

similar to that of a high-pull headgear. It is designed to deliver a superiorly and posteriorly directed

force to the mandibular condyles, via the chin. The appliance has been used for decades in an

attempt to correct mandibular prognathism in young patients by restraining or redirecting

mandibular condylar growth.

Appliance

• Class Class III functional appliances (Reverse functional appliances)

Various types of functional appliances that position the mandible posteriorly and rotate it open.

Such appliances are advocated for the correction of maxillary deficiency and/or mild mandibular

prognathism in a growing child. The mode of action of Class III functional appliances includes

correction of any anterior crossbite by labial tipping of the maxillary incisors and retroclination of

mandibular incisors (introducing an element of dental compensation for the existing skeletal

discrepancy). The prominence of the chin is decreased by causing the mandible to rotate down

and back and by increasing the lower face height. Treatment with such appliances is not indicated

for patients with excessive lower face height, as is often the case with Class III problems.

Appliance

• Combined functional/extraoral traction appliance

A functional appliance on which a facebow can be attached for extraoral traction (e.g. the Bass and

the Teuscher appliances), or on which a facebow is rigidly fixed (e.g. the Van Beek appliance).

[See Appliance, Bass appliance]

[See Appliance, Teuscher-Stцckli activator/headgear combination appliance]

[See Appliance, Van Beek appliance]

Appliance

• Crib

An interceptive appliance used for correction of deleterious habits such as a deviating tongue

position and/or digit-sucking. A crib typically consists of a fixed transpalatal [0.036-inch (0.90-mm)

or heavier gauge] wire, soldered on two maxillary first permanent molar bands. The wire extends

toward the anterior palate where it forms a crib-shaped “fence” meant to interfere with the habit. A

crib also can be incorporated in a removable appliance. Posterior (lateral) tongue cribs can be

used as part of removable appliances in patients with unilateral or bilateral posterior open bite.

[See Appliance, Habit-breaking appliance (Habit reminder)]

[See Crib]

Appliance

• Crozat appliance

Removable orthodontic appliance which was developed by G. Crozat in the early 1900s. In its

original design the appliance was fabricated entirely of precious metal. Heavy gold wires

constituted the framework and lighter gold fingersprings produced the desired tooth movement.

The Crozat appliance can be used in the maxilla and/or mandible. Tight circumferential clasps

(“cribs”) on the molars provide adequate retention to permit the use of light intermaxillary elastics

with the appliance.

[See Appliance, Crib ]

Appliance

• Delaire appliance

[See Appliance, Face mask (Reverse-pull headgear, Protraction headgear, Face frame)]

Appliance

• Edgewise appliance (Standard edgewise)

Fixed multi-banded orthodontic appliance, introduced by E. H. Angle in 1928. It involves a

rectangular labial archwire ligated into attachments (brackets) that are fixed on bands which are

cemented to individual teeth, or that are directly bonded to individual teeth. The term “edgewise”

refers to the fact that the bracket slot is fabricated in a way that permits insertion of the archwire

with its long dimension perpendicular to the long axis of the tooth, instead of parallel to it, as in the

(earlier) “ribbon arch” bracket.

Appliance

• Elastic open activator

A modification of the activator developed by G. Klammt. The appliance has reduced acrylic bulk,

facilitating increased appliance wear. The acrylic is replaced by wires which increase the flexibility

of the appliance. The flexible design allows isotonic muscular contractions (in contrast to rigid

appliances, which only allow isometric contractions).

Appliance

• Expansion appliance

An orthodontic appliance used to expand the maxillary or, less frequently, the mandibular dental

arch. An expansion appliance can be removable (e.g. split-plate appliance with a jackscrew) or

fixed on the teeth (e.g. the Hyrax appliance or the Quad-helix).

[See Expansion, Slow maxillary (palatal) expansion (SME or SPE)]

[See Expansion, Rapid maxillary (palatal) expansion (RME, RPE)]

[See Appliance, Haas appliance (Haas rapid maxillary expansion appliance, Haas palatal

separator)]

[See Expansion, Surgically assisted rapid maxillary expansion]

[See Appliance, Hyrax appliance (Hygienic rapid palatal expander)]

Appliance

• Extraoral traction appliance

An orthodontic appliance that makes use of extra-oral anchorage (e.g. headgear, face mask).

Appliance

• Face mask (Reverse-pull headgear, Protraction headgear, Face frame)

Extraoral appliance that utilizes rests on the chin and forehead (and occasionally the cheek bones)

as anchorage for elastic traction, with the purpose of orthopedically protracting the maxilla. This

maxillary protraction is performed as an early treatment modality in Class III malocclusions

associated with maxillary hypoplasia. The face mask also can be used as an orthodontic

appliance, to provide extraoral anchorage for protraction of posterior teeth. Usual side effects of

face mask treatment include elongation of the face (caused by extrusion of the teeth to which the

elastic traction is applied) and proclination of the maxillary incisors, when the traction is applied to

the maxilla. The appliance was designed by J. Delaire and subsequently modified by H. Petit and

others.

Appliance

• Fixed appliance

An appliance that is cemented or bonded to the teeth and thus cannot be removed by the patient.

The term commonly refers to fixed attachments (brackets, tubes, bands) placed on the teeth in

conjunction with archwires to move them to a new position.

Appliance

• Fixed/removable appliance

Orthodontic appliance that is fixed to the teeth but can be removed by the clinician for adjustment

and subsequently re-inserted, without taking off any brackets or bands. Fixed/removable

appliances make use of special sheaths welded on the palatal or lingual aspect of molar bands

(e.g. the fixed/removable lingual arch or transpalatal arch).

[See Sheath]

Appliance

• Frankel appliance (Function Regulator)

Group of functional appliances developed by R. Frдnkel to treat malocclusions, while aiding in the

maturation, training and reprogramming of the orofacial neuromuscular system. Four main types of

appliances have been described by Frдnkel: Function Regulator (FR)-I was designed for treatment

of Class I and Class II Division 1 malocclusions. The FR-II appliance is meant for patients with

Class II Division 1 and 2 malocclusions, the FR-III was designed for patients with Class III

malocclusions and the FR-IV for patients with hyperdivergent facial patterns and anterior open bite.

The appliances consist of acrylic buccal (vestibular) shields and lip pads, connected by wires, to

restrain and retrain aberrant musculature and to prevent the effects of restricting muscle forces on

the dentition. The extension of the buccal shields into the full depth of the vestibule is supposed to

stimulate the periosteum in order to achieve a skeletal expansion of the apical bases. Lingual

shields also are included to accomplish a gradual, stepwise advancement of the mandible.

Appliance

• Functional appliance

A removable or fixed appliance that alters the posture of the mandible and transmits the forces

created by the resulting stretch of the muscles and soft tissues and by the change of the

neuromuscular environment to the dental and skeletal tissues to produce movement of teeth and

modification of growth.

Appliance

• Haas appliance (Haas rapid maxillary expansion appliance, Haas palatal separator)

A fixed expansion appliance that was popularized by A. J. Haas. The appliance consists of bands

cemented on the maxillary first premolars and first molars that are rigidly connected to each other

with heavy-gauge wires on the buccal and palatal aspect of the teeth. Two acrylic pads encase the

palatal connecting wires and are joined with a midline jackscrew. The acrylic pads are in close

contact with the palatal mucosa. The Haas appliance was designed to expand the maxillary arch

by opening the midpalatal suture, thereby causing a skeletal expansion of the maxilla. According to

Haas, the contact of the pads with the palate allows the forces from the appliance to be dissipated

against the underlying hard and soft tissues of the palate, thus minimizing the amount of dental

tipping and maximizing the skeletal effect. Others consider this a disadvantage of the appliance

with regard to hygiene, resulting in inflammation of the palatal tissues.

[See Appliance, Expansion appliance]

[See Appliance, Hyrax appliance (Hygienic rapid palatal expander)]

[See Expansion, Rapid maxillary (palatal) expansion (RME, RPE)]

[See Expansion, Slow maxillary (palatal) expansion (SME or SPE)]

[See Expansion, Surgically assisted rapid maxillary expansion]

Appliance

• Habit-breaking appliance (Habit reminder)

Any removable or fixed appliance designed to correct undesirable habits such as digit-sucking,

tongue interposition, tongue-thrusting, or infantile swallow.

[See Appliance, Crib ]

[See Appliance, Vestibular shield (Vestibular screen)]

Appliance

• Harvold-Woodside activator

A modification of the activator developed by E. P. Harvold and D. G. Woodside. Its distinguishing

feature is the overextended vertical opening to which the appliance is constructed. The bite is

opened by 5 mm to 6 mm beyond the freeway space. The rationale is that maximum stretching of

the muscles will produce a force that will be transmitted to the bones and teeth, inducing a

compensatory anatomic correction. It is claimed that the Harvold-Woodside activator requires

minimal mandibular advancement to produce the desired sagittal correction, as the extreme

muscle stretch can cause intrusion (or inhibition of eruption) of the maxillary posterior teeth,

resulting in “closure” or counterclockwise rotation of the mandible with a relative Class II correction

(bite-block effect). Relieving the acrylic occlusally to the mandibular posterior teeth allows them to

erupt in a mesial direction, which also facilitates Class II correction.

Appliance

• Herren activator (L.S.U. activator)

A modification of the activator developed by P. Herren (also known as the Louisiana State

University modification of the same appliance). It is essentially an activator made to a construction

bite that positions the mandible forward and downward to asignificant degree. According to P.

Herren, the wearing of this appliance is not supposed to increase the activity of the lateral

pterygoid muscle.

Appliance

• Hickham protraction appliance

A modification of the face mask developed by J. H. Hickham. It consists of a chin cup with hooks

extending upwards and forwards, for application of anterior elastic traction to the maxilla and/or the

maxillary (or mandibular) dentition.

Appliance

• Harvold-Woodside activator

A modification of the activator developed by E. P. Harvold and D. G. Woodside. Its distinguishing

feature is the overextended vertical opening to which the appliance is constructed. The bite is

opened by 5 mm to 6 mm beyond the freeway space. The rationale is that maximum stretching of

the muscles will produce a force that will be transmitted to the bones and teeth, inducing a

compensatory anatomic correction. It is claimed that the Harvold-Woodside activator requires

minimal mandibular advancement to produce the desired sagittal correction, as the extreme

muscle stretch can cause intrusion (or inhibition of eruption) of the maxillary posterior teeth,

resulting in “closure” or counterclockwise rotation of the mandible with a relative Class II correction

(bite-block effect). Relieving the acrylic occlusally to the mandibular posterior teeth allows them to

erupt in a mesial direction, which also facilitates Class II correction.

Appliance

• Hyrax appliance (Hygienic rapid palatal expander)

A commonly used type of banded rapid maxillary expansion appliance developed by W. Biederman

and originally licensed to Dentaurum. The components now are available from several suppliers

internationally. The framework of the appliance is made entirely of stainless steel or cobaltchromium

alloy, with no acrylic contacting the palatal mucosa. Bands are cemented (usually) on

the maxillary first premolars and first molars. The bands are connected by means of rigid wires to a

special expansion screw which is located in the midline of the palate, in close proximity to the

palatal contour. Hyrax-type expansion screws are available in various sizes (more commonly 7

mm, 11 mm and 13 mm) depending on the application. Buccal and palatal support wires also may

be added for rigidity.

[See Expansion, Rapid maxillary (palatal) expansion (RME, RPE)]

[See Appliance, Expansion appliance]

[See Appliance, Haas appliance (Haas rapid maxillary expansion appliance, Haas palatal

separator)]

[See Expansion, Slow maxillary (palatal) expansion (SME or SPE)]

[See Expansion, Surgically assisted rapid maxillary expansion]

Appliance

• Jasper jumper appliance

A type of fixed functional appliance developed by J. J. Jasper. In essence it is a flexible version of

the Herbst appliance. The Jasper jumper is used in combination with fixed appliances for

correction of Class II malocclusions. It consists of two polyurethane-coated stainless steel coil

springs (force modules), attached at both ends to stainless steel end-caps. The force modules are

available in seven lengths (from 26 to 38 mm, in 2-mm increments). The end-caps carry holes so

they can be attached to the anchoring unit. One end-cap is attached to the distal aspect of the

headgear tube of the maxillary molar by means of a special ball pin attachment. The other end-cap

is attached to the mandibular arch, between the canine and the first premolar, either directly onto

the main archwire, or on a segment utilizing the auxiliary slot of the mandibular molar. Upon

insertion, the appliance bows out towards the cheek, promoting an anterior mandibular position.

The Jasper jumper may be used as an alternative to intermaxillary elastics and requires minimal

patient cooperation, as it is fixed on the archwires.

Appliance

• Jones jig

A fixed orthodontic appliance designed by R. D. Jones for unilateral or bilateral maxillary molar

distalization without patient cooperation. The appliance consists of a heavy-gauge wire and an

open-coil nickel-titanium spring delivering a force of approximately 0.7 to 0.8 N (70 to 80 g) over a

compression range of 1 to 5 mm. The distal end of the jig assembly carries a soldered additional

wire that is inserted into the main tube of the maxillary first molar band, whereas the heavy-gauge

wire is placed in the headgear tube. The sliding part of the jig is attached on the anchor teeth by a

stainless steel ligature so that the coil spring is compressed. The bands on the anchor teeth (which

can be either the first premolars, second premolars, or deciduous second molars) are soldered to a

large, modified Nance button to make maximal use of palatal anchorage.

Appliance

• Kinetor

A removable functional appliance developed by H. Stockfisch. The appliance consists of two acrylic

plates joined by vestibular steel loops and supported by occlusal rubber tubes. This design gives

the appliance a certain degree of flexibility, which is supposed to reinforce muscular impulses and

stimulate function.

Appliance

• Kingsley appliance (Bite-jumping appliance)

Probably the first removable functional appliance (developed by N. W. Kingsley in 1877). The

appliance consisted of a vulcanite palatal plate with an anterior inclined plane, which forced the

mandible in an anterior direction (“jumping of the bite”). It also contained a mechanism for

retraction of maxillary incisors and was retained by silk threads to the maxillary molars.

[See “Jumping of the bite”]

[See Appliance, Herbst appliance]

Appliance

• Labiolingual appliance

Early orthodontic fixed appliance system introduced by O. A. Oliver. The appliance consisted of

bands on the molar teeth in conjunction with heavy mandibular lingual and maxillary labial base

arches. Movement of individual teeth with this system was achieved by activating fingersprings and

other accessory springs soldered on the base archwires.

Appliance

• Lehman appliance (Lehman activator)

A combination activator-headgear appliance developed by R. Lehman. It consists of a maxillary

acrylic plate that carries two rigidly fixed outer bows and a mandibular lingual shield. The acrylic

plate covers the palate and it extends over the occlusal and incisal surfaces of the maxillary teeth,

up to the occlusal third of their buccal and labial surfaces.

Selective expansion of the maxillary arch is possible by appropriately activating the two transverse

expansion screws (one anterior and one posterior) that are embedded in the plate.

Occipital traction is applied through a headstrap attached on the outer bows, which are fixed at the

anterior aspect of the appliance. The mandibular lingual shield is connected to the maxillary plate

by means of two heavy S-shaped wires. Unlike many activator-type appliances which are

constructed with the mandible in a protruded position, this appliance is made from a bite

registration taken in centric occlusion. According to R. Lehman, the S-shaped wires are activated

by approximately 2 mm every 4 to 6 weeks, to achieve a gradual advancement of the mandible.

Appliance

• Lingual appliance

1. Any removable or fixed orthodontic appliance, placed on the lingual (palatal) side of the dental

arches.

2. An esthetic, “invisible” fixed orthodontic appliance consisting of special orthodontic attachments

bonded on the lingual surfaces of the teeth. The principle of a rectangular wire in a rectangular preadjusted

(straight-wire) slot is the same, but the design of the attachments is modified. The

maxillary anterior brackets have a flat surface that occludes with the mandibular incisors in patients

with deep bite and acts as an anterior bite plane. The archwire shape also is modified to fit the

configuration of the lingual surface of the dental arch (“mushroom” configuration). Accuracy of

bracket placement is critical, so indirect bonding is advocated. Disadvantages of the lingual

appliance include smaller interbracket distance, more difficult access, arguably reduced comfort for

the patient due to tongue impingement, and usually higher treatment fee.

Appliance

• Lip bumper

Intraoral removable orthodontic appliance consisting of a U-shaped 0.036-inch (0.90-mm) stainless

steel wire, which in its anterior portion may carry a plastic or acrylic pad. The ends of the lip

bumper are inserted into tubes on the mandibular first or second permanent molars. Its anterior

portion is adjusted to lie in the vestibular area, 2 to 3 mm away from the alveolar process and the

mandibular incisors (the vertical height varies).

Lip bumpers commonly are worn on a full-time basis and occasionally may be ligated in place (in

case of reduced patient compliance). They are used to control or increase the mandibular dental

arch length, to upright mesially or lingually tipped mandibular molars and to prevent the

interposition of the lower lip between the maxillary and mandibular incisors.

Depending on the anterior configuration (with or without lip pads) the appliance has two effects:

First, by removing the soft tissue forces from the labial aspect of the mandibular incisors it can

cause labial tipping of these teeth. Second, by transmitting the force from the lip to the mandibular

first molars, the lip bumper causes distal movement (mainly tipping) of these teeth. This distal

movement is accomplished more easily when the second molars are still unerupted or have been

extracted as part of the treatment plan.

Appliance

• Mouthguard

A removable appliance, usually made from flexible or rigid thermoplastic material, used to cover

and protect the teeth while engaging in contact sports.

Appliance

• Open activator

An activator with reduced acrylic coverage of the anterior palate in comparison to the classic

activator. It is meant to facilitate speech by allowing contact between the tongue and palate.

Appliance

• Pendulum appliance

A fixed orthodontic appliance introduced by J. J. Hilgers as a means for molar distalization without

patient compliance.

The appliance makes use of palatal anchorage through a large Nance button, which is retained

with bands on the maxillary first premolars and occlusal rests on the distal aspect of the maxillary

second premolars.

Two “pendulum” springs fabricated out of 0.032-inch (0.81-mm) TMA wire extend from the

posterior edge of the Nance button. Each spring contains a closed helix (close to the midline), a

small horizontal adjustment loop and a recurved portion that inserts into palatal sheaths soldered

on the bands of the maxillary first molars. The thickness of the palatal sheaths on the molar bands

is 0.036 inch (0.90 mm), so that the 0.032-inch (0.81-mm) diameter wire fits loosely in them. If

expansion of the maxillary arch is necessary, the appliance can be fabricated in a split-plate design

(“Pend-X” or “Pendex” appliance) by incorporating a midpalatal screw in the center of the Nance

button. Prior to cementation the springs are bent (preactivated) so that they lie parallel to the

midsagittal plane, and they subsequently are inserted into the sheaths.

As the molar is driven distally, it also moves palatally (on an arc). This palatal movement can be

counteracted by slightly opening the adjustment loop. Distal root movement of the molars also can

be produced by adjusting the recurved portion of the “pendulum” springs in order to avoid

distalization by mere tipping.

Appliance

• Pin-and-tube appliance

Early fixed orthodontic appliance (now archaic) consisting of vertical tubes soldered onto bands

placed on the permanent teeth. Movement of the teeth was achieved by use of an archwire with

soldered vertical pins that were forced into the tubes. The system, originally developed by E. H.

Angle, was later replaced by the ribbon-arch appliance.

Appliance

• Positioner (Tooth positioner)

A removable orthodontic appliance originally developed for closing band spaces after debanding. It

currently is used mainly to achieve fine adjustments and retain corrected positions following fixed

appliance treatment.

The positioner is fabricated of rubber or elastomeric plastic material covering the maxillary and

mandibular dental arches, as well as part of the alveolar process. For its construction, individual

teeth are cut from a plaster model and are reset subsequently in an ideal relationship.

The patient is instructed to wear the positioner immediately following fixed appliance removal and

to clench the teeth into it. The appliance functions by molding of the individual teeth into the correct

position within the arch through the forces generated by the elastic material in contact with the

teeth. When used in patients who exhibited a Class II malocclusion prior to treatment, the

positioner can be constructed in a slightly overcorrected Class I relationship, providing a “functional

appliance” component.

Advantages of the positioner include its resistance to fracture, stimulation of tissue tone and

continuous improvement of tooth position if it is worn properly. Disadvantages are its bulkiness

(making it less comfortable for the patients), and the possibility that it may keep teeth loose by

producing intermittent forces on them. Positioners are contraindicated in patients with airway

obstruction and in patients with a history of temporomandibular disorders. Their use often is

preferred in patients with minimal overbite or open bite tendency, as they tend to deepen the bite.

Appliance

• Propulsor (Mьhlemann appliance)

A removable functional appliance similar to the activator. The appliance carries a vestibular acrylic

extension over the maxillary alveolar process. The intention is to distribute the posteriorly directed

force over the basal bone to maximize the skeletal and to minimize the dentoalveolar effect.

Appliance

• Quad-helix appliance

An all-wire fixed orthodontic expansion appliance originally developed by E. Herbst and

popularized by R. W. Ricketts, among others. It typically consists of a 0.036-inch (0.90-mm)

stainless steel wire, containing four helices (two anteriorly and two posteriorly) to increase its range

and flexibility. The wire is soldered (or attached in a fixed/removable design) onto bands on the

maxillary first molars (and occasionally also on the maxillary first premolars). Various other

designs, such as a tri- or a bi-helix, also are described. The appliance is used for symmetrical or

asymmetrical expansion of the maxillary dental arch, as well as for derotation of the molars. It has

a tendency to produce buccal tipping of the teeth, and is not advocated in patients who require a

significant amount of expansion. It is considered advantageous for patients with cleft lip and palate,

in whom a localized expansion of the anterior aspect of the collapsed lesser maxillary alveolar

segment often is necessary.

Appliance

• Ribbon-arch appliance

A fixed multibanded orthodontic appliance developed by E. H. Angle, which marked another stage

towards the development of the edgewise appliance. Each band carried a vertical slot capable of

receiving a rectangular wire in a vertical orientation (with the longer dimension of the cross-section

parallel to the long axis of the tooth), hence the term ribbonwise. The archwire was retained in

place by pins. Control of buccolingual (third-order) root position was difficult with the appliance.

This problem was overcome later with the development of the edgewise appliance

[See “Ribbonwise”]

Appliance

• Sagittal appliance

An active removable appliance with expansion screws in the anteroposterior direction bilaterally

(“two-way sagittal”) or additionally in the transverse direction (“three-way sagittal”), when

expansion is also necessary. Retention is achieved by a combination of Adams clasps and

arrowhead clasps. Sagittal appliances are used mainly in patients with labially displaced canines to

increase the arch length by advancing the incisors and to apply a distalizing force on the posterior

teeth.

Appliance

• Schwarz appliance

A removable orthodontic appliance introduced by A. M. Schwarz for expansion of the maxillary and/

or the mandibular dental arch. The appliance consists of a horseshoe-shaped acrylic plate fitting

along the lingual surface of the teeth and covering a large portion of the lingual aspect of the

alveolar process or palate. A midline expansion screw is incorporated in the acrylic, and ball or

arrowhead clasps on the deciduous and permanent molars provide the necessary retention.

Although Schwarz developed a variety of “split-plate” appliances, the mandibular appliance is

widely considered as the one that bears his name.

Appliance

• SPEED appliance

(Strite Industries, Ltd. ) Fixed, self-ligating orthodontic appliance system developed by H. G.

Hanson. The appliance consists of miniaturized self-ligating brackets with built-in flexible, escapeproof

spring-clips that obviate the need for conventional elastomeric or stainless steel ligatures and

permit light force delivery. The spatial relationship between the spring-loaded clip and the archwire

allows a continuous dynamic interaction between them, while maintaining three-dimensional

control of tooth position. [SPEED is an acronym of the words Spring-loaded, Precision, Edgewise,

Energy and Delivery. ]

[See Bracket, Self-ligating bracket]

Appliance

• Split-plate appliance

See Appliance, Expansion.

[See Appliance, Expansion appliance]

Appliance

• Stabilization appliance

[See Splint, Relaxation splint (Stabilization splint, Muscle relaxation splint)]

Appliance

• Straight-wire appliance (Preadjusted appliance, SWA)

A modification of the edgewise appliance, introduced by L. F. Andrews in 1972. In the standard

edgewise appliance the orientation of the bracket slot was at right angles to the long axis of the

tooth and the thickness of the bracket base was the same for all types of teeth. During treatment,

bends were placed in the archwire to individually position each tooth in the buccolingual direction

(in-out or first-order bends), as well as to idealize the angulation of the long axis of the tooth in the

mesiodistal direction (tip or second-order bends) and in the buccolingual direction (torque or thirdorder

bends).

In the straight-wire appliance this information is incorporated in the brackets and tubes for each

individual tooth, by varying the thickness of the base and the angulation of the slot relative to the

long axis of the tooth, in both the mesiodistal and buccolingual directions. As a result, a “straight”

archwire can be used to ideally position the teeth, avoiding though not completely eliminating the

need for placing such bends in the archwire. Accurate placement of the brackets on the teeth is of

paramount importance with this appliance. Straight-wire appliances of various prescriptions (sets of

characteristic values for each individual tooth) are available on the market.

[See Appliance prescription]

[See Appliance, Edgewise appliance (Standard edgewise)]

Appliance

• Teuscher-Stцckli activator/headgear combination appliance

A modified activator used in combination with a high-pull headgear. The appliance was introduced

by U. M. Teuscher and P. W. Stцckli as a means to avoid the detrimental profile effects of cervical

traction when treating Class II malocclusions in growing individuals. Buccal headgear tubes are

incorporated in the interocclusal acrylic at the level of the maxillary second premolar or first molar.

The vector of the high-pull headgear force is directed through a point midway between the

estimated center of resistance of the maxilla and that of the maxillary dentition. In this way it is

claimed that the best compromise is reached between a resulting counterclockwise rotation of the

maxillary occlusal plane and a clockwise rotation of the maxilla itself, possibly maintaining the

inclination of the maxillary occlusal plane. The design includes reduced palatal acrylic coverage to

provide more space for the tongue. The acrylic covers the occlusal and incisal surfaces of the

maxillary teeth to distribute the headgear force over the entire dentition. The labial bow can be

substituted by torquing springs to counteract palatal tipping of the maxillary incisors. Long lingual

flanges extend from the lower portion of the appliance to enhance forward positioning of the

mandible. In addition, Frдnkel-type lower lip pads may be added to enhance normal perioral

muscle function. Finally, a jackscrew is added occasionally for controlled expansion.

Appliance

• Tip-Edge appliance

Fixed orthodontic appliance developed by P. C. Kesling as a combination of the Begg and the

straight-wire appliance (marketed by TP Orthodontics). The appliance consists of specially

designed brackets with modified slots that have the shape of an asymmetric bowtie. The brackets

are equipped with auxiliary vertical slots that can receive a variety of auxiliaries, including rotation

springs, uprighting springs, power pins and position indicators to facilitate bonding. The shape of

the main slots allows tipping of the teeth during space closure (a basic principle of the Begg

technique). After space closure the angulation of the teeth is idealized by uprighting springs (sidewinders).

When a rectangular archwire is used during this uprighting process, the beveling and the

dimensions of the modified, fully programmed slot permit gradual expression of the torque to

simultaneously control tooth inclination.

[See Appliance, Begg appliance (Light-wire appliance)]

Appliance

• Tongue crib

[See Appliance, Crib ]

Appliance

• Tri-helix appliance

A modification of the quad-helix, used in situations in which the constriction of the anterior maxilla

is too severe to accommodate two helices in the anterior aspect of the appliance (e.g. in patients

with a history of cleft lip and palate).

Appliance

• Twin arch appliance (Twin wire appliance)

An early orthodontic fixed appliance introduced by J. Johnson in 1931. The appliance made use of

the resilience of two thin-gauge stainless steel wires ranging in size from 0.09 inch (0.23 mm) to

0.014 inch (0.35 mm) in diameter. Two end-tubes were soldered onto the first molar bands,

capable of receiving the twin wire strands. The bands on the remaining teeth carried special locks

forming channels with a rectangular cross-section. The twin wires were held in the locks by special

sliding caps. Differential crown or root movement was achieved by using two archwires of different

sizes (one longer than the other) and by appropriately squeezing both into the lock so that they lie

on top of each other (in a coronal-apical direction). Occasionally, a lingual arch also was used in

conjunction with the appliance.

Appliance

• Twin block appliance

Tooth-borne removable functional appliance that was developed by W. J. Clark. It consists of a

maxillary and mandibular portion, which carry inclined planes constructed in such a way that an

anterior displacement of the mandible and a certain amount of vertical separation of the arches are

effected upon closure of the mouth. Due to the two-part design, the appliance is tolerated easily by

the patient and thus increased wear is facilitated. The maxillary portion of the appliance includes

capping of the molars, with an inclined plane at its mesial end. This plane engages a similar incline

on the mandibular portion of the appliance, thus causing the mandible to assume the desired

protruded position. Retention of the maxillary portion is achieved by modified Adams clasps that

span the second premolars and first molars. A labial bow with U-loops also is included in the

maxillary portion. A headgear can be attached to the maxillary portion of the appliance by inserting

a facebow into special coils incorporated in the delta clasps. The occasional addition of a midline

expansion screw can provide compensatory maxillary arch expansion as the anteroposterior

relationship improves. The mandibular portion of the appliance carries capping in the premolar

region only and is retained by delta clasps on the first premolars and C-clasps on the canines.

[See Clasp (Retention clasp), Delta clasp]

Appliance

• Two-by-four appliance (2×4)

A term denoting partial use of fixed orthodontic appliances, only including the 2 first permanent

molars and the 4 permanent incisors. A 2×4 is most often used for treatment in the mixed dentition,

e.g. for alignment, intrusion, or proclination of the incisors.

Appliance

• U-bow activator

A removable functional appliance developed by R. Karwetzky consisting of a maxillary and a

mandibular part, which are connected by a U-shaped bow on either side. These U-bows allow

gradual displacement of the mandible from its original position in small increments. The appliance

exists in three variations, proposed for the treatment of Class II, Class III, or asymmetric

malocclusions.

Appliance

• Universal appliance

An early fixed orthodontic appliance developed by S. R. Atkinson, combining some of the principles

of edgewise and ribbon-arch appliances to achieve precise control of individual teeth in all planes

of space. The appliance consisted of bands for all the teeth in both arches. Each band carried a

bracket with two horizontal slots, of which the larger, occlusal slot opened occlusally and the

smaller, gingival slot opened buccally. The occlusal slot could accommodate a ribbon arch of up to

0.015 x 0.028 inch (0.38 x 0.70 mm) in cross-section, or alternatively up to three 0.010-inch (0.25-

mm) archwires. The wires for the gingival slot were 0.008 inch (0.20 mm) to 0.014 inch (0.35 mm)

in diameter. Special lock pins held the archwires in place. A lingual arch was used, which was

secured in horizontal sheaths soldered on the lingual aspect of the molar bands.

Appliance

• Van Beek appliance

A removable functional appliance/high-pull headgear combination, developed by H. Van Beek. The

facebow of the headgear is embedded rigidly in the acrylic at the anterior aspect of the appliance

and is its only metal part. The appliance provides labial acrylic coverage of the maxillary incisors.

Appliance

• Vestibular shield (Vestibular screen)

A simple removable appliance made of 2- to 3-mm-thick acrylic or thermoplastic material,

occupying the vestibule and extending posteriorly to the distal margin of the last erupted molar.

The appliance can be constructed with the mandible placed in an anterior position so that the

incisors are in an edge-to-edge relationship. The appliance is intended to eliminate an abnormal

sucking habit or lip dysfunction, to establish a competent lip seal and to interrupt contact between

the tip of the tongue and the lower lip, promoting maturation of the swallowing pattern. In patients

with a persistent tongue thrust, the vestibular shield can be combined with a tongue crib.

[See Appliance, Oral screen]

Appliance prescription

The set of characteristic values (in degrees) for mesiodistal tip (“angulation”), buccolingual

inclination (“torque”), and rotational offset, which are incorporated into each bracket for every

individual tooth; the “specifications” of a fixed orthodontic appliance. The prescription of an

orthodontic appliance usually is specified by the clinician at the time of placing the order with the

manufacturer or distributor.

[See Appliance, Straight-wire appliance (Preadjusted appliance, SWA)]

Appliance setup

[See Bracket setup]

Appliance trimming

Selective grinding away of acrylic from a removable appliance at areas that contact the teeth. The

purpose of this process is to guide tooth eruption and aid in the development of a proper arch form.

Trimming is an important aspect of treatment with removable and functional appliances.

Arch

A structure with a curved or bow-like outline. The term sometimes is used in orthodontics as a

synonym for archwire.

SUBTERMS:

Arch

• Alveolar arch

The arch formed by the ridge of the U-shaped maxillary and mandibular alveolar processes.

Arch

• Auxiliary arch

An accessory archwire commonly used in addition to the main or base archwire.

Arch

• Base arch

The main archwire occupying the bracket slots of a fixed orthodontic appliance system. Use of the

term “base arch” implies the presence of other auxiliary arches or springs active at the same time.

Arch

• Closing-loop arch

An archwire in which closing loops are incorporated

(unilaterally or bilaterally), commonly used for retraction

of the incisors. A closing-loop arch usually is made out

of full-dimension stainless steel wire in an attempt to

maintain the inclination and angulation of the teeth as

they are being retracted.

Arch

• Dental arch

The arch formed by the maxillary or the mandibular teeth,

when viewed from the occlusal.

Arch

• Horseshoe arch

Special type of transpalatal arch with the shape of a horseshoe, oriented in the horizontal plane.

Arch

• Intrusive arch

An archwire used as the main wire, or as an auxiliary in the

segmented arch technique, to achieve leveling of the

dental arch by intrusion of the incisors. An intrusive arch is

activated for incisor intrusion by placing tip-back bends

mesial to the molar tubes.

[See Arch, Utility arch]

Arch

• Lingual arch

A single, heavy-gauge orthodontic wire, adapted to the lingual aspect of (usually) the mandibular

arch, attached to bands on the first permanent molars. Two U-loops, often bent into the wire mesial

to the first molars, offer the possibility of adjustment in the sagittal direction. The lingual arch is

generally used for stabilization (anchorage reinforcement), as a holding arch for space

maintenance, for expansion, for increase of dental arch length or for anchorage when

intermaxillary traction is used. Lingual arches can be of fixed (soldered) or fixed/removable design.

Arch

• Nance holding arch

Maxillary fixed appliance developed by H. N. Nance, consisting of a heavy palatal wire soldered to

the palatal aspect of the first molar bands. The wire is directed from the molars anteriorly and is

attached to an acrylic button that rests against the most superior and anterior aspect of the palatal

vault. Used as a space maintainer, or as a means to reinforce anchorage.

Arch

• Overlay arch (Piggyback arch)

An auxiliary archwire added to the main (base) archwire, most commonly used to achieve

transverse changes in the dental arch or individual tooth movements. An overlay arch can be

inserted in the auxiliary slots or the headgear tubes of the molar attachments, or it may be simply

tied onto the main archwire.

[See E-arch]

Arch

• Porter arch (W-arch)

Maxillary fixed/removable appliance consisting of a heavygauge

(0.036 inch or 0.90 mm) transpalatal wire with a Wshaped

configuration, secured to the palatal aspect of the

first molar bands. It is used to achieve expansion of the

maxillary dental arch and/or derotation of the molars.

Arch

• Transpalatal arch (TPA, Palatal bar, Goshgarian-type palatal arch)

Maxillary fixed or fixed/removable appliance consisting of a 0.036-inch (0.90-mm) or higher gauge

wire that extends from one maxillary first molar, along the contour of the palate, to the maxillary

first molar on the opposite side. The arch is adapted to the curvature of the palatal vault, so that it

lies 2 to 3 mm away from the palatal mucosa. A U-loop, which usually is incorporated midway

across its span, can be activated for expansion or constriction of the intermolar width. The TPA

also is used commonly for anchorage reinforcement, for derotation of the molars, or for producing

root movements of these teeth.

Arch

• Utility arch

A maxillary or mandibular continuous archwire bypassing the canines and/or premolars to achieve

leveling of the arch and/or uprighting of the molars, or to function as a stopped arch for incisor

proclination. The utility arch,

which was introduced by R. W.

Ricketts, usually is made out of

0.016 x 0.016-inch (0.41 x 0.41-mm) or 0.016 x 0.022-inch (0.41 x 0.56-mm) stainless steel or

cobalt-chromium wire. The wire is stepped away from the occlusal plane between the first molars

and lateral incisors for convenience and comfort. Avoiding engagement of the premolars and

canines results in improved load/deflection properties because of the length of wire between the

molar and incisor segments. The stepping of the archwire in a gingival direction in the buccal

segments also reduces the risk of deformation during mastication. The utility arch can be used for

movement of the incisors in the vertical and/or sagittal plane of space.

[See Arch, Intrusive arch]

Arch

• Stopped arch (Proclination arch, Advanced arch)

An orthodontic archwire with stops or loops (usually placed

mesial to the first molar tubes) to procline the incisors, or to

maintain the existing arch length.

Arch bars

Half-round, oval, round or flat wire bars, bent to fit the labial surface of the dental arches, in the

cervical third of the crowns.

Arch bars may carry

special bases so they can

be bonded to the teeth, or

more commonly, they can

be attached to them with

interdental ligature wires.

They may contain

supporting elements,

such as hooks or eyelets,

for attaching elastic bands or tie wires. Arch bars are used to facilitate intermaxillary fixation in

orthognathic surgery, or for stabilization of fractures of the maxilla or mandible. Single arch bars

also are used sometimes for stabilization of traumatized teeth.

Arch coordination

One of the aspects of fixed appliance orthodontic treatment

by which it is made sure that the maxillary and mandibular

dental arches fit harmoniously with each other, with

corresponding arch forms and good anterior and buccal

overjet.

[See Archwire coordination]

Arch depth

The perpendicular distance in the

midsagittal plane from the most labial

midpoint between the central incisors to a

line connecting the distal surfaces of two

posterior corresponding teeth in a dental

arch, usually the second premolars (or

second deciduous molars).

Arch form

The shape of an individual dental arch, or of an archwire formed to fit or shape that arch. The arch

form can be parabolic, hyperbolic, ellipsoidal, square, tapering, V-shaped etc.

Arch length (Arch perimeter)

A measurement of space available in the

dental arch, for alignment of the teeth.

Arch length discrepancy

A difference between the space available in the dental arch and the space required to align the

teeth. An arch length discrepancy can either be in the form of a deficiency or an excess of arch

length.

SUBTERMS:

Arch length deficiency (Crowding)

Arch length excess (Spacing)

• Arch length deficiency (Crowding)

A negative difference between the

space available in the dental arch and

the space required to align the teeth.

With regard to the severity of space

deficiency, crowding is divided into

three categories: first-degree (mild)

crowding, second-degree (moderate)

crowding and third-degree (severe)

crowding.

The classification into primary,

secondary and tertiary crowding takes

into account the etiology of the space

deficiency.

Primary (hereditary) crowding is

determined genetically and is caused by disproportionately sized teeth and jaws.

Secondary crowding is an acquired anomaly caused by mesial drifting of the posterior teeth after

premature loss of deciduous teeth in the lateral segments and/or lingual or distal displacement of

the anterior teeth.

The etiopathogenesis of tertiary crowding is still under debate. This type of crowding— primarily in

the mandibular anterior teeth— occurs during and after adolescence and was previously thought to

be associated with third molar eruption. Others attribute the anomaly to differential anteroposterior

growth of the maxilla and mandible terminating at different times, in combination with differential

rotation of the maxilla and mandible with growth. Malocclusions with crowding are more common in

modern populations than those involving interdental spacing and wide arches.

• Arch length excess (Spacing)

A positive difference between the

space available in the dental arch

and the space required to align the

teeth. As with crowding, a distinction

can be made between primary,

secondary and tertiary spacing.

Primary (hereditary) spacing is

determined genetically and is

caused by disproportionately sized

teeth and jaws, including tooth

agenesis.

Secondary spacing is an acquired

anomaly caused by drifting of teeth,

subsequent to loss of a permanent

tooth.

Tertiary spacing is caused by bone

loss due to periodontal disease,

resulting in a disturbance of the equilibrium of forces acting on the teeth and associated tooth

movement.

Arch width

The breadth of the dental arch, determined

by measuring distances between

corresponding contralateral teeth (e.g.

intercanine width, intermolar width).

Archwire (Arch wire)

A wire engaged in orthodontic attachments that are affixed to the crowns of two or more teeth to

cause or guide tooth movement.

SUBTERMS:

Continuous archwire

Finishing archwire

“Full dimension” archwire

Multiloop archwire

Sectional archwire (Segmental archwire)

Stabilizing archwire

Surgical archwires

Archwire (Arch wire)

• Continuous archwire

An archwire that engages, through crown attachments (brackets and tubes), many or all of the

erupted teeth in the maxillary or mandibular dental arch (i.e. from molar to molar).

Archwire (Arch wire)

• Finishing archwire

The archwire used in the finishing stage of treatment.

Archwire (Arch wire)

• “Full dimension” archwire

A large rectangular archwire that will practically “fill” the bracket slot. Usually referring to an 0.017 x

0.025-inch (0.43 x 0.64-mm) or 0.018 x 0.025-inch (0.46 x 0.64-mm) archwire, when a 0.018 x

0.025-inch (0.46x 0.64-mm) slot size is used, or an 0.021 x 0.025-inch (0.53 x 0.64-mm) archwire

when a 0.022 x 0.028-inch (0.56 x 0.70- mm) slot is used.

Archwire (Arch wire)

• Multiloop archwire

A stainless steel archwire with loops of various configurations bent in the interbracket spaces, to

increase the flexibility of the wire to facilitate bracket engagement. The use of multiloop archwires

was very common in earlier days of orthodontics, when the only way to reduce the load/deflection

characteristics of the appliance was to increase the length of wire between brackets. It has now

been largely replaced by multistrand wires, or wires made of various superelastic materials.

[See Loop]

[See Load/deflection rate (Force/deflection rate)]

Archwire (Arch wire)

• Sectional archwire (Segmental archwire)

An archwire that engages only a few teeth within an arch (e.g. only the four incisors, or only the

teeth in a posterior dental segment. )

[See Mechanics, Segmental arch mechanics (Sectional mechanics)]

Archwire (Arch wire)

• Stabilizing archwire

A stiff, full-dimension archwire, used to maintain the actual position of the teeth (e.g. prior to

orthognathic surgery), or to consolidate a number of teeth, forming a large anchorage segment.

Archwire (Arch wire)

• Surgical archwires

The stabilizing archwires that are in place during the orthognathic surgical procedure. They usually

are rectangular stainless steel wires to which hooks have been added in the interbracket spaces to

facilitate intermaxillary fixation. Surgical archwires must fit passively to be effective. If they create

any tooth movement after the impressions are made for the model surgery and for splint

construction, the splint will no longer fit.

Archwire coordination

The process of superimposing the maxillary and mandibular archwires prior to placing them in the

patient’s mouth, to ensure that their arch form fits with each other, with the objective of achieving

coordinated dental arches.

[See Arch coordination]

Archwire cross-section

Various diameters and cross-sectional shapes of orthodontic archwires exist. The ones most

commonly used, specified by the size of the cross-section in inches (mm) are:

Round:

0.012 inch (0.30 mm),

0.014 inch (0.35 mm),

0.016 inch (0.40 mm),

0.017 inch (0.43 mm),

0.018 inch (0.46 mm),

0.019 inch (0.48 mm),

0.020 inch (0.51 mm)

Square:

0.016 x 0.016 inch (0.41 x 0.41 mm),

0.017 x 0.017 inch (0.43 x 0.43 mm),

0.018 x 0.018 inch (0.46 x 0.46 mm),

0.019 x 0.019 inch (0.48 x 0.48 mm)

Rectangular:

0.016 x 0.022 inch (0.41 x 0.56 mm),

0.017 x 0.022 inch (0.43 x 0.56 mm),

0.017 x 0.025 inch (0.43 x 0.64 mm),

0.018 x 0.025 inch (0.46 x 0.64 mm),

0.019 x 0.025 inch (0.48 x 0.64 mm),

0.020 x 0.025 inch (0.51 x 0.64 mm),

0.021 x 0.025 inch (0.53 x 0.64 mm).

Archwire locks

[See Gurin lock]

Archwire stop

A bend, auxiliary attachment, or occasionally a

drop of solder placed on an archwire to prevent it

from sliding mesially or distally through the

orthodontic attachments.

Arthritis

Inflammation of a joint, usually accompanied by pain.

SUBTERMS:

Hypertrophic arthritis

Juvenile rheumatoid arthritis (JRA, Still’s disease)

Rheumatoid arthritis

Arthrography of the TMJ

Radiographic visualization of the TMJ.

SUBTERMS:

Single-contrast arthrography

Double-contrast arthrography

Single-space arthrography

Double-space arthrography

Arthrography of the TMJ

• Single-contrast arthrography

Arthrography following injection of a radiopaque contrast medium into the joint space(s) to

determine the location and integrity of intra-articular soft tissue structures, including disc position,

soft tissue contours, presence of perforations, joint motion, intra-articular free bodies and adhesive

capsulitis.

Arthrography of the TMJ

• Double-contrast arthrography

A procedure similar to single-contrast arthrography but with injection of a small amount of

radiopaque contrast agent followed by inflation of the joint with air.

Arthrography of the TMJ

• Single-space arthrography

Contrast arthrography with injection of a radiopaque contrast medium into either the upper or the

lower synovial joint compartment of the TMJ.

Arthrography of the TMJ

• Double-space arthrography

Contrast arthrography with injection of a radiopaque contrast agent into both the upper and lower

synovial joint spaces.

Arthrokinetics of the TMJ

Temporomandibular joint motion.

SUBTERMS:

Depression of the mandible

Distraction of the mandible

Elevation of the mandible

Lateral excursion of the mandible

Protrusion of the mandible

Retrusion of the mandible

Arthrokinetics of the TMJ

• Depression of the mandible

Movement of the mandibular alveolar process away from that of the maxilla.

Arthrokinetics of the TMJ

• Distraction of the mandible

Separation of the surfaces of the TMJ by extension, without injury or dislocation of the parts.

Arthrokinetics of the TMJ

• Elevation of the mandible

Movement of the mandibular alveolar process toward that of the maxilla.

Arthrokinetics of the TMJ

• Lateral excursion of the mandible

Right or left movement of the mandible away from the median plane.

[Compare with Mediotrusion]

[See Laterotrusion]

Arthrokinetics of the TMJ

• Protrusion of the mandible

Anterior mandibular movement with bilateral forward condylar translation.

Arthrokinetics of the TMJ

• Retrusion of the mandible

Posterior mandibular movement with bilateral backward condylar translation.

Arthroscopy

Direct visualization of a joint with an endoscope.

Arthrosis

Degeneration of a joint, evidenced by bony alterations.

Articular disc (Intra-articular disc, Meniscus)

A thin biconcave pad of dense fibrous connective tissue, interposed between the temporal bone

and the mandibular condyle, that divides the articular space into an upper and a lower

compartment. It is devoid of any blood vessels or nerve fibers and its anterior and posterior

borders (bands) are thick, whereas its central part (where the condylar head fits) is thinner.

Anteriorly it may be attached to fibers of the superior head of the lateral pterygoid muscle.

Posteriorly it attaches to a structure consisting of loose connective tissue, which is richly

vascularized and innervated, known as the retrodiscal tissue (retrodiscal lamina). The medial and

lateral aspects of the disc are attached to the lateral poles of the condyle by the collateral

ligaments, which permit rotational movement of the disc on the condyle during opening and closing

of the mouth.

Articular eminence

A convex bony ridge situated immediately anterior to the glenoid fossa of the temporal bone, that

also is involved in the temporomandibular joint. The degree of convexity of the articular eminence

is highly variable but important because the steepness of this surface dictates the pathway of the

condyle when the mandible is positioned anteriorly.

Articulator

A mechanical instrument that represents the temporomandibular joints and the jaws, to which

maxillary and mandibular casts may be attached, with the intention of reproducing mandibular

movements. Depending on the amount of adjustments that an articulat or can accommodate

(which increases the accuracy and precision of the simulation of the clinical situation), there are

non-adjustable, semi-adjustable (anatomic) and fully adjustable (gnathologic) articulators.

Articulators have all the mechanical limitations imposed by their construction. The various types

and models show great variation in their function depending on the way they were constructed and

the occlusal concepts on which they were based.

SUBTERMS:

Arcon articulator

Non-arcon articulator

Association

A recognized pattern of morphological defects or malformations that currently is not considered to

constitute a syndrome or an anomalad, but that may be reclassified as a syndrome or as an

anomalad as knowledge advances.

Atherton’s patch

The small red triangular patch of thin and non-keratinized gingival epithelium often observed on the

side opposite from the direction in which a tooth is moving. The first report of this phenomenon was

made by J. D. Atherton and N. W. Kerr in 1968, associated with the mesial aspect of maxillary

canines being distalized after extraction of the first premolars.

Attachment, Gingival

The part of the gingiva that is bound down to the underlying cementum and bone.

Attachment, Orthodontic

A precision component that can be welded or soldered

to a band, or bonded directly to a tooth, to facilitate the

application of forces during orthodontic treatment. The

general term encompasses items such as brackets,

tubes, buttons, eyelets, and “pigtail” attachments.

Attrition (Dental wear, Occlusal wear)

Loss of tooth structure due to repetitive physiological or parafunctional occlusal contact between

the teeth. Attrition results in the formation of flat areas on the surface of teeth (wear facets) that

have a polished appearance and readily reflect light. Although a certain degree of attrition is

considered physiological with age, the presence of deleterious parafunctional habits such as

bruxism may accelerate it. Attrition also affects the interproximal surfaces of the teeth.

[Compare with Abrasion]

Austenite

The face-centered cubic (FCC) crystalline structure of iron and steel, or the body-centered cubic

(BCC) structure in nickel-titanium alloys, at higher temperatures. In stainless steels, certain

elements such as nickel maintain the austenitic structure at room temperature. Appropriate cooling

of nickel-titanium alloys can induce a transformation to a close-packed hexagonal martensitic

phase (martensitic transformation). The transformation from austenite to martensite and vice versa

is what gives alloys such as nickel-titanium the characteristic properties of “shape memory” and

“superelasticity” (“pseudoelasticity”).

[See Martensitic transformation]

Autorotation (of the mandible)

The rotation of the mandible around the condylar axis (or an axis in the region of the condyles),

after repositioning of the osteotomized maxilla. Mandibular autorotation can be simulated

approximately during preparation of the surgical prediction tracing by rotating the mandibular

template until the mandibular teeth contact the repositioned maxillary teeth. The same can be

accomplished during model surgery using an articulator or one of the various operation simulation

systems. This significant step in the surgical treatment planning process will determine the

feasibility of a single-jaw (maxilla only) procedure, versus the need for bimaxillary surgery.

For example, in a patient with a Class II, Division 1, anterior open bite malocclusion, it may be

feasible to achieve an ideal overjet/overbite relationship and to decrease the elongated lower

anterior face height just by a maxillary differential impaction and subsequent mandibular

autorotation, without the need for a mandibular osteotomy.

Avascular necrosis

Bone infarction not associated with sepsis, but with circulatory impairment (occlusion of blood

vessels), leading to bony necrosis.

Avulsion

The complete separation of a tooth from its alveolus as a result of trauma.

Axes, System of

[See Global reference frame]

Axis of rotation

The line about which rotation of a three-dimensional object actually occurs.

[See Center of rotation (CRot)]

Banding

The process of cementing an orthodontic band in place, which involves the selection of the

appropriate band for a certain tooth, its fitting and adaptation and, finally, its fixation on the tooth by

means of cement.

Basilar kyphosis (Kyphosis of the cranial base)

A term indicating a reduced cranial base angle (NSBa).

[Compare with Platybasia]

Behavioral therapy

An attempt to change the attitude and habits of an individual, without the use of appliances or

medications; a means to improve patient cooperation and compliance. Behavioral therapy is

performed under the assumption that all elements of behavior can be learned. Essential in this

approach is a clear explanation of the rationale of the therapy and the importance of the necessary

motivation and persistence.

Bending test

Experimental setup to determine the material properties of a specimen in bending. This involves

the measurement of angular or linear deflection of an archwire segment, resulting from a bending

moment or an applied force. A bending test designed for orthodontic wires is the American National

Standards Institute/American Dental Association (ANSI/ADA) Specification No 32.

Bends (Archwire bends)

Localized permanent

deformations, placed into an

archwire, that change its direction

and/or orientation from the

original. Bends are added to an

archwire for various reasons.

Some bends are placed without

the purpose of generating any

forces (e.g. bends placed to

account for discrepancies in

bracket positioning or tooth

anatomy, to bypass teeth that will not be included in the archwire, or to avoid possible deformation

of the archwire due to chewing). However, most bends are added with the purpose of generating a

force system necessary for a specific tooth movement. Archwire bends were an indispensable part

of treatment with the standard edgewise appliance, whereas with the straight-wire appliance they

are supposed to be either avoided or greatly reduced. According to the orthodontic coordinate

system introduced by C. H. Tweed, bends on an orthodontic wire are roughly categorized as 1storder,

2nd-order and 3rd-order bends.

SUBTERMS:

Bends (Archwire bends)

• Artistic bends (Esthetic bends)

Bends to position anterior teeth for optimal

esthetic appeal. (Usually referring to second-order

bends on anterior teeth).

Bends (Archwire bends)

• Distal-end bends (Cinching bends, Distal-end

stops)

Bends (usually in a gingival and/or medial direction) made on the archwire (after it is placed in all

the brackets), distal to the terminal attachment, to secure the archwire in place and prevent it from

shifting through the brackets and causing soft tissue impingement during the time interval between

patient visits. Distal-end bends are also useful in avoiding excessive proclination of the anterior

teeth during leveling.

[See Cinching (of the archwire)]

Bends (Archwire bends)

• First-order bends (Offsets, In-out bends, Bayonet bends)

Labiolingual offsets (step bends) in the archwire in the horizontal plane (in the plane of the wire), to

accommodate for variations in the prominence and contour of labial/buccal surfaces of individual

teeth. Typical locations along the archwire in which first-order bends were placed with the standard

edgewise appliance were mesial to the maxillary lateral incisors (insets or step-in bends), canines

(offsets, canine eminence bends, curvature or step-out bends) and first molars (offsets, step-out or

molar bayonet bends). [Note: Vertical step bends that do not change the angulation of a tooth (e.g.

step-up mesial and equal step-down distal to a bracket) are also considered first-order bends. ]

Bends (Archwire bends)

• Second-order bends (Tip bends)

Offsets in the archwire in the vertical plane, to change

the angulation (mesiodistal tipping) of a tooth.

Bends (Archwire bends)

• Step bends

Labiolingual or occlusogingival offsets in an archwire,

in such a way that the segments of the wire on either

side of the bend remain parallel to each other. A step

bend generates equal and opposite forces and

moments of equal magnitude and identical sense

between the two teeth adjacent to it (corresponding

to Burstone’s geometry I). The magnitude of these

forces and moments depends on the size of the step,

the type and size of wire and the interbracket

distance. Unlike V-bends, the force system created

by a step bend remains practically unaffected by

changing the location (mesiodistal position) of the

step bend along the span between the two brackets.

[Compare with Bends (Archwire bends), V-bends

(Gable bends)]

Bends (Archwire bends)

• Stop bends

Bends that serve as archwire stops to keep the arch length constant, or to maintain the actual

position of certain teeth.

Bends (Archwire bends)

• Third-order bends (Torquing bends)

Twists in a rectangular archwire, placed when a change of the buccolingual or labiolingual

inclination of specific teeth is desired.

Bends (Archwire bends)

• Tip-back bends

V-bends placed to tip teeth distally (as is typically done

during the anchorage preparation stage of the Tweed

technique).

Bends (Archwire bends)

• Tip-forward bends

V-bends placed to tip teeth mesially.

[Compare with Bends (Archwire bends), Tip-back bends]

Bends (Archwire bends)

• Toe-in bends

V-bends in the horizontal plane, typically placed at the ends of an archwire, to

achieve derotation or constriction of the terminal molars.

Bends (Archwire bends)

• V-bends (Gable bends)

1. “V”-shaped bends with multiple applications, such as to avoid tipping of teeth into extraction

sites during space closure. V-bends generate different force systems between two teeth, or two

segments of teeth,

depending on the location of

the “V” along the wire (in

relation to the two brackets).

When the V-bend is in the

center of the interbracket

distance, the created force

system involves equal and

opposite moments between

the teeth (corresponding to

Burstone’s geometry VI).

[Note: According to the

above definition, a V-bend

changes the orientation of

the long axis of the wire (i.e.

the segment of the wire distal to the bend is no longer parallel with that mesial to it)].

2. The term V-bend occasionally is mentioned to denote a V-shaped stop (lug) bent into the

archwire, maintaining the original wire orientation distal to it, as it is mesial to the bend.

[See Burstone’s geometry classes]

[See Archwire stop]

Bennett angle

On a lateral mandibular excursion, the non-working side condyle moves inferiorly, anteriorly and

medially. The projection of this trajectory on the horizontal plane creates an angle with the sagittal

plane, called the Bennett angle.

Bennett movement

Lateral translation (sideshift) of the working side condyle during a lateral mandibular excursion.

[See Bennett angle]

Beta position

The posterior component of an orthodontic spring, or the posterior point of attachment of a spring.

[Compare with Alpha position]

Beta-titanium alloy (TMA, b-Ti, Titanium-molybdenum alloy)

A group of titanium-based alloys in which the elevated temperature body-centered cubic beta

phase (crystalline structure) is stable at room temperature, rather than the hexagonal close-packed

alpha phase. One such alloy, made of 77.8% titanium, 11.3% molybdenum, 6.6% zirconium, and

4.3% tin, was introduced to orthodontics in 1980 by C. J. Burstone and J. A. Goldberg, under the

commercial name TMA (Ormco/Sybron). TMA has a modulus of elasticity which is approximately

40% of that of stainless steel and double that of Nitinol. As well, it has excellent resilience and

reasonably good formability, which allows stops and loops to be bent into the wire. In addition,

beta-titanium wires can be spot-welded. However,its drawback is its high friction coefficient. The

properties of TMA make it a good choice for fabrication of auxiliary springs and for intermediate

and finishing archwires.

Bidimensional technique

A fixed-appliance orthodontic treatment approach, developed by A. A. Gianelly, that is aimed at

retraction of maxillary incisors by means of sliding mechanics, with good control of their inclination.

This is attempted by using a 0.022-inch (0.56-mm) non-torqued bracket setup and a 0.016 x 0.022-

inch (0.41 x 0.56-mm) stainless steel archwire, which has ninety-degree bends immediately distal

to the lateral incisors, so as to fit into the incisor slots in a “ribbonwise” fashion. Alternatively, the

incisors are bonded with 0.018-inch (0.46-mm) brackets and the canines, premolars and molars

with 0.022-inch (0.56-mm) brackets, while an edgewise 0.018 x 0.025-inch (0.46 x 0.64- mm)

stainless steel wire is used for retraction with sliding mechanics. The filling of the slot of the incisor

brackets by the full-dimension archwire is supposed to result in good control of their root position

and minimal lingual tipping as a side effect of retraction.

Bifid uvula

A congenitally “split” uvula; a mild form of cleft palate.

Bilateral

Occurring on both sides.

[Compare with Unilateral]

Biocompatibility

The ability to exist in harmony with the surrounding biological environment. The absence of all

material properties that can harm biological tissues. In general, biocompatibility is measured on the

basis of localized cytotoxicity (such as pulpal or mucosal response), systemic responses,

allergenicity and carcinogenicity.

Biofeedback

A method of behavioral modification in which signals are relayed to the patient regarding the status

of certain physiologic functions such as muscle activity, heart rate and blood pressure.

Bite block

An interocclusal acrylic shelf that can be incorporated in a functional or other removable appliance

to contact the occlusal surfaces of (usually) the posterior teeth. Posterior bite blocks that are high

enough to impinge into the freeway space are advocated by some clinicians for the treatment of

patients with a long anterior lower facial height and an anterior open bite tendency.

[See Appliance, Harvold-Woodside activator]

Bite collapse (Posterior bite collapse)

Reduction of the occlusal vertical dimension through (partial) loss or drifting of the posterior

supporting dentition, often resulting in protrusion (flaring) of the maxillary anterior teeth.

Bite collapse (Posterior bite collapse)

Reduction of the occlusal vertical dimension through (partial) loss or drifting of the posterior

supporting dentition, often resulting in protrusion (flaring) of the maxillary anterior teeth.

Bite force

The force exerted by the masticatory musculature during biting, measured between particular

occluding teeth—a parameter that is difficult to control. For standardization purposes, research

attempts sometimes have turned to measuring “maximum bite force,” a concept of relatively little

value as it is rarely attained in everyday human masticatory function.

Bite plane

The horizontal shelf-like part of a bite plate, on which the teeth touch. Bite planes also can be used

in a fixed design (i.e. bonded to the teeth, or attached to a palatal arch).

Bite plate

A removable

orthodontic

appliance

designed to

(temporarily)

disengage the

teeth and/or

prevent

selected teeth

from occluding.

A posterior bite

plate commonly

is used to

disclude the

anterior teeth

and thus facilitate correction of an anterior crossbite. Anterior bite plates can be used to increase

the lower anterior face height, to facilitate tooth movement and to correct a deep bite by extrusion

of posterior teeth.

Bite raising

The increase of lower face height by extrusion of the posterior teeth, as can be accomplished, for

example, by a maxillary anterior bite plate contacting the incisal edges of the mandibular anterior

teeth, while the opposing posterior teeth are kept apart and are free to erupt. Alternatively,

extrusion of the posterior teeth can be obtained by using an anterior bite plane and fixed

appliances, in combination with vertical posterior elastics.

[See Opening of the bite]

Bite registration (Wax bite)

A wax record of an occlusal relationship between the maxilla and mandible, used in the trimming of

orthodontic casts or in the mounting of casts on an articulator. A wax bite usually is taken in centric

occlusion, or in centric relation (if there is a large mandibular CR-CO shift).

[See Construction bite]

Bolton analysis

A method developed by W. Bolton (1958) for the evaluation of mesiodistal tooth size discrepancies

between sets of corresponding maxillary and mandibular teeth. The analysis distinguishes between

the “overall ratio,” which involves all permanent teeth except the second and third molars, and the

“anterior ratio,” which encompasses only the six anterior teeth of each jaw. For this analysis it is

assumed that the relatively smaller tooth material is the correct one. A table of standard values lists

the tooth width value in the opposing arch that is ideally related to this given correct value. The

difference between the ideal and actual dental width in the arch with the excess value gives an

estimate in millimeters of the severity of tooth size discrepancy between the arches.

[See Tooth size discrepancy (Bolton discrepancy)]

Bolton-Brush Growth Study

The Bolton Growth Study is a longitudinal study of over 4,000 subjects from birth to adulthood,

which was started in 1929 under the direction of B. H. Broadbent, Sr. , at Case Western Reserve

University in Ohio. The records that were obtained included lateral and P-A cephalometric

radiographs, hand-wrist radiographs and dental casts, as well as nutritional, dental and medical

health status data. Approximately 2,900 of the subjects of the Bolton study were also enrolled in

the Brush study, which involved radiographs of the entire skeleton taken on a yearly basis, as well

as extensive anthropometric, nutritional, health and psychological data, also recorded annually. All

records of subjects in both studies are currently housed and curated through the Bolton-Brush

Growth Study Center at Case Western Reserve University.

Bonding

The attachment (adhesion) of a material directly onto a tooth by means of a bonding agent. In

common orthodontic use the term denotes the process by which orthodontic attachments are

affixed to the teeth, which has become a routine part of fixed appliance therapy. The most

commonly used bonding techniques involve acid etching and composite resin, or conditioning and

glass-ionomer cement.

SUBTERMS:

Direct bonding

Indirect bonding

Sequential bonding

Bone

A dense type of connective tissue, consisting of cells in a matrix of intercellular ground substance

and collagen fibers. This organic matrix is impregnated with the mineral component of bone,

consisting mainly of calcium phosphate and hydroxyapatite, which imparts rigidity to bone. Bone is

a highly dynamic type of tissue that constantly remodels. Modeling and remodeling of bone

constitutes the basis of orthodontic tooth movement.

SUBTERMS:

Alveolar bone

Basal bone

Bundle bone

Cancellous bone

Cartilaginous bone (Endochondral bone)

Compact bone (Dense bone)

Cortical bone

(Intra)membranous bone

Lamellar bone

Woven bone

Bone apposition

Addition of new bone to bony surfaces by osteoblastic activity.

Bone plate

[See Fixation plate]

Bone resorption

The removal of bone by osteoclastic activity.

SUBTERMS:

Direct resorption (Frontal resorption)

Undermining resorption (Indirect resorption)

Bonwill triangle

An equilateral triangle, each side of which

is supposed to be 4 inches (102 mm) long,

as advocated by W. G. A. Bonwill in 1858.

The triangle is formed by connecting the

medial contact point of the mandibular

central incisors (or the midline of the

residual mandibular alveolar ridge) to the

centers of the condyles.

Boot loop

[See Loop]

Border movements (of the mandible)

Movements of the mandible at the boundary or margin of the envelope of movement, as

determined by the joint anatomy and function. All other mandibular movements take place within

the limits of the border movements.

Brachycephalic

Anthropometric term used to denote an individual with a

larger than average cranial width; having a cephalic index

greater than 81. Brachycephaly may result from premature

synostosis of the coronal suture.

[Compare with Dolichocephalic]

Bracket

Precisely fabricated orthodontic attachment made of metal, plastic or ceramic material, which can

be bonded to a tooth or welded to a band. It carries a horizontal and/or a vertical channel of

standard size, called a “slot,” that can receive an archwire or other orthodontic spring as part of a

fixed orthodontic appliance. The size and shape of the slot vary with the orthodontic technique

practiced and the type of appliance used. The base of the bracket usually contains a welded mesh

or other retentive structure to increase bonding strength.

[See Bracket slot]

[See Bracket setup]

[See Bracket wings]

SUBTERMS:

Broussard bracket

Ceramic bracket

Edgewise bracket

Esthetic bracket (Clear bracket)

Extraction series bracket

Fully programmed bracket

Lewis bracket

Metal bracket

Plastic bracket

Pre-angulated bracket

Pre-torqued bracket

Self-ligating bracket

Single bracket (Single-width bracket)

Twin bracket (Siamese bracket, Double-width bracket)

Bracket position indicator

A disposable, color-coded plastic attachment that is provided by the manufacturer with some types

of brackets. It is meant to facilitate bracket identification, as well as assist with the occlusogingival

placement and axial orientation of the bracket during bonding.

Bracket prescription

[See Appliance prescription]

Bracket setup

Usually referring to the size of the bracket slot. The term “0.018-inch (0.46-mm) setup” refers to a

bracket slot size of 0.018 x 0.025 inch (0.46 x 0.64 mm) and the term “0.022-inch (0.56-mm) setup”

refers to a slot size of 0.022 x 0.028 inch (0.56 x 0.70 mm).

[See Appliance prescription]

Bracket slot

A standard component of an orthodontic bracket. A precisely fabricated horizontal and/or vertical

channel, which can receive an archwire or other orthodontic mechanism as part of orthodontic

treatment. The size and shape of the slot vary with the orthodontic technique practiced and the

type of appliance used. The two bracket slot sizes most commonly used today, are 0.018 x 0.025

inch (0.46 x 0.64 mm) and 0.022 x 0.028 inch (0.56 x 0.70 mm).

SUBTERMS:

Main slot

Vertical slot

Bracket slot engagement

A measure of the play between the orthodontic archwire and bracket slot.

[See “Play” of an orthodontic wire in the bracket slot]

[See Second-order clearance]

[See Third-order clearance]

Bracket width

The mesiodistal dimension of an orthodontic bracket.

Bracket wings

Four projections (only two, in a single bracket) extending from the center of the bracket in a mesialocclusal,

distal-occlusal, mesiogingival and distogingival direction, creating undercuts that facilitate

retention of the elastic or stainless steel ligatures that secure the archwire in the bracket slot.

Bracket wings

Four projections (only two, in a single bracket) extending from the center of the bracket in a mesialocclusal,

distal-occlusal, mesiogingival and distogingival direction, creating undercuts that facilitate

retention of the elastic or stainless steel ligatures that secure the archwire in the bracket slot.

Brazing

[See Soldering]

Brittle

A material exhibiting little or no permanent deformation before fracture. In other words, a brittle

material fractures at or near its proportional limit.

Brittleness

The relative inability of a material to sustain plastic deformation before it fractures.

Bruxism

A diurnal or nocturnal parafunctional activity that includes clenching, bracing, gnashing and

grinding of the teeth. Bruxism is a common cause of dental wear, muscle hypertrophy, pain and

fatigue, and damage to the supporting tissues. It also is associated frequently with

temporomandibular joint problems. Some consider occlusal interferences as a major factor in its

etiology, whereas others believe that it is a centrally mediated phenomenon, related to emotional

tension and stress. In absence of subjective awareness, bruxism can be diagnosed from the

presence of shiny facets that are not generated by masticatory function. Bruxism can be observed

through sleep laboratory recordings.

Bruxism splint

[See Nightguard (Bruxism appliance)]

Buccally

In the direction of the cheeks.

Buccolingually

In a mediolateral direction, perpendicular to the sagittal plane (along the z-axis), for posterior teeth.

When referring to anterior teeth, the term “labiolingually” is appropriate.

[See Global reference frame]

[See Labiolingually]

Buccoversion

Buccal inclination of a tooth or a group of teeth.

Burlington Growth Study

A prospective longitudinal investigation that was started in 1952 in Burlington, Ontario, Canada, by

R. E. Moyers of the Faculty of Dentistry, University of Toronto, under the responsibility of F.

Popovitch. The 1,258 children in the Burlington sample represented 85% to 90% of the children in

Burlington, within the specified ages, at the time the study was started. By the time the data

collection was completed in 1971, the population of Burlington had risen to 90,000 (from an initial

9,000 in 1952). Records were collected annually from age 3 to 21 years. The records consisted of

medical history, periodontal evaluation, six cephalometric radiographs, one hand-wrist radiograph,

impressions for dental casts, intraoral radiographs (where necessary), height and weight records,

anthropometric data, social histories and electromyographic records for some subjects. The entire

material is currently housed at the Burlington Growth Centre, Faculty of Dentistry, University of

Toronto.

Burstone’s geometry classes

When two teeth or two toothsegments

are connected by a

straight wire fully engaged in

both brackets, the generated

force system varies depending

on the relative angulation of the two brackets. There are six different possibilities (6 geometry

classes) as described by C. J. Burstone and H. A. Koenig (1974), which are independent of the

interbracket distance. The geometries are based on the ratio between the angles (JA of the

anterior bracket and (JB of the posterior bracket with respect to a straight line passing through the

centers of the two brackets. In the description of the six geometries that follows, (JA is always (by

convention) the smaller of the two angles.

SUBTERMS:

Burstone’s geometry classes

• Geometry I

In Class I geometry both brackets are angulated in the same direction and by the same amount

(JA/JB = 1). The same situation is created when a straight wire is inserted between two brackets,

which lie at different vertical heights, with parallel slots (or equivalently, when a step bend is placed

on a wire between two aligned brackets). The force system generated in this situation consists of

two equal and opposite forces and two moments of equal magnitude and the same sense. Since

the moments at A and B are equal in magnitude, the ratio MA/MB = 1. Although the magnitude of

the moments may vary depending on the size of the vertical discrepancy (step) and the

interbracket distance (assuming the material and size of the wire segment is always constant), the

ratio MA/MB always remains +1 in Class I geometry.

Burstone’s geometry classes

• Geometry II

In Class II geometry, both brackets are angulated in the same direction but the angle of the A

bracket with the axis connecting the centers of the two brackets is half the size of that of the B

bracket (JA/JB = 0.5). As in geometry I, two equal and opposite forces are created at the positions

A and B, as well as two moments of the same sense. The magnitude of the moment at A is 0.8

times that of the moment at B (MA/MB = 0.8); thus it is reduced with respect to the value

developed in geometry I. Since the SM is reduced, the magnitudes of the forces are also reduced.

Burstone’s geometry classes

• Geometry III

This geometry is created when the slot of the bracket A is parallel to the line connecting the centers

of the two brackets (JA = 0, and consequently (JA/JB = 0). A straight wire engaged in the bracket

slot at A would thus pass through the center of the bracket B. As in the first two geometries, two

equal and opposite forces will be produced at the brackets A and B, as well as two moments of the

same sense. In this situation, the magnitude of the moment at the bracket A is only half of that at

the bracket B (MA/MB = 0.5). The magnitudes of both forces and moments are reduced with

respect to those developed in geometry II.

Burstone’s geometry classes

• Geometry IV

In this situation the ratio JA/JB is -0.5. In other words, the bracket at position A is angled one-half of

the bracket at the position B (and in the opposite direction) relative to the axis connecting the

centers of the two brackets. The wire is now said to be tied – to the A bracket – at the “point of

dissociation”. This means that forces are independent from moments at position A, where only a

force is present and no moment. The total force system that is produced by tying a straight wire

into two brackets with this geometry includes equal and opposite forces at the two brackets and a

moment at B, with no moment at A (MA/MB = 0). The SM and the magnitudes of the forces are

further reduced in this geometry compared to the previous ones.

Burstone’s geometry classes

• Geometry V

Class V geometry describes a situation with a ratio JA/JB of -0.75. In other words the two brackets

still have opposite angulation (as in geometry IV), but the bracket A is now angulated 75% as much

as the bracket B relative to the axis connecting the centers of the two brackets. In this situation the

moment at bracket A is opposite in sense to that of the moment generated at bracket B, and the

ratio between them is MA/MB = -0.4. The magnitude of MB is reduced further, as are the

magnitudes of the forces acting on the two brackets.

Burstone’s geometry classes

• Geometry VI

In this geometry the two brackets are tipped towards each other by an equal amount (JA/JB = 1).

The force system created consists of equal and opposite moments at the two brackets. No forces

are generated. SM, the sum of all the moments, is equal to zero and the ratio MA/MB is equal to 1.

Button

A small, mushroom-shaped orthodontic attachment that can be bonded directly onto a tooth or

welded on a band. Buttons are mainly used as handles for elastic traction.

[See Attachment, Orthodontic]

Calculus (Tartar)

Mineralized bacterial plaque, strongly attached to the tooth surface. According to its location there

are two general types: supragingival and subgingival.

Callus

The newly formed tissue (composed of varying amounts of fibrous tissue, cartilage and bone) that

initially connects the bony fragments where a fracture has occurred.

Camouflage orthodontic treatment

The treatment of malocclusions with underlying mild to moderate skeletal jaw discrepancies, which

achieves a good dental occlusion (Class I canine relationship and an ideal overjet and overbite),

through extraction of certain teeth, to mask the skeletal problem. This type of treatment should be

performed only if it will not have a harmful effect on facial esthetics, and if growth modification or

orthognathic surgery are not applicable or not accepted by the patient. Extraction of teeth provides

space for repositioning of the remaining teeth only in the anteroposterior plane of space. Patients

with vertical or transverse skeletal problems would not benefit from extractions for camouflage.

Similarly, if there is severe crowding, or excessive incisor protrusion in addition to a skeletal

discrepancy (so that the extraction spaces will merely be used for alignment of the remaining

teeth), camouflage treatment usually is contraindicated.

Canine guidance (Canine-protected occlusion, Canine “rise”)

A particular scheme of disclusion of

the dental arches during a lateral

mandibular excursion. The labial (or

distolabial) surface of the

mandibular canine on the working

side comes into contact with the

lingual (or mesiolingual) surface of

the maxillary canine, causing

disarticulation of all other teeth.

Canine retraction

Movement of the canine in a distal

direction, usually into an extraction

space. Individual retraction of the

canines often is performed in an attempt to preserve posterior anchorage in patients with Class II

malocclusions, and subsequently is followed by retraction of the incisors. Canine retraction can be

performed by sliding or sectional mechanics. Control of root position usually is critical, as bodily

movement of the canines generally is required.

[See Moment, Counter-moment]

Canine-to-canine retainer

See Retainer, Bonded lingual.

[See Retainer, Bonded lingual retainer]

Cartilage

A semi-rigid specialized form of supporting/connective tissue, the characteristics of which mainly

stem from the nature and predominance of ground substance in the extracellular matrix.

Proteoglycans make up the ground substance and account for the solid, yet flexible, consistency of

cartilage. Within the ground substance are embedded varying proportions of collagen and elastic

fibers giving rise to three main types of cartilage: hyaline cartilage, fibrocartilage and elastic

cartilage.

On completion of growth the cartilage mass consists of chondrocytes embedded in a large amount

of extracellular matrix. At the periphery of mature cartilage is a zone of condensed supporting

tissue called “perichondrium” containing chondroblasts with cartilage-forming potential. Growth of

cartilage occurs by interstitial growth from within and appositional growth at the periphery. Most

cartilage is devoid of blood vessels and consequently the exchange of metabolites between

chondrocytes and surrounding tissues depends on diffusion through the water of solvation of the

ground substance. This limits the thickness to which cartilage may develop whilst maintaining

viability of the innermost cells.

SUBTERMS:

Elastic cartilage

Fibrocartilage

Hyaline cartilage

Caudal

Inferior, towards the tail.

[Compare with Cephalic (Cranial)]

Cementation

The attachment of bands or a fixed orthodontic appliance on the teeth by means of a dental

cement.

Center of mass (CM)

A point in a body where its entire mass can be considered concentrated for theoretical purposes.

For homogeneous bodies with a regular geometrical shape, the CM is located at their geometric

center (i.e. the center of a sphere, or the junction point of all three-dimensional diagonals of a

cube).

Center of resistance (CRes)

The point in a body at which

resistance to movement can be

considered concentrated, for

mathematical analysis. For a free

object in non-gravitational space,

the center of resistance coincides

with the center of mass. However,

for a partially restrained object (as is

the case for a tooth that is partially

embedded in bone), the CRes is

determined by the mass, shape and

form of the tooth, as well as by the

characteristics of the constraining

elements (bone, PDL). [Other definition: CRes of a tooth is a point in the tooth on which the

application of a single force will produce bodily movement of the tooth. ] The location of the CRes

is estimated to be between halfway and two thirds along the distance between the crest of the

alveolar bone and the root apex in single-rooted teeth, and at the furcation area of multi-rooted

teeth (assuming that the periodontal support is intact).

Center of rotation (CRot)

The point around which rotation actually occurs, when an object is being moved. The location of

the CRot is variable and depends on the movement performed. The actual CRot of a tooth for a

specific movement is almost impossible to determine and can be estimated only by the initial and

final positions of the tooth. In orthodontics, the approximate location of the CRot can be controlled

by varying the moment-to-force ratio at the bracket. The CRot during bodily movement is

considered to lie at infinity. [For three-dimensional objects, the term “axis of rotation” is more

accurate. ]

Centric relation (CR)

A gnathological term that has been used in dentistry for many years, especially in prosthodontics

(as it was meant as a reproducible reference mandibular position, mainly in the construction of

complete dentures). Although CR has had a variety of definitions (which has led to great

confusion), it generally is considered to designate the relation of the mandible to the maxilla when

the condyles are in a physiologically stable position, independent of tooth contacts. Centric relation

has been described as:

1. The relation of the mandible to the maxilla when the mandible is in its most retruded, unstrained

position from which lateral movements can be performed, at any given degree of jaw separation;

also termed the “ligamentous” position, as it is determined mainly by the ligaments of the TMJ.

2. The maxillomandibular relationship in which the condyles articulate with the thinnest avascular

portion of their discs, with the disc-condyle complex in the anterior-superior position against the

slope of the articular eminence.

3. The most superoanterior position of the condyles in the articular fossae with the discs correctly

interposed. Centric relation may be impossible to record in the presence of dysfunction of the

masticatory system.

Cephalic (Cranial)

Towards the head.

[Compare with Caudal]

Cephalometer (Cephalostat)

A head-holding device introduced in 1931 by B. H. Broadbent in the USA and by H. Hofrath in

Germany. The original design included two ear rods for insertion into the external auditory canals,

an infraorbital pointer and a forehead clamp, to achieve parallelism of the Frankfort plane with the

floor. The cephalometer is used to obtain standardized and comparable craniofacial images on

radiographic film.

Cephalometric analysis

The process of evaluating skeletal, dental and soft tissue relationships of a patient, by comparing

measurements performed on the patient’s cephalometric tracing with population norms for the

respective measurements, to come to a diagnosis of the patient’s orthodontic problem. Refers also

to the various standardized sets of cephalometric measurements (e.g. Downs’ analysis, Steiner

analysis) commonly used in the evaluation.

SUBTERMS:

Burlington cephalometric analysis

Di Paolo (Quadrilateral) cephalometric analysis

Downs cephalometric analysis

Harvold cephalometric analysis

McNamara cephalometric analysis

Sassouni cephalometric analysis

Steiner cephalometric analysis

Tweed cephalometric analysis

Wylie cephalometric analysis

Cephalometric landmarks

Readily recognizable points on a cephalometric radiograph or tracing, representing certain hard or

soft tissue anatomical structures (anatomical landmarks) or intersections of lines (constructed

landmarks). Landmarks are used as reference points for the construction of various cephalometric

lines or planes and for subsequent numerical determination of cephalometric measurements.

In the definitions of the specific landmarks the following convention is used: “midsagittal” identifies

landmarks lying on the midsagittal plane, “unilateral” identifies landmarks corresponding to

unilateral structures and “bilateral” applies to landmarks corresponding to bilateral structures.

SUBTERMS:

A-point (Point A, Subspinale, ss)

Anterior nasal spine (ANS)

Articulare (Ar)

B-point (Point B, Supramentale, sm)

Basion (Ba)

Bolton (Bo)

Condylion (Co)

Crista galli

Dacryon

Glabella (G)

Gnathion (Gn)

Gonion (Go)

Incision inferius (Ii)

Incision superius (Is)

Infradentale (Id, Inferior prosthion)

L-point

Menton (Me)

Nasion (N, Na)

Opisthion (Op)

Orbitale (Or)

Pogonion (Pog, P, Pg)

Porion (Po)

Posterior nasal spine (PNS)

Prosthion (Pr, Superior prosthion, Supradentale)

Pterygomaxillary fissure (PTM, Pterygomaxillare)

R-point (Registration point)

Sella (S)

Cervical point (C)

Inferior labial sulcus (Ils)

Labrale inferior (Li)

Labrale superior (Ls)

Pronasale (Pn)

Soft tissue glabella (G’)

Soft tissue menton (Me’)

Soft tissue nasion (N’, Na’)

Soft tissue pogonion (Pg’, Pog’)

Stomion (St)

Stomion inferius (Sti)

Stomion superius (Sts)

Subnasale (Sn)

Superior labial sulcus (Sls)

Trichion (Tr)

Soft tissue gnathion (Gn’)

Cephalometric lines (planes)

Most analyses utilize one or more cephalometric lines that are joining two landmarks, are tangent

to an outline from a landmark, or are perpendicular to another line from a landmark.

SUBTERMS:

A-B plane

Basion-Nasion line (Ba-N)

Bolton plane

Camper’s base plane

De Coster line

E-line (E-plane, Esthetic line of Ricketts)

Facial axis of Ricketts

Facial plane (FP, Facial line)

Frankfort horizontal plane (FH, Frankfort horizontal line, Auriculo-orbital plane, Eye-ear plane)

H-line (Harmony line of Holdaway)

Intergonial line

Mandibular plane (MP, Mandibular line, ML)

Nasion-perpendicular

Occlusal plane (OP)

Palatal plane (ANS-PNS, PP, Nasal line, Nasal floor, Spinal plane)

Rees esthetic plane

Reference line

Riedel plane

S-line (Esthetic plane of Steiner)

Sella-Nasion line (SN, Nasion-Sella line, NSL)

True horizontal line

True vertical line

Y-axis (Growth axis)

Z-line (Profile line of Merrifield)

Cephalometric radiograph (Cephalogram)

A radiograph of the head obtained under standardized conditions, introduced simultaneously in the

United States and Germany (1931), by B. H. Broadbent and H. Hofrath, respectively.

Cephalometric radiographs are taken on a cephalometer, which dictates a standardized orientation

of the head and a precisely defined relationship among x-ray source, subject and film. By

convention, the dis-tance between x-ray source and the midsagittal plane of the subject is either 5

feet (152.4 cm) or 150 cm. The distance between the midsagittal plane of the subject and the film

may vary between 10 cm and 18 cm, depending on head size. Measurement of the subject-film

distance and the source-subject distance allows calculation of the image magnification. The

standard projections are lateral (profile), posteroanterior (P-A) and oblique projections.

SUBTERMS:

Lateral cephalometric radiograph

Oblique cephalometric radiograph

Posteroanterior (P-A) cephalometric radiograph

Cephalometric tracing

An overlay drawing produced from a

cephalometric radiograph by copying

specific outlines from it with a lead

pencil onto acetate paper, using an

illuminated view-box. Tracings are

used to facilitate cephalometric

analysis, as well as in

superimpositions, to evaluate

treatment and growth changes.

Chief complaint (CC)

The patient’s statement of the main problem or primary concern.

Chronic pain disorders

Persistent pain that lasts more than six months, with associated behavioral and psychosocial

factors.

Cinching (of the archwire)

Placing a sharp bend on the archwire distal to the terminal attachments in an arch. Cinching is

done to avoid excessive proclination of the anterior teeth during leveling or to prevent the archwire

from sliding in an anterior direction during the interval between patient visits.

[See Bends (Archwire bends), Distal-end bends (Cinching bends, Distal-end stops)]

Circumferential supracrestal fibrotomy (Edwards’ procedure)

An adjunctive periodontal surgical procedure developed by J. G. Edwards to reduce the relapse

tendency of corrected individual tooth rotations. The procedure consists of inserting the sharp point

of a fine blade into the gingival sulcus, down to the crest of the alveolar bone, to sever the gingival

fibers around the tooth (including the transseptal fibers between it and the adjacent teeth).

Clasp (Retention clasp)

An element of a removable appliance made of metal that serves to secure the appliance in place

by engaging on undercuts provided by the morphology and inclination of the teeth.

SUBTERMS:

Clasp (Retention clasp)

• Adams clasp (Modified arrowhead clasp)

A clasp made of stainless steel wire, which was designed by

C. P. Adams to retain removable appliances, by means of

point contact with the mesio- and distobuccal undercuts of

individual posterior teeth. The clasp is bent from a single

piece of round wire and crosses the occlusal table at the

mesial and distal embrasures of a posterior tooth (typically

first permanent molar). Itconsists of a mesial and a distal retentive U- or V-shaped loops, which are

pointed in a gingival direction and joined by a buccal bridge.

[See Clasp (Retention clasp), Arrowhead clasp (Arrow clasp)]

Clasp (Retention clasp)

• Arrowhead clasp (Arrow clasp)

Clasp made from stainless steel wire, bent in the shape

of an arrowhead. It is meant to engage the distobuccal

and mesiobuccal undercuts of adjacent teeth (in a

fashion similar to a ball clasp). Two or more arrowhead

clasps may be combined, joined by a buccal bridge.

[See Clasp (Retention clasp), Adams clasp (Modified

arrowhead clasp)]

Clasp (Retention clasp)

• Ball clasp

Clasp bent from round stainless steel wire, with a

ball-shaped end. The clasp crosses the occlusal table

at the embrasure between two adjacent teeth and

engages their mesiobuccal and distobuccal

undercuts.

Clasp (Retention clasp)

• Circumferential clasp (Three-quarter clasp, C-clasp)

A single-tooth cast or bent stainless

steel wire clasp that engages the

cervical region of the canines and

posterior teeth. The clasp usually

crosses the occlusal table at an

interproximal embrasure between two

teeth, then progresses gingivally toward

the other interproximal surface,

engaging in the interproximal gingival undercut, thus traversing three surfaces of the tooth.

The diameter of the wire used for its fabrication typically is 0.024 inch (0.60 mm) for deciduous

canines; 0.028 inch (0.70 mm) for deciduous molars, premolars and permanent canines; and 0.032

inch (0.80 mm) for permanent molars. Circumferential clasps function well on maxillary teeth as the

morphology and the inclination of the posterior teeth provide adequate undercuts. In the

mandibular dental arch this is not always the case. By creating artificial undercuts with composite,

circumferential clasps can provide firm retention of mandibular removable appliances. An

advantage of the circumferential clasp is the possibility of avoiding occlusal interference of the part

of the clasp that crosses the occlusal table.

Clasp (Retention clasp)

• Claw clasp

A clasp introduced by F. P. G. M. van der Linden

for retention on maxillar incisors. It is made of a

0.024-inch (0.60-mm) stainless steel springhard

wire crossing the incisal edge and forming

a small rectangular box on the labial surface of

those teeth. The addition of composite at that

point, to create an artificial undercut, greatly

enhances retention.

Clasp (Retention clasp)

• Delta clasp

A modification of the standard Adams clasp by W. J.

Clark, for retention of the twin block appliance. The

major difference is the shape of the retentive loops,

which in the case of the delta clasp are shaped in a

closed triangle, unlike the open V- or U-shaped loops, of

the Adams clasp. Subsequent modification of the delta

clasp produced circular loops, which are easier to

construct and have similar retentive properties. The

advantage of the delta clasp, according to its designer,

is that the loops do not open with repeated insertion and

removal of the appliance. Delta clasps, which are

constructed from 0.028-inch (0.70-mm) or 0.030-inch

(0.75-mm) stainless steel wire, can provide good

retention on mandibular premolars and can be used on

most posterior teeth.

[See Appliance, Twin block appliance]

Class I, II, III malocclusion

[See Angle classification]

Classification of gingival recession

[See Miller classification]

Cleft lip and/or palate (CLP)

The most common craniofacial anomaly (approximately 1 in 600 to 1 in 700 live births higher in

some populations), characterized by failure of fusion between certain embryological processes

(swellings) during facial morphogenesis. Failure of fusion between the medial and lateral nasal and

the maxillary swellings results in a cleft of the lip and/or alveolar process. Failure of fusion between

the lateral palatine swellings results in a cleft of the palate. These problems are thought to result

from a deficiency of mesenchyme in the facial region, brought about by failure of neural crest cells

to migrate or failure of the facial mesenchyme to proliferate. A cleft can be complete or incomplete,

and it can occur unilaterally or bilaterally. Cleft lip may occur without clefting of the alveolar process

or the palate, and cleft palate also can occur as an isolated phenomenon. A useful classification

divides the anatomy into primary and secondary palates. An individual thus may have clefting of

the primary palate, the secondary palate, or both. In addition, a CLP may be an isolated

phenomenon, or may occur as part of a syndrome.

The etiology of cleft lip and palate is thought to be multifactorial. Genetics is implicated in 20% to

30% of patients. Even in those individuals whose genetic background may verify familial

tendencies for clefting, the mode of inheritance is not understood completely. Environmental

factors that have been shown in experimental animals to result in clefting include nutritional

deficiencies, radiation, several drugs, hypoxia, viruses, and vitamin excesses or deficiencies. In

complete unilateral or bilateral clefts of the lip, alveolus and palate, the maxillary arch typically is

collapsed in the transverse direction, especially in the area of the cleft. The maxillary permanent

lateral incisors may be congenitally missing or malformed, and many atypically shaped

supernumerary teeth may be present in the area of the cleft.

The treatment of patients with cleft lip and/or palate is a long and involved process, requiring many

stages of intervention by many different specialists, forming a “cleft lip and palate team. ” The

involvement of the team orthodontist starts a few days after the baby is born, with presurgical infant

orthopedic treatment (if applicable), in preparation for the initial repair.

Repair of the lip usually is performed within the first three months after birth, and the palate

subsequently is repaired within the first year. The scar tissue created from these and other surgical

procedures is considered responsible for variable degrees of maxillary growth inhibition which is

commonly seen during subsequent growth.

When the cleft involves the alveolar process, a bone graft may be necessary to restore the alveolar

anatomy. Alveolar bone grafting usually is performed prior to the eruption of the permanent

maxillary canine on the side of the cleft.

Phase I of orthodontic treatment, in preparation for the alveolar bone graft, may consist of

expansion of the constricted maxilla and correction of any crossbites. Following alveolar bone

grafting, and when the patient is in the permanent dentition, phase II of orthodontic treatment is

performed to idealize the occlusion, or if a severe skeletal discrepancy is present, to prepare the

arches for orthognathic surgery.

[See Graft, Alveolar bone graft]

[See Palate, Secondary palate]

[See Palate, Primary palate]

Cleidocranial dysplasia (Cleidocranial dysostosis, CCD)

Inheritable disorder (autosomal dominant) affecting both intramembranous and endochondral bone

formation. The clinical features include a characteristic brachycephalic skull (cephalic index

commonly in excess of 81), with frontal and parietal bossing and the appearance of a small face.

Paranasal sinuses and mastoids often are underdeveloped or absent. Clavicles are hypoplastic or

aplastic, and closure of fontanels and cranial sutures is delayed, sometimes for life.

The palate is highly arched, and there may be a submucous or complete cleft palate. The maxilla is

underdeveloped and a skeletal Class III malocclusion usually is present. The dentition often

presents a chaotic appearance with multiple supernumerary teeth, multiple crown and root

abnormalities, ectopic development, retention of deciduous teeth and failure of eruption of

permanent teeth. Extraction of retained deciduous teeth usually does not facilitate the eruption of

their permanent successors. The molecular pathology of this condition was shown to be associated

with mutations of a gene called CBFA. This gene is a transcription factor essential for osteoblast

differentiation and bone formation, which explains the general bone dysplasia in the condition.

Clenching

Parafunctional activity characterized by hyperactivity of the elevator masticatory muscles, with the

teeth in contact. Clenching is considered to be stress-related and, together with bruxism, is thought

to be part of the predisposing/initiating/perpetuating factors in the development of

temporomandibular joint disorders.

Clicking

Brief, sharp sound (distinct snapping or cracking), audible with or without a stethoscope, or

detectable by palpation, emanating from one or both temporomandibular joints during mandibular

movements. The most common cause for clicking is anterior or antero-medial displacement of the

articular disc. Clicking may or may not be associated with internal derangement of the TMJ, and it

may occur only during the opening or closing movement of the mandible (single click), or during

both (reciprocal click).

SUBTERMS:

Clicking

• Early closing clicking

A clicking noise that occurs at the initiation of retrusive condylar translation.

Clicking

• Early opening clicking

A clicking sound from the TMJ that occurs at the initiation of protrusive condylar translation.

Clicking

• Late closing clicking (Terminal closing clicking)

A click that occurs before the end of retrusive condylar translation.

Clicking

• Late opening clicking (Terminal opening clicking)

A click that occurs just before the end of protrusive condylar translation.

Clicking

• Mid-closing clicking

A clicking noise that occurs midway along the condylar translatory path during closing.

Clicking

• Mid-opening clicking

A clicking noise that occurs midway along the condylar translatory path during opening.

Clicking

• Reciprocal clicking

A pair of clicking noises from the temporomandibular joint, heard during the mandibular opening

movement and again just before the teeth occlude during the closing movement. Reciprocal

clicking is a common characteristic of disc displacement with reduction. From a closed mouth

position, the temporarily misaligned disc reduces or improves its structural relation with the condyle

when mandibular translation occurs, which produces the first clicking noise. The closing noise is

usually of less magnitude and is thought to be produced by a displacement of the disc to its

previous position.

[Compare with Clicking, Single clicking]

Clicking

• Single clicking

An individual clicking noise, occurring either during the opening, or during the closing stage of

mandibular movement.

[Compare with Clicking, Reciprocal clicking]

Closed bite

Excessive vertical overlap of the anterior teeth; extremely deep bite.

Closed lock

[See Disc displacement (Disc derangement, Disc prolapse, Disc interference disorder), Disc

displacement without reduction]

Cobalt-chromium alloy (Co-Cr, Cobalt-chromium-nickel alloy, Chromium-cobalt alloy)

Highly corrosion-resistant alloys based on cobalt and chromium, used for fabrication of orthodontic

wires or clasps. Cobalt-chromium orthodontic wires are very similar in appearance, mechanical

properties, and joining characteristics to stainless steel wires, but have a significantly different

composition and considerably greater heat treatment response.

One of the most widely known alloys, introduced to orthodontics under the trademark

“Elgiloy” (Rocky Mountain Orthodontics), consists of approximately 40% cobalt, 20% chromium,

15% nickel, 15.8% iron, 7% molybdenum, 2% manganese, 0.15% carbon, and 0.04% beryllium.

Concerns about the toxicity of beryllium have led to the development of beryllium-free cobaltchromium

alloys such as “Remaloy” (Dentaurum).

Cobalt-chromium wires are available in different tempers. The soft-temper wires are popular with

clinicians because they are more easily formable and subsequently they can be hardened by heat

treatment. Cobalt-chromium alloys have a modulus of elasticity (E) equivalent to that of stainless

steel. However, they “feel” softer in the not-hardened state, as their yield strength and elastic range

are lower compared to the more resilient stainless steel alloys.

Cohesion

The property of a material by which its constituent molecules are attracted to each other, resisting

separation.

[Compare with Adhesion]

Collateral ligaments

Ligaments attaching the medial and lateral borders of the articular disc of the temporomandibular

joint to the respective poles of the condyle. These ligaments permit the disc to rotate anteriorly and

posteriorly on the articular surface of the condyle during mandibular movements.

Collimator

A diaphragm, cone or tube containing a lead disk with an aperture, designed to fit on an x-ray

source so as to restrict the size and shape of the primary beam, by eliminating its peripheral (more

divergent) portion. The aperture of the collimator may be circular or rectangular.

Coloboma

A congenitally occurring lack of continuity (“cleft”) in the orbital region. The defect may be restricted

to the eyelids or extend into the globe from the iris to the retina. Lower lid and/or lateral canthal

colobomas are commonly seen in patients with Treacher Collins syndrome.

[See Treacher Collins syndrome (Mandibulofacial dysostosis)]

Columella

The small fleshy column connecting the upper lip and the tip of the nose, between the nares; a

continuation of the nasal septum.

Comprehensive orthodontic treatment

Coordinated treatment aiming at improving a patient’s craniofacial dysfunction and/or dentofacial

deformity, taking into account anatomical, functional and esthetic factors. Treatment may

incorporate several phases, with specific objectives at various stages of dentofacial development.

Adjunctive procedures such as extractions, dentofacial orthopedic treatment, orthognathic surgery,

myofunctional or speech therapy, and restorative or periodontal treatment may be performed

concurrently to achieve the best attainable result. Typically, at the end of active comprehensive

orthodontic treatment each tooth is in its ideal position and the achievable optimum in occlusion

has been obtained. Long-term periodic reevaluation following active treatment is important for

maintenance of the achieved result. [Modified from the AAO Glossary of Dentofacial Orthopedic

Terms, 1993.]

[Compare with Limited orthodontic treatment]

Compressive deformation (Compressive strain)

The shape change of a body when it is subjected to compressive stress (e.g. the shortening of an

orthodontic open coil upon compression).

Computerized cephalometrics

The process of entering cephalometric data in digital format into a computer for cephalometric

analysis. Depending on the software and hardware available, the incorporation of data can be

performed by digitizing points on a tracing, by scanning a tracing or a conventional radiograph, or

by originally obtaining computerized radiographic images that are already in digital format, instead

of conventional radiographs. Computerized cephalometrics offers the advantages of instant

analysis; readily available race-, sex- and age-related norms for comparison; as well as ease of

soft tissue change and surgical predictions.

Concrescence

Union of the cellular cementum of two teeth that have developed from

two separate tooth buds.

[Compare with Fusion]

[Compare with Gemination]

[See Twinning]

Condylar growth

Proliferation of condylar cartilage, followed by endochondral ossification. The condyle, the coronoid

process and the ramus are the principal sites of growth of the mandible. As condylar growth

occurs, the mandible is translated inferiorly and anteriorly, which can be visualized by inspection of

cephalometric superimpositions using the cranial base as a reference. The upward and backward

direction of condylar growth is seen clearly by mandibular superimposition. Condylar growth

normally stops shortly after that of the rest of the face, although it may continue well beyond

adolescence, particularly in males.

[See Growth center]

[See Growth site]

Condylectomy

Surgical removal of the entire mandibular condyle.

Condylar guidance

The functional guidance of the mandibular excursions, as determined by the relationship between

the mandibular condyles and the contours of the glenoid fossae, articular eminences and articular

discs.

Condylar hyperplasia

Excessive growth of the condyle, usually unilateral, resulting in facial asymmetry and an

associated malocclusion. Such malocclusions often are associated with an open bite on the

affected side and/or a crossbite on the non-affected side, with a corresponding midline

discrepancy. The condition typically appears in the late teens, but may begin at an earlier age. A

bone scan (scintigram) with Tc99m, an isotope that is concentrated in areas of active bone

deposition, can be used to distinguish between an actively growing (“hot”) condyle and an enlarged

condyle that has ceased growing. The treatment for severe cases of condylar hyperplasia is

usually surgical.

Condylar growth

Proliferation of condylar cartilage, followed by endochondral ossification. The condyle, the coronoid

process and the ramus are the principal sites of growth of the mandible. As condylar growth

occurs, the mandible is translated inferiorly and anteriorly, which can be visualized by inspection of

cephalometric superimpositions using the cranial base as a reference. The upward and backward

direction of condylar growth is seen clearly by mandibular superimposition. Condylar growth

normally stops shortly after that of the rest of the face, although it may continue well beyond

adolescence, particularly in males.

[See Growth center]

[See Growth site]

Condylysis

Idiopathic resorption or dissolution of the condyle.

“Cone-funnel” mechanism

The mechanism by which it is theorized that interdigitation of posterior teeth is achieved in the late

stages of their eruption. Occlusal contacts between the maxillary and mandibular posterior teeth

dictate a series of adjustments in mesiodistal angulation and buccolingual inclination over a

relatively short period of time, leading to their final interdigitation.

Construction bite

A bite registration at the desired occlusal relationship, to permit articulator mounting of the casts for

fabrication of an (most commonly functional) appliance. The construction bite is sent to the

orthodontic laboratory, together with the impressions (or casts) and a prescription with the required

specifications of the appliance.

[See Bite registration (Wax bite)]

Contralateral

Referring to the side opposite to the one that is being considered.

[Compare with Ipsilateral]

Conversion (of a tube into a bracket)

The process of removing the buccal cap of a convertible tube of a molar attachment to transform

the tube into a bracket.

[See Tube (Molar tube), Convertible tube]

[See Orthodontic instruments, Conversion instrument]

Corrosion

A chemical or electrochemical degrading process, through which a material is attacked by

corrosive agents, such as acids (but also air and saliva, in the case of the intraoral environment),

resulting in partial or complete dissolution, deterioration, or weakening. Although glasses and other

nonmetals also are susceptible to environmental degradation, metals generally are more prone to

such an attack because of electrochemical reactions.

SUBTERMS:

Galvanic corrosion

Pitting corrosion

Stress corrosion

Cortical drift

All bone structures have one

growth principle in common,

which was termed “drift” by D.

H. Enlow. The cortical plate can

be relocated by simultaneous

apposition and resorption

processes on the opposing

periosteal and endosteal

surfaces (cortical drift). The

bony cortical plate drifts by

apposition and resorption of

bone substance on its outer and

inner surfaces, respectively, in the

direction of growth. If resorption and deposition take place at the same rate, the thickness of the

bone remains constant. Should more bone be deposited than resorbed, the thickness of the

structure increases, as during growth. The teeth follow the drift of the alveolar processes while the

jaw is growing, and thus they maintain their position within the surrounding bony structure, despite

the displacement of the entire bone.

[See Displacement, Displacement (of a bone)]

Cortical plate

The dense layer of cortical bone covering the buccal and lingual aspects of the alveolar process.

[See Bone, Cortical bone]

Corticotomy (Cortical osteotomy)

A partial osteotomy, involving only the cortical plate, to weaken the resistance of the bone to the

application of forces. Such a procedure is routinely performed prior to distraction osteogenesis for

elongation of the mandible or the maxilla.

[See Distraction osteogenesis (Distraction osteosynthesis, Ilizarov technique, Callus distraction,

Callotasis)]

Costen’s syndrome

Condition involving dizziness, tinnitus, earache, stuffiness of the ear, dry mouth, burning in the

tongue and throat, sinus pain and headaches, described by the otolaryngologist J. B. Costen in

1934. He attributed the symptoms to overclosure of the bite and posterior displacement of the

mandibular condyle. [Term formerly used for “temporomandibular joint disorders. “]

Cortical plate

The dense layer of cortical bone covering the buccal and lingual aspects of the alveolar process.

[See Bone, Cortical bone]

Cranial base

The bones of endochondral origin that form the antero-inferior aspect of the brain case. Because

the bones of the cranial base stop growing relatively early, they often are used in the

superimposition of se-rial cephalograms or tracings as reference structures to assess growth of the

jaws or treatment results.

Craniofacial clefts

Rarely occurring clefts that are not limited to the lip and palate, but also involve the facial soft

tissues and underlying bone. They result from problems in the migration of neural crest cells and

failure of fusion between facial processes (swellings), or from differentiation defects of facial

tissues of mesodermal origin in the first trimester of pregnancy. Some craniofacial clefts produce

extensive facial defects with severe tissue deficits. There are many kinds of craniofacial clefts,

commonly classified under a system described by P. Tessier, which involves numbers from 0 to 14,

centered around the eye.

Craniometry

A branch of anthropometry dealing with the measurements of dimensions and angles of the bony

skull.

Craniosynostosis

A birth defect that may occur as an isolated phenomenon or as part of a syndrome, consisting of

premature fusion of one or more skull sutures. Craniosynostosis results in craniofacial deformity

and potentially in increased intercranial pressure, which can be deleterious to brain function. For

this reason, surgical release of the fused sutures sometimes is undertaken quite early in life. A

number of craniofacial syndromes sharing the clinical feature of craniosynostosis (such as Crouzon

syndrome, Pfeiffer syndrome and Apert syndrome) have been found to result from mutations in the

genes for fibroblast growth factor receptors (FGFR gene mutations).

Crefcoeur spring

[See Appliance, Crefcoeur appliance]

Crepitus (Crepitation, Grating sound)

Rough, sandy, diffuse noise or vibration, produced by the rubbing together of irregular bone or

cartilage surfaces, usually identified with osteoarthritic changes when heard in joints.

Crimpable attachments

A number of different orthodontic attachments (e.g. hooks, stops) that can be fixed on an archwire

by squeezing their base with special sharp-beaked pliers or cutters.

Crossbite

An abnormal relationship of one or more teeth to one or more teeth of the opposing arch, in the

buccolingual or labiolingual direction. A crossbite can be dental or skeletal in etiology. [Note: The

appropriate type of crossbite can be specified by identifying the teeth or jaws that deviate the most

from their ideal position (e.g. when a crossbite is mainly due to a narrow maxillary arch the correct

term is “maxillary posterior lingual crossbite” as opposed to “mandibular posterior buccal

crossbite”). ]

SUBTERMS:

Crossbite

• Anterior crossbite

Situation in which one or more primary or permanent mandibular incisors are labial to their

antagonists (or one or more maxillary incisors are lingual to their antagonists) in habitual occlusion.

Crossbite

• Buccal crossbite

A crossbite due to buccal displacement of the affected tooth (or group of teeth) from its (their) ideal

position relative to its (their) antagonist(s).

Crossbite

• Complete mandibular buccal crossbite

A situation in which the mandibular dental arch is wide and lies entirely buccal to (contains) the

maxillary dental arch. This rare situation is sometimes seen in extreme Class III anomalies

associated with mandibular hyperplasia.

[Compare with Crossbite, Complete maxillary palatal crossbite]

Crossbite

• Complete maxillary buccal crossbite (Brodie syndrome)

A situation in which the maxillary dental arch is

wide and lies entirely buccal to (contains) the

mandibular dental arch (named after A. G. Brodie).

This rare situation sometimes is seen in extreme

Class II anomalies associated with maxillary

hyperplasia.

[Compare with Crossbite, Complete mandibular

lingual crossbite]

Crossbite

• Complete maxillary palatal crossbite

A situation in which the maxillary

dental arch is narrow and lies

entirely lingual to (contained within)

the mandibular dental arch. This rare

situation sometimes is seen in

extreme Class III anomalies

associated with maxillary

hypoplasia.

[Compare with Crossbite, Complete

mandibular buccal crossbite]

Crossbite

• Dental crossbite

An abnormal relationship between antagonist teeth that is due to deviations in the position or

inclination of one or a few teeth (i.e. the relationship between the maxilla and mandible is

harmonious). Such crossbites usually are treatable by means of tooth movement alone.

[Compare with Crossbite, Skeletal crossbite]

Crossbite

• Functional crossbite (Pseudo-crossbite)

A crossbite that is due to a shift of the mandible (i.e. forced bite) into a faulty habitual occlusion

(CO) because of a premature occlusal interference in centric relation (CR). The shift may occur in

an anterior and/or in a lateral direction. Such crossbites often are seen in children, typically

because of interferences caused by lack of wear of their deciduous canines. The treatment

advocated for such problems may be enameloplasty of the deciduous canines or expansion of the

maxillary dental arch.

[See Lateroclusion]

[See Mandibular shift (CR-CO shift, Mandibular slide, Forced bite, Slide in centric)]

Crossbite

• Lingual crossbite

A crossbite mainly due to lingual displacement of the affected mandibular tooth (or group of teeth)

from its (their) ideal position relative to its (their) antagonist(s).

Crossbite

• Palatal crossbite

A crossbite mainly due to palatal displacement of the affected maxillary tooth (or group of teeth)

from its (their) ideal position relative to its (their) antagonist(s).

Crossbite

• Posterior crossbite

A type of crossbite in which one or more deciduous or permanent posterior teeth occlude in an

abnormal buccolingual relation with their antagonists. Posterior crossbites may occur unilaterally or

bilaterally. They may be maxillary or mandibular, buccal or lingual, and may be accompanied by a

lateral functional shift of the mandible (especially in the case of unilateral posterior crossbites).

Crossbite

• Skeletal crossbite

Anterior or posterior (unilateral or bilateral) crossbite that is due to a sagittal or transverse

incoordination in the size or shape of the maxilla and/or mandible. The treatment of such

crossbites usually requires a skeletal expansion by means of rapid maxillary expansion or

orthognathic surgery.

[See Crossbite, Dental crossbite]

Crossbite

• Telescoping bite

A term denoting either a complete

mandibular lingual, or a complete

maxillary buccal crossbite. The

opposite (i.e. a complete maxillary

palatal or a complete mandibular

buccal crossbite) sometimes is called a

reverse telescoping bite.

Cross-section of orthodontic wires

[See Archwire cross-section]

Curettage

Soft tissue periodontal procedure aiming at removal of necrotic tissue lining the soft tissue wall of

periodontal pockets by means of a curet.

SUBTERMS:

Closed curettage

Open curettage

Curve of Monson

A three-dimensional combination of the curves of Spee and

Wilson. According to G. S. Monson, who introduced this

concept (1920), all cusps and incisal edges in a natural

dentition are tangent to a surface of a sphere, approximately 4

inches (10.2 cm) in radius, with its center in the area of the

glabella.

Curve of Spee (Compensating curve)

The curve displayed in the sagittal plane (or

rather, in a plane parallel with the body of the

mandible on either side) by the cusps and incisal

edges of the mandibular teeth. The convex

aspect of the curve of Spee is pointing inferiorly.

The concept was first introduced by F. Graf von

Spee in 1890, who theorized that the extension

of this curve would be tangent to the anterior

surface of the mandibular condyles, bilaterally.

SUBTERMS:

• Reverse curve of Spee

In many patients with a deep overbite, the curve formed by the cusps and incisal edges of the

maxillary teeth is reverse to the curve of Spee, namely having its convex aspect pointing

superiorly. When using continuous archwire mechanics for leveling of the mandibular arch, some

clinicians incorporate a reverse curve of Spee in the mandibular archwire. Conversely, during

leveling of the maxillary arch in a patient with a reverse curve of Spee, the opposite curve (i.e.

accentuated curve of Spee) is incorporated into the maxillary archwire.

Curve of Wilson

When looking at a coronal section of the mandibular

dentition one can see that the long axes of the

mandibular molars and premolars converge towards

the midline (i.e. they are tipped lingually). From this

view the occlusal surfaces of these teeth bilaterally

form a curve in a buccolingual direction. This

imaginary curve that is defined by a line tangent to

the buccal and lingual cusps of the mandibular

posterior teeth bilaterally, is termed the curve of

Wilson.

Cusp

A conical-shaped, pointed or rounded eminence, on or near the occlusal surface of posterior teeth

and on the lingual surface of anterior teeth, which may come into occlusal contact with a tooth of

the opposing dental arch.

SUBTERMS:

Cusp

• Functional cusps (Supporting cusps)

The palatal cusps of the maxillary posterior teeth and the buccal cusps of the mandibular posterior

teeth that come into occlusal contact in intercuspal position, maintaining the occlusal vertical

dimension.

Cusp

• Non-functional cusps (Non-supporting cusps)

The buccal cusps of the maxillary posterior teeth and the lingual cusps of the mandibular posterior

teeth that do not directly contact the opposing teeth in intercuspal position. They act like the rim of

a pestle to prevent food from escaping from the occlusal table, and they protect the buccal mucosa

and the tongue by keeping them away from the functional cusps.

Cusp

• Plunger cusp

A cusp that tends to forcibly wedge food into the interproximal area of two teeth of the opposing

arch.

Cuspid

[See Canine guidance (Canine-protected occlusion, Canine “rise”)]

[See Canine-to-canine retainer]

[See Canine rise]

[See Canine retraction]

Cyclosporine

A pharmacological substance that can cause gingival hyperplasia. It is an immunosuppressant and

antifungal agent, sometimes used to prevent rejection in recipients of organ transplants.

Cytokines

A family of growth factors that mediate considerable roles in growth, differentiation and tissue

damage by cellular receptors.

Deactivation

The process following the activation of an appliance (or an appliance part), during which the stored

force is delivered to the dentition.

Debanding

The removal of cemented orthodontic bands.

Debonding

The removal of bonded orthodontic attachments.

Decalcification

The removal of various minerals from a bone or tooth.

[See White spot lesion (Decalcification)]

Decompensation

The process of removing the dentoalveolar compensations that

may be present (by re-establishing the correct tooth position

with regard to the skeletal base), usually prior to surgical

correction of a skeletal malocclusion.

[See Dentoalveolar compensation]

Decompression

Force delivered by a component of an appliance that has been activated previously by elastically

constricting its characteristic shape (e.g. the compression of an open coil spring).

[Compare with Traction]

Decompression of a joint (Unloading of a joint)

Removal or release of pressure (stress) from a joint.

Deep bite

Excessive overbite. Type of malocclusion in which the vertical overlap of the anterior teeth is

increased beyond the ideal relationship; it is frequently associated with decreased vertical facial

dimensions. Impingement of the mandibular incisors in the mucosa palatal to the maxillary incisors

commonly is seen in malocclusions with extremely deep bite. As well, in some Class II, Division 2

malocclusions with minimal overjet the retroclined maxillary incisors may impinge in the keratinized

tissue labial to the mandibular incisors, causing gingival recession.

Deflection

A bending type of deformation, such as the deviation from the straight line (curving or arching) of a

beam under an applied load.

Deflection (of the mandible on opening)

Eccentric displacement of the mandible away from the midsagittal plane on mouth opening, without

return to the centered position upon full opening.

[Compare with Deviation (of the mandible on opening)]

Deformable body

A body that changes its shape when subjected to external forces, as opposed to a rigid body (an

ideal concept).

Deformation

A change in geometry (size and/or shape) of a body produced by the application of a mechanical

force: an adaptive process of materials to stress.

SUBTERMS:

Deformation

• Elastic deformation

A temporary change of shape brought about on a body by the application of a mechanical force,

within the elastic limit of the material from which the body is made. Upon removal of the deforming

force there is full recovery to the original configuration, as the atoms in the crystalline structure of

the body that were temporarily displaced resume their original position.

Deformation

• Permanent (Plastic, Inelastic) deformation

A permanent change of shape or dimension brought about on a body by a mechanical force that

exceeds the proportional limit of the material from which the body is made. The material will not

recover its original shape on removal of the deforming force, as a permanent change has occurred

in its crystalline structure.

Deformable body

A body that changes its shape when subjected to external forces, as opposed to a rigid body (an

ideal concept).

Degeneration

Deterioration of soft tissue, cartilage and bone into a tissue of inferior quality. When referring to a

complex structure such as a joint or articulation, it describes the failure to adapt to loading forces,

resulting in impaired function.

Deglutition

[See Swallow]

Degrees of freedom

The number of independent coordinates required to specify the complete position of a body. For

example, a body pivoting about a fixed axis has a single degree of freedom, reflecting the fact that

motion is permitted in only one plane. A rigid body in space (such as a tooth) has six degrees of

freedom, corresponding to its six possible motions: linear motion along the x-, y- and z- axes and

angular motion (rotation) about the three axes x-, y- and z-.

Dehiscence

An isolated vertical soft tissue and bony defect, exposing a part of the root of a tooth. It occurs

more commonly on the vestibular aspect of anterior teeth, especially mandibular incisors.

Delaire face mask

[See Appliance, Face mask (Reverse-pull headgear, Protraction headgear, Face frame)]

Dens evaginatus (Leong’s premolar)

A dental anomaly characterized by a supernumerary cusp on the occlusal aspect of an otherwise

normal tooth. It is thought to be the reverse of dens invaginatus and occurs in approximately 2% of

the Asian and Native American population. Histologically, the extra cusp is composed of a thin

pulpal extension surrounded by dentin and enamel. Dens evaginatus occurs most commonly in

premolars as an extra cusp which may be large enough to cause occlusal interferences. Any

attempt at occlusal equilibration, or simply occlusal wear or trauma, can result in pulpal

degeneration and periapical inflammation. The teeth with the anomaly typically are caries-free, and

may have an immature root. If extractions are indicated as part of the orthodontic treatment plan,

the premolars with the anomaly typically are given preference, as endodontic treatment may have

a poor prognosis due to the immature root or arrested root formation of these teeth.

De-impaction

Any process aiming at bringing an impacted tooth into the dental arch.

Dens invaginatus (Dens in dente)

A developmental defect resulting in invagination of a pit or fissure in the crown, before it is calcified,

into the future pulp space, giving the appearance of “a tooth within a tooth”. The invagination is

partially or completely lined with enamel and may extend all the way to the apex. Dens invaginatus

is occasionally seen in (peg-shaped) maxillary lateral incisors. In the presence of caries an acute

or chronic pulpal inflammation could rapidly occur, and thus these teeth should be preferred when

extractions are indicated, especially since their crowns and/or roots typically are malformed.

Dental compensation

[See Dentoalveolar compensation]

Dental mobility

[See Tooth mobility]

Dentinogenesis imperfecta

A hereditary disorder that can appear in several different types, which affects the development of

dentin and may be accompanied by a similar disturbance of the bones. Clinically the teeth may

appear opalescent or gray with bulbous crowns; attrition is rapid and enamel chips easily. Usually,

extensive prosthetic restorations are indicated.

Dentition

The complement of teeth.

SUBTERMS:

Dentition

• Deciduous dentition (Primary dentition)

The deciduous teeth.

Dentition

• Mixed dentition (Transitional dentition)

The dentition in the period spanning from the eruption of the first permanent tooth until the

shedding of the last deciduous tooth, during which both permanent and deciduous teeth are

present in the mouth.

Dentition

• Permanent dentition

The permanent teeth.

Dentoalveolar

Concerning the teeth and the alveolar bone. [The term often is used to indicate a correction that is

achieved by adaptation of the teeth and alveolar processes, without any skeletal effect. ]

Dentoalveolar compensation

The natural adaptive changes of the dentition, which tend to mask the severity of any skeletal

discrepancy that may be present between the maxilla and mandible (e.g. proclination of the

maxillary incisors and retroclination of the mandibular incisors resulting in a positive overjet in a

skeletal Class III malocclusion).

Dento-periosteal fibers

[See Gingival fibers]

Depression of the mandible

[See Arthrokinetics of the TMJ]

Derotation of molars

The term usually is meant to describe the procedure aimed at correction of the mesiolingual

rotation (about the large palatal root) of the maxillary first permanent molars, a common finding in

Class II malocclusions. Derotation of molars can be achieved with various treatment modalities,

e.g. by using a transpalatal arch.

Development

In the normal youngster, growth and development are processes that work in concert with one

another and actually are inseparable. It is helpful, however in understanding the contributions that

each one makes to the progress of individual change to divide them arbitrarily into their actual

areas of manifestation. Therefore development is considered the area of differentiation and

maturation that leads to increase in skill, more comprehensive function and sexual dimorphism in

progress towards maturity.

Growth, arbitrarily separated from development, relates to the changes in physical size, which may

be measured in increments of weight or linear change.

Through this artificial separation of these two elements one is able to note individual changes that

may exhibit an increase in size but be lacking in maturational evolution, whereas, on the other

hand, one may observe conditions in which the natural maturational processes toward adulthood

take place without a significant or measurable increase in size.

[See Growth]

Developmental guidance

An orthodontic and orthopedic effort to influence changes in the dentition, growth of the jaws, and

functional conditions with the objective of guiding abnormal development into a normal situation.

This generally requires a combination of carefully timed interceptive procedures or appliance

therapies based on supervisory examinations, involving radiographic and other diagnostic records

at various stages of development. This may be required from the earliest date of detection of a

developing malformation until the craniofacial skeleton is mature. [Modified from the AAO Glossary

of Dentofacial Orthopedic Terms, 1993.]

Deviation (of the mandible on opening)

Eccentric displacement of the mandible on mouth opening, away from the midsagittal plane, with

correction to the centered position upon full opening.

[Compare with Deflection (of the mandible on opening)]

Diagnostic setup (Kesling setup)

A laboratory procedure first described by H. D. Kesling. The teeth are cut from a duplicate study

model and realigned in the desired position using wax to evaluate the predicted occlusal result of a

specific orthodontic treatment plan or diagnose a tooth size discrepancy.

Diastema

A space between two adjacent teeth in the same arch.

[See Midline diastema]

Differential force theory

A theory proposed by P. R. Begg (1956), which constitutes the basic philosophy behind the Begg

technique. According to this, the force applied for space closure should be light enough to exceed

the “critical threshold of stress” necessary for tooth movement on the active segment of teeth, but

still be below the “critical stress threshold” for movement of the anchorage segment, so that no

anchorage loss occurs. The area of root surface over which the force is dissipated is a determining

factor for the amount of movement that will be experienced by a specific tooth (or segment of

teeth). Incorporating more teeth in the anchorage segment increases the root surface area,

reducing the stress in the periodontal ligament for the same magnitude of force.

According to the same theory, it is hypothesized that there is a certain level of stress in the

periodontal ligament beyond which hyalinization will occur. If a force of such a high magnitude is

used during space closure, there may be no or little movement of the active segment because of

hyalinization, but the resulting stress over the larger root surface area of the anchorage segment

could exceed its threshold for tooth movement, resulting in anchorage loss.

[See Appliance, Begg appliance (Light-wire appliance)]

Differentiation

The change from generalized cells or tissues to more specialized ones during development. It is a

change in quality or kind.

Digitization (of radiographs)

Conversion of landmarks on a radiograph or tracing to numerical values on a two- (or three-)

dimensional coordinate system, usually for the purpose of computerized cephalometric analysis.

The process allows for automatic measurement of landmark relationships.

[See Computerized cephalometrics]

Dilaceration

A developmental distortion of the form of a tooth, whereby the root or the apex forms an angle with

the long axis of the tooth (i.e. the tooth appears sharply “curved” or “bent”). Dilacerations can occur

as a result of trauma or mechanical impedance of tooth eruption. In the latter situation, the

developing apical part of the erupting tooth is forced to move in a direction opposite to that of

eruption, inducing resorption of bone in an area where it usually does not occur. Teeth with severe

dilaceration may be impossible to align in an ideal way and in severe cases extraction may be

indicated.

Dillon dimple

A latching indentation on the palatal

wall of a sheath, in which the doubled

end of the palatal arch fits tightly,

providing a “lock” to retain the palatal

arch in position. Named after its

innovator, C. F. S. Dillon.

[See Sheath]

Direction (Line of action)

One of the four characteristics of vectorial quantities (the other three are point of application, sense

and magnitude). Direction refers to the line on which the specific vector lies. It can be defined by

specifying the angular deviation (in degrees) of the vector from a given reference line or axis.

Disc-condyle complex

The condyle and its disc articulation, which functions as a simple hinge joint.

Disc displacement (Disc derangement, Disc prolapse, Disc interference disorder)

The dislocation of the articular disc of the temporomandibular joint from its physiologic position on

the head of the condyle. It most often occurs in an anteromedial direction. Disc displacements are

a common etiologic factor for joint sounds (clicks or pops) and often result in an unusual opening

and closing trajectory of the mandible, or in limitation of maximal opening.

SUBTERMS:

Disc displacement (Disc derangement, Disc prolapse, Disc interference disorder)

• Disc displacement with reduction

A situation in which the articular disc of the temporomandibular joint is displaced (usually in an

anteromedial direction) when the mandible is in the intercuspal position, but resumes a normal

anatomic relationship with the condyle (is “re-captured” by the condyle) on mandibular movement.

[See Clicking, Reciprocal clicking]

Disc displacement (Disc derangement, Disc prolapse, Disc interference disorder)

• Disc displacement without reduction

A situation in which the articular disc of the temporomandibular joint is displaced when the

mandible is at the intercuspal position and does not resume a physiologic anatomic relationship

with the condyle upon mandibular movement.

Disc locking

[See Disc displacement (Disc derangement, Disc prolapse, Disc interference disorder), Disc

displacement without reduction]

Disc perforation

A circumscribed tear in the articular disc of the TMJ, usually as a result of a degenerative thinning

in its central portion, permitting communication between the superior and inferior joint spaces and

direct contact between the articular surfaces of the condyle and temporal bone.

Disc-repositioning surgery

Arthrotomy of the TMJ with the purpose of reestablishing a physiologic anatomic disc-to-condyle

relationship.

[See Plication]

Discectomy (Meniscectomy)

Surgical removal of the articular disc of a joint.

“Dished-in” profile

A profile with severely reduced lip prominence. The term originally referred to the side effect of

early orthodontic treatment attempts to “camouflage” an underlying skeletal discrepancy (usually a

Class II malocclusion) by removing premolar teeth (a routine treatment method up until the 1970’s).

More recently, the advancement of orthognathic surgical techniques as well as the rise in

popularity of growth modification in North America have led to increased awareness of the esthetic

facial changes brought upon by various orthodontic treatment options.

[See Camouflage orthodontic treatment]

Dislocation of the condyle (Luxation, Open lock)

Non-reducible displacement of the mandibular condyle in an anterior direction, past the articular

eminence.

Disruption

A morphological defect of an organ, part of an organ, or a larger region of the body resulting from a

breakdown of, or interference with, an originally normal developmental process. An example is an

amputation of a digit in utero, or a atypical facial cleft caused by an amniotic band.

[Compare with Malformation]

[Compare with Deformity]

Dissociation, Point of

[See Burstone’s geometry classes, Geometry IV]

Distal

Away from a point of reference. In the case of teeth, away from the dental midline, along the dental

arch (in a right or left direction when referring to anterior teeth, or in a posterior direction when

referring to posterior teeth).

[Compare with Mesial]

Dissociation, Point of

[See Burstone’s geometry classes, Geometry IV]

Discrepancy

Inconsistency, incongruency or disagreement.

[See Midline discrepancy (Midline shift, Midline deviation)]

[See Tooth size discrepancy (Bolton discrepancy)]

[See Arch length discrepancy]

Disclusion (Disocclusion, Disarticulation)

Separation of the mandible from the maxilla through tooth-guided contacts during mandibular

excursive movements.

Distal tipping

Tipping of the crown of a tooth in the distal direction.

Distalization

The movement of teeth to the distal.

SUBTERMS:

Distalization

• Molar distalization

A treatment procedure designed to provide space for alignment of teeth and achievement of ideal

overjet and overbite, as an alternative to premolar extraction. The procedure can be performed

with or without extraction of the second molars. Various appliances are designed for this purpose,

including the ACCO and pendulum appliances, appliances with compressed coils or repelling

magnets, and extraoral traction appliances.

Distortion

Deviation of a radiographic image from the true outline or shape of the object or structure.

Distoversion

Distal tipping (angulation) of a tooth or group of teeth.

Distraction (of the condyle)

Separation or forced downward movement of the condyle from the articular fossa.

Distraction (of the mandible)

[See Arthrokinetics of the TMJ]

Distraction osteogenesis (Distraction osteosynthesis, Ilizarov technique, Callus distraction,

Callotasis)

A technique for lengthening of long bones of the extremities attributed to G. A. Ilizarov, although it

was first described by A. Codivilla in 1905. Other applications of the method in orthopedics are in

the treatment of fractures or malunions. It also is used in the craniofacial area for the correction of

bone defects in the skull and for the treatment of hypoplasias of the maxilla or the mandible. It

involves a corticotomy followed by gradual distraction of the segments, with formation of new bone

(“regenerate” bone) between them. The distraction can be performed by an extraoral or an

intraoral device containing some type of screw that can be wound gradually, in a manner similar to

rapid maxillary expansion.

The advantage of the technique is that it allows simultaneous expansion of the surrounding soft

tissue envelope and generates bone without the need for a graft. The disadvantages include the

facial scars and inconvenience in the case of an extra-oral procedure, as well as the lack of

adequate control of the direction of movement (mainly in the case of the proximal segments in

mandibular distraction). Furthermore, little is known about the potential implications of a

mandibular distraction procedure on the TMJs.

Dolichocephalic

Anthropometric term denoting an individual with a long, narrow cranial

form; having a cephalic index smaller than 76. Severe dolichocephaly may

result from premature synostosis of the sagittal suture.

[Compare with Brachycephalic]

Donor site

The area of the body from which a graft is taken.

[Compare with Recipient site (Host site)]

Down-fracture (of the maxilla)

An orthognathic procedure in which all or part of the maxillary alveolar and basal bone is separated

from the more superior elements of the midfacial skeleton. The procedure usually involves a Le

Fort I or sometimes a Le Fort II osteotomy.

Down-fracture (of the maxilla)

An orthognathic procedure in which all or part of the maxillary alveolar and basal bone is separated

from the more superior elements of the midfacial skeleton. The procedure usually involves a Le

Fort I or sometimes a Le Fort II osteotomy.

Drift (of bones)

A term established by D. H. Enlow to signify the movement of a bony structure in relation to

adjacent structures, caused by simultaneous bone apposition and resorption processes on

opposing surfaces.

[See Cortical drift]

Drift (of teeth)

Spontaneous movement of teeth without the direct application of orthodontic forces.

SUBTERMS:

Drift (of teeth)

• Distal drift

1. The occasional tendency of teeth mesial to an edentulous space to move distally into it.

2. The spontaneous distal movement of teeth associated with active distalization of adjacent teeth

(e.g. the distal drift of the maxillary premolars following molar distalization. )

Drift (of teeth)

• Mesial drift (Mesial migration, Approximal drift)

A term applied to either a natural developmental phenomenon whereby the posterior teeth

continually move in a mesial direction as a result of interproximal surface wear, or to the tendency

of teeth distal to an edentulous space to move mesially into it.

[See Physiologic tooth movement, Post-eruptive tooth movement]

Dual bite

A situation in which a patient has two positions of habitual occlusion (intercuspal position) that

differ by more than 2 mm.

Ductility

The ability of a material to sustain a large permanent deformation under a tensile load without

rupture. A metal that can be drawn readily into a wire is said to be ductile. Ductility is heavily

dependent on strength.

[Compare with Malleability]

Dynamic friction

[See Friction]

Dynamics

The branch of mechanics that considers forces on bodies which are being accelerated positively or

negatively. Dynamics plays a relatively minor role in orthodontics, where accelerations or

decelerations are practically negligible. Dynamics is comprised further of “kinematics” and

“kinetics.”

SUBTERMS:

Kinematics

Kinetics

Dysfunction

Abnormal, impaired or altered function.

Dysostosis

A pathological condition characterized by defective ossification, especially involving fetal cartilages.

Dysplasia

Abnormality of development.

Eccentric extraoral traction

[See Headgear, Asymmetric headgear (Eccentric headgear)]

Ectopic eruption

The eruption of a tooth in an abnormal position. In the

permanent dentition, this condition occurs most often in

maxillary first molars and maxillary or mandibular incisors and

canines. A typical example is the eruption of a maxillary first

permanent molar in a mesial position under the distal part of the

crown of the adjacent second deciduous molar.

Edge bevel

Rounding of the edges of orthodontic wires with square or

rectangular cross section, as part of their manufacturing process. A certain amount of edge

beveling is desirable to prevent discomfort of the soft tissues and to facilitate engagement of the

archwire in the bracket slot. If the amount of rounding is excessive, it can be of clinical significance

for control of the buccolingual inclination of the teeth provided by the archwire-bracket combination.

Edge-to-edge bite (End-to-end bite)

A situation in which the maxillary and mandibular incisors meet with contact of their incisal edges.

This type of occlusal relationship is most commonly seen in malocclusions with a Class III

component.

Edgewise bracket

[See Appliance, Edgewise appliance (Standard edgewise)]

Elastic limit

The maximum deformation that a body (e.g. orthodontic wire or appliance part) can undergo before

permanent (plastic) deformation occurs. Precise experimental distinction between the proportional

limit and the elastic limit is difficult, and for all practical purposes they can be considered

indistinguishable.

Elastic material

A material that undergoes no permanent deformation (fully recovers its original shape), after it has

been subjected to a certain stress.

[See Elasticity]

Elastic modulus (E)

S. Modulus of elasticity.

[See Modulus of elasticity E (Young’s modulus of elasticity, E-modulus)]

Elastic range

The strain up to which no plastic deformation occurs. [On a stress/strain diagram, the horizontal

(strain) coordinate of the elastic limit. ]

Elastic strength

The load (stress) up to which no plastic deformation occurs. [On a stress/strain diagram, the

vertical (stress) coordinate of the elastic limit. ]

Elasticity

The property of a material to exhibit reversible deformation under load (i.e. changing its shape

without undergoing permanent deformation). An elastic material regains its original shape when the

load is removed.

[See Modulus of elasticity E (Young’s modulus of elasticity, E-modulus)]

Elastomer (Elastomeric material)

A polymer (soft, rubber-like material) containing large molecules with weak interaction among

them, cross-linked at certain points to form a three-dimensional structure. Elastomers may be

stretched when their chains are pulled apart and uncoiled, but on removal of the stress they snap

back to their relaxed state and practically their original dimensions.

Elastomeric modules

Different configurations of elastomeric material in the shape of small circles (ligatures), chains or

threads, with various orthodontic applications.

SUBTERMS:

Elastomeric modules

• Elastomeric chain

A chain of connected elastomeric rings used as a force-producing mechanism for orthodontic tooth

movement. Elastomeric chains can be open or closed, depending on whether or not there is a

distance between the rings at its passive state.

Elastomeric modules

• Elastomeric ligature (“Donut,” “O-ring”)

Small round band of elastomeric material that is stretched around the tie-wings of an orthodontic

bracket for the purpose of preventing disengagement of an archwire or auxiliary from a bracket

slot.

Elastomeric modules

• Elastomeric thread

A stretchable thread made of elastomeric material available in various cross-sectional thicknesses.

It is used as a force-producing mechanism for tooth movement.

Electromyography (EMG)

Detection and recording of changes in the intrinsic electric potentials of skeletal muscles, by means

of surface (“surface EMG”) or needle electrodes (“deep EMG”).

Elevation of the mandible

[See Arthrokinetics of the TMJ]

Elevator masticatory muscles

Paired masseter, medial pterygoid and temporalis muscles, the main action of which is to elevate

the mandible.

Elgiloy wire

[See Cobalt-chromium alloy (Co-Cr, Cobalt-chromium-nickel alloy, Chromium-cobalt alloy)]

Elongation

Overall deformation (elastic and plastic) of a material as a result of tensile force application.

Emergence

The stage of the eruption process involving the initial penetration of the gingiva by the erupting

tooth and its first appearance in the oral cavity. The term sometimes is used to signify breaking

through the alveolar bone during eruption.

Eminectomy

Surgical removal of part of the articular eminence of the temporomandibular joint or recontouring of

its surface. Eminectomy occasionally is contemplated as a treatment modality for some types of

TMD.

Emission scintigraphy (Planar scintigraphy)

Two-dimensional imaging process in which the area of interest is scanned with a gamma camera 2

to 4 hours after the administration of a radio-labeled material. When bone is to be assessed,

technetium 99m is the radioisotope of choice due to its tendency to accumulate in areas of

osteoblastic activity. Increased uptake of the radioisotope in the tissue scanned is indi-cative of

increased cellular activity (as for instance an active area of growth in children, neoplasia or

inflammation).

“En masse” retraction

Retraction of a number of teeth (usually the four incisors, or all six anterior teeth) together, as a

group.

“End-on”

Anteroposterior deviation of an occlusal relationship from the ideal (Angle Class I) by one half cusp

(half the mesiodistal width of a premolar). The term can be used for either Class II or Class III

occlusal relationships.

Enucleation

Surgical removal of a bone cyst together with its lining, or of a

tooth that has not yet emerged into the oral cavity. Enucleation of

premolars sometimes is contemplated as part of a serial extraction

protocol, but depending on the technique and the situation, it

carries a chance of creat-ing a residual bony defect at the site.

Enucleation of the mandibular third molars sometimes is

advocated as a means to increase the available space in a

severely crowded mandibular arch.

Envelope of discrepancy

A diagram devised by W. R. Proffit and J. L. Ackerman to illustrate

graphically the amount of change that can be produced by

orthodontic tooth movement alone (inner envelope), orthodontic

tooth movement combined with growth modification (middle

envelope), and orthognathic surgery (outer envelope) in the

sagittal and vertical planes of space, based on the authors’ clinical

judgment.

Envelope of motion

The three-dimensional space circumscribed by border mandibular movements and by the incisal

and occlusal contacts of a given point of the mandible.

Epicanthal folds

Excess skin and subcutaneous tissue lateral to the nasal bridge, concealing the medial canthi.

Epicanthal folds may be a result of racial phenotype (common in Asians), nasal bridge hypoplasia,

orbital hypotelorism, surgery, or trauma.

Epidemiology

The science concerned with the frequency and distribution of a disease or state. Its focus is on the

total population rather than the individual, and its purpose is disease classification and prevention.

Equilibrium

The state of a body (i.e. a tooth or dental segment) or a system when the sum of all the forces and

the sum of all the moments acting on it is equal to zero. The assumption that a system is in static

equilibrium at a given point is the basis for static analysis of all mechanical systems.

Eruption path

The path traversed by a tooth, through surrounding tissues, from the initiation of its eruptive

movement until its arrival at its functional position in the mouth.

Eruption theories

[See Tooth eruption mechanisms]

Etiologic factors

Factors that may be involved in, or cause the development of a disease or condition.

Euryprosopic

Having a wide and short facial form.

Excursion of the mandible

Movement of the mandible away from the median position or the intercuspal occlusion position.

[See Arthrokinetics of the TMJ]

SUBTERMS:

Excursion of the mandible

• Lateral excursion

Right or left move-ment of the mandible away from the midsagittal plane (to the side).

[Compare with Mediotrusion]

[Compare with Laterotrusion]

Excursion of the mandible

• Protrusive excursion

Anterior movement of the mandible from the intercuspal position.

Exfoliation (Shedding)

Physiological loss of a deciduous tooth prior to the eruption of its successor.

Exostosis

A hyperplastic osseous overgrowth projecting outward from the surface of a bone (e.g. torus

palatinus, torus mandibularis).

Expansion

Enlargement; increase in volume, surface or extent. The term often is used to refer to the process

of widening of the dental arches.

SUBTERMS:

Expansion

• Asymmetric expansion

At the level of the dental arch, asymmetric expansion can be attempted by pitting the segment of

teeth that primarily needs to be expanded against an anchorage segment of increased size. In

practice this is done by incorporating more teeth or a larger palatal surface in the anchorage

segment (anchorage reinforcement) and/or by expanding the teeth on the active segment one at a

time. In any case, some buccal displacement of the teeth in the anchorage segment will be

observed as a side effect.

Expansion

• Rapid maxillary (palatal) expansion (RME, RPE)

A method of increasing the maxillary arch width by opening the midpalatal suture, thereby

achieving some degree of skeletal expansion. The method, which was popularized by A. J. Haas,

involves the use of a fixed (cemented or bonded) maxillary appliance of several possible designs,

using an expansion screw of the same type as in the Hyrax appliance. The screw typically is

activated by at least 0.20 to 0.25 mm (one quarter turn) daily and may produce a force as high as

100 N (10 kg or 20 lb). Expansion usually is continued until the lingual cusps of the maxillary

posterior teeth come into contact with the lingual inclines of the buccal cusps of the mandibular

posterior teeth. A diastema commonly

appears between the central incisors

as the midpalatal suture separates,

which closes spontaneously in the few

weeks following the procedure due to

the pull of the supracrestal fibers.

When active expansion has been

completed, a 3- to 5-month retention

period is recommended with the

appliance in place. It is advocated that

this type of expansion may have more

of a skeletal effect and may minimize

the amount of dental tipping, which is

a common (usually undesirable) side

effect of orthodontic arch expansion.

[See Appliance, Haas appliance

(Haas rapid maxillary expansion

appliance, Haas palatal separator)]

[See Appliance, Hyrax appliance

(Hygienic rapid palatal expander)]

[See Appliance, Expansion appliance]

[See Expansion, Slow maxillary (palatal) expansion (SME or SPE)]

[See Expansion, Surgically assisted rapid maxillary expansion]

Expansion

• Slow maxillary (palatal) expansion (SME or SPE)

A method of increasing the maxillary dental arch width by using a maxillary removable appliance

that normally carries an expansion screw in the midline. The appliance commonly is activated by

0.20 to 0.50 mm (one or two quarter turns) per week and is advocated in patients that require

limited expansion, since it produces expansion mainly

by dental tipping.

[See Appliance, Expansion appliance]

[See Appliance, Haas appliance (Haas rapid maxillary

expansion appliance, Haas palatal separator)]

[See Appliance, Hyrax appliance (Hygienic rapid palatal expander)]

[See Expansion, Rapid maxillary (palatal) expansion (RME, RPE)]

[See Expansion, Surgically assisted rapid maxillary expansion]

Expansion

• Surgically assisted rapid maxillary expansion

In adult patients in whom the midpalatal suture is fused, the resistance to suture separation can be

decreased by bilateral osteotomies of the lateral maxillary buttress, with or without a midpalatal

osteotomy. After the lateral osteotomies are performed, the screw is turned a few times in the

operating room to achieve separation of the suture and is subsequently turned back. The patient

can begin activating the appliance the following day. If correction of a unilateral maxillary palatal

crossbite is necessary, the lateral osteotomy can be made only on one side, thus creating a

differential anchorage situation.

[See Appliance, Expansion appliance]

[See Appliance, Haas appliance (Haas rapid maxillary expansion appliance, Haas palatal

separator)]

[See Appliance, Hyrax appliance (Hygienic rapid palatal expander)]

[See Expansion, Rapid maxillary (palatal) expansion (RME, RPE)]

[See Expansion, Slow maxillary (palatal) expansion (SME or SPE)]

Expansion screw (Jackscrew or Glenn Ross screw)

A mechanical device incorporated in a removable or fixed appliance used to enlarge the dental

arch, usually in the transverse dimension. Expansion screws also can be used as part of a

removable appliance for individual tooth movement or for incisor proclination, as well as in a bone

distraction device for distraction osteogenesis.

Expansion screw key

An instrument used to turn the jackscrew of an expansion appliance.

Extraction

Removal of teeth.

Extraction therapy

Orthodontic treatment requiring the extraction of one or more permanent teeth.

Extraction vs. non-extraction debate

A long-standing controversial issue in orthodontics, over whether or not extraction of permanent

teeth is advisable and necessary as part of orthodontic treatment. This debate started in the early

1900s between E. H. Angle and his former student C. S. Case, and has been continuing, on and

off, ever since. Angle’s thesis was that “there shall be a full complement of teeth and each tooth

shall be made to occupy its normal position. ” He believed in the universal applicability of the

“normal occlusion theory” in which every tooth must have its ideal position and serve its specific

function. Case, on the other hand, defended the judicious use of extraction as a practical

procedure. Following his own precisely set rules, he claimed to extract in only 12% to 15% of his

cases.

The climax of this conflict was a fierce debate in 1911 between Case and M. Dewey (who

represented Angle’s views) at the annual meeting of the National Dental Association (former name

of the ADA). It took many years after this episode for the problem to become a matter of calm and

objective evaluation and respectful appreciation of various points of view, each of which has made

its contribution to orthodontics.

Extraoral traction

The use of extraoral anchorage to apply forces to the dentition or the jaws.

Eyelet

A small orthodontic attachment in the shape of a closed helix soldered onto a bonding base or

welded directly on an orthodontic band. Eyelets mainly are used as handles for elastic traction.

[See Attachment, Orthodontic]

Facebow (of an articulator)

An instrument used to enable the mounting of dental casts on an articulator. The facebow is used

to record the relationship of the patient’s maxillary arch with respect to the opening axis of the

temporomandibular joint and the Frankfort horizontal plane and subsequently to transfer this

relationship to the articulator.

Facebow (of a headgear)

The rigid wire component of a headgear used to transfer extraoral forces to the maxilla (or

occasionally the mandible) and the teeth. A facebow consists of two coplanar metal bows, brazed

or (laser-)welded at the midline. The smaller of the two bows (inner bow) inserts intraorally into

specially manufactured tubes that usually are attached to the bands of the maxillary first molars, or

incorporated into the acrylic of a removable orthodontic appliance. The hooks at both ends of the

larger, outer bow attach to the headgear strap, which produces an extraoral force of variable

direction, depending on the type of headgear (cervical, occipital, etc. ).

Facial asymmetry

A term denoting a dissimilarity or disproportionality between the right and left sides of the face,

usually meant as an undesirable lack of balance. The asymmetry can be due to the underlying

facial skeleton or to the soft tissue drape.

Facial concavity

A term commonly used in profile analysis. A concave facial profile is one in which an inwardly

rounded curve is formed from the forehead to the lips to the chin, as often associated with a Class

III malocclusion (Downs’ angle of convexity (NAPg) has anegative value). [Modified from the AAO

Glossary of Dentofacial Orthopedic Terms, 1993.]

Facial esthetics

A term pertaining to the beauty and appeal of the face. It is an entity which carries a great deal of

subjectivity and is impossible to describe and quantify accurately, but it generally is believed that

symmetry, balance and proportion play a major role.

Facial form

The term usually refers to the configuration (shape) of the face from an anterior (frontal) view.

Facial growth

The physiological process of enlargement and change of the facial skeleton and overlying soft

tissues over time.

Facial pattern

A term generally used to describe the facial configuration, or the directional tendency of facial

growth, from a lateral (profile) view.

Facial type

1. When referring to the lateral (profile) view the facial type can be described as: retrognathic

(opisthognathic), mesognathic (orthognathic) or prognathic.

2. When referring to the frontal view, the three facial type options are: brachycephalic or

euryprosopic (wide and short), mesocephalic or mesoprosopic (average) and dolichocephalic or

leptoprosopic (long and narrow).

Facies

A distinctive facial appearance characteristic of certain disorders (i.e. Down syndrome).

Fatigue

Degradation of materials subjected to a number of load changes. Tendency to fracture under cyclic

stresses.

Fatigue failure

The phenomenon in which stress values well below the ultimate tensile stress of a material can

produce a premature fracture because microscopic flaws grow slowly over many cycles of stress.

Depending on the type of loading situation, a material can exhibit either static or dynamic fatigue

failure.

SUBTERMS:

Fatigue failure

• Dynamic fatigue failure

Most prosthetic and restoration fractures develop progressively over many cycles of periodic

occlusal loading after initiation of a crack from a critical flaw and subsequently by propagation of

the crack until a sudden fracture occurs.

Fatigue failure

• Static fatigue failure

Fracture of a material attributed to the interaction of a constantly applied stress with structural flaws

over time.

Fenestration

Round or oval perforation of the buccal or lingual cortical plate of the alveolar process over the root

of a tooth, which does not involve the alveolar crest.

Ferrite

One of the three possible lattice structures of iron, on which the different classes of steels also are

based.

The body-centered cubic (BCC) structure that pure iron has at room temperature. This phase is

stable in temperatures as high as 912° C.

[See Martensite]

[See Austenite]

FGF

[See Growth factors]

Fibrosis

Formation of fibrous connective tissue to replace normal tissue lost through injury or infection.

Figure-eight ligature

A stainless steel ligature tied around two or more brackets on teeth of the same arch, so that its

two ends cross over each other at the interproximal spaces, forming a figure of eight. It is used to

prevent closed spaces from reopening and to consolidate teeth together, forming a multi-tooth

anchorage segment.

[See Laceback (Lace)]

Finishing

The final stage of fixed appliance orthodontic treatment, during which final detailing takes place to

idealize individual tooth position.

Finite element analysis

An engineering technique of stress analysis, the basic concept of which is the visualization of a

structure as an assemblage of a finite number of discrete structural elements connected at a finite

number of points. The finite elements are formed by figuratively “cutting the original structure into

segments. ” For two-dimensional applications, triangles of various sizes and shapes usually are

the finite elements of choice. Each element retains the mechanical characteristics of the original

structure. Some characteristics of the material have to be specified (depending on whether it is

isotropic or not).

Additionally, a numbering system is required to identify the elements and their connecting points,

called “nodes. ” A coordinate system also must be established to identify uniquely the location of

the nodal points. A large number of simultaneous linear equations are computer-generated, which

establishes compatibility within each element.

The technique has some very distinct advantages as a research tool, among which is the ability to

obtain an estimate of the stresses throughout the structure under consideration. Further, the

inclusion of any type of anisotropy and inhomogeneity conceptually is possible by inserting the

appropriate distribution of material properties at the nodes of the elements. However, when it is

applied to structures such as a tooth, there are some practical limitations, as relatively little is

known about the mechanical properties of dental and especially periodontal tissues.

First transitional period

The period during which the deciduous maxillary and mandibular incisors are replaced by the

permanent incisors (starting from the time of exfoliation of the first deciduous incisor, or from the

time of emergence of the first permanent molar in the mouth, and ending with the eruption of the

last incisor).

Fistula

An abnormal passage or communication between two anatomical cavities, or between an

anatomical cavity and the external body surface.

SUBTERMS:

Fistula

• Oronasal fistula

A fistula connecting the nasal and oral cavities, a common finding in patients with a history of cleft

lip and palate.

Fixation, Surgical

Immobilization of bones following a fracture or a surgical procedure to facilitate and accelerate the

healing process.

SUBTERMS:

Fixation, Surgical

• Intermaxillary fixation (IMF, Maxillo-mandibular fixation)

Traditional method of fixation utilizing stainless steel wires between the maxillary and mandibular

teeth to immobilize the mandible. The wires can be ligated on special hooks soldered or crimped

on the orthodontic archwires, or on arch bars if no fixedorthodontic appliances are present. Typical

duration of IMF is between 6 and 8 weeks, during which the patient is fed liquid diet through the

retromolar area. Intermaxillary fixation is sometimes combined with RIF, in which case its duration

is shorter.

Fixation, Surgical

• Rigid internal fixation (RIF)

Fixation technique in which bony segments are

immobilized by use of small titanium bone plates (fixation

plates) and/or screws across the osteotomy or fracture line.

Bone plates must be contoured carefully to adapt to the

bony surfaces prior to their application. By directly and

rigidly fixing bony segments together, the period of

intermaxillary fixation can be reduced or completely

eliminated after surgery. Rigid internal fixation occasionally

is combined with IMF following orthognathic surgery.

Fixation plate

Titanium plates of various configurations that carry holes

for placement of osseous screws, used for rigid internal

fixation.

Fixation screws

Titanium osseous screws (2.0 to 3.5 mm in diameter or larger) used for stabilization of the bone

plates in rigid internal fixation.

SUBTERMS:

Fixation screws

• Bicortical (Position) screw

Fully threaded screw that binds in both cortices of the two bony segments to which it is applied. As

the screw is tightened, no compression is possible because with the screw

threads engaging both segments, the distance between them is maintained.

Fixation screws

• Lag screw

Partially threaded screw (only has threads close to its tip) that is placed so that

its threads only bind the cortex of

the bony segment that lies farthest

away from the point of entry (i.e. the

medial/distal segment in the case of

a BSSO). The same size hole is

drilled in both segments. As the lag

screw is tightened, it engages the

medial/distal cortex but is free to

rotate in the lateral/proximal cortex,

which eventually produces compression of the

segments against each other.

[See Segment, Distal segment]

Fixture

A device that is firmly fastened in place in a mechanical sense, often used to secure other devices.

[In implantology the term commonly is used to denote the body of an osseointegrated dental

implant (i.e. the portion of the implant that is placed into the bone surgically). ]

Flange

A projecting rim of a removable orthodontic appliance, usually consisting of an acrylic extension of

its main body. Flanges commonly are used in functional appliances to dictate the desired

mandibular position. Vestibular and lingual flanges also serve to remove the pressures from the

surrounding soft tissues on the alveolar processes and teeth.

Flap

A loosened section of tissue, separated from its surrounding tissues except at its base.

SUBTERMS:

Flap

• Repositioned flap

A flap that is moved laterally, coronally or apically to a new position.

Flared teeth

A term used to indicate generalized labial tipping of the maxillary and/or mandibular anterior teeth,

or generalized buccal tipping of posterior teeth.

Flexibility

The property of certain materials that can undergo a larger strain or deformation under the

influence of a relatively small stress. The maximum flexibility is defined as the strain that occurs

when the material is stressed to its proportional limit. It is desirable that orthodontic wires and

springs have a high flexibility as well as a high value for the elastic limit (the stress above which a

wire will not recover its original shape).

Flexion-extension injury (Whiplash)

Sudden, exaggerated traumatic movement of joints through the extremes of their range of motion

with hyperflexion and then hyperextension, resulting in ligamentous sprain, muscular strain,

inflammation and subsequent reflex muscle splinting.

Flux

A substance that promotes the flow of solder over two metal parts by preventing the production of

oxides.

Force

The action of one body on another body that tends to change the state of rest or motion of the

latter. Orthodontics is based on the application of forces on teeth, under the influence of which

tooth movement can be achieved. Force is a vectorial quantity. This means that to adequately

describe a force, its magnitude, direction (line of action), sign (sense) and point of application have

to be defined. Forces are depicted in a coordinate system as vectors. The inclination of the vector

(or the angle between it and a specified reference line or axis) shows the direction of the force, the

length of the vector is proportional to the magnitude of the force, and the arrowhead denotes the

sense of the force. Force, though defined in Newtons, commonly (but, strictly speaking,

inaccurately) is reported in mass units (grams or ounces).

SUBTERMS:

Force

• Component forces

The constituent forces (two or more) of a certain force system.

Force

• Concurrent forces

Two or more forces that have the same point of application.

Force

• Constant force

A force whose magnitude

remains the same as at

the time of activation, for

a certain time interval

(e.g. from one patient visit

to the next). This is a

theoretical concept, as in

clinical reality a true

constant force cannot be

generated, but only

approximated.

Force

• Continuous force

A force that is maintained

between certain intervals

(e.g. does not drop to zero

between patient visits).

Force

• Coplanar forces

Two or more forces whose vectorial direction is on the same plane of space (regardless of their

sense).

Force

• Extraoral force

Force generated by (elastically) deforming an activating element of an orthodontic or orthopedic

appliance, located outside the oral cavity.

[See Anchorage, Extraoral anchorage]

Force

• Heavy force

A force of high magnitude.

[Compare with Force, Light force]

Force

• Intermittent force

A force whose magnitude abruptly drops to zero, as is the case when an orthodontic appliance is

removed by the patient and then resumes again, as when the appliance is re-inserted into the

mouth. Intermittent forces are produced by all appliances that require patient cooperation, such as

removable appliances, headgear, and elastics.

Force

• Interrupted force

A force whose magnitude declines to zero between activations. Most conventional orthodontic

force-producing mechanisms (with the exception of super-elastic wires and coils) generate

interrupted forces that sharply or smoothly decline as some tooth movement occurs, and require

re-activation after a certain time period.

Force

• “Jiggling” forces

Interrupted forces causing the teeth to move in one and then in another direction. Occlusal forces

are thought to be of the “jiggling” type, especially in cases of occlusal trauma. No clear-cut

pressure and tension zones can be identified histologically in affected teeth, but rather there is a

combination of pressure and tension.

[See “Jiggling” (of a tooth)]

[See Round-tripping]

Force

• Light force

A force of low magnitude. The term is used freely and arbitrarily, as there is neither universal

consensus nor sound scientific evidence regarding specific numeric values of magnitude. As well, it

is application-dependent: a force that is considered too high for a certain application may be ideal

for another.

Force

• Normal force (FN)

Any force acting in a direction perpendicular to the plane under consideration. In the case of friction

between two bodies, the force acting in a direction perpendicular to the contacting surfaces. The

magnitude of the normal force is directly proportional to the magnitude of the frictional force.

[See Frictional coefficient (μ)]

Force

• Orthodontic force

Force applied to teeth for the purpose of effecting tooth movement, generally having a magnitude

lower than an orthopedic force. There is no clear distinction between orthodontic and orthopedic

forces in terms of magnitude, but rather many widely variable, arbitrary suggestions exist in the

literature.

Force

• Orthopedic force

Force of higher magnitude in relation to an orthodontic force that, when delivered via the teeth for

12 to 16 hours a day, is supposed to produce a skeletal effect on the maxillofacial complex. Little

scientific evidence exists regarding the magnitude that a force should have in order to produce a

skeletal effect.

Force

• Reaction force

A force identical in magnitude and direction to the active force that is used for a certain orthodontic

application, but of opposite sense.

[See Newton’s laws, III. Law of action and reaction]

Force

• Resultant force

A single force that can substitute two or more individual

forces (component forces) acting on a body, and produce

the same effect on it. It can be expressed as the vector

sum of all component forces. The resultant force can be

determined by one of two methods: the geometric method

or the analytical (trigonometric) method. The analytical

method is preferred when the calculation of a resultant of

coplanar, non-concurrent forces is to be performed.

[See Force composition (Combination of forces)]

Force composition (Combination of forces)

Determination of a resultant force by combination of two or more component forces. When two

component forces have a common point of application, the resultant force is determined by

considering the two vectors to be sides of a parallelogram (geometric method). The resultant force

then is the diagonal of the parallelogram. Its length indicates the magnitude of the resultant force

on the same scale as the original forces. It is important to understand that the resultant force will

have the identical effect on movement of the tooth as the two separate forces. A tooth or a set of

teeth moves in response to the net effect of all forces. If the resultant force is the same, the

movement will be the same, regardless of how many individual forces are applied to the tooth and

regardless of their direction.

To determine the resultant of more than two forces that have a common point of application, a

series of successive parallelograms is constructed. Each time, the resultant from any two forces

replaces those forces and is used to construct the next parallelogram. The sequence in which

forces are combined is of no consequence. However, different forces on a tooth usually are not

applied at the same point, as was assumed previously. According to the law of transmissibility of

force, the point of application of a force may be considered to be anywhere along its line of action.

Consequently, the resultant of two forces with different points of application can be determined by

extending their lines of action to construct a common point of application.

[See Law of transmissibility of force]

Force couple

[See Couple]

Force delivery

A force produced by an orthodontic wire, spring or other auxiliary against a tooth.

Force resolution (Decomposition of forces)

Rather than combining two or more forces into a single resultant, it often is useful to divide a single

force into components at right angles to each other (in two or three dimensions). In this instance,

the parallelogram procedure for composition of forces is reversed. Every force can be considered

as the diagonal of a parallelogram and its components can be drawn along the orthogonal axes.

With more than one force on a tooth, there are two methods for determining the overall component

forces. First, the applied forces can be combined into a single resultant , and then this resultant

can be resolved into its components. Alternatively, the components for each force can be

determined separately, and these components then can be combined to determine the net

component vectors.

[See Force composition (Combination of forces)]

[See Global reference frame]

Force system

Combination of all the forces and moments acting on a body. A 3-dimensional force system

consists of three forces in the principal dimensions of space (Fx, Fy, Fz) and three moments

considered about the three axes (Mx, My, Mz).

SUBTERMS:

Force system

• Applied force system

The force system acting at the point of application of the forces (usually the bracket of a tooth).

Force system

• Consistent force system

A force system that only includes forces and moments that are

desirable for the intended tooth movement.

Force system

• Effective force system

The combination of forces and moments considered at the center

or resistance (CRes) of a body (tooth). It can be used to predict

the type of movement that will occur.

Force system

• Equivalent force systems

Two force systems are equivalent if they cause the same effect on a body. In such a case, the sum

of all the forces and the sum of all the moments in system A have to be equal to those in system B

in all three principal dimensions of space.

Force system

• Inconsistent force system

A force system that contains one or more components

(forces or moments) which are not com-patible with the

intended tooth movement and thus would lead to

unwanted side effects.

Force system

• Statically determinate/indeterminate force system

As stated by the first law of Newton, when a body is in

static equilibrium then the sum of all the forces and the

sum of all the moments acting on it must be equal to

zero (SF = 0 and SM = 0). This generates a total of six

equations in 3 dimensions. When the number of static

equilibrium equations is larger than or equal to the

number of unknowns, then the force system is

determinate, which allows calculation of the applied

forces and moments and prediction (to an extent) of

the resulting tooth movement. This is done by

considering the system at one specific instant in time

and by assuming that it is, at that time, in static

equilibrium.

When a wire connects two teeth (or two segments of teeth that have been joined together so that

they can be assumed to be rigid bodies and their CRes can be estimated) then specific equilibrium

equations may be formulated for them, which allow a description of the force system and an

approximate prediction of the tooth movement that will occur (determinate force system).

Conversely, when a continuous wire engages more than two teeth, the forces and moments acting

on each tooth will interact with the force systems on the adjacent teeth. The result is a situation

with more unknowns than available equilibrium equations, which does not permit analysis of the

resulting forces and moments. The force system then is said to be statically indeterminate.

Mandibular shift (CR-CO shift, Mandibular slide, Forced bite, Slide in centric)

A deflection of the mandible in an anterior, posterior and/or lateral direction, as a result of a

premature contact occurring when the mandible is in centric relation.

[See Occlusal interference (Premature occlusal contact, Supracontact, Deflective occlusal contact,

“Prematurity”), Centric interference]

Forced bite

• Anterior forced bite

A mandibular shift in an anterior direction from CR to CO. An

anterior forced bite may result in an anterior functional

crossbite.

[See Crossbite, Functional crossbite (Pseudo-crossbite)]

Forced bite

• Lateral forced bite

A mandibular shift in a

lateral direction after an

occlusal interference in CR.

A lateral forced bite may be

the cause a posterior functional crossbite.

[See Lateroclusion]

Forced eruption (of a tooth)

The application of orthodontic traction to guide an unerupted or

impacted tooth into its proper position in the dental arch, usually following its surgical exposure.

[See Surgical exposure (of a tooth)]

Formability

The amount of permanent deformation that a material can withstand before failing. In the case of

an orthodontic wire, it represents the amount of permanent bending the wire will tolerate (e.g. while

being formed into a clinically useful spring or loop) before it breaks. High formability is a property

that an ideal wire alloy for orthodontic purposes should possess.

Forme fruste

An atypically mild or incomplete manifestation of a disease or anomaly (e.g. forme fruste cleft lip).

Fracture

Break or discontinuity of an entity (pertaining to a fractured bone, tooth, cartilage, but also wire,

appliance part, ceramic bracket etc. ).

SUBTERMS:

Fracture

• Comminuted fracture

A fracture resulting in multiple small segments, fragments or splinters.

Fracture

• Complex fracture

A fracture involving vital structures adjacent to the fracture site.

Fracture

• Compound (open) fracture

A fracture that has communication with the external surface (e.g. when a bony segment per-forates

the skin or penetrates the oral mucosa).

Fracture

• Displaced fracture

A fracture leading to gross discontinuity of the segments involved, as compared with the normal

anatomy.

Fracture

• Greenstick fracture

An incomplete fracture, in which one side of a bone (one cortical plate) is broken and the other side

is bent (usually the fracture only involves the convex side of the curve).

Fracture

• Intracapsular fracture

A fracture occurring within the capsule of a joint. In the case of the mandibular condyle, an

intracapsular fracture involves the portion of the condylar head that is enclosed by the

temporomandibular joint capsule.

Fracture

• Pathologic fracture

A fracture due to the weakening of bone structure by pathologic processes such as osteomalacia,

osteomyelitis, tumors or osteogenesis imperfecta. In instances of severe destruction of bone,

fractures of the jaws can occur spontaneously during chewing,yawning or talking.

Fracture line

Linear radiolucency seen on a radiograph indicating a break in a bone or tooth.

Free body diagram

A depiction of an object (e.g. a tooth) or system as a free body, upon which all the acting forces

and moments can be considered, and the Newtonian laws of static equilibrium can be applied, for

purposes of mechanical analysis.

Free vector

A vector whose action is not confined to or associated with a unique line in space. A free vector can

produce the same effect on a body regardless of the point on the body where it is applied. The

moment of a couple is an example of a free vector commonly encountered in orthodontics.

Freeway space (Interocclusal clearance, Interocclusal separation)

The distance between the occlusal surfaces of the ma-xillary and mandibular teeth when the

mandible is in its rest position.

Fremitus

Vibration of a tooth due to a premature contact with its antagonist in centric occlusion, which can

be clinically detected by palpation.

Frenectomy

The surgical repositioning or excision of a (labial) frenum in cases where it is felt that its fibers may

interfere with the stability of an orthodontically corrected midline diastema, or with its spontaneous

closure during and after eruption of the maxillary canines. Frenectomy also is indicated when a

frenum is involved in causing localized gingival recession or in cases of ankyloglossia.

[See Ankyloglossia (Tongue-tie)]

Frenum (Frenulum)

A fold of mucous membrane and underlying fibrous tissue.

SUBTERMS:

Buccal frenum

Labial frenum

Lingual frenum

Friction

A force resisting the relative dis-placement of two contacting bodies, in a direction tangent to the

plane of contact. Because of friction, part of the mechanical energy intended for movement of the

two bodies relative to each other is dissipated as thermal energy.

Static friction is the component of frictional force that has to be overcome to initiate motion.

Dynamic (kinetic) friction is the component of frictional force that has to be overcome to maintain

motion. The static frictional force usually is somewhat higher than the dynamic frictional force.

Frictional coefficient (μ)

The law of friction theorized by Coulomb states that the magnitude of the frictional force F is equal

to the product of the normal force FN acting perpendicular to the contact surface, multiplied by the

frictional coefficient μ (F = FN x μ). The frictional coefficient μ depends on the surface roughness

and the combination of the materials involved. It does not depend on the area of the contacting

surfaces and varies only slightly with the velocity of movement. With respect to the type of friction,

a static and a dynamic frictional coefficient can be distinguished.

[See Friction]

Frontal plane (Coronal plane)

Any plane passing longitudinally through the body from side to side, at right angles to the median

plane and dividing the body into front and back parts.

Function

The specialized, normal or proper physiologic activity of an organ or part.

Functional jaw orthopedics

Treatment with functional appliances, making use of forces created by the musculature of the

patient to bring about the desired dentofacial and functional changes.

Functional matrix theory

A hypothesis put forth by M. L. Moss to provide a theoretical explanation of the interrelationship

between osteogenesis and local functional demands. According to Moss, each function in the head

is controlled by a specific functional cranial component. The size, shape and spatial position of the

individual cranial components are relatively independent of one another. Each cranial component

consists of two parts: a “functional matrix” that actually carries out the function and a “skeletal unit,”

whose role is to protect and/or support its specific functional matrix.

Skeletal units may be composed of bone, cartilage or ligaments, but they are not the equivalent of

the “bones” of classic osteology. Skeletal units are distinguished as microskeletal or macroskeletal

units. The sum of all microskeletal units of a skull component makes up the macroskeletal unit. For

example, the mandible is a macroskeletal unit consisting of the condylar, coronoid, angular,

alveolar and basal microskeletal units.

The functional matrix includes the functioning spaces and the soft tissue components required for a

specific function. Teeth also are a functional matrix. When a functional matrix grows, or changes in

size, shape or spatial position, the related skeletal unit will respond accordingly. Movement of teeth

with orthodontic treatment induces changes on the alveolar skeletal unit. In a similar fashion, the

blood vessels and nerves of the mandibular canal have an effect on the mandibular basal

microskeletal unit.

There are two types of functional matrices, the “periosteal” matrix and the “capsular” matrix (their

designation indicates the sites of their activity). The periosteal matrices include muscles and teeth,

whereas the capsular matrices are conceived of as volumes enclosed and protected by both the

neurocranial and the orofacial capsules. In the neural skull the capsular matrix is the neural mass.

In the facial skull this matrix consists of the functioning spaces of the oronasopharyngeal and

orbital cavities.

The capsular and periosteal matrices have completely different effects on the growth process.

Periosteal matrices act upon skeletal units in a direct fashion by the processes of osseous

deposition and resorption (or by the processes of cartilaginous and fibrous tissue manipulation).

Their net effect is to alter the form (size and shape) of their respective skeletal units. On the other

hand, capsular matrices act upon functional cranial components as a whole, in a secondary and

indirect manner, by altering the volume of the capsules within which the functional cranial

components are embedded. The effect of such growth changes is to cause a passive translation of

these cranial components in space.

Cranial growth is a result of combined activity of both types of matrix. Growth is accomplished by

both spatial translation and changes in form.

Fusion

Abnormality of dental morphology involving a union of the

dentin (and enamel) of two teeth, from two separate tooth

buds.

[Compare with Twinning]

[See Concrescence]

[See Gemination]

Genial

Of or pertaining to the chin.

Gemination

Abnormality of dental morphology due to incomplete division of a

single tooth bud.

[Compare with Twinning]

[See Fusion]

[See Concrescence]

Genioplasty

An orthognathic surgical procedure designed to reshape the contour of the chin, giving it a more

esthetic appearance. The procedure is performed intraorally by a vestibular incision and,

depending on the situation, can augment or reduce the prominence of the chin in the

anteroposterior, vertical or transverse plane of space. This can be performed by various

approaches, such as by sliding the distal (genial) segment on the proximal (mandibular) segment

and/or by removal of a wedge of bone. Alloplastic grafts to increase the prominence of the chin are

no longer widely performed, due to their side effects.

Gingiva

The fibrous investing tissue, covered by keratinized epithelium, that immediately surrounds a tooth

and is contiguous with its periodontal ligament and with the mucosal tissues of the oral cavity. Two

types of gingiva can generally be distinguished, attached and free gingiva.

SUBTERMS:

Attached gingiva

Free gingiva

Marginal gingiva

Gingival col

A valley-like depression of the interdental gingiva that connects facial and lingual papillae and

conforms to the shape of the interproximal contact area.

Gingival fibers

Collagen (predominantly), reticulin and elastic fibers, which together with the different cells (e.g.

fibroblasts, macrophages) and the ground substance (proteoglycans and glucoproteins) make up

the connective tissue content ofthe gingiva. Depending on their orientation, they are organized into

five principal groupings: the dento-gingival, alveolo-gingival, dento-periosteal, circular and

transseptal fibers.

SUBTERMS:

Alveolo-gingival fibers

Circular fibers

Dento-gingival fibers

Dento-periosteal fibers

Transseptal fibers

Gingival fibrotomy

[See Circumferential supracrestal fibrotomy (Edwards’ procedure)]

Gingival hyperplasia

An enlargement of the gingiva owing to an increase in the number of cells.

Ginglymoid joint

Hinging joint with one convex and one concave surface, with movement in only one plane of

space.

Glenoid fossa (Mandibular fossa, Temporal fossa, Articular fossa of the temporal bone)

A depression on the inferior surface of the squamous portion of the temporal bone at the base of

the zygomatic process, in which the mandibular condyle is situated. Posterior to the glenoid fossa

is the squamotympanic fissure, which extends mediolaterally. Medially the fossa is limited by the

spine of the sphenoid and laterally by the root of the zygomatic process of the temporal bone.

Anteriorly, the fossa is bounded by the articular eminence. The middle part of the glenoid fossa is

separated from the middle cranial fossa and temporal lobe of the brain by a fairly thin plate of

bone.

Global reference frame

A coordinate system of three mutually perpendicular, intersecting axes (x = sagittal/anteroposterior,

y = vertical/occlusogingival, and z = transverse/mediolateral), used as a reference for various

measurements or vector analysis within a dental arch, or in relation to the entire dentofacial

complex. The x-axis is defined as the intersection of the sagittal and occlusal planes, the y-axis as

the intersection of the sagittal and coronal planes and the z-axis as the intersection of the coronal

and occlusal planes.

Glycosaminoglycans (GAGs)

One of the types of macromolecules that constitute the extracellular matrix. Glycosaminoglycans

are long, unbranched polysaccharide chains composed of repeating disaccharide units. Examples

of GAGs include hyaluronic acid, dermatan sulfate and heparin.

The major characteristic of GAGs is that they are strongly hydrophilic and have the capacity to

withhold water. Thus, GAGs tend to adopt highly extended, so-called random coil conformations,

which occupy a large volume relative to their mass (as their polysaccharide chains are too

inflexible to fold into more compact structures), and they form gels even at very low concentrations.

These gels osmotically absorb large amounts of water into the matrix, enabling the matrix to

withstand compressive forces (in contrast to collagen fibrils, which resist stretching forces).

Cartilage matrix, for example, resists compression by this mechanism.

Goldenhar syndrome

A variant of hemifacial microsomia which additionally may include epibulbar dermoids (soft tissue

tumors on the cornea of the eyes), lipomas around the orbits and vertebral abnormalities.

[See Hemifacial microsomia (First and second branchial arch syndrome)]

Graft

Any material or tissue that is not normally part of an organ or tissue, implanted or transplanted for

the purpose of reconstructing or repairing.

SUBTERMS:

Allogenic graft (Allograft, Allogeneic graft)

Alloplastic graft (Alloplast)

Alveolar bone graft

Autologous (Autogenous) graft

Costochondral graft

Free graft

Free gingival graft (Epithelialized free soft tissue graft)

Full thickness periodontal graft (Mucoperiosteal periodontal graft)

Heterologous (Xenogenic, Heterogenous) graft

Homologous (Homogenous) graft

Isologous (Syngeneic) graft

Split thickness periodontal graft (Partial thickness periodontal graft, Mucosal periodontal graft)

Subepithelial connective tissue graft

Grating joint sound

[See Crepitus (Crepitation, Grating sound)]

Grinding (of teeth)

[See Bruxism]

Group function

Term used to describe a particular scheme of disclusion of the dental arches during a lateral

mandibular excursion. The maxillary and mandibular canines, premolars and, on occasion, molars

on the working side come into contact as the mandible moves laterally, causing disarticulation of

the remaining teeth.

Growth

The age-related increase in size or mass, involving changes in amount of living substance. Growth

is the quantitative aspect of biologic development and is measured in units of increase per units of

time (e.g. inches per year or grams per day). Enlargement of living matter with growth may be the

direct result of cellular division or the indirect product of biologic activity (e.g. bones and teeth).

Although growth typically is equated with enlargement, there are instances in which it results in

normal decrease in size (e.g. the thymus gland after puberty).

[See Development]

Growth center

A location at which independent (genetically controlled) growth occurs, as opposed to a growth

site, which is merely a location at which growth occurs. All growth centers also are growth sites,

whereas the reverse is not true. For example, as a result mainly of transplantation studies, it is now

known that the sutures between the membranous bones of the cranium and the maxilla that

previously were considered as primary growth centers, actually are mere sites of growth.

Conversely, the epiphyseal plates of the long bones are considered to be growth centers, as they

continue to grow when transplanted to a new location or even in culture, indicating an innate

growth potential.

Growth factors

Highly specific serum polypeptides that are directly and specifically involved in stimulating cell

division and/or differentiation. Growth factors act in complex manners in regulating a certain

function: most cell types probably depend on a specific combination of growth factors rather than a

single specific growth factor. Some growth factors are present in the circulation, but most act as

local chemical mediators.

Examples of growth factors include the platelet-derived growth factor (PDGF), which stimulates

proliferation of connective tissue cells and is involved in wound-healing; the insulinlike growth

factors I and II (IGF-I and IGF-II), which stimulate proliferation of fat cells and connective tissue

cells; the transforming growth factor b (TGF-b), which potentates or inhibits the response of most

cells to other growth factors and regulates differentiation of some cell types; and the fibroblast

growth factor (FGF), which stimulates proliferation of many cell types, including fibroblasts,

endothelial cells and myoblasts.

Growth potential

The amount of growth yet to occur.

Growth prediction

In general, an estimation of the amount of growth to be expected. In orthodontics, the term refers

to the estimation of the amount and direction of growth of the bones of the craniofacial skeleton

and the overlying soft tissues. Due to the large inter-individual variation, growth prediction

generally is considered a procedure with relatively low accuracy.

Growth site

A location at which growth occurs.

[Compare with Growth center]

Guidance of eruption

A planned sequence of selective, timed extraction of deciduous teeth with the objective of

facilitating the eruption of the permanent successors into improved positions. Guidance of eruption

involves no extractions of permanent teeth.

[Compare with Serial extraction]

Guide plane

An acrylic surface of a removable or functional appliance that contacts a tooth and transmits the

desired intermittent forces to it. A guide plane also may be the part of the functional appliance that

serves to induce the desired anterior (or posterior) mandibular position.

Guided tissue regeneration (GTR)

Periodontal surgical procedure attempting to regenerate lost periodontal structures through

differential tissue responses. Such procedures make use of barrier techniques, where membranes

made of materials such as expanded polytetrafluoroethylene, polyglactin, polylactic acid and

collagen are employed to exclude the epithelial tissue from the root surface and bone, in the belief

that it interferes with regeneration.

“Gummy” smile

Excessive amount of gingival exposure upon smiling.

[See Tooth-to-lip relationship]

Gurin lock

Adjustable archwire attachment that can be locked

onto an archwire to serve as a stop, without the need

for bending, welding or soldering. A Gurin lock

consists of a small screw that is split along its long

axis, allowing it to be positioned “riding” the archwire

and is secured in place by a hexagon-head lock-nut.

Its advantage is that it can be easily removed or

repositioned along the archwire at any time, and with

no consequences for the archwire. Gurin locks also

are available with hooks, used for attachment of

elastics directly on the archwire (instead of a

Kobayashi hook on a certain tooth).

Hand and wrist radiograph

A radiograph of the carpal, metacarpal and phalangeal bones of the hand and wrist, traditionally

used to determine the skeletal maturation status of children, as skeletal or developmental age does

not always correspond with chronological age. The procedure involves the appraisal of the degree

of development of various carpal, metacarpal and epiphyseal centers of ossification, in comparison

with standards provided from growth studies. The standards are published in an atlas format,

based on the average appearance of a hand and wrist radiograph at various chronological ages.

Hardening

A process used to increase the yield strength and resistance to indentation of a metal.

SUBTERMS:

Hardening

• Work-hardening (Cold-working)

Hardening of a wire by repetitive plastic deformation in the cold state. Placing repetitive bends on

an orthodontic wire increases its strength and hardness because of work-hardening, but also

makes the wire more brittle.

Hardness (of a material)

Resistance to indentation on the surface. Depending on the type of indentor used for the hardness

test, one can distinguish between Brinell hardness, Rockwell hardness and Vickers hardness.

Among the properties that are important to the hardness of a material are strength, proportional

limit, and ductility.

Hawley wire

The labial bow of the Hawley retainer.

[See Labial bow]

[See Retainer, Hawley retainer]

Headgear

Extraoral appliance making use of cervical or cranial anchorage to apply forces to the jaws and

teeth, with the purpose of growth modification or tooth movement. The choice of direction of pull of

the headgear usually is based on the patient’s facial pattern: the more vertically excessive growth

is present, the higher the direction of pull and vice versa. It should be kept in mind, however, that

considerable variation in growth response can occur. [Note: To apply Newton’s laws for theoretical

biomechanical consideration on use of different types of headgears, the facebow is assumed to be

completely rigid. ]

SUBTERMS:

Headgear

• Asymmetric headgear (Eccentric headgear)

A modification in the design of a cervical or straight-pull headgear to

achieve differential magnitude of force between the two sides, when

attempting asymmetric molar distalization. This is usually performed using

a facebow with an asymmetric outer bow. One of the arms is kept longer

(and/or more laterally offset) on the side that requires the greater

distalization to generate a higher force magnitude. The disadvantage of

asymmetric headgear traction is the creation of transverse (buccolingual)

forces, which are difficult to control and may have detrimental effects on the

maxillary arch and the occlusion, especially if an asymmetric headgear is

used for a prolonged period.

Headgear

• Cervical headgear (Kloehn-type headgear, Low-pull headgear)

A type of headgear consisting of a standard facebow inserting into the headgear tubes of the

maxillary first permanent molar attachments and a cervical neckstrap. The cervical headgear,

which was made popular by S. Kloehn, is used to restrict anterior growth of the maxilla and to

distalize or maintain the sagittal position of the maxillary molars. Because of the cervical

anchorage, the direction of the traction with this type of headgear produces an extrusive force on

the maxillary first molars, in addition to the distal force. Depending on the orientation and length of

the outer bow, as well as the number of teeth included, the vector of the force can be made to pass

through, below or above the center of resistance of the unit, resulting in a bodily or tipping

movement.

Headgear

• High-pull headgear (Occipital headgear)

This consists of a high-pull headstrap and a standard facebow, the outer arms of which are cut

shorter and/or bent upwards slightly, so that the force vector is directed through, below or above

the center of resistance of the maxillary first permanent molars, or that of the entire maxilla. The

line of action of the force forms an angle of approximately 45° with the occlusal plane. A high-pull

headgear also can be attached to a removable or functional appliance. When a high-pull headgear

is used directly on the maxillary first permanent molars without any fixed appliances on the

remaining teeth, the insertion of a transpalatal arch on the first molars can serve to prevent

undesirable buccal tipping. The objectives of high-pull headgear treatment are restriction of

anterior and downward maxillary growth and/ or molar distalization, intrusion, or control of their

eruption. The high-pull headgear is commonly used in the treatment of growing patients with Class

II malocclusions, increased vertical dimension, minimal overbite and increased gingival exposure

on smiling.

Headgear

• J-hook headgear

A type of headgear consisting of a high-pull or straight-pull headstrap, attaching to hooks or loops

on the archwire by means of a J-hook assembly through the commisures (i.e. without a facebow).

A J-hook headgear also may be used to provide the necessary force for distal movement of teeth

(such as retraction of canines) with sliding mechanics, by attaching to a sliding jig or directly to the

archwire, mesial to the teeth that are to be retracted. Use in conjunction with a removable

appliance again is feasible.

Headgear

• Mandibular headgear

A headgear directing extraoral forces to the mandibular arch by means of a standard facebow and

a cervical neckstrap. Because of the mobility of the mandible, the line of action of the force

produced by a mandibular headgear changes depending on the degree of opening.

Headgear

• Straight-pull headgear (Combination headgear, Horizontal-pull headgear)

A headgear with a modified headstrap designed to produce a horizontal

force (approximately parallel to the occlusal plane). A similar direction of

force can be produced by simultaneously attaching a high-pull

headstrap and a cervical neckstrap on the same facebow. Varying the

proportions of the total force derived from the two straps, as well as

varying the length and inclination of the outer bow, allows the resultant

vector to be altered.

Headgear

• Vertical-pull headgear

A type of headgear consisting of a standard facebow and a modified headcap, capable of

generating a force vector passing at approximately 65° to the occlusal plane (force vectors passing

anteriorly to that would dislodge the headcap, unless a special custom made headcap is used).

This type of headgear is used when intrusion of the buccal segments is attempted. The headcap of

a vertical-pull headgear is usually versatile, in that it has multiple notches allowing variation in the

direction of the traction force.

Headstrap (Headcap)

The component of an extraoral traction appliance that distributes and transfers reaction forces to

the cranium. The headstrap allows a posterior and upward force vector. It usually carries safetyrelease

force modules to reduce the chance of accidental injury. Modified headstraps also are used

with straight-pull (combination) headgears or with vertical-pull headgears.

[Compare with Neckstrap]

Helix

A spiral bend placed in an orthodontic wire in the shape of a

closed circle. Used as a stop along the archwire, or for the

attachment of various modules such as elastics or J-hooks.

Additionally, helices can be added in the design of various

orthodontic springs to lower their force/deflection rate.

Hemifacial microsomia (First and second branchial arch syndrome)

An umbrella term denoting a family of congenital anomalies characterized by malformation,

underdevelopment or absence of certain structures which are derived from the first and second

branchial arches during embryological development. Variations of the condition have been named

Goldenhar syndrome, oculoauriculovertebral spectrum, necrotic facial dysplasia, otomandibular

dysostosis, and craniofacial microsomia.

The disorder can involve the maxilla, mandible, ears, eyes, orbits, nose, frontonasal structures,

zygoma, facial soft tissue and musculature, parotid gland and the facial nerve. Unilateral or

bilateral cleft lip and/or palate can be co-existing in 7% to 15% of the cases. Cardiac, renal,

vertebral and central nervous system abnormalities also have been reported.

The exact mechanism of its etiology remains unknown; however, vascular abnormalities,

disturbance of neural crest cell migration, chromosomal abnormalities and certain teratologic

agents have been hypothesized. The frequency is approximately 1:5600 live births and there

seems to be a male predominance of about 3:2 and a predominance of 3:2 of right-sided versus

left-sided involvement in truly unilateral cases.

The disorder is expressed to varying degrees, ranging from a mild facial asymmetry to involvement

of many facial structures, unilateral or bilateral, which can be functionally and psychologically

debilitating. The clinical appearance most often involves a unilateral hypoplasia of the mandibular

condyle and ramus, leading to deviation of the chin to the affected

side. Depending on the severity, a number of mandibular posterior

teeth may be missing ipsilaterally. Canting of the maxillary occlusal

plane (up on the affected side) is a common finding, as are

preauricular tags of skin and cartilage.

Treatment of patients with hemifacial microsomia often includes

multi-stage procedures such as reconstruction of the mandibular

condyle and/or fossa, microvascular free-flap transfer for soft tissue

augmentation, auricular reconstruction, facial reanimation,

functional appliance treatment, ramus lengthening by distraction

osteogenesis or bimaxillary orthognathic surgery.

Hemisection (of a tooth)

The surgical separation of an endodontically treated multi-rooted

tooth (most commonly a mandibular molar) through the furcation.

“High-angle” patient (“Vertical” patient, Long face syndrome, Hyperdivergent face)

A general term used to describe a patient with a predominantly vertical growth pattern, a long lower

face height and a steep mandibular plane. A Class II malocclusion with an anterior open bite

tendency may be associated, typically with excessive gingival exposure on smiling, vertical

maxillary excess and lip incompetence. (Referring to the mandibular plane angle. )

[Compare with “Low-angle” patient (“Horizontal” patient, Hypodivergent face)]

Hinge axis

The theoretical single horizontal axis about which the pure rotational movement of the mandible

occurs, during the initial phase of jaw opening.

Holding arch

[See Arch, Lingual arch]

[See Arch, Nance holding arch]

Homeostasis of the dentition

The state of equilibrium of the position of the teeth, as determined by their morphology, the

relationship between their supporting bones, the occlusion, the periodontium and forces from

muscles and other structures involved.

Hooks

Attachments soldered, welded or crimped onto an orthodontic

archwire, to aid in placement of elastics, headgear (i.e. J-hook), elastic

chains, etc. , or to facilitate intermaxillary fixation during orthognathic

surgery.

Howes’ analysis

A plaster cast analysis aimed at evaluating the relationship of the maxillary and mandibular dental

arch width to the width of the respective apical bases, taking into account the existing tooth

material.

According to A. E. Howes, the ratio of the premolar width (the linear distance between the tips of

the buccal cusps of the first premolars bilaterally) over the existing tooth material (the sum of the

mesiodistal widths of the first permanent molars, premolars, canines and incisors), in either the

maxillary or the mandibular arch, should be approximately 43%. Correspondingly, the ratio of the

canine fossa width (the width of the apical base measured on the plaster cast at the level of the

apex of the first premolars) over the existing tooth material (the sum of the mesiodistal widths of all

the teeth anterior to the second molars, as explained previously) for the same arch should be

approximately 44%, whether this concerns the maxillary or the mandibular arch.

When the former ratio is much smaller than the latter, the arch can be expanded to eliminate any

existing crowding. If the opposite is true, then according to Howes, extractions are indicated in the

presence of crowding.

Howship’s lacunae

Small pits or hollow depressions in bone undergoing resorption, containing osteoclasts. Similar

lacunae also can be found in cementum, in which cementoclasts may or may not be located.

Hyalinization

A term describing the loss of cells from an area of the PDL because of trauma, as seen by light

microscopy. Hyalinization occurs often on the compression side of the PDL during tooth movement.

When this happens, no remodeling of the alveolar bone can occur because no cells are present;

therefore hyalinization causes tooth movement to cease. Only after the hyalinized portion of the

ligament is removed by osteoclasts coming from the bone marrow on the endosteal side, does

tooth movement start again.

[See Bone resorption, Undermining resorption (Indirect resorption)]

[See Bone resorption, Direct resorption (Frontal resorption)]

Hyperdivergent

A facial pattern that is characterized by a steep mandibular plane angle, a long anterior lower facial

height with an open bite tendency, a retrognathic mandible with an associated Class II

malocclusion and lip incompetence. Named so because of the cephalometrically observed

excessive divergence of the skeletal planes (mandibular, occlusal and palatal) in relation to each

other or to the cranial base.

[See Hypodivergent]

[See “High-angle” patient (“Vertical” patient, Long face syndrome, Hyperdivergent face)]

Hypernasality (Rhinolalia aperta)

The defective voice quality that is characteriz-ed by excessive nasal resonance during speech. It

can result from a structural (i.e. hypomobility or shortness of the soft palate in cleft palate patients)

or a functional problem of the velopharyngeal mechanism.

[Compare with Hyponasality (Rhinolalia clausa)]

Hyperplasia

Excessive enlargement of a tissue or structure due to increase in the number of cells.

Hypertrophy

Excessive enlargement of an organ or structure due to increase in the size but not the number of

its individual constituent cells, as well as increase of intercellular matrix.

Hypodivergent

A facial pattern characteriz-ed by relative parallelism of the skeletal planes (mandibular, occlusal

and palatal) in relation to each other or to the cranial base, as observed cephalometrically. This

facial pattern often is associated with a Class II,Division 2 malocclusion typically exhibiting a

decreased gonial angle, short anterior lower facial height, deep overbite, strong chin and retrusive

lips.

[See “Low-angle” patient (“Horizontal” patient, Hypodivergent face)]

[See Hyperdivergent]

Hypodontia

Congenital absence of one or more, but not all teeth.

[Compare with Supernumerary teeth (Hyperodontia)]

[Compare with Anodontia]

Hyponasality (Rhinolalia clausa)

Phonation with insufficient nasal resonance, usually due to a blockage of the nasal airway.

[Compare with Hypernasality (Rhinolalia aperta)]

Hypoplasia

Incomplete or defective development of a tissue or structure. [The term implies fewer than the

usual number of cells. ]

Iatrogenic

An unfavorable response or condition, caused by medical or dental personnel, diagnostic tests or

treatment procedures.

Ideal occlusion

A theoretical concept of an ideal arrangement of the teeth within the dental arches, combined with

an ideal interarch relationship, which concentrates optimal esthetics, function, and stability of the

dentition and supporting structures.

[See Six keys of occlusion]

Idiopathic

Pain, disease or disorder of unknown etiology.

Imbrication

The overlapping of incisors and canines in the same arch, usually due to crowding.

Immobilization

[See Fixation, Surgical]

[See Splinting (of teeth)]

Impaction (of food)

The forceful wedging of food into the interproximal space during mastication.

Impaction (of the maxilla)

An orthognathic surgical procedure involving superior repositioning of the maxilla, usually by

means of a Le Fort I osteotomy. A maxillary impaction is used for correction of a high smile line,

associated with vertical maxillary excess. In the instance of surgical correction of a skeletal open

bite, a differential maxillary impaction is performed, whereby the anterior aspect of the maxilla is

moved superiorly to a lesser extent than its posterior aspect.

Implant

An alloplastic material or device that is surgically placed into the body. In dentistry, implants are

placed beneath the mucosal or periosteal layer or within bone for functional, therapeutic or esthetic

purposes. Root-form, endosseous, screw-threaded implants are the most commonly used implants

in clinical practice.

SUBTERMS:

Endosseous implant

Orthodontic implant

Subperiosteal implant

Transosteal implant

Impression

An accurate negative imprint of the maxillary or mandibular dental arch and surrounding structures,

from which a positive reproduction (cast, model) can be made. When taking an impression for

orthodontic purposes the flanges of the impression tray are extended to allow maximum

reproduction of the alveolar process. Alginate is by far the most commonly used impression

material in orthodontics.

[See Orthodontic casts (Orthodontic models)]

[See Orthodontic impression trays]

Incidence

The number of new patients acquiring a disease or condition over a predetermined time period, as

generated by an analytic epidemiological investigation of a prospective longitudinal nature.

[Compare with Prevalence]

Incisal

Pertaining to, or in the direction of, the incisal edge of the anterior teeth.

Inclination (Third order, “Torque”)

Angular deviation of the long axis of a tooth from a line

perpendicular to the occlusal plane, in the labiolingual, or

buccolingual direction.

[Compare with Angulation (Second order, “Tip”)]

Inclined plane

An oblique surface (slope) used to correct a crossbite of one or more incisors.

The inclined plane can be part of a removable appliance or it can be fixed on the

teeth of the opposing arch. Inclined planes also have been used as part of

functional appliances to induce an anterior or posterior mandibular position.

Index

A relative or arbitrary system of measurement used to describe or quantify a condition. The

purpose of an index is to reduce the multitude of variables that enter into a diagnosis and influence

the assessment of the severity and prognosis of a condition, to a format (numerical or categorical)

that permits direct comparison.

Many indices have been advocated in orthodontics; some have been developed to classify

malocclusion into types (the Angle classification being a prime example), others to record

prevalence of malocclusion in epidemiological studies. In addition, certain occlusal indices (such as

the IOTN and PAR index) are meant mainly as methods of determining the need for treatment, or

as indicators of the clinical outcome of treatment.

SUBTERMS:

Index

• Cephalic index

A numerical expression of the ratio between biparietal diameter

and fronto-occipital diameter of a living person’s head.

[Compare with Index, Cranial. ] The cephalic index is calculated

by the formula “maximum head width x 100/maximum head

length. ” It is used in anthropometry to classify skulls as

dolichocephalic (cephalic index up to 75.9), mesocephalic

(between 76 and 80.9) or brachycephalic (81 or larger).

[Compare with Index, Cranial index]

Index

• Cranial index

The equivalent of the cephalic index in a dry skull; a craniometric measurement.

Index

• Facial index

A numerical expression of the proportionality of the face. The facial index is calculated by the

formula: “facial height x 100/zygomatic width. ” It is used in anthropometry to classify faces as

euryprosopic, mesoprosopic or leptoprosopic.

Index

• Index of orthodontic treatment need (IOTN)

An index developed by P. H. Brook and W. C. Shaw in 1989. The IOTN ranks malocclusions in

terms of the significance of their various components for the individual’s dental health and

perceived esthetic impairment. The intention is to identify those individuals who would most likely

benefit from orthodontic treatment. It incorporates a dental health and an esthetic component. The

dental health component can be applied either clinically or on study casts, by categorizing each

occlusal trait contributing to the malocclusion into one of five grades (grade 1 = no need for

treatment, grade 5 = great need). The measurements are facilitated by a specially designed ruler.

The esthetic component consists of a 10-point scale illustrated by a series of numbered

photographs to which the patient’s situation is compared.

Index

• Irregularity index

An index introduced by R. M. Little in 1975 for standardized assessment of mandibular anterior

crowding. It involves measuring the linear displacement of the anatomic contact points (as

distinguished from the clinical contact points) of each mandibular incisor from the respective points

of the adjacent teeth. The sum of these five displacements represents the relative degree of

anterior irregularity. Perfect alignment from the mesial aspect of the left to the right canine would

yield a score of 0, with increased crowding represented by greater displacement, and thus a higher

index score. The measurements are performed with a caliper, parallel to the occlusal plane.

Vertical discrepancies between adjacent contact points are not taken into account, as it is assumed

that correction of such discrepancies would not appreciably affect anterior arch length. Mesiodistal

interdental spacing also is disregarded, provided the teeth in question are in proper arch form. If

spacing as well as rotations are present, only the labiolingual displacement from the proper arch

form is recorded.

Index

• Peer assessment rating (PAR) index

An index for recording the severity of a malocclusion in the mixed and permanent dentition,

developed in 1987 by a group of 10 orthodontists in Great Britain (British Orthodontic Standards

Working Party). The index consists of a scoring system of study casts, facilitated by a ruler.

Individual scores for the components of alignment and occlusion finally are summed to calculate an

overall score. Thus, a score of zero would indicate perfect alignment and occlusion, with scores

above zero (but rarely beyond 50) indicating increasing levels of irregularity. The index is applied to

both the start and end of treatment study casts, and the change in the total score reflects the

success of treatment with regard to the alignment and occlusion.

Inelastic

Deviating from a proportional relationship of stress and strain.

Inertia

The property of matter that causes it to resist change in motion.

Inferior joint space (Inferior joint compartment)

The intra-articular space between the head of the mandibular condyle and the inferior surface of

the articular disc of the TMJ. During the early opening stage of mandibular movement, only the

inferior joint space is involved (by rotational movement of the condyle).

[See Joint, Temporomandibular joint (TMJ, Craniomandibular articulation)]

[See Superior joint space (Superior joint compartment)]

Informed consent

The outline by any health professional, including the orthodontist, of the patient’s problems along

with the possible solutions, in a simplified fashion comprehensible to the reasonable layman, in

order to obtain the patient’s consent to treatment. The health professional is supposed to establish

treatment priorities through discussion with the patient. Reasonable treatment alternatives and the

risks and benefits of each alternative should be provided, including that of no treatment. In this

way, the patient is able to make an informed decision. Informed consent is a legal requirement

prior to treating patients and is encouraged by the American Association of Orthodontists.

Infraorbital pointer

The component of an articulator facebow that records the position of the infraorbital rim to facilitate

alignment of the plane of the facebow with the Frank-fort horizontal plane.

Infraposition (Infraocclusion)

A situation in which a tooth or group of teeth is positioned below the occlusal plane; commonly due

to a deleterious habit or to ankylosis. Infraposition is a more general term that contains

undereruption.

[Compare with Undereruption (Infraeruption)]

Initiating factors

Factors that cause the onset of a disease or disorder.

Intensifying screen (Rare-earth screen)

A screen used to intensify the latent images on an x-ray film. It usually consists of a thin sheet of

plastic coated with a fluorescent material, which is mounted in the cassette in close contact with

the film. The x-rays cause the screen to produce visible light, which intensifies the generation of

the latent images on the film, greatly reducing the exposure of the patient to radiation.

Interbracket span (Interbracket distance)

The distance between orthodontic brackets (measured between adjacent slot ends) that

determines the length of a straight wire connecting them. The smaller the width of the brackets, the

longer the interbracket span, the lower the load/deflection rate of the wire and vice versa.

[See Load/deflection rate (Force/deflection rate)]

Interceptive orthodontic treatment

Intervention in the incipient stages of a problem to lessen its severity or possible future adverse

effects and to eliminate its cause. Such treatment may take place in the deciduous or transitional

dentition and may include redirection of ectopically erupting teeth, slicing or extraction of deciduous

teeth, correction of isolated dental crossbites or recovery of minor space loss. The presence of

complicating factors such as skeletal disharmonies, overall space deficiency, or other conditions

requiring present or future comprehensive therapy are beyond the realm of interceptive therapy.

[Modified from the AAO Glossary of Dento facial Orthopedic Terms, 1993.]

Interdental spacing

Spacing between the teeth.

Interdigitation (Intercuspation)

The interlocking of the cusps of the posterior teeth in the fossae and embrasures of their

antagonists.

Interlabial gap

The vertical separation of the lips at rest. A 2- to 3-mm interlabial gap generally is considered to be

esthetically pleasing.

[See Cephalometric measurements, Interlabial gap]

Intermaxillary

Between the maxilla and the mandible.

[Compare with Intramaxillary]

Intermediate splint

[See Splint, Surgical splint (Surgical wafer)]

Internal derangement

Disturbed arrangement of intracapsular joint components that interferes with smooth joint

movements. In the TMJ it can be associated with elongation, tear or rupture of the ligaments or

capsule, causing altered disc position or morphology. Although this is not always the case, chronic

dysfunction of internally deranged TMJs generally is thought to follow a progression to more

severe stages of breakdown, eventually leading to degenerative joint disease.

Interocclusal splint

[See Splint]

Interproximal stripping (Interproximal reduction of enamel, Reproximation, Slenderizing)

Reduction of the mesiodistal width of the teeth by removal of interproximal enamel. This procedure

can be achieved by means of handheld or motor-driven abrasive strips, or handpiece-mounted

abrasive discs, or by means of a tapered fissure carbide bur. It most commonly is performed in the

mandibular or maxillary incisor area in patients with a tooth-size discrepancy. Generalized stripping

of the entire arch is advocated by J. J. Sheridan to relieve crowding without extractions. According

to him, up to 0.3 or 0.4 mm of enamel can be removed per tooth surface, depending on the size

and shape of the teeth.

It has been advocated that interproximal stripping, if carried out to an extreme, may cause the

mandibular incisor roots to approximate excessively, resulting in thinning of the interradicular

alveolar bone, perhaps making it more prone to later periodontal bone loss. Another potential side

effect is the resulting enamel roughness that may contribute to increased plaque accumulation.

Interproximal stripping (Interproximal reduction of enamel, Reproximation, Slenderizing)

Reduction of the mesiodistal width of the teeth by removal of interproximal enamel. This procedure

can be achieved by means of handheld or motor-driven abrasive strips, or handpiece-mounted

abrasive discs, or by means of a tapered fissure carbide bur. It most commonly is performed in the

mandibular or maxillary incisor area in patients with a tooth-size discrepancy. Generalized stripping

of the entire arch is advocated by J. J. Sheridan to relieve crowding without extractions. According

to him, up to 0.3 or 0.4 mm of enamel can be removed per tooth surface, depending on the size

and shape of the teeth.

It has been advocated that interproximal stripping, if carried out to an extreme, may cause the

mandibular incisor roots to approximate excessively, resulting in thinning of the interradicular

alveolar bone, perhaps making it more prone to later periodontal bone loss. Another potential side

effect is the resulting enamel roughness that may contribute to increased plaque accumulation.

Interpupillary line

A line connecting the pupils of the eyes, used as a

reference in the evaluation of frontal facial asymmetry.

Intersegmental

Between segments of teeth (usually within the same dental arch).

[Compare with Intrasegmental]

Interstitial growth

Growth within a tissue. Histologically, a characteristic type of growth of soft tissues and cartilage

occurring by a combination of cellular hyperplasia and hypertrophy. Interstitial growth does not

occur in calcified tissues such as teeth or bone.

Intracapsular

Located within the capsule of a joint.

Intracoronal retainer

[See Retainer, Bonded lingual retainer]

Intramaxillary

Within the same dental arch.

[Compare with Intermaxillary]

Intrasegmental

Within the same segment of teeth.

[Compare with Intersegmental]

Invisible braces

A lay term applied to lingual orthodontic appliances, or to those made of a clear material (ceramic

or plastic brackets).

[See Appliance, Lingual appliance ]

Ion implantation

A surface modification technique involving a ballistic process through which an element is

imbedded into the surface of a substrate. The main advantage of this process is that the surface

properties of the substrate are improved, while the bulk properties and tolerances remain

unchanged. Ion implantation is used in orthodontics to optimize the frictional characteristics of b-Ti

archwires.

Isometric contraction

Muscle contraction without change in length.

Isotonic contraction

Muscle contraction with shortening of the muscle length, without appreciable change in magnitude

of the produced force.

Jaw

Either of the two bony structures (maxilla or mandible) in most vertebrates that border the mouth

and bear teeth.

SUBTERMS:

Jaw

• Lower jaw

[See Mandible]

“Jiggling” (of a tooth)

Repetitive limited movement of a tooth in one and then in the opposite direction, as is commonly

thought to occur under the influence of occlusal forces. Most types of orthodontic tooth movement

in reality take place as a series of minute “jiggling” movements. This translates into continuous

reversal of the root surfaces that sustain compression and tension which is, at the histological

level, equivalent to round-tripping.

[See Round-tripping]

Joint

The place of union between two or more bones.

SUBTERMS:

Joint

• Arthrodial joint

A joint that permits gliding movements (translation).

Joint

• Cartilaginous joint

A joint in which cartilage is interposed between the implicated bones and the fibrous tissue (in the

sequence: bone-cartilage-fibrous tissue-cartilage-bone). Examples are the costochondral joint and

the pubic symphysis. Cartilaginous joints permit little if any movement of the bones involved.

Joint

• Fibrous joint

A joint in which the bones are connected by fibrous tissue. Three types are described:

Suture, a joint that permits little or no movement. Its function also is to permit bone growth.

Gomphosis, a joint such as the one that connects a tooth to its surrounding bone by the fibrous

periodontal ligament.

Syndesmosis, a joint in which the two bony components are some distance apart, but are

connected by a ligament that permits limited movement (e.g. the joint between the fibula and tibia,

or that between the radius and ulna).

[See Suture]

Joint

• Ginglymoid joint

A joint that permits hinging movement (rotation) in one plane.

Joint

• Synovial joint

A type of joint by which two bones are united and surrounded by a fibrous capsule, thus creating a

joint cavity. [Note: The name comes from the latin word ova (egg) because the opposing bones of

such joints are separated by an enclosed space filled with fluid which, when examined with the

naked eye, resembles egg white. ] The capsule is continuous with periosteum of the bones

involved in the joint and is lined on its inner surface by a synovial membrane. The synovial

membrane secretes synovial fluid that fills the joint cavity. The articulating surfaces of the bones

are covered with hyaline cartilage (the temporomandibular, acromioclavicular and ster-noclavicular

joints are exceptions in that their articulating surfaces are covered by fibrous tissue). The cavity

may or may not possess a fibrous articular disc, separating it into two compartments. Various

ligaments are associated with synovial joints to strengthen the articulation and limit excess

movement.

Synovial joints are classified further by the number of axes in which the bones involved can move

(uniaxial or multiaxial) and by the shapes of the articulating surfaces (planar, ginglymoid, pivot,

condyloid, saddle, and ball-and-socket). Movements in a synovial joint are initiated and performed

by muscles working together in a highly coordinated manner.

Joint

• Temporomandibular joint (TMJ, Craniomandibular articulation)

Paired synovial joint capable of both gliding (translation) and hinge (rotation) movements; thus

considered a ginglymoarthrodial joint. The TMJ is formed by the mandibular condyle fitting into the

glenoid fossa of the temporal bone. Separating these two bones from direct contact is the articular

disc. In the healthy joint, the articular portion of the disc is composed of dense fibrous connective

tissue, devoid of any nerves or vessels. Conversely the posterior attachment of the disc is richly

vascularized and innervated.

The disc also is attached to the condyle both medially and laterally by collateral (discal) ligaments.

These ligaments permit rotational movement of the disc on the condyle during opening and closing

of the mouth. This so-called condyle-disc complex translates out of the fossa during over-extended

mouth opening.

Surrounding the joint is a fibrous capsule (capsular ligament) that extends from the margins of the

glenoid fossa, including the articular eminence anteriorly, to envelop the head of the condyle before

fusing inferiorly with the periosteum of the condylar process. Other ligaments reinforcing the joint

are the lateral (temporomandibular) ligament, which reinforces the lateral wall of the capsule,

preventing lateral dislocation of the condyle, as well as the sphenomandibular and stylomandibular

ligaments.

In the healthy joint, rotational movement occurs between the condyle and the inferior surface of the

disc (the inferior joint space) during early opening. During later stages of opening, translation takes

place in the space between the superior surface of the disc and the fossa (the superior joint

space). The synovial fluid serves as a lubricant and also acts as a medium for transporting

nutrients to and waste products away from the joint components.

Unlike most synovial joints the articulating surfaces of the TMJs are lined with dense fibrous

connective tissue, not hyaline cartilage. This is an important feature because fibrous connective

tissue has a greater ability to repair itself than does hyaline cartilage. Movement and stability of the

TMJs is achieved by the muscles of mastication. These include the masseter, medial pterygoid and

temporal muscles, which predominantly elevate the mandible; the digastric muscles, which assist

in mandibular depression; the inferior lateral pterygoid muscles, which assist in protruding the

mandible; and the superior lateral pterygoid muscles, which provide stabilization for the condyle

and disc during function.

Joint noises

[See Clicking]

[See Crepitus (Crepitation, Grating sound)]

Joint symptoms

Symptoms of TMD.

“Jumping of the bite”

1. An expression credited to N. W. Kingsley in the late 1800s, referring to the avoidance of the prior

intercuspal position by anterior repositioning of the

mandible. Such an effect can be brought up by a

functional-type appliance for the correction of mandibular

retrognathism.

2. The same expression also is used to connote correction

of an anterior crossbite by movement of the affected tooth

over the opposing dental arch.

[See Appliance, Kingsley appliance (Bite-jumping

appliance)]

[See Appliance, Herbst appliance]

Junctional epithelium (Epithelial attachment)

A single or multiple layer of non-keratinized cells adhering to the tooth surface at the base of the

gingival crevice.

Key ridge

The radiographic image of the zygomatic process of the maxilla as commonly seen on a lateral

cephalometric radiograph.

“Keystoning”

The reshaping of the interproximal aspects of the mandibular

incisors to provide an interlocking pattern to resist rotational

relapse. “Keystoning” is done by oblique interproximal

stripping, so that rotational tendency of one tooth would be counteracted by the reverse rotational

relapse tendency of its adjacent tooth.

Kinesiograph

Instrument used to record and provide graphic representation of mandibular movements.

Kinetic friction

[See Friction]

Kobayashi hook (Kobayashi tie, Kobayashi ligature)

A ligature fabricated from 0.012-inch (0.30-mm) or 0.014-inch (0.35-

mm) annealed stainless steel wire, whose legs are welded onto each

other, forming a helical “hook” at its end. It is placed on a bracket

below the archwire or in the same way as a regular stainless steel

ligature and it is used for the attachment of orthodontic elastics.

Labial

Of or pertaining to the lips, or in a direction towards the lips. Also identifies a surface facing the lips.

[Compare with Lingual]

Labial bow

A part of a removable orthodontic appliance, typically consisting of a stainless steel wire that lies

on (or at a distance from) the labial surface of the maxillary or mandibular anterior teeth, usually at

the mid-crown level. A labial bow may be embedded in the acrylic of the appliance and cross the

occlusal table at the embrasures mesial or distal to the first premolars, or it may be soldered

directly onto the molar clasps. It is used to enhance retention of the appliance, to relieve pressure

from the lips as well as (when activated) to tip the incisors lingually and close spaces. A labial bow

can be covered with clear acrylic in the case of some retainers.

[See Retainer, Hawley retainer]

[See Retainer, Spring retainer (Barrer retainer)]

Labiolingual tipping

Tipping of a tooth in a labiolingual direction.

[See Inclination (Third order, “Torque”)]

Labioversion

Labial inclination of one or more teeth.

Laceback (Lace)

Stainless steel ligature placed passively in a figure-eight

mode (usually from the terminal molar to the canine of the

same quadrant), as part of the leveling and alignment

stage of treatment with the straight-wire appliance. For

example, when a canine is slightly upright at the time of

insertion of the initial archwire, a laceback serves to

maintain the sagittal position of its crown, so that the

angulation of the tooth is improved by distal movement of

the root.

[See Figure-eight ligature]

Lacunae

Small pits or hollow cavities.

[See Howship’s lacunae]

Lateroclusion

A functional posterior cross-bite associated with a lateral shift of the mandible that occurs only in

centric occlusion (CO or ICP). In centric relation (CR) the mandible is centered in the midsagittal

plane. This type of crossbite is caused by dental interferences and can be treated by maxillary

expansion and/or by occlusal equilibration.

[See Crossbite, Functional crossbite (Pseudo-crossbite)]

[See Laterognathia]

[See Forced bite, Lateral forced bite]

Laterognathia

A posterior crossbite in CO, associated with a lateral shift of the mandible that does not improve

when the mandible is in CR (a true skeletal asymmetry). In severe situations the only treatment

option is orthognathic surgery.

[Compare with Lateroclusion]

Laterotrusion

The movement away from the median of the ipsilateral (working) half of the mandible and the

respective condyle, during a lateral mandibular excursion.

[Compare with Mediotrusion]

Lavage

The process of washing out or irrigating a cavity or an organ.

Law of transmissibility of force

According to this law, the point of application of any force applied to a rigid body can be considered

to lie anywhere along the line of action of the force.

For example, a single retraction force on the crown of a maxillary incisor will have the same effect

on the tooth whether it is applied on the labial or on the palatal aspect of the crown, provided the

line of action is the same. Similarly, the outer arms of a facebow used with a high-pull headgear

can be cut short or bent upwards without changing the force system “felt” by the molars, provided

the line of force from the headstrap is the same.

The law of transmissibility of force is applied when combining two or more

forces with different points of application to construct their resultant force.

Leeway space

The difference between the combined width of the deciduous canine, first

and second molars in each quadrant, and their successors (permanent

canine, first and second premolars). The term was introduced by H. N. Nance (1947). The average

value is approximately 1.0 mm for each maxillary quadrant and 1.7 mm for each mandibular

quadrant, although there are large individual variations. These “spaces” normally are closed by

mesial drift of the first permanent molars as the deciduous teeth are replaced.

Le Fort I, II and III surgical procedures

[See Osteotomy, Complete maxillary osteotomy]

Leptoprosopic

Having a narrow and long facial form.

Leveling

The phase of comprehensive orthodontic treatment

aiming at flattening the curve of Spee until the marginal

ridges of all the teeth in the arch lie more or less in the

same horizontal plane. Thus, leveling refers to correction

in the vertical plane.

Leveling wire

Any archwire used for leveling.

Ligament

Flexible band of fibrous tissue composed of parallel collagenous bundles, binding joints together,

as well as connecting various bones and cartilages.

Ligature

A tie that secures an archwire or other auxiliary in the bracket slot, by being placed under the tiewings

of the bracket. Ligatures are typically made of stainless steel wire, rubber, or elastomeric

material.

SUBTERMS:

Stainless steel ligature

Limited orthodontic treatment

Orthodontic treatment with a limited objective, not involving the entire dentition. It may be directed

at the only existing problem, or at only one aspect of a larger problem in which a decision is made

to defer or forego more comprehensive therapy. Examples of this type of treatment would be

single-arch treatment to improve alignment, partial treatment to close or to open space, or to

upright a tooth in preparation for prosthodontic treatment. [Modified from the AAO Glossary of

Dentofacial Orthopedic Terms, 1993.]

Lingual

Of or pertaining to the tongue; or in a direction towards the tongue. Also identifies a surface facing

the tongue.

[Compare with Labial]

Lingual cleat

A low-profile attachment that can be bonded directly to a tooth

or welded on a band. Its functions are to accommodate the

attachment of elastics, to aid as a seating lug during band

fitting, and to facilitate band removal.

Lingual crown torque

[See Torque, Root torque]

[See Torque, Crown torque]

Linguoversion

Lingual inclination of one or more teeth.

Lip exercises

Exercises aiming at stimulating the musculature of the lips, with the objective of achieving a

competent lip seal. A key component of functional appliance treatment, stressed by R. Frдnkel.

Lip incompetence (Incompetent lip seal)

Excessive separation of the lips at rest.

Lip interposition

The habit of placing the lower lip between the maxillary and mandibular

anterior teeth, or between the mandibular anterior teeth and the palate

(often seen in patients with an increased overjet).

Lisping

Incorrect pronunciation of a sibilant or affricate sound, most commonly

heard on /s/ and /z/.

Load/deflection rate (Force/deflection rate)

A mechanical characteristic of orthodontic springs or wires, describing

the dependence of the magnitude of the generated force on the amount of deflection (deformation,

activation). It expresses force per unit displacement of the spring, and is measured in cN/mm (g/

mm). A spring with a low load/deflection rate is capable of generating forces that approximate

constancy and do not depend very much on the amount of activation. The five major parameters

available to the clinician for varying the load/deflection rate are:

1. Wire cross-section

The load/deflection rate varies directly with the fourth power of the diameter of a round wire and

with the third power of the width (large dimension) of a rectangular wire. Therefore, reducing the

cross-section of the wire can reduce the load/deflection characteristics of an orthodontic appliance

significantly.

2. Wire length

The load/deflection rate varies inversely with the third power of the length of a wire segment (or

cantilever); thus small increases in wire length can reduce the load/deflection rate dramatically. In

continuous archwire multi-attachment appliances, the wire length is, to a great extent, dictated by

the interbracket span between adjacent teeth. The addition of loops to the wire can serve in

increasing the length, lowering the load/deflection rate.

3. Wire material

The load/deflection rate is proportional to the modulus of elasticity (E) of the material. For the same

size and cross-sectional shape, a wire material with a low E will deliver less force for an equal

deflection, than a wire with a high E.

4. Wire configuration

Bending loops of various shapes into an archwire reduces its load/deflection rate by increasing the

wire length.

5. Constraint conditions

The load/deflection rate of a wire segment depends on its mode of ligation between two teeth. A

wire segment tightly ligated in two edgewise brackets delivers a much higher load, for a standard

deflection, than a cantilever of the same material, length and cross-section ligated in only one of

the brackets (one fixed end).

[See Orthodontic springs, Cantilever spring]

[See Archwire cross-section]

[See Loop]

[See Interbracket span (Interbracket distance)]

[See Archwire (Arch wire), Multiloop archwire]

[See Modulus of elasticity E (Young’s modulus of elasticity, E-modulus)]

Lock, Archwire

[See Gurin lock]

Locking of a joint

[See Disc displacement (Disc derangement, Disc prolapse, Disc interference disorder), Disc

displacement without reduction]

Long-axis rotation

[See Orthodontic tooth movement, Pure rotation]

Long face syndrome

[See “High-angle” patient (“Vertical” patient, Long face syndrome, Hyperdivergent face)]

Loop

Orthodontic spring of various shapes and configurations. Loops are used for a number of

purposes, such as to lower the load/deflection rate by addition of more wire, to achieve frictionless

tooth movement, to avoid the inconsistency of the force system delivered by a straight wire, and to

achieve dissociation of forces and moments in the created force system (i.e. changes in forces do

not automatically alter the moments)

[See Archwire (Arch wire), Multiloop archwire]

[See Load/deflection rate (Force/deflection rate)]

SUBTERMS:

Loop

• Box loop

A rectangular or square-shaped loop bent into a continuous

archwire (the loop has no free end). It is used to increase

the flexibility of the wire at a certain localized point where

this is necessary (e.g. when there is only one tooth that is

not well aligned within the arch), while maintaining rigidity of

the archwire in the remainder of the arch for anchorage

purposes. A box loop offers flexibility in both the horizontal

and vertical plane.

[Compare with Loop, Rectangular loop]

[See Loop, Closed loop (Reverse loop)]

Loop

• Closed loop (Reverse loop)

A loop bent in such a way that the separation between its vertical

legs is reduced when activated by traction (the base of the loop

remains closed–”safety-pin” principle), in contrast to an open loop.

[See Loop, Box loop]

Loop

• Closing loop

Any loop which, upon mesiodistal-pulling activation, is

capable of generating a force in the direction of the

activation. A closing loop can be open or closed and can

have various configurations. Closing loops are used for

space closure, either by movement of an individual tooth

(e.g. canine retraction), or as part of a closing loop arch for

“en masse” movement of teeth.

[See Arch, Closing-loop arch]

[See Loop, L-loop (Boot loop)]

[See Loop, Vertical loop]

[See Loop, T-loop]

[See Loop, Teardrop loop]

Loop

• L-loop (Boot loop)

An orthodontic loop in the shape of an “L” (or a “boot”). It combines

flexibility in both horizontal (mesiodistal and buccolingual) and

vertical dimension. The L-loop delivers a force system that is

different at the two sides of the loop. As a simple rule, the smaller

moment is developed at the bracket that faces the L-loop.

[See Loop, Closing loop]

[See Loop, T-loop]

Loop

• Omega loop

An W-shaped loop used primarily for space closure, or for attachment of intermaxillary elastics.

Loop

• Open loop

A loop whose vertical leg separation increases when activated by

traction (the base of the loop is open), in contrast to a closed loop.

[Compare with Loop, Closed loop (Reverse loop)]

[See Loop, Vertical loop]

Loop

• Opening loop

A loop used to create space, in a fashion comparable to an open coil spring. The loop is

compressed to engage the archwire in the brackets, so deactivation of the loop will tend to

increase the arch length.

[See Orthodontic springs, Coil spring, Open]

[Compare with Loop, Closing loop]

Loop

• Rectangular loop

A rectangular-shaped loop bent into a segmental wire (the

posteriorly directed, horizontal end of the loop is free). The

rectangular loop is used to overcome problems of inconsistency

of force system delivered by a straight wire, where either the

forces or the moments are in an undesirable direction. The

desired combination of forces and moments can be reached by

varying the point of ligation along the horizontal free end of the

loop, and by controlling the horizontal dimension of the loop.

[Compare with Loop, Vertical loop]

[Compare with Loop, Box loop]

Loop

• T-loop

Orthodontic loop in the shape of a “T. ” A T-loop is basically a double L-loop, but is more flexible in

the vertical plane than an L-loop of the same dimensions that is made from the same orthodontic

wire. Used primarily as a force-producing mechanism for space closure or alignment.

[See Loop, L-loop (Boot loop)]

[See Loop, Rectangular loop]

[See Loop, Closing loop]

Loop

• Teardrop loop

A modified version of a vertical loop with its legs touching each

other at its base, giving it the shape of an inverted teardrop. Its

advantage is that it required less interbracket space than a

regular closed or open loop of the same dimensions.

[See Loop, Open loop]

[See Loop, Vertical loop]

[See Loop, Closing loop]

Loop

• Vertical loop

A simple U-shaped loop that can be bent into a continuous

archwire or used as a segmental spring. The greatest

degree of flexibility of a vertical loop is in the mesiodistal

dimension, somewhat less in the buccolingual, and very

little in the vertical dimension. When preactivation bends

are placed in the wire on either side of a vertical loop, it

behaves according to the V-bend principle. Although it

does reduce the force/deflection rate, when placed

between two misaligned brackets a vertical loop produces

a force system corresponding to that of a straight wire.

[Compare with Loop, Rectangular loop]

[See Loop, Teardrop loop]

[See Loop, Closing loop]

[See Loop, Open loop]

Loop

• Wilson loop

A U-shaped loop, similar in shape, but smaller than a Coffin spring, often incorporated in a

transpalatal arch (midway between the maxillary first molars), or in a lingual arch (mesial to the

mandibular first molars, bilaterally), to facilitate adjustment in the transverse or sagittal direction,

respectively.

“Low-angle” patient (“Horizontal” patient,

Hypodivergent face)

A general term used to describe a patient with a

predominantly horizontal growth pattern, a short

lower face height and a flat mandibular plane. A

Class II malocclusion with a deep, occasionally

impinging overbite may be associated. (Referring to

the mandibular plane angle. )

[Compare with “High-angle” patient (“Vertical”

patient, Long face syndrome, Hyperdivergent face)]

Luxation (of a tooth)

Partial or complete detachment of a tooth from its socket.

[See Subluxation (of a tooth)]

Macrodontia

A term denoting larger than normal tooth size. Although no standardization is agreed upon, two

standard deviations above the mean of the general population can be considered a cut-off point

beyond which a diagnosis of macrodontia can be established.

[Compare with Microdontia]

Macroglossia

Abnormally large tongue, commonly associated with the presence of an open bite and spacing of

teeth. Indentations may be evident on the side of the tongue. Macroglossia is a common finding in

certain pathologic conditions such as Down syndrome, Beckwith-Wiedemann syndrome,

myxedema, cretinism, or hypophyseal gigantism. A partial glossectomy is advocated by some

clinicians as a means of treatment in severe situations.

Magnetic resonance imaging (MRI)

Non-invasive, non-ionizing imaging technique that uses a combination of magnetic fields and

radiofrequency waves. As with computerized tomography, the images can be restricted to narrow

planes and in this way multisectional views of the body can be obtained.

Human tissues consist of molecules contain hydrogen nuclei (protons). Each proton has an axial

spin and because of its charge, behaves like a small magnet. Normally the protons are arranged

randomly; however, when the patient is placed in a strong magnetic field the direction of the spin of

the protons aligns with that of the field. In addition, the protons precess or wobble with a frequency

determined by the strength of the magnetic field, but out of phase with each other. The application

of a pulsed, resonant radiofrequency causes the protons to be deflected from their alignment and

to precess in phase. With cessation of the radiofrequency, the protons realign with the applied

magnetic field by transferring their acquired energy to their surroundings and revert to precessing

out of phase. The rate at which the protons realign is referred to as the “T1 relaxation time”; the

“T2 relaxation time” is the period in which protons remain in phase before returning to a random

pattern. The energy released by the relaxation of the hydrogen nuclei is converted by a computer

into a visual image.

Diagnostic MRI allows multiplanar imaging and offers better soft tissue contrast compared with CT.

Additionally, it has no known harmful effects to the tissues. On the other hand, it does not display

bone as well, since bone has a low signal intensity. Magnetic resonance imaging may be

contraindicated in patients with ferromagnetic surgical clips and cardiac pacemakers.

Magnification

The enlargement of the image of an object on a radiograph in relation to the actual object due to

divergence of the x-ray beam (depending on the object-film distance).

Magnitude

A characteristic of both scalar and vectorial quantities, denoting size or amount, in physical units of

measurement.

Main archwire

[See Arch, Base arch]

Malar midfacial augmentation

Augmentation of the malar and of the infraorbital and paranasal areas, which may be

accomplished by a modified Le Fort I or II osteotomy, or with alloplastic materials or onlay cortical

bone grafts placed simultaneously with a Le Fort I osteotomy.

[See Osteotomy, Complete maxillary osteotomy]

Malformation

A morphological structural defect of an organ, part of an organ, or a larger area of the body

resulting from an intrinsically abnormal developmental process (e.g. cleft lip, or polydactyly).

Malformations may be relatively simple or complex. The later the defect is initiated, the simpler the

malformation. Malformations initiated earlier during organogenesis tend to have more far-reaching

consequences.

[Compare with Disruption]

[Compare with Deformity]

Malformation syndromes

Recognized patterns of malformation presumably having the same etiology and currently not

interpreted as the consequence of a single localized error in morphogenesis (e.g. Down

syndrome).

[See Down syndrome (Trisomy 21)]

Malleability

The ability of a material to sustain considerable permanent deformation without rupture, under

compression (as in hammering, or rolling into a sheet). Malleability is not as dependent on strength

of the material as ductility is. Gold is the most ductile and malleable pure metal and silver is

second.

[Compare with Ductility]

Malocclusion

Any deviation from the normal or ideal occlusion.

[See Angle classification]

Mandible

The lower jaw, consisting of a curved, horizontal portion, the body, and two perpendicular portions,

the rami. Each of the rami carries a coronoid and a condylar process. The condyles articulate with

the temporal fossae by means of the temporomandibular joint. Fifteen pairs of muscles attach on

the mandible. Its embryological development is guided by Meckel’s cartilage. At birth, the bone

consists of two halves united by a synchondrosis (mandibular symphysis), which ossifies during

the first postnatal year.

Mandibular rotation

To visualize the following concepts, one has to imagine the core of the mandible as the bone that

surrounds the inferior alveolar nerve. The rest of the mandible consists of its various functional

processes. If implants are placed in areas of stable bone away from the functional processes, it

can be observed that in most individuals the core of the mandible rotates during growth, in a sense

that would tend to decrease the mandibular plane angle (i.e. counterclockwise, with the standard

head orientation toward the right side). The concept of mandibular rotation during growth was

elucidated mainly by the metallic implant experiments of A. Bjцrk in the 1960s. Following are the

most commonly encountered terms on components of mandibular rotation (the terminology varies

greatly depending on the source):

SUBTERMS:

Mandibular rotation

• Clockwise rotation (Backward rotation, Posterior

rotation)

Displacement of the mandible in the direction of mouth

opening (clockwise, with the patient facing to the right),

due to increased posterior vertical growth. Clockwise

mandibular rotation also can occur as a consequence

of orthodontic treatment, when posterior teeth are

extruded in a non-growing patient. Clockwise rotation

of the mandible usually is accompanied by an increase

of the anterior lower face height and a reduction of the

overbite.

Mandibular rotation

• Counterclockwise rotation (Forward rotation,

Anterior rotation)

Rotation of the mandible in the direction of mouth

closing (counterclockwise, with the patient facing to

the right), due to increased posterior, compared to

anterior growth. Counter-clockwise rotation of the

mandible would tend to cause a relative reduction in

the anterior lower face height and a deepening of the

overbite.

Mandibular rotation

• Intramatrix rotation (External rotation)

Rotation within the body of the mandible, due to angular remodeling of the inferior border relative

to the core of the mandible (which affects the orientation of the mandibular plane with regard to the

cranial base).

Mandibular rotation

• Matrix rotation (Apparent rotation)

Rotation of the entire mandible around its condylar axis (which affects the orientation of the

mandible as a whole relative to the cranial base).

Mandibular rotation

• Total rotation (True rotation, Internal rotation)

The actual rotation of the core of the mandible (the part of the bone that surrounds the inferior

alveolar nerve) relative to the cranial base, which is a combination of the intramatrix and matrix

rotation.

Mandibular shift (CR-CO shift, Mandibular slide, Forced bite, Slide in centric)

A deflection of the mandible in an anterior, posterior and/or lateral direction, as a result of a

premature contact occurring when the mandible is in centric relation.

[See Occlusal interference (Premature occlusal contact, Supracontact, Deflective occlusal contact,

“Prematurity”), Centric interference]

Mandibular symphysis (Mental sym-physis)

The line of fusion of the lateral halves of the anterior portion of the mandible at the median plane. It

is wide open during fetal life and ossifies by intramembranous ossification in the first year of life,

usually before the emergence of the mandibular deciduous central incisors.

Marking pencil (Arch marker)

Wax pencil usually in white or red for marking archwires intraorally to indicate the desired location

for adjustment bends or loops.

Martensite

A body-centered cubic phase in stainless steels, or a monoclinic, triclinic or hexagonal crystalline

structure of nickel-titanium alloys. The martensitic phase of nickel-titanium exists at lower

temperatures and is characterized by high ductility. It is formed as a result of quenching (rapid

cooling) or cold working the austenite phase. [See also Austenite; Martensitic transformation. ]

[See Martensitic transformation]

[See Austenite]

Mandibular shift (CR-CO shift, Mandibular slide, Forced bite, Slide in centric)

A deflection of the mandible in an anterior, posterior and/or lateral direction, as a result of a

premature contact occurring when the mandible is in centric relation.

[See Occlusal interference (Premature occlusal contact, Supracontact, Deflective occlusal contact,

“Prematurity”), Centric interference]

Masticatory muscles

A group of skeletal muscles providing movement of the mandible and safeguarding the stability of

the TMJs. The masticatory muscles involve the masseter, medial pterygoid and temporal muscles,

which predominantly elevate the mandible (mouth closing); the digastric muscles, which assist in

mandibular depression (mouth opening); the inferior lateral pterygoid muscles, which assist in

protrusion and in contralateral movements of the mandible; and the superior lateral pterygoid

muscles, which provide stability for the condyle and disc during function. The masticatory muscles

are recruited during talking, swallowing and masticating, as well as during nonfunctional

(parafunctional) actions such as grinding and clenching. Motor innervation of the muscles of

mastication is supplied by the trigeminal nerve (CV).

[See Muscle]

Materia alba

White accumulation or aggregation of microorganisms, desquamated epithelial cells, blood cells

and food debris, loosely adhered to surfaces of teeth, soft tissues, dental restorations and

orthodontic appliances.

Maturation

The qualitative changes that occur with ripening or aging. Rapid maturation as well as accelerated

physical growth occurs during puberty.

Maxilla (Upper jaw)

An irregularly shaped paired bone that makes up a major part of the bony framework of the facial

skeleton. It consists of the body of the maxilla and the zygomatic, nasal, palatine and alveolar

processes. The suture between the right and left portions of the maxilla persists into adulthood.

Maxillary

Of or pertaining to the upper jaw.

Maxillary incisor-lip line relationship

See Tooth-to-lip relationship.

[See Tooth-to-lip relationship]

Mechanics

The physical science that deals with the state of rest or motion of bodies under the action of forces.

Mechanics includes two sub-disciplines, statics and dynamics, and is also associated very closely

with materials science. In orthodontics the term often is used as a synonym for mechanotherapy.

SUBTERMS:

Mechanics

• Cantilever mechanics

Orthodontic mechanotherapy using

cantilever springs to generate the

appropriate force systems for specific

types of tooth movement. Because full

bracket engagement is allowed only at

the fixed end of the cantilever with onepoint

contact at the other end, a

statically determinate force system is

achieved. This allows determination of

the produced forces and moments at

both ends of the cantilever by simple

measurements and calculations.

Moreover, the cantilever offers the

possibility of a low load/deflection rate

and a relatively long range of

deactivation, generating an almost

continuous force that generally is

considered desirable for tooth

movement.

[See Orthodontic springs, Cantilever spring]

Mechanics

• Class I mechanics

Orthodontic mechanotherapy utilizing intramaxillary anchorage for tooth movement.

Mechanics

• Class II mechanics

Orthodontic mechanotherapy making use of intermaxillary anchorage (e.g. elastics) between the

anterior aspect of the maxillary and the posterior aspect of the mandibular arch.

Mechanics

• Class III mechanics

Orthodontic mechanotherapy utilizing intermaxillary an-chorage (e.g. elastics) between the anterior

aspect of the mandibular and the posterior aspect of the maxillary arch.

Mechanics

• Continuous archwire mechanics

Orthodontic mechanotherapy utilizing continuous archwires in the entire dental arch (as opposed to

segments of archwires encompassing segments of teeth).

Mechanics

• Frictionless mechanics

The use of strategies or appliances that do not involve friction between archwire and bracket

during tooth movement (e.g. retraction of a tooth by means of a segmental spring).

Mechanics

• Intermaxillary mechanics

The application of forces and/or moments from one arch to the other.

Mechanics

• Intersegmental mechanics

The application of forces and/or moments from one segment of teeth to another.

Mechanics

• Intrasegmental mechanics

The application of forces and moments between teeth that belong to the same segment of an arch.

Mechanics

• Segmental arch mechanics (Sectional mechanics)

Orthodontic mechanotherapy in which not all teeth within an arch are included in the same

archwire, but rather anchorage and active segments are created by consolidating teeth together

using wire segments. Various orthodontic loops and springs (e.g. cantilever springs) and different

types of arches (e.g. intrusive arches) are used to generate the force systems required for

movement of the active segments. Advantages of segmental arch mechanics include the

avoidance of friction and the ability to design statically determinate force systems.

Mechanics

• Sliding mechanics

Mechanotherapy involving sliding of brackets along the archwire during tooth movement (i.e. the

classic “pearls on a chain” example). The archwire generates the counter-moment necessary for

bodily movement of the teeth. Frictional forces are present when tooth movement is performed by

sliding mechanics.

Mechanotherapy

Collective term encompassing all procedures, appliances, and strategies adopted in specific

phases of orthodontic treatment.

[See Mechanics]

Meckel’s cartilage

A curved cylindrical rod of cartilage derived from the first branchial arch that embryologically has a

close positional relationship and guides the development of the mandible. The greater part of

Meckel’s cartilage disappears without contributing directly to the formation of the bone of the

mandible. Only a small part of the cartilage between the future mental foramen and the midline

contributes to the mandible by endochondral ossification. The cartilage at the mandibular

symphysis is not derived from Meckel’s cartilage but differentiates from the connective tissue in the

midline. After the 10th embryonic week, by which time the rudimentary mandible is formed (almost

entirely by intramembranous ossification), Meckel’s cartilage forms the malleus and incus of the

inner ear, the anterior ligament of the malleus, and the sphenomandibular ligament.

[Compare with Reichert’s cartilage]

Median plane (Midsagittal plane)

The imaginary plane passing longitudinally through the middle of the body, dividing it into left and

right halves.

[See Sagittal plane (Parasagittal plane)]

Mediolaterally

In a direction perpendicular to the sagittal plane of the dentofacial complex (along the z-axis). For

incisor teeth this coincides with the mesiodistal direction. For all other teeth, it signifies a

buccolingual direction.

[See Global reference frame]

Mediotrusion

Movement in a medial direction of the contralateral (non-working) half of the mandible and the

respective condyle during a lateral mandibular excursion.

[Compare with Laterotrusion]

Mentolabial fold (Labiomental sulcus)

The shallow groove created where the curvature of the lower lip merges with that of the chin.

Mesial

Toward the midline, following the dental arch. The term is used to describe surfaces of teeth as

well as direction.

[Compare with Distal]

Mesial tipping

Tipping of the crown of a tooth in the mesial direction.

Mesiodens

A supernumerary tooth in the midline of the maxillary alveolar

process. A mesiodens often is unerupted, and it may interfere

with the eruption and position of the maxillary permanent

central incisors.

Mesiodistally

In a direction along the dental arch. For incisor teeth this term signifies a direction approximately

perpendicular to the sagittal plane (along the z-axis), whereas for all other teeth it actually indicates

a direction approximately parallel to the sagittal plane (along the x-axis).

[See Global reference frame]

Mesocephalic

Anthropometric term used to denote a cranial form of average proportions (cephalic index between

76.0 and 80.9).

Michigan Growth Study (University of Michigan Growth Study)

The University of Michigan Elementary and Secondary School Growth Study was founded by Dean

W. Olsen in 1935. It consists of 714 subjects, primarily of Northern European ancestry, on whom

anthropometric, psychometric and craniofacial growth data were obtained on an annual basis while

they were enrolled as students in the University School, a laboratory school located within the

School of Education on the Ann Arbor campus. Collection of cephalometric and other data of

orthodontic interest started in 1953 under the direction of R. E. Moyers. The number of annual

records was variable among subjects and depended on the number of years that each student

attended the University School. Major data collection ended in 1970, but several long-term recall

studies have been conducted since that time. The Michigan Growth Study material is currently

housed at the Schools of Education and Dentistry, University of Michigan in Ann Arbor.

Microdontia

A term denoting smaller than normal tooth size.

[Compare with Macrodontia]

Micrognathia

Abnormally small jaw size.

Midline

A central reference line of a structure about which symmetry between the right and left halves can

be evaluated.

SUBTERMS:

Midline

• Facial midline

An imaginary line splitting the face in two approximately equal right and left halves. In the ideal

situation of absolute symmetry, the facial midline can be considered as a perpendicular to the

interpupillary line from glabella, passing through the tip of the nose, the midpoint of the philtrum of

the upper lip and the midline of the chin.

Midline

• Mandibular dental midline

A line perpendicular to the mandibular occlusal plane, passing through the interproximal contact

point between the mandibular central incisors (or, in absence of contact, the midpoint of the

diastema between them).

Midline

• Maxillary dental midline

A line perpendicular to the maxillary occlusal plane, passing through the interproximal contact point

between the maxillary central incisors (or, in absence of contact, the midpoint of the diastema

between them).

Midline

• Midline of the chin

A line drawn perpendicular to the mandibular plane, dividing the chin in two (right and left) halves.

Midline diastema

A space between the central incisors of the maxillary (common) or mandibular arch (relatively

rare), which may be associated with the presence of a hyperplastic labial frenum, or tongue frenum

in the case of a mandibular diastema.

Midline discrepancy (Midline shift, Midline deviation)

Incongruency between the midlines of the maxillary and mandibular dental arch and/or between

them and the facial midline.

Migration, Pathologic

Spontaneous movement of a tooth out of its natural position, usually as a result of periodontal

disease.

Miller classification

A classification of gingival recession, widely used in periodontology, introduced by P. D. Miller

(1985) as follows:

Class I

Gingival recession in which the marginal tissues have not receded beyond the mucogingival

junction and there is no loss of interproximal soft tissue or bone. In such recessions 100% root

coverage is possible.

Class II

Gingival recession in which the marginal tissues have receded beyond the mucogingival junction,

still with no loss of the interproximal soft tissue or bone. Again, 100% root coverage is possible in

such recessions.

Class III

Class I or Class II gingival recession, combined with loss of interproximal bone, such that the soft

tissue now is apical to the cementoenamel interproximal junction but coronal to the marginal tissue.

100% root coverage is not possible.

Class IV

Gingival recession combined with loss of interproximal bone that is such that one or both of the

adjacent interdental areas is level with the marginal gingiva. No root coverage is possible in Class

IV recessions.

Mixed dentition analysis

The analysis of space available for alignment of the permanent teeth, when the patient is in the

mixed dentition (which involves estimation of the size of the unerupted permanent teeth). There are

three basic approaches to this:

1. Measurement of the size of the unerupted teeth on radiographs. This method is best performed

with individual periapical films, but the accuracy is still limited by the inevitable presence of

distortion, especially in the case of the canines. In addition appropriate compensation for

enlargement is required, which dictates the use of a proportionality ratio (e.g. true width of

deciduous molar/radiographically measured width of deciduous molar = true width of unerupted

premolar/radiographically measured width of unerupted premolar).

2. Estimation from proportionality tables, without the use of radiographs. These data have been

tabulated for white American children by R. E. Moyers based on the combined mesiodistal width of

the mandibular permanent incisors, which is used to predict the size of both the mandibular and

maxillary unerupted canines and premolars. The size of the mandibular incisors correlates better

with the size of the maxillary canines and premolars than does the size of the maxillary incisors,

because maxillary lateral incisors show great variability in size and shape. This method shows a

tendency to overestimate the size of unerupted teeth. An alternative method for predicting the size

of the unerupted canines and premolars by using the width of the mandibular incisors is the

method developed by M. M. Tanaka and L. E. Johnston, Jr. According to that, the width of the

mandibular canine and premolars in one quadrant can be calculated by adding 10.5 mm to half of

the measured mesiodistal width of the four mandibular incisors. Similarly, the width of the maxillary

canine and premolars in one quadrant can be determined by adding 11.0 mm to half of the

measured mesiodistal width of the four mandibular incisors. The method shows a small tendency

toward overestimating the unerupted tooth sizes. Its advantage is that it does not require

radiographs or reference tables.

3. Combination of the radiographic and prediction table methods. Since the major problem with

using radiographic images comes in evaluating the canine teeth, another option is to use the size

of the permanent incisors measured from the dental casts and the size of the permanent premolars

measured from the films to predict the size of the unerupted canines. Graphs are available (such

as that by R. N. Staley and R. E. Kerber) that allow determination of the mandibular canine from

the sum of incisor and premolar widths. The technique is limited to the mandibular arch and

requires periapical radiographs.

Mode of force application (Force regime)

The time-related aspect of orthodontic

force application: the magnitude of a

continuous force is more or less

maintained between activations, that of

an intermittent force declines with time

until a reactivation is performed, whereas

that of an interrupted force drops to zero

between activations (the force is

removed temporarily).

[See Force]

Model surgery

A simulation of the actual surgical

procedure using the patient’s presurgical casts, which are mounted on an articulator. The purposes

of this simulation are to verify that the movements planned by the surgical prediction tracing

actually can be performed and to relate the casts in the position where the surgical splints will be

fabricated. If both jaws are to be repositioned, the maxillary cast is moved first and fixed on the

articulator. In this position, the first surgical splint (intermediate splint) is made. Then the

mandibular cast is repositioned to simulate the occlusion at the completion of surgery. The final

surgical splint is made with the casts in this position. The model surgery is based on a combination

of the surgical prediction and the presurgical clinical diagnostic information.

[See Splint, Surgical splint (Surgical wafer)]

Model trimmer

A device used for trimming plaster and stone casts. Its main component is a large rotating grinding

wheel, which is kept wet by a stream of water to reduce dust and keep the cutting wheel clean.

Modeling (of bone)

A process involving independent sites of resorption and formation that change the intrinsic form

(shape and/or size) of a bone, in contrast to the term “remodeling,” which signifies a specific

coupled sequence of resorption and formation events to replace previously existing bone. Bone

modeling is the dominant process in growth as well as in adaptation to applied loads such as those

produced with headgear, rapid palatal expansion, functional appliances, etc. Traumatic or surgical

wounding usually results in intense but localized modeling and remodeling responses. Following

fractures, osteotomies or placement of endosseous implants, the processes of callus formation and

resorption of necrotic osseous margins are modeling processes. In contrast, replacement of the

devitalized cortical bone surrounding these sites is a remodeling activity.

[See Remodeling (of bone)]

Models, Plaster

[See Orthodontic casts (Orthodontic models)]

Modulus of elasticity E (Young’s modulus of elasticity, E-modulus)

The slope of the stress/strain curve in its linear portion (below the elastic limit) (E = s/e). It is an

inherent property of the material, which measures its stiffness. A material with a high modulus of

elasticity deforms less than a material with a low modulus, when subjected to identical loads. The

modulus of elasticity of a certain material is not influenced by its geometrical shape (length and

cross-sectional area) and it cannot be altered appreciably by heat treatment, work-hardening, or

any other type of conditioning. The modulus of elasticity of an orthodontic wire determines its load/

deflection rate, and it can be changed only by changing the wire material.

[See Stress/strain diagram (Stress/strain curve)]

[See Load/deflection rate (Force/deflection rate)]

Moment

Rotational tendency.

SUBTERMS:

Moment

• Counter-moment

When a single force is applied at the bracket of a tooth, uncontrolled tipping probably will result,

due to generation of a moment (since the force is applied at a distance from the center of

resistance of the tooth). This will tend to move the crown in the direction of the force and the apex

in the opposite direction. If bodily movement of the tooth is desired, a reverse moment (countermoment)

must be applied simultaneously to prevent the unwanted movement of the apex.

This counter-moment can be generated either by a second force or, more commonly, by a couple.

When sliding mechanics is used for retraction of a canine, the counter-moment is generated by a

couple, formed by contact of the archwire with the mesial-gingival and distal-occlusal wings of the

canine bracket, following a small initial unopposed distal tipping movement. When a segmental

spring (loop) is used for canine retraction, the counter-moment is generated by the spring itself.

[See Canine retraction]

[See Moment-to-force ratio]

Moment of a couple

Unlike the curvilinear motion produced by a

moment of a force, the moment of a couple

produces a tendency to pure rotation around

the center of mass (when applied on a free

body), or around the center of resistance

(when a partially constrained body, e.g. a

tooth, is involved).

The moment produced by a couple is a

vectorial quantity. It has a magnitude equal to

the product of the magnitude of one of the two

forces F, times the perpendicular distance d

between the two forces (Mcouple = F x d);

thus it is measured in units of force x distance

(i.e. N mm, or g mm). Its direction is

perpendicular to the plane of the pair of the

forces, and its sense is either clockwise or

counterclockwise, as viewed looking into the plane of the couple. A couple can be applied

anywhere on a rigid object, creating the same rotational effect. This is why the moment of a couple

is said to be a free vector.

[See Couple]

Moment of a force

The moment of a force about a specified point or line is a measure of

the potential of that force to rotate the body, upon which the force

acts, about the particular point or line.

The moment M of a force F about a point is also a vectorial quantity.

Its magnitude is given by the formula M = F x d (where d is the

“moment arm”). A moment of a force is also measured in units of

force x distance (i.e. N mm, or g mm). The direction of the moment

vector is perpendicular to the plane defined by the force vector and

the point about which the moment is considered. The sense of the

vector is determined by a rule associated with the rotational

tendency, as viewed from above the plane of the force vector and the

point about which the moment is considered. By convention,

counterclockwise moments (out of the plane) are said to be positive,

whereas clockwise moments (into the plane) are considered

negative.

The shorter the moment arm, the smaller the moment of a force. A

moment of a force acting on a body can be considered about any

specific point on the body; in orthodontics the center of resistance is

commonly used. A force passing through an arbitrary point obviously

produces no moment about it.

Moment arm

The perpendicular distance (d) of the point about which the moment is determined to the line of

action of the force producing the moment.

Moment-to-force ratio

The ratio of magnitudes of the uprighting (counter-)moment applied at the bracket of a tooth to

control the location of the center of rotation, to the tooth-moving force that is applied at the same

point (the bracket).

The counter-moment usually is the moment of a couple. In terms of sense, the counter-moment

always is opposite to that of the moment of the force, relative to the center of resistance. Since

moments are measured in gram millimeters and forces in grams, the ratio of the two has units of

millimeters; this represents the distance away from the bracket that a single force will produce the

same effect. [However, it has become conventional in orthodontics to ignore these units and just

speak of the moment-to-force ratio as a pure number. ]

The moment-to-force ratio is used in two-dimensional analysis as an indicator of the type of tooth

movement that will occur. C. J. Burstone and R. J. Pryputniewicz estimated the different momentto-

force ratios required for various types of tooth movement for a 3-D model of an ideal maxillary

central incisor with intact periodontium. When only a force is applied at the bracket of a tooth (M/F

ratio of zero), the center of rotation is at, or just apical to, its center of resistance. The resulting

tooth movement is uncontrolled tipping. The more the counter-moment increases, the more the

center of rotation moves in an apical direction. With a distance from the bracket to the center of

resistance of 10 mm, the center of rotation approaches infinity as the M/F ratio approaches 10:1.

As soon as the M/F ratio exceeds 10:1, the net moment at the center of resistance changes

direction, since the magnitude of the counter-moment is now greater than that of the moment

produced by the applied force. The center of rotation is slightly incisal to the center of resistance.

When the M/F ratio becomes 12:1 or 13:1, the center of rotation is displaced at the incisal edge,

resulting in pure root movement. Further increase of the M/F ratio up to about 20:1 causes the

center of rotation to gradually move to a location just incisal to the center of resistance. It is

obvious that small changes in the M/F ratio have major effects on the clinically observed tooth

movement.

As mentioned previously, it is the ratio between the applied counter-moment and force (and not

their absolute magnitudes) that determines the type of tooth movement. However, this mechanical

principle does not take into account the fact that the magnitudes of forces and couples are

important in determining the biologic response to an orthodontic force system.

[See Orthodontic tooth movement]

Mouth breathing

The habit of breathing primarily through the oral cavity, which traditionally has been associated with

some detrimental dentofacial changes and associated malocclusion. Specifically, the theory is that

breathing through the mouth, rather than the nose, could bring about some postural changes,

namely tipping of the head back and lowering of the mandible and tongue, in order to facilitate

respiration. If these postural changes are maintained, face height may increase and the posterior

teeth may overerupt, with resulting downward and backward rotation of the mandible, steep

mandibular plane and open bite tendency. As well, the change in equilibrium between the soft

tissues and the jaws and teeth could result in compensatory dental changes, such as a constricted

maxillary arch, tendency to a crossbite and upright mandibular incisors. In addition, mouth

breathing creates xerostomia, which can predispose to gingival hyperplasia and inflammation, as

well as caries, at least in the anterior aspect of the dental arches.

The possible association of mouth breathing and the above described craniofacial pattern, as well

as its relationship to nasal airway obstruction, is yet another controversial issue, which has led to

many referrals of orthodontic patients for adenoidectomy over the years.

[See “Adenoid facies”]

Mucogingival junction (MGJ)

The junction between the keratinized gingiva and the non-keratinized oral mucosa.

Mucosa

The epithelial lining of body cavities opening to the outside, consisting of a mucous membrane.

SUBTERMS:

Alveolar mucosa

Masticatory mucosa

Oral mucosa

Multidisciplinary treatment

Coordinated collaboration of multiple specialties in the treatment of a single individual.

Multifactorial

Resulting from the combined action of several factors.

Muscle

Tissue composed of contractile fibers that effect movements of an organ or body part. Muscle

types include striated (skeletal and cardiac) muscles and non-striated, smooth (visceral) muscles.

SUBTERMS:

Buccinator muscle

Digastric muscle

Lateral (External) pterygoid muscle

Masseter muscle

Medial (Internal) pterygoid muscle

Orbicularis oris

Scalene muscles

Sternocleidomastoid muscle

Suprahyoid muscles

Temporalis muscle

Trapezius muscle

Muscle contraction

The development of tension or shortening of a muscle.

Muscle spasm (Myospasm, Muscle cramp)

Spasmodic continuous involuntary contraction of a muscle or group of muscles, typically

associated with acute pain and dysfunction.

[Compare with Protective muscle splinting (Reflex muscle splinting)]

Myalgia

Muscle pain.

Myofascial

Pertaining to the muscle and its attaching fascia.

Myofascial pain (Myofascial pain dysfunction syndrome, MPDS)

Regional pain referred from or emanating around active myofascial trigger points.

Myofascial trigger point

Hyperirritable spot, usually within a taut band of skeletal muscle or in the muscle fascia that is

painful on compression and can give rise to characteristic referred pain, tenderness and autonomic

phenomena. Myofascial trigger points are subdivided into active and latent.

SUBTERMS:

Myofascial trigger point

• Active myofascial trigger point

Myofascial trigger point responsible for local or referred current pain, or symptoms without

stimulation through palpation.

Myofascial trigger point

• Latent myofascial trigger point

Myofascial trigger point with all the characteristics of an active myofascial trigger point, including

referred pain with palpation, but not currently causing spontaneous clinical pain or symptoms.

Myofunctional therapy (Muscle exercises)

Therapy aiming at improvement of muscle function and the habitual position of soft tissues (e.g.

therapy for correction of a tongue-thrust habit) to prevent or maintain the correction of any occlusal

or dental abnormalities associated with them. The concept was introduced to orthodontics by A.

Rogers in 1918.

Nasal obstruction

Inhibition of normal nasal breathing due to a mechanical impediment of the nasopharyngeal airway.

Nasal obstruction generally induces mouth breathing, but the reverse is not always true (i.e. the

presence of mouth breathing does not necessarily suggest nasal obstruction), as mouth breathing

could be habitual.

[See “Adenoid facies”]

Natural head position

A standardized orientation of the head that is reproducible for each individual and is used as a

means of standardization during analysis of dentofacial morphology. The concept of natural head

position was introduced by C. F. A. Moorrees and M. R Kean in 1958 and now is a common

method of head orientation for cephalometric radiography.

To accomplish natural head position, the patient is asked to look into a mirror placed in front of him/

her at eye level (as if he/she were looking at the horizon), with the interpupillary line parallel to the

floor. Advocates of this method maintain that registration of the head in its natural position while

obtaining a cephalogram has the advantage that an extracranial line (the true vertical or a line

perpendicular to that) can be used as a reference line for cephalometric analysis, thus bypassing

the difficulties imposed by the biologic variation of intracranial reference lines.

[Compare with Natural head posture]

Neckstrap

The component of an extraoral appliance (e.g. cervical headgear) that distributes and transfers

reaction forces to the cervical area.

Neuralgia

Paroxysmal or constant pain, typically with sharp, stabbing, itching or burning character, in the

distribution of a nerve.

Newton’s laws

All principles of mechanics are based on three physical laws presented in 1686 by Sir I. Newton in

his “Philosophea Naturalis Mathematica. ” The laws of Newton are:

SUBTERMS:

Newton’s laws

• I. Law of inertia

When the sum of all the external forces acting on a body is zero, the motion of the body is

unchanged (the body either remains at rest, or continues its motion at a straight line with a

constant velocity).

Newton’s laws

• II. Law of acceleration

If the sum of all the forces acting on a body is not equal to zero, the motion of the body is

accelerated along the line of action of the resultant force. The acceleration is proportional to the

resultant force and inversely proportional to the mass of the body.

Newton’s laws

• III. Law of action and reaction

To every force (action) in a given system, there is an equal and opposite reaction force, so that the

sum of all the forces (SF) and the sum of all the moments (SM) in the system always is equal to

zero.

Neurotrophism

The hypothesis that skeletal growth is under control of the nervous system, assumedly by

transmission of substances through the axons of the nerves, much like neural activity controls

muscle growth and activity.

Neutral position

During the activation process of an orthodontic spring, the position of the spring with only the

activation moments placed on it (but with zero force).

Nickel-titanium alloy (Ni-Ti)

Family of alloys primarily consisting of nickel (approximately 55%), titanium (approximately 45%)

and optionally of third elements such as cobalt or copper. Nickel-titanium alloys were first reported

in the orthodontic literature by G. F. Andreasen in 1971. The name of the first commercially

available product was Nitinol. Nitinol was developed originally for the U. S. Navy, in the early

1960s, by W. F. Buehler, a research metallurgist at the Naval Ordnance Laboratory in Maryland.

[The name “nitinol” is an acronym derived from nickel and titanium composition, along with the

suffix -nol which stands for Naval Ordnance Laboratory. ] Although the original nitinol wire (Unitek/

3M) did not exhibit superelastic behavior, it possessed two features of considerable importance for

clinical orthodontics:

1. A very low elastic modulus (E), corresponding to about one-fifth of the force delivery of stainless

steel wires, and half the force delivery of beta-titanium archwires of the same length and crosssectional

dimensions.

2. An extremely wide working range. A “second generation” superelastic Chinese nickel-titanium

alloy (marketed as “Ni-Ti” by Ormco/Sybron) exhibits non-linear loading and unloading

characteristics more pronounced than those of the original nitinol wire.

A “third generation” Japanese nickel-titanium alloy (marketed as “Sentalloy” by GAC International)

was subsequently introduced, which also exhibits superelastic behavior. [The name Sentalloy is an

acronym of the words superelastic nickel titanium alloy. ] The unloading characteristics of this type

of Ni-Ti alloys exhibit initial and final regions of relatively steep slope, along with an extensive

intermediate region where there is little or no change in stress.

The superelastic behavior and shape memory characteristics of nickel-titanium alloys are based on

a reversible transformation between the austenitic and martensitic Ni-Ti phases. Some of the

available nickel-titanium wires are termed “thermally activated” wires due to the fact that their

transition temperature is close to the level of body temperature.

Nickel-titanium alloys have characteristic properties that are very useful in orthodontics, namely

superelasticity, excellent springback, large working range and low stiffness. However, Ni-Ti wires

cannot be soldered or welded without losing their properties, and their friction coefficient is higher

than that of stainless steel (although still lower than that of beta-titanium). Ion-implantation may aid

in reducing the frictional resistance of nickel-titanium wires.

[See Martensitic transformation]

[See Shape memory]

Nickel-titanium wire

[See Nickel-titanium alloy (Ni-Ti)]

Nightguard (Bruxism appliance)

A removable acrylic interocclusal appliance worn at night to prevent or reduce dental wear resulting

from bruxism.

Nitinol

[See Nickel-titanium alloy (Ni-Ti)]

Nociception

Stimulation of specialized nerve endings designed to transmit information to the central nervous

system concerning potential or actual tissue damage (painful sensation).

Non-extraction therapy

Orthodontic treatment without any extractions of permanent teeth (wisdom teeth generally

excluded).

Non-invasive

Denoting any diagnostic or therapeutic procedure that does not require penetration of the skin or

entrance into a cavity or organ of the body.

Non-occlusion

Any situation in which teeth do not have maximal contact with their antagonists in habitual

occlusion. Non-occlusion may be caused by disturbances in tooth eruption (e.g. ankylosis) or by

factors that inhibit further eruption, such as digit-sucking or tongue interposition. According to its

localization, non-occlusion can be classified as anterior, posterior or total non-occlusion.

[Compare with Open bite (Negative overbite)]

SUBTERMS:

Non-occlusion

• Anterior non-occlusion

Non-occlusion in the incisor area, which may be combined with some degree of vertical overlap of

the incisors, as frequently seen in Class II, Division 1 malocclusions.

Non-occlusion

• Posterior non-occlusion

Non-occlusion in the premolar or molar area, with great variation in the number of teeth and in the

occlusal surfaces involved.

Non-occlusion

• Total non-occlusion

A situation characterized by absence of maximal occlusal contact of all posterior teeth, combined

with an anterior non-occlusion. In total non-occlusions the tongue usually is positioned between all

opposing teeth most of the time.

Non-steroidal anti-inflammatory drug (NSAID)

Class of anti-inflammatory medications that also provide analgesia, but lack the detrimental side

effects associated with steroid use.

Non-working side (Mediotrusive side, Non-functioning side, Balancing side)

The side opposite to the functioning (working) side on a lateral excursion of the mandible. The side

the mandible is moving away from, during a lateral excursion.

Normal occlusion theory of Angle

[See Extraction vs. non-extraction debate]

Obstructive sleep apnea (OSA, Obstructive sleep apnea syndrome, OSAS)

Breathing abnormality occurring during sleep, characterized by repeated collapse of the upper

airway, producing hypopnea, apnea and, ultimately, desaturation of hemoglobin. The hypopneic

and apneic episodes produce frequent arousal from sleep patterns. The effects of repeated

desaturation significantly alter normal cardiovascular and pulmonary function, resulting in

pulmonary and systemic hypertension as well as arrhythmias, which if untreated can lead to death.

The etiology of OSA appears to be neurogenic failure to preserve the patency of the pharyngeal

airway during sleep. The condition often is combined with airway obstruction at various anatomic

locations, such as the nasal cavity, adenoids, soft palate, tonsils or base of the tongue. Obesity is

considered a predisposing factor in the etiology. In the adult OSA population, males are affected 10

to 20 times more often than females. Almost all apneic patients snore loudly at night. The diagnosis

of OSA is made by polysomnography (multiphysiologic sleep recording).

Various treatment modalities advocated include weight loss (if patient is obese), nasal continuous

positive air pressure (nasal CPAP), or surgical uvulo-palato-pharyngoplasty (UPPP). Removable

intra-oral appliances that advance the mandible sometimes are used to re-establish the patency of

the airway, as well as to determine whether an orthognathic surgical correction is indicated.

Obturator

A dental prosthesis or appliance used to close a congenital or acquired opening. Sometimes used

to cover a remaining oronasal fistula or to facilitate the velopharyngeal mechanism in a patient with

a history of cleft lip and palate.

Occlusal

Pertaining to the masticatory surfaces of the posterior teeth. (Also may be used to identify a

coronal direction. )

Occlusal contact

A contact between maxillary and mandibular teeth during occlusion.

SUBTERMS:

Occlusal contact

• Non-working side contact (Mediotrusive contact, Balancing contact)

A contact between maxillary and mandibular teeth on the side opposite to the working side during a

lateral mandibular excursion. [Note: The term “non-working contact” is used when there is at least

one simultaneous contact on the working side. If the occlusal contact on the non-working side

causes disclusion of the teeth on the working side, the term “non-working interference” is used. ]

[See Occlusal interference (Premature occlusal contact, Supracontact, Deflective occlusal contact,

“Prematurity”), Non-working side interference (Mediotrusive side interference, Balancing

interference)]

Occlusal contact

• Working side contact (Laterotrusive occlusal contact)

A contact between maxillary and mandibular teeth on the ipsilateral side during guided lateral

excursive movement of the mandible.

Occlusal dysfunction

A malocclusion with impaired function.

Occlusal equilibration (Occlusal adjustment)

Selective grinding of occlusal surfaces of the teeth in an effort to eliminate premature contacts and

occlusal interferences, to achieve balancing of the functional occlusal load on the teeth, to

eliminate occlusal trauma, to address muscle tension and associated pain, to improve functional

relations or to aid in the stabilization of orthodontic results.

Occlusal equilibrium

The stage of eruptive tooth movement starting at the point that a tooth reaches the occlusal level

and is in complete function. Occlusal equilibrium is divided into juvenile and adult phases.

SUBTERMS:

Occlusal equilibrium

• Adult occlusal equilibrium

The final phase of tooth eruption after the end of the pubertal growth spurt. During this phase the

rate of tooth eruption is extremely slow.

[See Physiologic tooth movement]

[See Post-emergent spurt]

Occlusal equilibrium

• Juvenile occlusal equilibrium

The phase of tooth eruption after the post-emergent spurt and during the period of the pubertal

growth spurt. During the juvenile equilibrium, teeth that are in function erupt at a rate that parallels

the rate of vertical growth of the mandibular ramus. The rate of tooth eruption during this stage is

much slower than during the post-emergent spurt, but faster than during the adult equilibrium.

[See Post-emergent spurt]

[See Physiologic tooth movement]

Occlusal guidance

The contact pattern between teeth during dentally guided mandibular movement away from or

toward maximum intercuspation.

Occlusal interference (Premature occlusal contact, Supracontact, Deflective occlusal

contact, “Prematurity”)

Undesirable occlusal contact that may produce mandibular deviation during closure to maximum

intercuspation or may hinder smooth passage to and from the intercuspal position.

SUBTERMS:

Occlusal interference (Premature occlusal contact, Supracontact, Deflective occlusal contact,

“Prematurity”)

• Centric interference

A premature contact occurring when the mandible closes with the condyles in their optimum

position in the glenoid fossae (centric relation), which causes a deflection (shift) of the mandible in

an anterior, posterior and/or lateral direction.

Occlusal interference (Premature occlusal contact, Supracontact, Deflective occlusal contact,

“Prematurity”)

• Non-working side interference (Mediotrusive side interference, Balancing interference)

A contact between maxillary and mandibular teeth on the non-working side that causes disclusion

of the teeth on the working side during a lateral mandibular excursion.

[Compare with Occlusal contact, Non-working side contact (Mediotrusive contact, Balancing

contact)]

Occlusal interference (Premature occlusal contact, Supracontact, Deflective occlusal contact,

“Prematurity”)

• Protrusive interference

An occlusal contact between maxillary and mandibular posterior teeth discluding the incisors

during a protrusive mandibular excursion.

Occlusal plane (OP)

An imaginary surface that passes through the occlusion of the teeth. This surface usually is curved

and is, strictly speaking, not a plane, but commonly is approximated by one (straight line in the

lateral view), based on specific reference points with in the dental arches. The maxillary occlusal

plane passes through the occlusal cusps of the posterior teeth and the incisal edges of the

maxillary incisors. The mandibular occlusal plane is tangent to the occlusal cusps of the posterior

teeth and the incisal edges of the mandibular incisors.

[See Cephalometric lines (planes), Occlusal plane (OP)]

Occlusal rest (Occlusal lug, Occlusal stop)

The part of a removable appliance that rests on the occlusal surface of a tooth and prevents

movement of the appliance toward the soft tissue. Occlusal rests sometimes are soldered on fixed

appliances, such as a “band and loop” space maintainer, to resist dislodgment of the appliance as

a result of the forces of mastication.

Occlusal trauma (Traumatic occlusion, Trauma from occlusion, Periodontal trauma)

1. Injury to the periodontium resulting from occlusal forces in excess of the reparative capacity of

the periodontal attachment. The affected teeth usually exhibit widening of the PDL space, wear

facets and some degree of hypermobility.

2. The same term sometimes is used to denote a palatally impinging overbite.

[See Tooth mobility, Increased mobility (Hypermobility)]

[See Impinging overbite]

SUBTERMS:

Primary occlusal trauma

Secondary occlusal trauma

Occlusion

The relationship of the maxillary and mandibular teeth, as they are brought into functional contact.

SUBTERMS:

Occlusion

• Centric occlusion (CO, Intercuspal position, ICP, Habitual occlusion)

Mandibular position dictated by maximum and habitual intercuspation of the maxillary and

mandibular teeth. It is a dentally determined position, independent of condylar position.

Occlusion

• Functional occlusion (Physiological occlusion)

A static and dynamic relationship of the teeth combining minimum stress on the

temporomandibular joint, optimal function of the orofacial complex, stability and esthetics of the

dentition and protection and health of the periodontium.

Occlusion

• Optimal occlusion (Ideal occlusion)

An ideal relationship of maxillary and mandibular teeth combining a functional occlusion with the

absence of malocclusion (as described by the six keys of occlusion).

[See Ideal occlusion]

[See Occlusion, Functional occlusion (Physiological occlusion)]

Occlusal trauma (Traumatic occlusion, Trauma from occlusion, Periodontal trauma)

1. Injury to the periodontium resulting from occlusal forces in excess of the reparative capacity of

the periodontal attachment. The affected teeth usually exhibit widening of the PDL space, wear

facets and some degree of hypermobility.

2. The same term sometimes is used to denote a palatally impinging overbite.

[See Tooth mobility, Increased mobility (Hypermobility)]

[See Impinging overbite]

SUBTERMS:

Primary occlusal trauma

Secondary occlusal trauma

Occlusogingivally (Occlusoapically)

In a direction perpendicular to the occlusal plane, along the y-axis.

[See Global reference frame]

Occlusogram

A graphic representation of the arches from the occlusal view. Occlusograms are mainly used as

treatment planning aids to assist in defining the specific tooth movements required within and

between arches (in the sagittal and transverse planes) to achieve treatment goals. An occlusogram

is essentially a two-dimensional diagnostic setup and is directly correlated with the Visual

Treatment Objective (VTO). It can be constructed from tracings of photographic or photostatic

copies of the occlusal aspects of the maxillary and mandibular study casts. The tracings of the

teeth of both arches are superimposed on each other to reproduce the existing occlusal

relationship, using index points that are marked on the models and subsequently transferred to the

tracings. Anticipated movements of individual teeth as well as the need for extractions then can be

determined, to simulate the desired treatment goal.

[See Visual treatment objective (VTO)]

[See Diagnostic setup (Kesling setup)]

Occult cleft

[See Submucous cleft palate]

Oculoauriculovertebral spectrum

[See Hemifacial microsomia (First and second branchial arch syndrome)]

Oligodontia

The congenital absence of multiple teeth (a severe form of hypodontia). In many such patients, the

existing teeth are smaller than normal and can be shaped atypically.

[Compare with Anodontia]

Open bite (Negative overbite)

Inherited, developmental or acquired malocclusion whereby no vertical overlap exists between

maxillary and mandibular anterior teeth (anterior open bite), or no vertical contact is exhibited

between maxillary and mandibular posterior teeth (posterior open bite). An open bite may be

localized and thus involve only a few teeth due to a digit-sucking habit or other local factors (dental

open bite), or it may be caused by divergence of the skeletal planes (skeletal open bite or

apertognathia).

[Compare with Non-occlusion]

Opening of the bite

The correction of a deep bite. This can be performed by extrusion of posterior teeth, often resulting

in clockwise rotation of the mandible (increased separation between the mandibular and palatal

planes); by intrusion of the anterior teeth; or by a combination of the two methods (relative intrusion

of the anterior teeth).

[See Bite raising]

Optimal force theory

The hypothesis that there exists a force of certain magnitude and temporal characteristics

(continuous vs. intermittent, constant vs. declining, etc. ) that is capable of producing a maximum

rate of tooth movement with no tissue damage and maximum patient comfort. The optimal force for

tooth movement may differ for each tooth, or for each individual patient.

Orbital hypertelorism

The increased distance between the medial orbital walls, reflecting an increased distance between

the orbits (greater than 2 standard deviations from the norm). The anatomic landmarks used

commonly for the measure-ment of interorbital distance are the dacryon points (bilaterally).

Hypertelorism is described on the basis of skeletal measurements, because the presence of

epicanthal folds or strabismus (exotropia), or other soft-tissue variations such as increased

distance between the medial canthi (telecanthus) clinically may give a false impression of

hypertelorism. Orbital hypertelorism is common in a number of craniofacial malformations such as

Crouzon syndrome and frontonasal dysplasia.

[Compare with Telecanthus]

[Compare with Orbital hypotelorism]

Orbital hypotelorism

The decreased distance between the medial orbital walls, a common finding in patients born with

malformations such as a median cleft. A patient with orbital hypotelorism has a much greater

chance of severe brain abnormality than does one with hypertelorism.

[Compare with Orbital hypertelorism]

Orofacial

Pertaining to the mouth and face.

Oronasal communication

[See Fistula, Oronasal fistula]

Orthodontic attachment

[See Attachment, Orthodontic]

[See Button]

[See Eyelet]

[See “Pigtail” attachment (Coil eyelet)]

[See Tube (Molar tube)]

Orthodontic band

A ring, usually made of a thin strip of stainless steel, that serves to secure orthodontic attachments

to a tooth. Bands are prefabricated in varying shapes to fit closely around the crowns of specific

teeth. Each shape comes in different sizes to accommodate individual tooth size variation. Most

bands have an occluso-gingival taper to fit the tooth, with the incisal edge straight and the cervical

edge contoured, similar to the cementoenamel junction. Orthodontic bands can be plain or have

buccal (brackets or tubes) or lingual (buttons, sheaths, cleats, seating lugs) attachments welded or

brazed on them. The inner surface of the band can be conditioned by various methods such as

pattern rolling, sandblasting, photo- or laser-etching to increase retention.

Orthodontic cement

Dental cement used for fixation of orthodontic bands to the teeth.

SUBTERMS:

Glass-ionomer cement

Resin-modified glass-ionomer cement (Dual-cured glass-ionomer cement)

Zinc oxide-eugenol (ZOE) cement

Zinc phosphate cement

Orthodontic elastics (Rubber bands)

Flexible bands, usually made of elastomeric material, used to produce forces for tooth movement.

SUBTERMS:

Orthodontic elastics (Rubber bands)

• Anterior diagonal elastics (Anterior oblique elastics)

Anterior intermaxillary elastics crossing the midline (e.g.

extending from the maxillary right canine to the

mandibular left lateral incisor), often used to facilitate the

correction of non-coinciding maxillary and mandibular

dental midlines.

Orthodontic elastics (Rubber bands)

• Asymmetric elastics

Various combinations of intermaxillary elastics (e.g. Class III elastics on one side and Class II

elastics on the other) used to correct an asymmetry in the buccal segment occlusion, with or

without an associated midline discrepancy.

Orthodontic elastics (Rubber bands)

• Class II elastics

Intermaxillary elastics extending unilaterally or

bilaterally from the anterior aspect of the maxillary

dental arch to the posterior aspect of the mandibular

one (e.g. from the maxillary canines to the mandibular

first molars). They are used to aid in Class II correction,

to reduce the overjet, to minimize anchorage loss

during maxillary incisor retraction by taking advantage

of intermaxillary anchorage, etc. In addition to the

desired sagittal force, Class II elastics create vertical

forces (especially when the patient opens their mouth)

as well as certain transverse forces, both of which often

are undesirable.

Orthodontic elastics (Rubber bands)

• Class III elastics

Intermaxillary elastics with the opposite orientation to

Class II elastics (from the anterior aspect of the

mandibular dental arch to the posterior aspect of the

maxillary one). As in the instance of Class II elastics,

Class III elastics can be used unilaterally or bilaterally.

They have various applications: to facilitate protraction

of maxillary posterior teeth, to improve the incisor

relationship in an edge-to-edge or anterior crossbite situation, or to make use of intermaxillary

anchorage during mandibular incisor retraction. In addition to the desired sagittal force, Class III

elastics create vertical forces (especially when the patient opens their mouth), as well as certain

transverse forces, both of which often are undesirable.

Orthodontic elastics (Rubber bands)

• Crossbite elastics (Criss-cross elastics, Through-the-bite elastics)

Elastics extending from the palatal (lingual) aspect of one or more maxillary teeth,

to the buccal aspect of one or more mandibular teeth (or the reverse), to aid in

correction of a crossbite. Crossbite elastics create vertical forces in addition to the

desirable trans-verse or anteroposterior forces; they therefore should be used with

caution, especially in patients with minimal overbite and long anterior lower facial

height.

Orthodontic elastics (Rubber bands)

• Intermaxillary elastics (Intermaxillary traction)

Elastics running between maxillary and mandibular teeth for sagittal, transverse or

vertical coordination of the arches, or a combination of the above. Class II, Class

III and crossbite elastics are all examples of intermaxillary traction. Intermaxillary elastics generate

forces in all three planes of space, only some of which are usually desirable. They therefore should

be used with caution, especially in patients with minimal overbite and long anterior lower facial

height.

Orthodontic elastics (Rubber bands)

• Intramaxillary elastics (Class I elastics, Intramaxillary

traction)

Elastic traction between teeth or groups of teeth of the same

arch. For example, patients sometimes are requested to

wear such elastics during canine retraction using sliding

mechanics.

Orthodontic elastics (Rubber bands)

• Transpalatal elastics

Intramaxillary form of elastic traction extending across the palatal vault (e.g. between two lingual

cleats on the second molar bands) in an attempt to constrict the maxillary arch form, or to

reciprocally move buccally displaced teeth into the arch.

Orthodontic elastics (Rubber bands)

• Vertical elastics (Up-down

elastics, Box elastics,

Triangular elastics, Zig-zag

elastics, “Spaghetti” elastics)

Intermaxillary elastics in various configurations, aiming at extrusion of teeth. They are used to aid

in settling (improve the interdigitation) in the final stages of active treat-ment, to achieve closure of

a localized open bite, or to aid in postsurgical leveling of the mandibular curve of Spee by premolar

extrusion (e.g. in Class II, Division 2 patients with short lower facial height).

Orthodontic impression trays

Stainless steel, aluminum or plastic trays used to receive the impression material (usually alginate)

during orthodontic impression taking. An orthodontic impression tray consists of a main body and a

handle, which is either welded or riveted to the body. The maxillary tray allows for coverage of the

maxillary alveolar process and the palate, whereas the mandibular tray allows for coverage of the

mandibular alveolar process. Some tray bodies are perforated to increase retention of the

impression material. Trays are available in various sizes and shapes. The flanges of the tray are

usually extended with rope wax to achieve representation of the full depth of the vestibule during

taking of impressions for orthodontic study models.

Orthodontic instruments

Orthodontic procedures demand the use of many specialized instruments, along with several also

used in other areas of dentistry.

SUBTERMS:

Orthodontic instruments

• Adams pliers (Universal pliers)

Heavy wire pliers with sharply tapered beaks forming a four-sided pyramid when closed. Used for

bending heavy-gauge wires and adjusting removable appliances.

Orthodontic instruments

• Arch-forming pliers (Arch-contouring pliers, De la Rossa

pliers)

Pliers with straight, thick, parallel beaks; the concave beak

fits around the opposing cylindrical one. The cylindrical beak

may have grooves of varying sizes or may be non-grooved.

Used to form and contour archwires, either round or

rectangular, as well as to incorporate (reverse) curve of Spee into an archwire.

Orthodontic instruments

• Band burnisher (Beaver-tail burnisher)

Stainless steel instrument with a heavy, hollow handle

for palm grip, similar to a Mershon band pusher. The

shank ends in an angled beaver-tail-shaped tip that

can be smooth or serrated and flattened for easier

access to band margins under buccal tubes or bracket

wings. Used for burnishing and adapting margins of

bands to the tooth contour.

Orthodontic instruments

• Band-contouring pliers

Pliers with two long, tapering and slightly bowed

beaks. The convex tip at the end of the one beak fits

into the opposing concave tip in a ball- and-socket

manner. The diameter and shape of the tips vary with

the manufacturer. Used for adaptation and contouring

of stainless steel orthodontic bands.

Orthodontic instruments

• Band pusher (Mershon band pusher)

Stainless steel instrument with a large, tapering handle

for palm grip and a long shank with an angled tip. The

tip is rectangular and serrated to prevent slippage of

the instrument during use. Used for positioning and

seating the band properly, as wellas for burnishing or

adapting the edges of the band around the tooth.

Orthodontic instruments

• Band-removing (Debanding) pliers, Anterior

Pliers with a longer, flat-sided curved beak placed on the

incisal edge of teeth, opposing a shorter, sharper beak

positioned under the gingival aspect of the band or

attachment. The longer incisal beak may have a

replaceable plastic or rubber tip to prevent

fractures of the incisal edge of the teeth. The

beaks generally do not make contact when the

handles are closed fully. Used to remove bands

from anterior teeth.

Orthodontic instruments

• Band-removing (Debanding) pliers, Posterior

Pliers with two beaks, one longer than the other. The longer beak, which carries a replaceable

plastic cap, is placed on the occlusal surface of a tooth, while the shorter, sharpened beak

engages and lifts the gingival margin of the band. Anterior and posterior band removing pliers can

be combined in a “Universal” design.

Orthodontic instruments

• Band seater (Band biter)

Plastic or metal instrument consisting of a handle

and a bite stick that makes use of the patient’s

biting force to aid the clinician in seating a band.

The tip of the bite stick has two sides. The one

that is placed on the occlusal margin of the band

is made of stainless steel and is available in

several sizes and shapes. As well, it usually is

serrated to minimize slippage of the instrument

during use. The opposite side of the tip, which

comes in contact with the patient’s teeth during biting, usually consists of a plastic bite shelf.

Orthodontic instruments

• Bird-beak (no. 139) pliers

Pliers with two short beaks (one of which is

conical and the other pyramidal in shape) used

for bending small wires and springs.

Orthodontic instruments

• Bracket-positioning instrument (Bracket-height gauge)

Device of various designs used to facilitate the

placement of brackets at standard distances from

the incisal edges or occlusal surfaces of specific

teeth. It usually has a ledge that rests on the

incisal edge (occlusal surface) of the tooth, while

a shorter arm is inserted into the bracket slot.

Orthodontic instruments

• Bracket-removing pliers (Debonding pliers)

Pliers used to remove brackets bonded to teeth.

There are various designs depending on the type

of bracket (e.g. stainless steel, ceramic, plastic).

The standard design for stainless steel brackets

has two mirror-image jaws with the sharp cutting

tips formed around a cylindrical opening. The

cutting tips generally do not make contact when

the handles are closed fully. The bracket is

removed by peel and shear forces by placing the

cutting tips at the bracket-adhesive junction and

squeezing.

Orthodontic instruments

• Conversion instrument

An orthodontic instrument that is inserted into the mesial opening of a convertible tube and

functions in a “can-opener” fashion to remove its convertible cap and thus turn it into a bracket.

[See Tube (Molar tube), Convertible tube]

[See Conversion (of a tube into a bracket)]

Orthodontic instruments

• Coon ligature-tying pliers

Reverse-action pliers

(squeezing the handles

increases the separation of the

tips), consisting of two opposing

mirror-image parts (handle,

shank and tip, all one piece)

joined just below the shank by a

round metal cylinder with a

channel. The opposing handles

are attached by a spring that

holds them apart, causing the

tips to touch when the

instrument is passive. It is used

for tying metal ligatures. The opposing tips are blunted and forked to facilitate retention of the

ligature wire. As the handles are compressed, spreading the tips, the channel locks the ligature

wire automatically. Because of the reverse action, the initial twist and the pressure are exerted at

the bracket-archwire junction and then twisted away from the bracket. This gives the ligature a

tighter fit around the bracket, forcing the archwire further into the slot.

Orthodontic instruments

• Distal-end cutter

A special wire cutter with the juxtaposed

cutting edges set at right angles to the

long axis of the instrument to facilitate

cutting of the distal end of the archwire,

intraorally. May have a safety hold

mechanism provided either by a thick wire

running parallel to the cutting edges, or by

a rectangular shoulder immediately below

the cutting edges. This mechanism serves

to grip the loose end of the cut archwire

and prevent it from being lost in the

mouth, so that it can be discarded easily.

It can be used to cut round wires up to

0.020 inch or 0.51 mm in diameter and

rectangular wires up to 0.022 x 0.028 inch

or 0.56 x 0.70 mm.

Orthodontic instruments

• Elastic separator pliers (Separator pliers)

Reverse-action pliers

(squeezing the handles

increases the separation of

the beaks) with two long

beaks that are angled for

better access. The beaks are

connected with a circular

hinge and carry tapered,

grooved, blunted tips, which

can retain elastic separators

(modules). They are used to

stretch, hold and place elastic separators.

Orthodontic instruments

• Facebow-adjusting pliers

Heavy-duty pliers with a box-jointed pivot construction, having two parallel beaks and an opposing

one that fits between the former when the pliers are closed. Each beak has a rounded notch at a

right angle to the beak near the tip on the opposing surfaces. Used for adjusting the inner and

outer arches of facebows, or for contouring wires of large diameter (up to 0.062 inch or 1.55 mm).

Orthodontic instruments

• Hard wire cutter

Cutter of design similar to a pin and ligature wire cutter, only larger, and capable of cutting fulldimension

archwires.

Orthodontic instruments

• Hemostat (Mosquito pliers)

Small and light pliers with scissor-like design, provided with a mechanical locking mechanism

located between the handles. The handles are available in various lengths. The serrated beaks

ligatures. Used for placement of elastomeric ligatures

(donuts).

Orthodontic instruments

• Howes utility pliers

Pliers with two long, round beaks tapered to a

pyramid shape and bowed, terminating in

juxtaposed flat round serrated pads. The pads

are positioned at right angles to the long axis

of the beaks; their diameter varies with the

manufacturer. The beaks may be straight or

offset at a 45° angle. Used mainly for gripping

and handling archwires and stainless steel

ligatures during placement in the mouth.

Orthodontic instruments

• Ligature director (Pitchfork instrument)

Stainless steel instrument carrying a straight or angled tip with a notch capable of engaging wires.

Available in double-ended versions or in combination with amalgam-pluggers, scalers or other tips.

Used to tuck and direct stainless steel ligatures under the archwire or bracket wings, or to push

archwires or auxiliaries into position.

Orthodontic instruments

• Light-wire pliers

Essentially identical to bird-beak pliers, only with longer

and more slender beaks. Some designs have one or

more grooves at the tip of the pyramidal beak to aid in

making reproducible loops and helices. Used mainly to

form various loop designs in orthodontic wires

(generally light, round wires), to make minor adjustment

bends in archwires or to place metal spring separators.

[See Orthodontic wire, Australian wire]

Orthodontic instruments

• Mathieu-style ligature-tying pliers

Pliers with long, thin handles equipped with a positivelocking

ratchet and spring for instant opening and closing. The opposing tips are serrated and may

have tungsten carbide inserts for longer instrument life. The tips vary in length and taper by the

manufacturer. The pliers are available in various sizes. Used mainly for tying stainless steel

ligatures as well as for placing elastomeric ligatures (donuts).

Orthodontic instruments

• Parallel-action pliers with cutter (Sargent’s heavy-duty pliers)

Heavy-duty pliers with parallel, flat, serrated opposing

beaks. One of the beaks carries a wire cutter on its nonserrated

side. Used mainly for bending, cutting or holding

large-diameter wires in laboratory procedures.

Orthodontic instruments

• Pin and ligature wire cutter

Cutter with two tapered and pointed opposing beaks,

terminating in delicate and sharp cutting edges. The

cutting edges may have carbide inserts that can be

sharpened or replaced when dull or damaged, without

replacing the entire instrument. It is available in various

angles, the straight and 15° to the long axis being the

most common. The tape and size of the tips vary with

the manufacturer. Used to cut soft ligature wires

(generally up to 0.016 inch or 0.41 mm) and archretaining

pins.

Orthodontic instruments

• Serrated amalgam-plugger

A single-ended or double-ended (in combination with a

ligature director or other tip) stainless steel instrument,

sometimes used to seat and position bands or to tuck

steel ligatures. The tip is available in various lengths,

angles and diameters and usually is serrated for better

control in pushing motion.

Orthodontic instruments

• Steiner ligature-tying pliers

Identical to the Coon ligature-tying pliers, differing

only in that the round metal cylinder at the shank of

the instrument does not carry the special channel to

engage the end of the ligature wire. The ligature

wire is retained on the instrument by manually

wrapping its free ends around the round metal

cylinder.

Orthodontic instruments

• Torquing key

Usually a cross-shaped stainless steel instrument, each of the four ends of which carries a milled

slot to engage the wire for placement of torque. Each slot is a different size to accommodate

various gauge wires. Used to place torque in an archwire or to assist full engagement of a wire into

a bracket slot. Various other kinds of torquing keys are used in combination with special pliers to

place torque for an individual tooth.

Orthodontic instruments

• Triple-beaked pliers (Three-jaw pliers, Clasp-adjusting

pliers)

Pliers similar to but smaller than the facebow-adjusting

pliers, with a box-jointed pivot construction. The

double-sectioned beak is opposed by a single beak, so

that a squeezing motion can produce a sharp bend in

the wire. Used for adjusting wires, particularly labial

bows or clasps on retainers, as well as for placing a curve on flexible or heavier wires, or stainless

steel tubing.

Orthodontic instruments

• Turret

Tubular metal device of various circumferences carrying grooves of various calibrated sizes, used

to shape straight lengths of orthodontic wire into

an arch form. Some turrets are equipped with

angulated grooves to place torque into rectangular

wire during shaping of the arch form.

Orthodontic instruments

• Tweed arch-adjusting (no. 142) pliers

Pliers used exclusively for handling or adjusting

square or rectangular wires. The beaks are

symmetrically flattened blades that are parallel at a

separation of 0.020 inch (0.51 mm).

Orthodontic instruments

• Tweed loop-forming pliers (Omega pliers,

Optical pliers)

Pliers with two opposed parallel beaks, one with

concave and one with round cross-section. The

round beak generally is stepped, having three

sections of different diameters (most commonly

0.045, 0.060, and 0.075 inch or 1.12, 1.50 and

1.90 mm). The tip of the round beak may be

replaceable. Used to form various loops or short

curved sections in orthodontic wire.

Orthodontic instruments

• Weingart utility pliers

Pliers with two long, slender beaks with opposing, serrated tips. The tips are oblong and pointed

and can be straight or curved from the long axis of the pliers to provide a better working angle for

intraoral adjustments. Used for holding or

gripping the archwire to place it and remove it

from the mouth, or to make adjustment bends.

Orthodontic magnets

Magnets have had various applications in medicine (mainly to aid in fracture healing) and in

dentistry (mainly for retention of prostheses). The miniaturization of magnets as a result of the

introduction of rare-earth or lanthanide elements facilitated their intraoral applications. In

orthodontics, magnetic forces from repelling or attracting poles have been utilized to achieve

palatal expansion, intrusion of posterior teeth, molar distalization, forced eruption of unerupted

teeth, anterior repositioning of the mandible during treatment with some functional appliances,

retraction or alignment of teeth, as well as retention of diastema closure. Neodymium-iron-boron

(Nd2Fe14B) and samarium-cobalt (SmCo5) are the types of rare-earth magnets most commonly

used. The greatest disadvantage of magnets is their low corrosion resistance in the presence of

saliva. Corrosion products are toxic to the tissues, for which reason magnets must be coated with

appropriate materials (usually parylene or acrylic), or be enclosed in a stainless steel casing, when

intended for intraoral use. The possibility of adverse effects of magnetic fields on cells and tissues

is an issue of controversy.

Orthodontic springs

Force-producing modules or appliance components, made of metal.

SUBTERMS:

Orthodontic springs

• Cantilever spring

In principle, any piece of wire, one end of which is

inserted fully into a bracket or tube, while the

other end is ligated to another unit with only a

one-point contact. The advantage of using

cantilever mechanics is that the created force

system can be estimated easily at both units

(statically determinate force system) by knowing

the length of the cantilever and by measuring the

force exerted at its ligated end with a force

gauge. Moreover, the relatively long range of

deactivation of the spring results in a low

magnitude continuous force (low load/deflection

ratio) that generally is considered desirable for

tooth movement.

[See Mechanics, Cantilever mechanics]

Orthodontic springs

• Closed spring

A spring (usually part of a removable appliance) having both ends attached.

Orthodontic springs

• Coffin spring

An omega-shaped (_) spring made of heavygauge

wire, spanning across the palate as part

of some removable orthodontic appliances

(e.g. the Bimler or the Crozat appliance). The

function of a Coffin spring is to offer the

possibility of expansion or constriction of the

maxillary dental arch.

Orthodontic springs

• Coil spring, Closed

Spring made of fine (typically 0.010 to 0.012 inch, or 0.25 to 0.30 mm) orthodontic wire wound into

a coil whose helices tightly contact each other; thus it cannot be compressed. A closed coil spring

usually comes in a spool and is cut to the appropriate length according to the intended application.

It most commonly is used to maintain a space during fixed appliance orthodontic treatment (e.g.

the space of a missing tooth that eventually will be replaced prosthetically).

Orthodontic springs

• Coil spring, Open

Spring made of fine (typically 0.010 to 0.012 inch, or 0.25 to 0.30 mm) orthodontic wire wound into

a coil whose helices are spaced, so it can be compressed along its long axis. An open coil spring

comes in a spool and usually is cut to a length larger than the interbracket distance between the

teeth that are intended to be moved away from each other. It is compressed prior to insertion,

generating equal and opposite forces on either end.

Orthodontic springs

• Coil spring, Retraction (Pletcher spring, Closing coil spring)

Spring made of fine (typically 0.010 to 0.012 inch, or 0.25 to

0.30 mm) orthodontic wire wound into a coil with tightly

contacting helices. The coils are prefabricated from

superelastic or stainless steel wire and come in

predetermined lengths with two eyelets on either end.

Retraction coil springs are used to generate forces for

retraction of teeth or space closure by extending them beyond their initial length.

Orthodontic springs

• Finger spring

A free-end spring usually incorporated in removable orthodontic appliances to produce various

tipping movements of teeth. Finger springs can contain helices to increase the effective wire length

for added flexibility.

Orthodontic springs

• Free-end spring (Open spring)

A broad category of springs (usually part of a removable appliance) having only one end

embedded in acrylic.

Orthodontic springs

• PG spring (Gjessing spring)

A universal retraction spring made of 0.016 x 0.022-inch

stainless steel wire, introduced by P. Gjessing. The spring

consists of a 10 mm-long, double, ovoid-shaped, closed

loop extending gingivally, continuing with a small (2 mm in

diameter) occlusal helix. This configuration was designed to reduce the load/deflection rate to

approximately 45 g per millimeter of activation. The spring also has an anti-tip moment-to-force

ratio of approximately 11:1 and an anti-rotation moment-to-force ratio of approximately 7:1.

It is meant to be used as a segmental spring for frictionless segmental canine retraction by

translation, or for “en masse” retraction of the maxillary incisors without undesirable lingual tipping.

The spring is supposed to be activated every 4 to 6 weeks, to the point where the double loop is

separated, which is calibrated to produce approximately 100 g of force.

Orthodontic springs

• Root spring

An orthodontic spring that can cause movement of the root of a tooth with relatively little movement

of the crown. Uprighting springs and torquing springs both are subcategories of root springs.

Orthodontic springs

• Rotation spring

Auxiliary orthodontic spring, commonly used with single

brackets (usually inserted into the vertical slot) to generate

the moment required for rotation of a tooth around its long

axis.

Orthodontic springs

• Torquing spring

Auxiliary orthodontic spring used to move the root of a tooth in

the labiolingual or buccolingual direction.

Orthodontic springs

• Uprighting spring

Auxiliary orthodontic spring used to move

the root of a tooth in the mesiodistal

direction. Uprighting springs commonly

are used in the bracket vertical slot with

the Begg technique and its modifications

(e.g. the side-winder springs of the Tip-

Edge appliance).

Orthodontic springs

• Z-spring (Recurved spring)

A spring bent in the form of a “Z,” commonly incorporated into a

removable appliance to tip an individual tooth or groups of teeth buccally

or labially.

Orthodontic tooth movement

Movement of a tooth under the influence of a mechanical force.

Orthodontic tooth movement is possible because of the regenerative

and remodeling capacity of the alveolar bone and the periodontal

ligament. The mechanism regulating the transduction of a mechanical

stimulus into specific cellular activity is not yet entirely understood.

SUBTERMS:

Orthodontic tooth movement

• Extrusion

A translational type of tooth movement parallel

to the long axis of the tooth in the direction of

the occlusal plane.

Orthodontic tooth movement

• Intrusion

A translational type of tooth movement parallel

to the long axis of the tooth in an apical

direction.

Orthodontic tooth movement

• Pure crown movement

The type of tooth movement for which the

center of rotation is at the apex of a tooth.

[Note: the term is somewhat misleading, as

this type of movement also affects part of the root. ]

[See Orthodontic tooth movement, Tipping, Controlled]

Orthodontic tooth movement

• Pure root movement

The type of tooth movement for which the center of rotation is at the incisal edge (or for all practical

purposes, at the bracket) of a tooth. For an average maxillary central incisor with intact

periodontium the M/F ratio for this type of movement is estimated to be 12:1 to 13:1. Pure root

movement is the intended type of movement when “torquing” incisor teeth, when uprighting canine

roots following extraction space closure, or when uprighting mesially tipped molars. [Note: the term

is somewhat misleading, as this type of movement also affects part of the crown. ]

Orthodontic tooth movement

• Pure rotation

Rotation of a tooth about its long axis, most evident when viewing the tooth from an occlusal

perspective. To achieve this type of tooth movement, the application of a couple is required.

Orthodontic tooth movement

• Tipping, Controlled

A type of tooth movement consisting of rotation about the apex of the tooth. It is achieved clinically

by the application of a force at the level of the bracket (as in uncontrolled tipping) as well as a

counter-moment to prevent movement of the root apex in the opposite direction. For an average

maxillary central incisor with no periodontal loss, the M/F ratio for controlled tipping is estimated to

be between 7:1 and 8:1.

[See Orthodontic tooth movement, Pure crown movement]

Orthodontic tooth movement

• Tipping, Uncontrolled (Simple)

A single horizontal force applied to the crown of the tooth at the level of the bracket will cause

movement of the crown and the apex of a tooth in opposite directions. The center of rotation for

this movement is approximately at (or slightly apical to) the center of resistance of the tooth. This is

the simplest type of tooth movement, but it often is undesirable. The moment-to-force ratio for

uncontrolled tipping is 0:1 (no counter-moment is applied, but only a single force).

Orthodontic tooth movement

• Translation (Bodily movement)

The type of tooth movement during which all points on a tooth move in the same direction by the

same amount. During bodily movement, the center of rotation can be assum-ed to lie at infinity. A

single force passing through the center of resistance canproduce translation of a tooth along its

line of action. Alternatively, a force and a (counter-)moment have to be applied at the bracket of a

tooth. For an average maxillary central incisor tooth with intact periodontium, a moment-to-force

ratio of approximately 10:1 at the level of the bracket is typical of translation.

Orthodontic wire

In orthodontics, wires of various alloys having various cross-sectional shapes and dimensions are

used.

SUBTERMS:

Orthodontic wire

• Australian wire

A round austenitic stainless steel wire, introduced by the A. J. Wilcock Co. in Australia, and

selected by P. R. Begg as the main material from which archwires were made for his light-wire

technique. The wire is heat-treated and cold-drawn down to its proper diameter from round wire of

larger diameter. It exhibits high toughness and tensile strength, combined with increased

resilience, but low corrosion resistance because of the presence of copper as an alloying element

of the steel. There are various grades of Australian wire, but Begg mainly used the 0.016-inch

(0.41-mm), so-called “Special Plus” wire. Another characteristic of the wire is its brittleness. It is

recommended that when bending Australian wire, the flat rather than the round beak of the pliers

be used and that the bend be placed very slowly, to avoid breakage. Following bending, the

archwire can be heat-treated, which makes it harder and more resistant to permanent deformation.

[See Appliance, Begg appliance (Light-wire appliance)]

Orthodontic wire

• Multistrand wire (Braided wire, Coaxial wire)

Orthodontic wire fabricated by braiding multiple strands of wire of the same material and usually of

the same diameter. This method of combining a number of strands of wire that individually would

not be strong enough for a particular application is used to achieve a wire with high flexibility and

adequate strength. Multistrand archwires can be round or rectangular and commonly are used for

initial alignment.

Orthodontic wire

• Nickel-titanium wire

[See Nickel-titanium alloy (Ni-Ti)]

Orthodontic wire

• Rectangular wire

An orthodontic wire with rectangular cross-section.

[See Archwire cross-section]

Orthodontic wire

• Round wire

An orthodontic wire with round cross-section.

[See Archwire cross-section]

Orthodontic wire

• Square wire

An orthodontic wire with square cross-section.

[See Archwire cross-section]

Orthodontic wire

• TMA wire

[See Beta-titanium alloy (TMA, b-Ti, Titanium-molybdenum alloy)]

Orthognathic (Mesognathic)

A facial type with normal anteroposterior relationship of the maxilla and mandible in relation to each

other and to the cranial base.

[See Facial type]

Orthognathic surgery

Surgical reposition-ing of all or parts of the maxilla and/or mandible to correct malpositions or

deformities. Usually accomplished in conjunction with orthodontic treatment.

[See Osteotomy]

SUBTERMS:

Orthognathic surgery

• Bimaxillary surgery (Two-jaw surgery)

Orthognathic surgical procedure involving repositioning of both the maxilla and the mandible.

Orthognathic surgery

• Single-jaw surgery (One-jaw surgery)

Orthognathic surgical procedure during which either the mandible or the maxilla are surgically

repositioned.

Osseointegration

A direct structural connection between bone and the surface of an implant. The host bone

responds in a safe, predictable and versatile manner to the placement of an implant, with a healing

cascade leading to interfacial osteogenesis and immobility of the implant.

Ossification

Formation and development of bone. Histologically two types of ossification are distinguished:

endochondral and intramembranous.

SUBTERMS:

Ossification

• Endochondral ossification

Bone formation taking place on a cartilage matrix; the cartilage immediately preceding bone in

development. This type of ossification occurs embryologically as the chondrocranium ossifies at

the epiphyses of all long bones, vertebrae and ribs, at the head of the mandibular condyle, and at

the synchondroses of the base of the skull.

Ossification

• Intramembranous ossification

Bone formation directly within a connective tissue membrane, without any intermediate formation

of cartilage. This type of ossification occurs embryonically at many sites, such as the cranial vault,

the maxilla, the body of the mandible, and at the diaphyses (midshaft) of long bones, initially by

proliferation and condensation of mesenchymal cells. As vascularity increases at these sites of

condensed mesenchyme, osteoblasts differentiate and begin to produce bone matrix de novo.

Ostectomy

Surgical removal of a bone, or part of a bone.

Osteoarthritis (Degenerative joint disease, DJD, Degenerative arthritis)

Chronic disease resulting in joint deformity caused by degenerative changes in the articular

cartilage, fibrous connective tissue and/or disc. In its late stage it is accompanied by proliferation of

new bony tissue at the margins of the joint surface, known as marginal osteophytes, lipping, spurs,

or ridges. The fibrillation and breakdown of cartilage is not an inflammatory process, but the

breakdown is accompanied by inflammation. The most common etiologic factor that either causes

or contributes to osteoarthritis is overloading of the joint structures. In the case of the TMJ it often

is painful, and symptoms are accentuated by jaw movement. Crepitation is a common finding.

Osteoarthrosis

Chronic non-inflammatory joint disorder characterized by progressive deterioration and loss of

articular cartilage and subchondral bone.

Osteoblast

Uninucleated cell that synthesizes both collagenous and noncollagenous bone proteins (the

organic matrix, osteoid). Osteoblasts are responsible for mineralization and are thought to derive

from multipotent mesenchymal cells or, alternatively, from perivascular cells. The osteoblast

generally is considered to differentiate through a precursor cell, the preosteoblast. Osteoblasts

secrete, in addition to Type I and Type V collagen, small amounts of several noncollagenous

proteins and a variety of cytokines. Under physiologic conditions supporting resorption rather than

formation of bone, osteoblasts can be stimulated by lymphokines and by prostaglandins to produce

interleukin 6, a factor that increases the resorbing activity of the osteoclast.

Osteoclast

Large multinucleated type of cell involved in the degradation and removal of hard tissue.

Osteoclasts are derived from monocytes and typically are found against the bone surface,

occupying shallow depressions called “Howship’s lacunae.” To break down hard tissue, osteoclasts

attach to mineralized tissue and create a sealed environment that is first acidified to cause

demineralization. Following that, the organic matrix is broken down through the secretion of

proteolytic enzymes.

Osteoconductive material

A material that acts as a scaffold for new bone formation.

[Compare with Osteoinductive material]

Osteocyte

As osteoblasts secrete bone matrix, some of them become entrapped in bone and are then called

osteocytes. The number of osteoblasts that become osteocytes depends on the rate of bone

formation: the more rapid the formation, the more osteocytes are present per unit volume. As a

general rule, embryonic (woven) bone has more osteocytes than does lamellar bone.

Osteogenesis imperfecta

As a diagnostic term, osteogenesis imperfecta represents a heterogeneous group of inherited

disorders characterized by defects in both mineralized and non-mineralized connective tissues,

resulting from mutations in Type I collagen. Males and females are affected equally, and the

incidence is between 1 in 5,000 and 1 in 14,000 live births. The classification of the clinical features

of the various types of osteogenesis imperfecta according to D. O. Sillence is as follows:

Type I:

Normal stature, increased frequency of fractures prior to puberty and after menopause, little or no

deformity following fracture repair, hearing loss in about 50% of families, blue sclerae,

dentinogenesis imperfecta is uncommon.

Type II:

Death in the perinatal period due to extreme bone fragility, poor mineralization of the calvarium,

intrauterine fractures of endochondral and membranous bones, blue/black sclerae in virtually all

affected individuals, long bone and rib deformities.

Type III:

Short stature, characteristic facies, long bone deformity following fracture repair, scoliosis,

dentinogenesis imperfecta common, hearing loss common, scleral discoloration variable, reduced

lifespan.

Type IV:

Mild to moderate short stature, mild to moderate long bone deformity following fracture repair,

normal scleral hue, dentinogenesis imperfecta is common, hearing loss occurs in some families.

Osteoinductive material

A material that causes the conversion of mesenchymal cells into bone progenitor cells.

[Compare with Osteoconductive material]

Osteomyelitis

Inflammation of bone, especially of the marrow, caused by pathogenic organisms.

Osteophyte

Bony outgrowth. Marginal adaptation of a joint, formed by bony tissue. In the case of the TMJ, the

anterior aspect of the mandibular condyle (in the region of the attachment of the lateral pterygoid

muscle) is a relatively common location where osteophytes can be found.

Osteotomy

Surgical procedure involving the cutting of bone.

SUBTERMS:

Osteotomy

• Anterior maxillary segmental (subapical) osteotomy

Osteotomy of the anterior maxillary segment, usually from canine to canine, with displacement in a

posterior, inferior, superior or rotational manner. Most commonly a combination of posterior and

inferior repositioning of the anterior segment is performed, into the space created by simultaneous

extraction of the maxillary first premolars. Anterior repositioning of the segment is almost

impossible because of difficulties in stabilization and fixation, even with bone grafting, and because

the soft tissue pedicles often are insufficient to cover the surgical defects. The most popular

techniques for this type of osteotomy are the Wassmund and Wunderer techniques.

Wassmund technique

An approach to anterior maxillary segmental osteotomy described by M. Wassmund (1927), which

relies on maintaining both the labial and palatal pedicles for vascular supply to the anterior

maxillary segment. The osteotomies are carried out through mucosal tunnels created on the

vestibular side by vertical incisions at the midline and at the level of the first premolar and through

palatal tunnels created by connecting the extraction sockets of the first premolars to a midpalatal

incision.

Wunderer technique

An alternative approach to anterior maxillary segmental osteotomy described by S. Wunderer

(1963). The technique relies on the vestibular pedicle for vascular supply to the anterior maxillary

segment, together with some blood supply from the incisive canal. Bilateral vertical incisions are

performed on the vestibular side at the level of the first premolars. These are connected by a

transpalatal horizontal incision, allowing reflection of the palatal flap posteriorly.

Osteotomy

• Bilateral sagittal split osteotomy (BSSO)

A mandibular orthognathic surgical procedure first reported in the English literature by R. Trauner

and H. L. Obwegeser (1957), and subsequently modified by others. In this procedure the rami of

the mandible are split parallel with the sagittal plane to allow repositioning of the mandibular body

into a more favorable relationship with the maxilla and the face. The procedure currently is

routinely performed through an intraoral approach and can be used for advancement, setback and

rotation of the distal (mandibular) segment.

When the distal segment is advanced, a gap is created in the buccal plate. When it is set back, a

section of the buccal plate is removed to allow good approximation of the buccal cortex of the

proximal segment against the lingual cortex of the distal segment on each side. The osteotomy

design spares the mandibular nerve and provides a broad interface of the bony segments to aid

with fixation and healing. Fixation is achieved by bone screws or bone plates, or through

circumosseous fixation wires in combination with IMF.

[See Segment, Proximal segment]

[See Segment, Distal segment]

Osteotomy

• Complete maxillary osteotomy

Maxillary osteotomies traditionally are described in comparison with the common fracture patterns

of the midfacial skeleton, named after the work of R. Le Fort (1900). The Le Fort I, II and III

fractures indicate the general levels at which the maxilla may be sectioned selectively from the rest

of the skull, although the osteotomies are tailored to the individual patients and may deviate from

the known fracture patterns.

Le Fort I osteotomy

The most frequently performed of all midfacial osteotomies. It sections the midface through the

walls of the maxillary sinuses, the lateral nasal walls and the nasal septum, at a level just superior

to the apices of the maxillary teeth. Starting at the inferior-lateral margin of the pyriform aperture of

the nose, the osteotomy line traverses the lateral walls of the maxillary sinus approximately 3 to 4

mm above the apices of the canine, premolars and molars. It passes across the canine fossa to

the base of the zygomatic buttress and curves around and above the maxillary tuberosity to the

lowest part of the pterygomaxillary fissure, where it crosses the posterior wall of the sinus at the

same level. It then turns anteriorly through the lateral wall of the nose below the inferior turbinate to

join the point of origin. The cut is made bilaterally. Following this, the pterygomaxillary plates are

separated from the posterior aspects of the maxillary tuberosities, and the nasal septum is

detached from the superior aspect of the hard palate by dividing it along its length with a chisel, so

that the maxillary segment is freed. The Le Fort I osteotomy offers a great number of options as

the freed maxilla can be reoriented in all spatial planes. Further segmentation of the maxilla can be

performed to correct transverse, anteroposterior and vertical discrepancies between the maxilla

and the mandible.

Le Fort II osteotomy

A pyramid-shaped osteotomy that is identical to the Le Fort I procedure from the pterygoid column

to the zygomatic buttress. From that point, instead of continuing anteriorly to the pyriform aperture

of the nose, the cut is directed superiorly, towards the orbit. The cut is kept anteromedial to the

infraorbital foramen and crosses the inferior orbital margin at a point halfway between the lacrimal

duct medially and the infraorbital canal laterally. It then is continued posteriorly along the floor of

the orbit and at right angles to the orbital rim until past the lacrimal groove and its contained

lacrimal sac. The cut then is turned medially and anteriorly across the apex of the lacrimal groove

and emerges medially to the orbit, just below the midpoint of the medial canthal attachment. The

frontal process of the maxilla then is crossed and the cut becomes continuous with the osteotomy

of the other side across the nasal bones. The nasal septum is divided at a higher level than during

the Le Fort I osteotomy, passing from the nasal bones anteriorly in a downward and backward

direction to the posterior part of the septum just above the posterior nasal spine. The lateral nasal

walls are fractured during mobilization of the maxilla at levels corresponding to the septal cut.

Le Fort III osteotomy

The basic Le Fort III osteotomy, as originally described by P. Tessier (1971), was designed to

achieve anteroposterior movement of the whole facial mass, establishing normal dental occlusion

and increasing orbital capacity, enlarging both the height and the depth of the orbits. The aim is to

separate the facial mass from the cranial base along the inter-frontofacial and the interpterygomaxillary

planes. To do this, the osteotomy traverses, on each side, the medial orbital wall,

the orbital floor and the lateral orbital wall to reach the region of the frontozygomatic suture. The

frontal process of the zygomatic bone then is split sagittally (effectively splitting the lateral wall of

the orbit) and the cut is continued inferiorly to complete division of the zygoma. The two sides are

connected centrally through the frontona-sal area, as in the Le Fort II osteotomy. Pterygomaxillary

and septal separation then are completed as in the Le Fort II operation and the central facial block

is mobilized. Many variants of Le Fort III procedures exist that can be applied in the treatment of a

variety of craniofacial problems and can be combined with surgery of the cranial vault.

Kьfner osteotomy

A modification of the Le Fort II osteotomy originally described by J. Kьfner (1971). It is intended for

patients with good nasal bridge and projection, but exhibiting retrusion of the infraorbital region and

maxillary dentoalveolar area, with zygomatic flatness. The difference is that the osteotomy does

not involve the nasal bridge, but is extended laterally to include the infraorbital rim and zygomatic

process.

Osteotomy

• Multiple-piece maxillary osteotomy

When a severe transverse discrepancy between the maxillary and mandibular arches exists, a twoor

a three- and sometimes even a four-piece maxillary procedure is performed, following a Le Fort I

osteotomy, to reposition each segment separately to an ideal relationship with the mandibular arch.

Due to the increased risks entailed in the segmental procedures, most clinicians prefer to limit the

number of segments into which they divide the maxilla.

[Compare with Osteotomy, One-piece maxillary osteotomy (Single-piece maxillary osteotomy, Total

maxillary osteotomy)]

Osteotomy

• One-piece maxillary osteotomy (Single-piece maxillary osteotomy, Total maxillary osteotomy)

Any osteotomy that mobilizes the maxilla as a whole.

[Compare with Osteotomy, Multiple-piece maxillary osteotomy]

Osteotomy

• Transoral vertical ramus osteotomy (TOVRO, Intraoral vertical ramus Osteotomy, IVRO)

A vertical osteotomy of the mandibular ramus performed via a transoral approach for correction of

mandibular prognathism. It commonly is carried out in conjunction with a coronoidectomy. The

coronoid fragment with attached temporalis tendon is allowed to retract. The line of the osteotomy

extends from an area in front of the condyle to a point at or near the angle of the mandible.

This osteotomy is reserved for patients who require a mandibular setback, as it necessitates fullthickness

overlap between the mandibular segments. After the setback the condylar segment lies

laterally to the distal mandibular segment. Stabilization can be provided by a circumramus suture

or wire, by rigid fixation screws, or alternatively no stabilization is used. In the latter case, patients

are left in intermaxillary fixation for 4 to 6 weeks. The TOVRO is advocated to be less likely than

the BSSO to produce neurosensory changes.

Overbite (Vertical overbite)

The degree of vertical overlap of the mandibular incisors by their maxillary antagonists, usually

measured perpendicular to the occlusal plane. It is reported either in millimeters, or as a

percentage of the total crown length of the mandibular incisors that is overlapped by the maxillary

incisors.

[Compare with Overjet (Sagittal overbite)]

SUBTERMS:

Overbite (Vertical overbite)

• Impinging overbite

Extremely deep bite with impingement of the mandibular incisors in the mucosa palatal to the

maxillary incisors; commonly seen in patients with severe Class II, Division 2 malocclusions.

Overbite (Vertical overbite)

• Positive overbite

A term indicating the presence of vertical overlap between the maxillary and mandibular anterior

teeth. Positive overbite is a characteristic of the ideal occlusion, but also of deep bite

malocclusions.

Overclosure

Reduced vertical dimension with the teeth in occlusion.

Overcorrection

The notion of continuing a certain type of treatment even after an ideal relationship has been

achieved, in anticipation of some degree of relapse after the end of active treatment. For example,

the overcorrection of a typical Class II deep bite malocclusion to an end-to-end anterior relationship

sometimes is advocated.

Overeruption (Supraeruption, Supraposition, Supraocclusion)

The situation whereby an unopposed or non-occluding tooth

extends beyond the occlusal plane.

Overjet (Sagittal overbite)

The distance between the labial surface of the mandibular

incisors and the labial aspect of the incisal edge of the

maxillary incisors, usually measured parallel to the occlusal

plane. When not otherwise specified, the term is generally

assumed to refer to the most prominent central incisors.

The extent of overjet is determined primarily by the differences of labiolingual

position and inclination of the maxillary and mandibular central incisors. Only in a

minority of cases is the anteroposterior skeletal relationship reflected directly in

the amount of overjet.

[Compare with Overbite (Vertical overbite)]

SUBTERMS:

Overjet (Sagittal overbite)

• Buccal overjet

The distance between the buccal surfaces of the maxillary posterior teeth and the buccal surfaces

of their mandibular antagonists. An unofficial term sometimes used to indicate whether or not there

is a tendency for a posterior crossbite.

Overjet (Sagittal overbite)

• Negative overjet(Reverse overjet)

A situation usually associated with Class III malocclusions in which the maxillary

incisors occlude lingually to the mandibular incisors.

Overjet (Sagittal overbite)

• Positive overjet

A term denoting that the maxillary incisors occlude labially to the mandibular

incisors, as is seen commonly in Class I or Class II malocclusions.

Palatal rugae

The irregular ridges in the masticatory mucosa covering the anterior hard palate.

Palate

The structure that serves as the roof of the oral cavity and the floor of the nasal cavity, consisting

anteriorly of the hard palate and posteriorly of the soft palate.

SUBTERMS:

Palate

• Hard palate

The anterior part of the palate, the osseous framework of which consists of the palatine processes

of the maxilla and the horizontal parts of the palatine bones.

Palate

• Primary palate

The embryological structure that forms during the 5th to 7th weeks of human intrauterine life,

originating from the fused medial nasal and maxillary processes. The primary palate eventually

forms the upper lip, the anterior portion of the maxillary alveolar process and the hard palate

anterior to the incisive canal.

[See Premaxilla]

Palate

• Secondary palate

The embryological structure that forms during the 6th-9th weeks of human intrauterine life by

fusion of the palatine processes (of the maxillary process) at the midline. The anterior parts of the

palatine processes (palatal shelves) also unite with the nasal septum, eventually forming the hard

palate. In the posterior region, where there is no attachment to the nasal septum, the soft palate

and uvula eventually develop.

Palate

• Soft palate (Velum)

The posterior mobile part of the palate, which is suspended anteriorly from the hard palate. Its

sides blend with the pharynx and its posterior portion forms the uvula. In its relaxed position the

soft palate is continuous with the roof of the mouth. During the process of deglutition or sucking, as

well as during production of certain speech sounds, it is elevated, thus separating the nasal cavity

and nasopharynx from the posterior part of the oral cavity and the oral portion of the pharynx.

Palate-splitting appliance

[See Appliance, Expansion appliance]

[See Appliance, Hyrax appliance (Hygienic rapid palatal expander)]

[See Appliance, Haas appliance (Haas rapid maxillary expansion appliance, Haas palatal

separator)]

Pantograph

A tracking device attached to the mandible and maxilla that enables recording of mandibular

movements in three planes of space.

Parafunction (Parafunctional activity, Parafunctional habit)

Non-physiological activity, including clenching and bruxing, nail-biting, and lip- or cheek-chewing.

Paresthesia

Diminished or abnormal sensation, such as burning, prickling, tingling, or numbness; a common

finding following orthognathic surgery. Almost all patients have some degree of paresthesia of the

lower lip over the distribution of the mental nerve immediately following mandibular ramus surgery

(e.g. bilateral sagittal split osteotomy). Return of sensation may be rapid, may occur over a few

weeks, or may occur gradually over 12 to 18 months. In some instances a permanent degree of

paresthesia remains.

Pathognomonic

Specifically distinctive characteristic (sign or symptom) of a disease or pathologic condition, on the

basis of which a diagnosis of the disease can be made.

“Peg-shaped” lateral incisors

Atypical, undersized, pointed and tapered crown form of the maxillary permanent lateral incisors.

Perikymata

The numerous small transverse ridges and grooves on the surface of the enamel of permanent

teeth, representing the rhythmic deposition of enamel. With continued abrasion the surface of the

enamel becomes eroded and the perikymata eventually disappear.

Periodontal ligament (PDL)

A dense, highly specialized connective tissue situated between the root of a tooth and the alveolar

bone. Its principal function is to connect the tooth to the bone while resisting the stress created by

the various forces exerted on the teeth. This is achieved by the masses of collagen fiber bundles

that follow an undulated course between the bone and the tooth, and by an incompressible gel-like

matrix consisting of 70% water (ground substance). The second function of the PDL is to provide

sensory input (proprioception) on the level and type of strain that it experiences, partially through

specialized sensory receptors. Other than fibers and ground substance, the PDL contains many

cells (mainly fibroblasts, epithelial cells and undifferentiated mesenchymal cells), blood vessels

and nerves.

Fibers of the PDL

The majority of fibers of the periodontal ligament are collagen fibers, mainly a mixture of Type I and

Type III. The greatest proportion of the collagen fibers in the PDL are arranged in definite and

distinct fiber bundles. The principal groups of bundles are as follows:

1. The alveolar crest group, attached to the cementum just below the cementoenamel junction and

running downward to insert into the rim of the alveolus.

2. The horizontal group, occurring just apical to the alveolar crest group and running at right angles

to the long axis of the tooth from cementum to bone just below the alveolar crest.

3. The oblique group, by far the most numerous in the PDL, running from the cementum in an

oblique direction, to insert into bone coronally.

4. The apical group, radiating from the cementum around the apex of the root to the bone, forming

the base of the socket.

5. The interradicular group, found only between the roots of multirooted teeth and running from the

cementum into the bone, forming the crest of the interradicular septum.

At each end, all the principal fibers of the PDL are embedded in cementum or bone. The

embedded portion is called a Sharpey’s fiber. Other than collagen, the PDL also contains some

elastic fibers, consisting of two types of immature elastin, namely oxytalan and eluanin.

Width of the PDL

In humans the width of the PDL ranges from 0.15 to 0.38 mm, with its narrowest aspect at the

middle third of the root and its widest aspect cervically. Occlusal loading in function affects the

width of the PDL. If occlusal forces are within physiologic limits, increased function leads to an

increase in width through a thickening of the fiber bundles and an increase in diameter and number

of Sharpey’s fibers. Unphysiologic situations such as traumatic occlusion typically cause widening

of the PDL. Conversely, when function is diminished or absent, the width of the PDL decreases.

The fibers are reduced in number and density and they show a tendency to become oriented

parallel to the root surface. A widening of the PDL also typically is associated with active

orthodontic tooth movement.

Perpetuating factors

Factors that interfere with resolution of, or enhance the progression of, a disease or disorder.

Pharyngeal flap operation

A surgical procedure for lengthening the soft palate by attaching a flap from the posterior

pharyngeal wall to it. Depending on the way that the pharyngeal flap is raised, a superiorlybased

and an inferiorlybased pharyngeal flap can be distinguished.

[See Velopharyngeal insufficiency (Velopharyngeal incompetence, VPI)]

[See Hypernasality (Rhinolalia aperta)]

Philtral columns

Normal ridges in the skin of the central portion of the upper lip, extending bilaterally from the

vermilion border of the upper lip to the columella of the nose, and containing the philtrum.

Photoelasticity

Engineering technique of stress analysis based on the property of some transparent materials to

exhibit patterns of color when viewed with polarized light. These patterns occur as the result of

alteration of the polarized light by the internal stresses into waves that travel at different velocities.

The patterns that develop consequently are related to the distribution of internal stresses and are

called the photoelastic effect. A research technique with many orthodontic applications.

Physiologic migration

[See Drift (of teeth)]

Physiologic rest position (of the mandible)

The mandibular position assumed when the head is in an upright position and the involved

muscles, particularly the elevator and depressor groups, are in equilibrium in tonic contraction, and

the condyles are in a neutral, unstrained position.

Physiologic tooth movement

Movement of the teeth taking place as part of the natural process from their early stages of

development until they become functional at the level of the occlusal plane, and extending to the

end of their lifespan in the mouth. The movements teeth make are complex and may be

distinguished as “pre-eruptive,” “eruptive” and “post-eruptive.” Superimposed on these is a

progression from deciduous to permanent dentition, involving the exfoliation of the deciduous

dentition. This categorization of tooth movement merely serves descriptive purposes; it must be

recognized that what is being described is a continuous series of events.

SUBTERMS:

Physiologic tooth movement

• Eruptive tooth movement

This includes “pre-emergent” and “post-emergent” tooth movement. The mechanism of eruption of

deciduous and permanent teeth is thought to be similar, bringing about the axial and occlusal

movement of the tooth from its developmental position within the jaw to its final functional position

within the occlusal plane. Pre-emergent tooth movement seems to be controlled by a different

mechanism than post-emergent tooth movement.

Eruptive movement begins soon after the root begins to form. The PDL also develops only after

root formation has been initiated, and once established, it must be remodel-ed to permit eruptive

tooth movement. The remodeling of the PDL fiber bundles is achieved by fibroblasts, which

simultaneously degrade and synthesize the collagen fibers as required across the entire extent of

the ligament. As the tooth moves occlusally, bone is resorbed occlusal to it and new bone is formed

apical to the tooth.

At the time of emergence of the tooth into the oral cavity, its dental follicle fuses with the oral

epithelium. Following emergence the tooth erupts rapidly until it approaches the occlusal level

(post-emergent spurt). Environmental factors such as muscle forces from the tongue, cheeks and

lips, as well as forces of contact of the erupting tooth with other erupted teeth, help determine the

final position of the tooth in the dental arch. The effect of thumbsucking onthe dentition is an

obvious example of environmental determination of tooth position.

[See Post-emergent spurt]

[See “Cone-funnel” mechanism]

Physiologic tooth movement

• Post-eruptive tooth movement

Movement of the teeth after they have reached their functional position in the occlusal plane. The

same mechanisms that control post-emergent tooth movement seem to regulate post-eruptive

tooth movement in the vertical plane. Post-eruptive tooth movement can be divided into three

categories:

1. Vertical movement occurring in concert with jaw growth (“juvenile occlusal equilibrium”). This

movement is completed toward the end of the second decade, when jaw growth ceases, and it

occurs earlier in girls than in boys. It is related to the growth of the mandibular ramus, which

causes the maxilla and mandible to grow apart from each other, permitting further eruptive

movement of the teeth.

2. Movement to compensate for the continuous occlusal wear of the teeth (“adult occlusal

equilibrium”). This axial post-eruptive movement occurs even after the apices of the teeth are fully

formed. It is demonstrable by the tendency of teeth to overerupt when their antagonist is lost, at

any age.

3. Movement to compensate for interproximal wear. Wear also occurs at the contact points

between teeth on their proximal surfaces, and its extent can be considerable (more than 7 mm in

the mandibular dental arch). This interproximal wear is compensated for by a process known as

“mesial drift.” The mechanism of this mesial drift is multifactorial and is attributed to the anterior

component of the occlusal force, to contraction of the transseptal fibers and/or pressure from the

perioral and intraoral soft tissues (cheeks and tongue).

[See Drift (of teeth), Mesial drift (Mesial migration, Approximal drift)]

[See Occlusal equilibrium, Juvenile occlusal equilibrium]

[See Occlusal equilibrium, Adult occlusal equilibrium]

Physiologic tooth movement

• Pre-eruptive tooth movement

Movement of the deciduous and permanent tooth germs within the tissues of the jaw before they

begin to erupt. As the deciduous tooth germs grow, the space for them in the developing jaw

becomes less, and initially they are “crowded” in the anterior region. This “crowding” usually is

alleviated before emergence by growth of the jaws, mainly in the midline, which permits mesial

movement of the anterior tooth germs.

The deciduous molar germs gradually increase in size and become displaced distally in

association with sagittal growth of the jaws. At the same time, the tooth germs are moving

occlusally with the increase in height of the jaws. The permanent anterior tooth germs initially

develop on the lingual aspect of their predecessors. From this position they shift considerably as

the jaws develop (e.g. the incisors eventually come to occupy a position on the lingual aspect of

the roots of their predecessors, and the premolar germs are positioned between the divergent

roots of the deciduous molars). In the maxilla, the permanent molar germs initially develop with

their occlusal surfaces facing distally, and swing into position only when the maxilla has grown

sufficiently to provide space for such movement. In the mandible, the permanent molars develop

with their axes showing a mesial inclination, which gradually becomes more vertical.

“Pigtail”

The twisted, cut end of a stainless steel ligature or brass separator that is tucked under the

archwire, under a bracket wing, or in the interproximal area for patient comfort.

“Pigtail” attachment (Coil eyelet)

A small orthodontic attachment consisting of a pigtail-shaped wire soldered onto a bonding base.

“Pigtail” attachments are used mainly as handles for elastic traction.

[See Attachment, Orthodontic]

Pin

T-shaped orthodontic auxiliary, used mainly in the Begg technique and its modifications. The pins

are inserted in the vertical slots of the brackets, and their primary purpose is to retain the archwire

in the main slot.

SUBTERMS:

Pin

• Bi-level pin

Used to create an additional slot for a second archwire, which can be inserted between the bi-level

pin and the gingival tie-wing of the bracket.

Pin

• Power pin

Used as an attachment to anchor orthodontic elastic bands for the application of traction.

Placebo

Inactive substance, device or measure that is believed by the patient to have an active therapeutic

value, but in fact, does not. Placebos sometimes are used in controlled studies to determine the

effect of drugs without the influence of bias.

Plagiocephalic

An individual with an asymmetric skull shape. Plagiocephaly may be produced by unilateral

synostosis of the coronal or the lambdoidal suture.

[Compare with Trigonocephalic]

Plate

A non-specific term implying a removable orthodontic appliance constructed at least partially of

acrylic.

Platybasia

A term denoting a more obtuse than normal cranial base angle (saddle angle, BaSN).

[Compare with Basilar kyphosis (Kyphosis of the cranial base)]

“Play” of an orthodontic wire in the bracket slot

The amount of freedom allowed at the bracket-to-wire interface due to the difference in size

between the wire and the bracket slot. The amount of “play” varies depending on the relative size

of the bracket and wire and refers to the type of individual movement intended (usually a distinction

is made between second-order and third-order clearance). For example, to achieve a certain

amount of torquing movement of an individual tooth, more activation (in degrees) is necessary

when using a 0.016 x 0.022-inch (0.41 x 0.56-mm) archwire, compared to using an 0.018 x 0.025-

inch (0.46 x 0.64-mm) archwire, because of the increased torsional play in the former case.

[See Second-order clearance]

[See Third-order clearance]

Plication

The stitching of folds or tucks in a tissue to reduce its size, as in the retrodiscal tissue of the

temporomandibular joint, in an attempt to reposition an anteriorly displaced articular disc and reestablish

a physiologic anatomic disc-to-condyle relationship. A type of disc-repositioning surgery.

Point of application

One of the four characteristics of vectorial quantities (the other three are line of action, sense and

magnitude). The point on a body where the vector is applied.

Point of application

One of the four characteristics of vectorial quantities (the other three are line of action, sense and

magnitude). The point on a body where the vector is applied.

Point of dissociation

[See Burstone’s geometry classes, Geometry IV]

Pontic

The part of a restoration that replaces a missing natural tooth.

Post-emergence eruption

[See Physiologic tooth movement, Eruptive tooth movement]

Post-emergent spurt

The phase of relatively rapid eruptive movement, from the time a tooth first penetrates the gingiva

until it reaches the occlusal level.

[See Occlusal equilibration (Occlusal adjustment)]

Postural

Related to position.

Post-emergence eruption

[See Physiologic tooth movement, Eruptive tooth movement]

Predisposing factors

Factors that increase the risk of developing a disease or condition.

Preferred provider organization (PPO)

A formal agreement between a purchaser of a health benefits program and a defined group of

health care practitioners for the delivery of services to a specific patient population, usually as an

adjunct to a traditional plan, using discounted fees for cost savings. Preferred provider

organizations provide a reduced fee for each service, rather than a fixed fee for all services.

Preferred provider organizations allow treatment by a non-PPO physician or dentist, for a higher

fee. [Modified from the AAO Glossary of Dentofacial Orthopedic Terms, 1993.]

[Compare with Health maintenance organization (HMO)]

Premature loss

Loss of a deciduous tooth prior to its normal time of exfoliation, due to extraction or undue

resorption of its root. An example of the latter is the situation in which there is severe lack of space

in the dental arch for eruption of a permanent incisor, which sometimes results in resorption of the

root of not only its predecessor, but also of that of the adjacent deciduous tooth.

Premaxilla

The triangular part of the hard palate anterior to the incisive foramen, including the four maxillary

incisor teeth, extending in the midline up to the piriform rim. The premaxilla is derived

embryologically from the primary palate. It is a separate bone in most animals; however, in humans

it generally is not independent of the maxilla, even in the early developmental stages.

[See Segment, Premaxillary segment]

Presurgical infant orthopedics (PSIO, Presurgical orthopedic treatment, PSOT, Neonatal

maxillary orthopedics)

Any orthopedic manipulation of the segments of the clefted maxilla in a newborn with complete

unilateral or bilateral CLPaiming at establishing a more normal maxillary alveolar arch form or at

retracting a protruding premaxilla to facilitate the surgical repair of the lip. This procedure, the value

of which is under investigation, usually involves the use of plates