Orthodontic Definitions Flashcards
Class I Molar
The mesiobuccal cusp of the upper first molar occludes in the buccal groove of the lower first molar
Class II Molar
The mesiobuccal cusp of the upper first molar occludes anterior to the buccal groove of the lower first molar
Class III Molar
The mesiobuccal cusp of the upper first molar occludes posterior to the buccal groove on the lower first molar
Class I Incisor
The lower incisors edges occlude with or lie immediately below the cingulum plateau of the upper central incisors
Class IIi Incisors
The lower incisal edge occludes posterior to the cingulum plateau of the upper central incisors
* Central incisors = proclined
* increased overjet
Class IIii Incisors
The lower incisor edges occlude posterior to cingulum plateau of the upper central incisors
* Upper Centrals= retroclined
*Overjet= reduced or increased
*upper laterals = proclined
Class III Incisors
The lower incisal edges occlude anterior the cingulum plateau of the upper central incisors
* Overjet= reduced or reversed
Class I Canine
The upper canine occludes and lies in the embrasure of the lower canine and the first premolar
Class II Canine
The upper canine occludes and lies in the embrasure of the lower canine and the lower lateral incisor
Class III Canine
The upper canine occludes and lies in the embrasure of the lower first and lower second premolar
Hypodontia
Missing teeth
*congenital absence of one of more teeth
Oligondontia
6> teeth missing
Anodontia
Total loss of teeth
Supernumerary
An extra tooth
Impaction
Failure to erupt due to crowding or obstruction Eg. Impacted canine
Deepbite
Vertical overlap of the upper incisors over the lower incisors 4mm >
Normal overbite
Upper incisors cover 1/3 of the lower incisors
Increased Overbite
Upper incisors cover 1/3 > of the lower incisors
Decreased Overbite
Upper incisors cover < 1/3 of the lower incisors
Incomplete Overbite
Lower incisors do not come into contact with hard or soft tissues
Complete Overbite
Lower incisors come into contact with hard and soft tissues
Anterior Open Bite
No vertical overlap of the upper and lower incisors when occluding
Posterior Open Bite
No vertical overlap of the upper and lower posterior teeth when occluding
Crossbite
An abnormal relationship between the opposing teeth in the buccopalatal or buccolingual direction
Posterior Crossbite
Buccal cusp of the lower tooth occludes buccally to the buccal cusp of the upper tooth when occluding
Lingual/ scissor Crossbite
The buccal cusp of the lower tooth occludes palatally to the palatal cusp of the upper tooth when occluding
Anterior Crossbites
Maxillary incisors occlude lingually to the lower incisors when occluding
Overjet
distance between the upper incisors and the lower incisors in the horizontal plane.
Normal is 2-4mm
Bimaxillary Proclination
Upper and lower incisors are proclined
Centre of Resistance
Point in the body where resistance to movement is concentrated
Force Moment
The Component found within a force that causes rotation
Force Couple
Fixed Appliance Eg. Archwire connects into a bracket slot and a force is created. This achieves Rotation, Inclination and torqueing.
Dental Panoramic Tomography
DPT, OPT, OPG
Radiograph that gives a two dimensional view of the mandible and the maxilla.
Cephalometric Radiograph
A true lateral view of the skull, a two dimensional image of a three dimensional object presenting the skull and facial bones
Upper Standard Occlusal Radiograph
USO
A radiograph of the upper anterior part of the Maxilla and anterior teeth
Parallax
A technique used when assessing or localising the position of unerupted teeth
Anchorage
Control of unwanted tooth movement
IOTN
Index of Orthodontic Treatment Need
To asses the need of Treatment
PAR
Peer Assessment Rating
used to measure the success of treatment
Cleft Lip and Palate
A cranio facial malformation
Tooth Fusion
when two individual teeth are fused together. Each tooth has an individual pulp and root canal
Tooth Germination
When two teeth develop together and form one tooth. A large crown is present and only one root
