Orthodontic Definitions

Question 1

Class I Molar

Answer 1

The mesiobuccal cusp of the upper first molar occludes in the buccal groove of the lower first molar

Question 2

Class II Molar

Answer 2

The mesiobuccal cusp of the upper first molar occludes anterior to the buccal groove of the lower first molar

Question 3

Class III Molar

Answer 3

The mesiobuccal cusp of the upper first molar occludes posterior to the buccal groove on the lower first molar

Question 4

Class I Incisor

Answer 4

The lower incisors edges occlude with or lie immediately below the cingulum plateau of the upper central incisors

Question 5

Class IIi Incisors

Answer 5

The lower incisal edge occludes posterior to the cingulum plateau of the upper central incisors
* Central incisors = proclined
* increased overjet

Question 6

Class IIii Incisors

Answer 6

The lower incisor edges occlude posterior to cingulum plateau of the upper central incisors
* Upper Centrals= retroclined
*Overjet= reduced or increased
*upper laterals = proclined

Question 7

Class III Incisors

Answer 7

The lower incisal edges occlude anterior the cingulum plateau of the upper central incisors
* Overjet= reduced or reversed

Question 8

Class I Canine

Answer 8

The upper canine occludes and lies in the embrasure of the lower canine and the first premolar

Question 9

Class II Canine

Answer 9

The upper canine occludes and lies in the embrasure of the lower canine and the lower lateral incisor

Question 10

Class III Canine

Answer 10

The upper canine occludes and lies in the embrasure of the lower first and lower second premolar

Question 11

Hypodontia

Answer 11

Missing teeth
*congenital absence of one of more teeth

Question 12

Oligondontia

Answer 12

6> teeth missing

Question 13

Anodontia

Answer 13

Total loss of teeth

Question 14

Supernumerary

Answer 14

An extra tooth

Question 15

Impaction

Answer 15

Failure to erupt due to crowding or obstruction Eg. Impacted canine

Question 16

Deepbite

Answer 16

Vertical overlap of the upper incisors over the lower incisors 4mm >

Question 17

Normal overbite

Answer 17

Upper incisors cover 1/3 of the lower incisors

Question 18

Increased Overbite

Answer 18

Upper incisors cover 1/3 > of the lower incisors

Question 19

Decreased Overbite

Answer 19

Upper incisors cover < 1/3 of the lower incisors

Question 20

Incomplete Overbite

Answer 20

Lower incisors do not come into contact with hard or soft tissues

Question 21

Complete Overbite

Answer 21

Lower incisors come into contact with hard and soft tissues

Question 22

Anterior Open Bite

Answer 22

No vertical overlap of the upper and lower incisors when occluding

Question 23

Posterior Open Bite

Answer 23

No vertical overlap of the upper and lower posterior teeth when occluding

Question 24

Crossbite

Answer 24

An abnormal relationship between the opposing teeth in the buccopalatal or buccolingual direction

Question 25

Posterior Crossbite

Answer 25

Buccal cusp of the lower tooth occludes buccally to the buccal cusp of the upper tooth when occluding

Question 26

Lingual/ scissor Crossbite

Answer 26

The buccal cusp of the lower tooth occludes palatally to the palatal cusp of the upper tooth when occluding

Question 27

Anterior Crossbites

Answer 27

Maxillary incisors occlude lingually to the lower incisors when occluding

Question 28

Overjet

Answer 28

distance between the upper incisors and the lower incisors in the horizontal plane. Normal is 2-4mm

Question 29

Bimaxillary Proclination

Answer 29

Upper and lower incisors are proclined

Question 30

Centre of Resistance

Answer 30

Point in the body where resistance to movement is concentrated

Question 31

Force Moment

Answer 31

The Component found within a force that causes rotation

Question 32

Force Couple

Answer 32

Fixed Appliance Eg. Archwire connects into a bracket slot and a force is created. This achieves Rotation, Inclination and torqueing.

Question 33

Dental Panoramic Tomography DPT, OPT, OPG

Answer 33

Radiograph that gives a two dimensional view of the mandible and the maxilla.

Question 34

Cephalometric Radiograph

Answer 34

A true lateral view of the skull, a two dimensional image of a three dimensional object presenting the skull and facial bones

Question 35

Upper Standard Occlusal Radiograph USO

Answer 35

A radiograph of the upper anterior part of the Maxilla and anterior teeth

Question 36

Parallax

Answer 36

A technique used when assessing or localising the position of unerupted teeth

Question 37

Anchorage

Answer 37

Control of unwanted tooth movement

Question 38

IOTN Index of Orthodontic Treatment Need

Answer 38

To asses the need of Treatment

Question 39

PAR Peer Assessment Rating

Answer 39

used to measure the success of treatment

Question 40

Cleft Lip and Palate

Answer 40

A cranio facial malformation

Question 41

Tooth Fusion

Answer 41

when two individual teeth are fused together. Each tooth has an individual pulp and root canal

Question 42

Tooth Germination

Answer 42

When two teeth develop together and form one tooth. A large crown is present and only one root