Orthodontic Terms

Question 1

Anchorage

Answer 1

The source of resistance to the forces generated in reaction to the active components of an appliance.

Question 2

Angulation

Answer 2

Degree of tip of a tooth in the mesiodistal plane

Question 3

Anterior Open bite

Answer 3

There is no vertical overlap of the incisors when the buccal segment teeth are in occlusion.

Question 4

Balancing extraction

Answer 4

Extraction of the same (or adjacent) teeth on the opposite side of the arch to preserve asymmetry

Question 5

Bimaxillary proclination

Answer 5

Both upper and lower incisors are proclined relative to the skeletal bases

Question 6

Bimaxillary retroclination

Answer 6

Both upper and lower incisors are retroclined relative to the skeletal bases

Question 7

Bodily movement

Answer 7

Equal movement of the root apex and crown of a tooth in the same direction

Question 8

Buccal crossbite

Answer 8

The buccal cusps of the lower premolars and/or molars occlude buccally to the buccal cusps of the upper premolars and/or molars

Question 9

Centric occlusion

Answer 9

Position of maximum interdigitation

Question 10

Centric relation

Answer 10

The condyle is in its most superior anterior position in the glenoid fossa

Question 11

Cingulum plateau

Answer 11

The convexity of the cervical third of the lingual/ palatal aspect of the incisor and canines

Question 12

Compensating extraction

Answer 12

Extraction of the same tooth in the opposing arch

Question 13

Competent lips

Answer 13

Upper and lower lips contact without muscular activity at rest

Question 14

Complete overbite

Answer 14

The lower incisors occlude with the upper incisors or palatal mucosa

Question 15

Crowding

Answer 15

Where there is insufficient space to accomodate the teeth in perfect alignment in an arch, or segment of an arch

Question 16

Curve of Spee

Answer 16

Curvature of the occlusal plane in the sagittal plane

Question 17

Dento-alveolar compensation

Answer 17

The inclination of the teeth compensates for the underlying skeletal pattern, so that the occlusal relationship between the arches is less marked

Question 18

Hypodontia

Answer 18

This term is used when one or more pemanent teeth (excluding third molars) are congenitally absent.

Question 19

Ideal occlusion

Answer 19

Anatomically perfect arrangement of the teeth. Rare.
Andrew desrcibed the “six keys to an ideal occlusion”

Question 20

Impaction

Answer 20

Impeded tooth eruption, usually because of displacement of the tooth or mechanical obstruction, eg crowding or a supernumerary tooth

Question 21

Inclination

Answer 21

Degree of tip of a tooth in the labiopalatal plane

Question 22

Incompetent lips

Answer 22

Some muscular activity is required for the lips to meet together

Question 23

Incomplete overbite

Answer 23

The lower incisors do not occlude with the opposing upper incisors or the palatal mucosa when the buccal segment teeth are in occlusion

Question 24

Intermaxillary

Answer 24

Between the arches

Question 25

Intramaxillary

Answer 25

Within the same arch

Question 26

Leeway space

Answer 26

The difference in diameter between the deciduous canine, first molar, and second molar and ther permanent successors (canine, first premolar, and second premolar)

Question 27

Lingual crossbite

Answer 27

The buccal cusps of the lower premolars and/or molars occude lingually to the lingual cusps of the upper premolars or molars. Sometimes referred to as a scissors bite

Question 28

Malocclusion

Answer 28

Variation from ideal occlusion which has dental health and/or psychosocial implications for the individual. NB The borderline between normal occlusion and malocclusion is contentious

Question 29

Mandibular deviation

Answer 29

The path of closure of the mandible starts from a postured position

Question 30

Mandibular displacement

Answer 30

When closing from the rest position, the mandible displaces (either laterally or anteriorly) to avoid a premature contact. The premature contact can be determined by placing the mandible into the retruded contact position (centric relation)

Question 31

Midline diastema

Answer 31

A space between the central incisors. Most common in the upper arch.

Question 32

Normal occlusion

Answer 32

Acceptable variation from ideal occlusion

Question 33

Overbite

Answer 33

Vertical overlap of the upper and lower incisors when viewed anteriorly.

Question 34

Overjet

Answer 34

Distance between the upper and lower incisors in the horizontal plane. Normal overjet is 2-3 mm

Question 35

Posterior open bite

Answer 35

When the teeth are in occlusion, there is a space between the posterior teeh

Question 36

Relapse

Answer 36

The return, following correction, of features of the original malocclusion

Question 37

Reverse overjet

Answer 37

The lower incisors lie anterior to the upper incisors. When only one or two incisors are involved, the term anterior crossbite is commonly used

Question 38

Rotation

Answer 38

A tooth is twisted around its long axis

Question 39

Spacing

Answer 39

Where the teeth do not touch interproximally and there are gaps between adjacent teeth. Can be localized or generalized.

Question 40

Tipping movements

Answer 40

Movement of the rooth apex and crown in opposite directions around a fulcrum

Question 41

Torque

Answer 41

Movement of the root apex buccolingually, either with no or minimal movement of the crown in the same direction

Question 42

Traumatic overbite

Answer 42

The occlusion of the lower incisors with the palatal mucosa has led to ulceration. It is also possible to have ulceration of the labial mucosa of the lower incisors due to the upper incisor's occlusion.