Aetiology of malocclusion

Question 1

What is a local cause of malocclusion and name some?

Answer 1

Localised problem within either arch, usually confined to one or two teeth producing a malocclusion

Variation in tooth number
Variation in tooth size or form
Abnormalities of tooth position (crowding)
Local abnormalities of soft tissues
Local pathology

Question 2

Name some conditions of tooth NUMBER that affect malocclusion

Answer 2

Supernumerary teeth
Hypodontia
Retained primary teeth
Early exfoliation
Unscheduled loss

Question 3

What is a supernumerary tooth and list 4 types?

Answer 3

A supernumerary tooth is any tooth that is deemed “extra” to the normal

Conical, tuberculate, supplemental, odontome

Question 4

What is a supplemental tooth?

Answer 4

A tooth that has normal shape and morphology but is EXTRA to the normal number of teeth.

Question 5

What is a lateral cephalogram?

Answer 5

Standardised lateral radiographs of the face and base of skull
Reproducible - patient positioned in a cephalostat a set distance from the cone and the film

Question 6

What is dento-alveolar compensation?

Answer 6

When soft tissues mould the teeth inclination to try to maintain contact with opposing teeth.

Question 7

Which type of supernumerary tooth is likely to DISRUPT ERUPTION of adjacent/ central incisor teeth?

Answer 7

Tuberculate

Question 8

What is meant by the term BALANCING extraction and what is the purpose of it?

Answer 8

Extracting a tooth from the opposite side of the same arch

Designed to minimise the midline shift

Question 9

What is a COMPENSATING extraction and what is the purpose of it?

Answer 9

Extraction of a tooth from the opposing arch of the same side

Designed to maintain occlusal relationship

Question 10

What are the types of variation that can occur in tooth size?

Answer 10

Macrodontia - too large
Microdontia - too small
Abnormal form

Question 11

If permanent canines are present, when should they be palpable buccally?

Answer 11

Should be able to buccally palpate from 9 years onwards

Question 12

What are things that should be clinically assessed for ectopic canines?

Answer 12

1. Visualisation/ palpation of any obvious bumps of 3
2. Inclination of 2
3. Mobility of c or 2
4. Colour of c or 2

Question 13

Name some local abnormalities of soft tissues that may cause malocclusion?

Answer 13

Digit sucking
Fraenum
Tongue thrust

Question 14

What are some local pathology factors that may cause malocclusion?

Answer 14

Caries
Cysts
Tumours