Class I Malocclusion

Question 1

Define Class I Malocclusion?

Answer 1

The lower incisor edge lies on or immediately below the cingulum plateau of the upper central incisor

Question 2

Incidence?

Answer 2

60%

Question 3

What skeletal pattern can it be?

Answer 3

SK 1 - normal incisor angles

MILD Sk2 - normal upper incisors / proclined lower incisors

MILD SK3 - proclined upper incisor/ retroclined lower incisors

Question 4

Skeletal pattern in Class I

A/P?
Vertical?
Lateral?

Answer 4

A/P - usually ANB 2-4 but not always

Vertical - full range, mostly average but can be increased or reduced.

Lateral - facial asymmetry possible

Question 5

Common Features …

Answer 5

Crowding - very common - too much tooth tissue for arch size

Question 6

Common Features …

Answer 6

Crowding - very common - too much tooth tissue for arch size

Spacing -
Small teeth on normal jaws
Normal teeth on large jaws
Missing teeth

Bimaxillary proclination - Upper and lower incisors proclined - influenced by soft tissues

Question 7

Local Factors…

Answer 7

Supernumeraries
Hypodontia
Macrodont
Microdont
Impeded / impacted / ectopic
Transposition
Fraenum
Cysts
AOB
Crossbite