Classification of malocclusion

Question 0

What is Angles normal occlusion?

Answer 0

The line of occlusion involves the incisal edges and buccal cusps of the mandibular teeth coinciding with the cingulum of anterior and canines as well as the fossae of the premolars and molars in the maxillary arch

Question 1

What is the Dewey-Anderson Classification of malocclusioon?

Answer 1

1) Class I,type1: typical CI with crowding and rotations
2) Class I, type II: Proclined incisors and spaced upper incisors
3) Class I, type III: ANterior crossbite
4) Class I, type 4: posterior crossbite
5) Class I, type V: posterior crowding
6) Class III, type I: anteriors edge to edge
7) Class III, type II: normal overbite and overjet
8) Class III, type 3: anterior crossbite

Question 2

Describe angles Class I occlusion (neutroocclusion)

Answer 2

1) Normally overbite of about 20%
2) Can either be crowded or spaced
3) Facial profile normally fairly straight
4) An example of a modification would be bimaxillary protrusion in which the canines and molars occlude in a Class I but the incisors are proclined relative to the apical base

Question 3

Describe angles class II malocclusion (distoclusion)

Answer 3

1) The bite can be deep or open
2) Crowding is highly variable
3) Arch form: Div I normally V-shaped upper arch while with Div II its normally broad and flattened
4) Often invovles a retrognathic mandible (80% of cases) and occasionally a prognathic maxilla
5) Often a bugs bunny facial type with deep labo-mmental fold and entrapment of lower lip

Question 4

What are the variations that can occur with an Angles class II malocclusion?

Answer 4

1) Subdivision:
One side class I. Can present as a midline shift. Implies assymetry.
2) Indefinite:
Buccal occlusion is class II but overjet not due to incisor procclination. this implies a skeletal origin.

Question 5

Describe the features of an Angles Class III malocclusion.

Answer 5

1) Bite can be deep or open
2) Crowding: Normally more severe in upper arch
3) Arch form: A constricted upper arch is common, uni or bilateral buccal segment crossbites
4) Usually due to prognathic mandible but sometimes could be a retrognathic maxilla
5) Incisors normally eddge to edge crossbite

Question 6

What are the modifications that can be applied to an Angles Class III malocclusion?

Answer 6

1) Subdivision:
Implies one side is Class I
2) Pseudo or functionnal Class III:
ONly a class III when closed implying mandibular shifting