Lec7_Classification of Malocclusion

Question 1

What is Angle’s classification accurate for?

Answer 1

Accurate for anterior posterior dental classification only.

Does not involve the skeleton.

Question 2

What is the problem with Angle’s classification?

Answer 2

It isn’t very detailed. Only describes the 1st molar.

Also, it assumes the maxillary molar is in constant position to cranium. This isn’t true!!

Doesn’t consider protrusion, other teeth, vertical dimension, etc.

Question 3

What did Dewey do?

Answer 3

Proposed subdivisions of class I.

Question 4

What is the Simon classification?

Answer 4

An effort to relate casts and teeth to the cranium. Still use this.

Question 5

What is the Ackerman-Proffit classification?

Answer 5

5 categories to classify occlusion: skeletal, dental, soft tissue in all 3 planes.

Question 6

What is normal occlusion?

Answer 6

Technically is class I occlusion with good alignment and tooth position.

Question 7

What is the range between classifications?

Answer 7

6mm!

Question 8

Is malocclusion heritable?

Answer 8

Yes, very heritable. Note that the dental arch size and arrangement has low heritability.

Question 9

What is the etiology for each of these?

Answer 9

Crowding = genetics + environment
Class I non-skeletal (crossbites, malocclusion) = environmental
Class II skeletal = genetic
Class III skeletal = genetic
Openbite = environmental (thumb, breathing) or genetic (vertical growth)

Question 10

Which is the most common Angle classification?

Answer 10

Class I