Angles of classification

Question 1

What is it?

Answer 1

developed by DR Edward Angle + used to describe + classify occlusion + malocclusion. Assumes that a pt is occluding in the centric position
The basis of this is the first permanent molar is the key to occasion
-similar to skeletal classifications but relates to the teeth in each jaw

Question 2

Class I (most common) bite is normal

Answer 2

• the upper teeth are slightly overlap lower teeth, the cusp of upper 6 occludes with buccal grove of lower 6
• the incisal edge of lower incisor bites on or below cingulum of upper incisors.
• There is a possibility that the relationship in posterior teeth is class I but anterior teeth or tooth are misaligned + may be other irregularities

Question 3

Class II Division I

Answer 3

• When the maxilla is forward relative to the mandible, anterior teeth are proclaimed. The position of the front teeth means they can be damaged more easily
• The messy buccal cusp of the upper first molar occludes medial to the medial buccal cup of the lower first molar
• The upper incisors are proclined or upright + lower incisors bite behind the cingulum of upper incisors

Question 4

Class II Division II

Answer 4

• upper incisors are retroclined
• the position of teeth when closed can lead to trauma of lower labial gingivae + upper palatal gingivae
• lower incisors bite behind the cingulum

Question 5

Class III

Answer 5

Class III when lower jaw protrudes or juts forward, causing lower jaw and teeth to overlap upper jaw +teeth. The body of mandible is abnormal relationship to maxilla.

• The mesial buccal cusp of upper 1st molar occludes in interdental space between distal cusp of lower 1st molar
• the distal buccal cusp of upper 1st molar occludes with mesial cusp of second molar in mandible

Question 6

Overjet

Answer 6

the horizontal overlap of incisal teeth (2-4mm of horizontal overlap)

Question 7

Overbite

Answer 7

the vertical overlap of incisal teeth (50% vertical overlap)

Question 8

Crossbite

Answer 8

Normally teeth meet with labial or buccal half of the crowns on the upper teeth outside those of lower teeth, if this is reversed its called cross bite
Unilateral - 1 side only
Bilateral - both sides