Class 2 Div 1 Flashcards
1
Q
Types of malocclusion
A
Class 2 div 1 - 15-20%
2
Q
Definition of Class 2 div 1
A
- lower incisor edges lie posterior to the cingulum plateau of upper incisors
- increased OJ
- upper central incisors are proclined or average inclination
3
Q
Why treat class 2 div 1?
A
- aesthetics
- dental health
- prominent incisors at risk of trauma especially if incompetent lips
- OJ > 9mm twice as likely to suffer trauma
- OJ > 9mm, IOTN 5a
4
Q
What includes in aetiology and features?
A
- skeletal pattern (A/P, vertical, transverse)
- soft tissues
- dental factors
- habits
5
Q
Skeletal pattern of class 2 div 1 (A/P)
A
- associated with class 2 sk pattern
- due to retrognathic mandible
- less common to have maxillary protrusion
- can happen in skeletal class 1
- rarely in class 3
6
Q
OJ might be due to?
A
- sk pattern
- tooth inclination
- combination of both
7
Q
Sk pattern - Vertical
A
- found in association with a range of vertical sk pattern
8
Q
Sk pattern (transverse)
A
- no particular association with transverse
9
Q
Normal values for SNA
A
81 +/- 3
10
Q
Normal values of SNB
A
78 +/- 3
11
Q
Normal values of ANB
A
3 +/- 2
12
Q
Normal values of UI/MxP
A
109 +/- 6
13
Q
Normal values of LI/ MnP
A
93 +/- 6
14
Q
Lateral ceph labelling
A
15
Q
Normal values for LAFH/ TAFH
A
55%