lecture 5 Flashcards
1
Q
Predisposing Factors to Malocclusion
A
*Disturbances in Embryologic Development
*Heredity (genetics)
*Functional matrix
*Traumas: Especially mandibular fractures.
2
Q
malocclusion etiology flow chart
A
3
Q
Normal skeletal relationship reference point
A
- Cranial base as a reference
- Position and projection of the upper jaw
- Position and projection of the lower jaw
4
Q
Types of malocclusion
A
- Malocclusion occurs in 3 dimensions (4 including time)
- Angle classification is based on AP relationships
5
Q
% occurrence of different occlusions
A
6
Q
are class I malocc always simple
A
no, could be skeletal abnormalities present
7
Q
skeletal patterns
A
8
Q
class 2 div 1 malocc
A
- Mandibular retrognathism
- 40% present bimaxillary retrusion
- Rarely true maxillary prognathism
majority of class 2 cases are this
can lead to sleep apnea
9
Q
class 2 div 2 malocc
A
only 10% cases
strong genetic component
L inclined CI and B inclined LI
10
Q
Typical Skeletal class II
A
- Mandibular retrognathism
- Proclined upper incisors
- Deep bite
- However, multiple presentations are possible
11
Q
Cl I maloccusion
A
- Jaws are well aligned in the anteroposterior dimension
- Vertical and transverse dimensions are variable.
12
Q
Transverse dimension measurements
A
ntermolar distance
Intercanine distance
Arch shape
13
Q
McGill ceph angles
A
14
Q
Class III
malocclusion
A
- Maxillary Retrognathism- majority
- Mandibular prognatjism
- Usually a combination of the two conditions
- Vertical dimension is variable Deepbite to openbite
15
Q
prevalence cl 3 malocc
- Southeast Asian
- Middle eastern
- Indian
- European
A
- Depends on the population
- Southeast Asian ~15%
- Middle eastern ~10%
- Indian ~1%
- European ~1-4%
16
Q
Genetics of Class III
A
- Suggest a **polygenic **model as primary cause of Class III malocclusion
- Linkage Analysis studies
- Used to determine the chromosome loci associated
with the condition - Suggested loci: 1p22, 1p36, 3q26.2, 6q25, 11q22, 12q13, 12q23, 19p32.2
