Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BDS3 ORTHODONTICS > 3 - Aetiology of malocclusion > Flashcards

3 - Aetiology of malocclusion Flashcards

1
Q

What are the general aetiology factors of malocclusion?

A
  • skeletal, the shape and relative position of jaws
  • muscular, form and function of muscles that surround teeth
  • dentoalveolar, size of teeth in relation to jaws
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the components of the facial skeleton?

A
  • maxillary base
  • mandibular base
  • maxillary and mandibular alveolar bases
  • maxillary complex
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What can cause variation in the facial skeleton?

A
  • size and shape of maxilla, mandible and alveolar processes
  • size and angle of cranial base
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What can cause skeletal variation?

A
  • genetic and environmental factors
  • strong hereditary features in class III
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are environmental factors that can affect malocclusion?

A
  • masticatory muscles
  • mouth breathing (increased vertical dimension causes teeth to erupt more)
  • head posture
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define SNA.

A

Value between maxilla and anterior cranial base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Define SNB.

A

Value between mandible and anterior cranial base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define ANB.

A

Value between mandible and maxilla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the average SNA value for class I?

A

81° +/- 3°

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the average SNB value for class I?

A

78° +/- 3°

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the average ANB value for class I?

A

3° +/- 2°

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Define S in SNA.

A

Sella turcica

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define N in SNA.

A

Nasion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define A in SNA.

A

Maximum concavity of upper incisor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Define B in SNB.

A

Maximum concavity of lower incisor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does class II present in cephalometrics?

A
  • SNA usually average but can be increased if maxilla is prognathic
  • SNB usually decreased
  • ANB > 5°
17
Q

How does class III present in cephalometrics?

A
  • SNA decreased if maxilla deficient
  • SNB average or increased if mandible prognathic
  • ANB < 1° or negative
18
Q

What is dentoalveolar compensation?

A
  • dentoalveolar structures can disguise underlying skeletal discrepancies
  • muscular forces can incline teeth to appear closer together
  • ie. retroclined lowers by muscular strap
19
Q

What are the average vertical jaw relationship values?

A

Lower anterior face height = 55% of total anterior face height

20
Q

Where do you measure UAFH?

A

Glabella to base of nose

21
Q

Where do you measure LAFH?

A

Base of nose to inferior aspect of chin

22
Q

What is the average FMPA?

A

27° +/- 4°

23
Q

What is the FMPA?

A
  • Frankfort plane (inferior of orbit to EAM)
  • mandibular plane (menton to gonion)
  • angle between these 2 planes
24
Q

What are the features of long face syndrome?

A
  • convex profile
  • incompetent lips (can appear to be straining)
  • steeply inclined mandibular plane
  • anterior open bite tendency
  • backward mandibular growth rotation
25
Q

What are the cephalometric values for long face syndrome?

A
  • LAFH > 55%
  • FMPA > 31°
26
Q

What are the features of a short face type?

A
  • parallelism of jaws
  • forward mandibular growth rotation
  • deep overbite tendency
27
Q

What are the cephalometric values for short facial type?

A
  • LAFH < 55%
  • FMPA < 23°
28
Q

Describe arch width discrepancies.

A
  • disproportion of maxillary and mandibular arches
  • unilateral or bilateral segment crossbites
  • can be exaggerated by AP discrepancies
29
Q

What causes mandibular displacement?

A
  • inter-arch width discrepancies causes teeth to meet cusp to cusp
  • mandible is forced to deviate to achieve ICP
  • can be associated with TMD
30
Q

What is transverse dentoalveolar compensation?

A
  • the molars in the upper can tilt in order to achieve ICP
  • narrow maxilla can lead to flared molars
  • broad maxilla can lead to more upright molars
31
Q

What are the causes of facial asymmetry?

A
  • dental, unilateral crossbite can displace mandible
  • true mandibular asymmetry
32
Q

What are the different types of true mandibular asymmetry?

A
  • hemimandibular hyperplasia
  • condylar hyperplasia
33
Q

What can cause dento-alveolar disproportion?

A

Crowding
- small jaws and normal sized teeth
- macrodontia
Spacing
- large jaws and normal sized teeth
- microdontia (also linked to missing teeth)

BDS3 ORTHODONTICS (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions