Year 3

Question 1

Problems w each malocclusion

Answer 1

AOB: can make eating difficult/embarrassing, may predispose to TMD (controversial)

Overjet: when 9mm or more, trauma risk 40% more

Anterior crossbite: displacement of lower central labially -> apical migration of gingiva and dehiscence + md displacement and wear

Deep overbite: damage to soft tissues (labial gingiva of lower incisors) + retroclined incisors act as stop for md growth

Question 2

What age is thumb sucking/tongue thrust normal until?

Answer 2

Thumb sucking: after 6/7 (early mixed dentition) to prevent arch distortion and class II, consider appliances

Tongue thrust: normal for 2-4yo, not a cause of malocclusion but rather the effect of

Question 3

Appliances for thumb sucking

Answer 3

Quad helix and tongue crib

Question 4

Causes of dental vs skeletal & combination class II

Answer 4

dental:
- early loss of primary teeth
- tooth-arch discrepancy
- thumbsucking

skeletal:
- prognathic mx
- retrognathic md

combination:
early loss of upper Es causes mesial drift of 1st molars + retrusive md

Question 5

What should diagnosis determine

Answer 5

• sagittal discrepancy: dental or skeletal or mixed?
• skeletal discrepancy: which jaw at fault & severity
• vertical discrepancy: open or deep bite?
• transverse: is the posterior crossbite skeletal, dental or combination
• age and growth potential
• presence or absence of CO-CR discrepancies

Question 6

What should diagnosis determine

Answer 6

• sagittal discrepancy: dental or skeletal or mixed?
• skeletal discrepancy: which jaw at fault & severity
• vertical discrepancy: open or deep bite?
• transverse: is the posterior crossbite skeletal, dental or combination
• age and growth potential
• presence or absence of CO-CR discrepancies

Question 7

Class II fixed and removable appliances for growing children

Answer 7

• Twin block (removable): restrains mx growth and encourages md growth, bite blocks to use forces of occlusion as functional mechanism
• Herbst (fixed): appliance on molars, puts backwards pressure on mx and forward on md
• Jasper jumper (fixed): spring

Question 8

What is pseudo class III?

Answer 8

class I skeletal
insufficient mx OJ and incisor interferences, anterior crossbite due to functional displacement of md to avoid anterior interference in CR and achieve maximum intercuspation
- most cases: retroclined mx and proclined md incisors
-> if there is CR-CO shift when guiding md into CO then it is pseudo, if not change in anterior crossbite then true class III

Question 9

Space gaining strategies other than exo

Answer 9

SPEED
stripping (IPR)
proclination
expansion
lEeway space
distalisation

Question 10

Maxillary expansion indications in class I non-exo cases

Answer 10

1. crossbite: dental or skeletal
2. space gaining (needs this and some other transverse problem)
3. excessive buccal corridor

Question 11

Types of maxillary expansion appliances

Answer 11

• Removable
• Fixed:
  RME (rapid) e.g. Hass, HYRAX (screw)
  SME (slow) e.g. Quad-Helix, W arch

Question 12

What might be used to procline teeth to gain space?

Answer 12

Removable devices:
- Z-spring
- Palatal expansion screw
- labial bow
- occlusal coverage