Treatment of class III

Question 1

What is class III?

Answer 1

Lower incisor occludes in front of the upper incisor cingulum plateau

Question 2

What does correction of class III depend on?

Answer 2

Skeletal pattern - Dento-alveolar compensation - can the pt achieve edge to edge incisors?
Overbite (if bad probs made worse with Tx)
Growth can be unfavourable

Question 3

Aetiology of class III?

Answer 3

Mandibular protrusion = main cause
Maxillary retrusion
Both

Question 4

Dento alveolar compensation in class III?

Answer 4

If teeth compensate for occlusal pattern - upper incisors proclined and lower incisors upright or retroclined

Question 5

How to decrease an overbite?

Answer 5

Loss of overbite as tooth proclined - must retain tooth at end of treatment

Question 6

How to treat a normal overbite in class III?

Answer 6

No lower extractions

Do not extract in upper arch

Question 7

How to treat a moderate class III skeletal pattern?

Answer 7

Loss of overbite
Poor prognosis for stability
U and L fixed appliance
XLA in lower arch

Question 8

How to treat a reduced overbite with mild skeletal class III? Reduced overbite with moderate to severe skeletal class III?

Answer 8

Accept skeletal pattern and align teeth

Moderate to severe = poor prognosis, align teeth and accept incisor relationship or surgery

Question 9

Moderate or severe skeletal class III pattern treatment?

Answer 9

Surgery

OR moderate = upper and lower XLA

Question 10

When to do early intervention?

Answer 10

Skeletal pattern - growth modification to bring maxilla forwards

Question 11

-

Answer 11

-

Question 12

-

Answer 12

-

Question 13

How to move:
Mandible back?
Maxilla forwards?
Both?

Answer 13

Chin cup
Face mask
Class 3 functional appliance e.g. CBT

Question 14

Chin cup features?

Answer 14

No evidence of mandible affected
Retroclines lower incisors
Possible TMD problems

Question 15

How to wear face masks?

Answer 15

Worn full time 20 hrs a day for 4-6 months

Question 16

What do frankel 3 appliances do?

Answer 16

Procline uppers

Retrocline lowers

Question 17

Problems with class III functional appliances?

Answer 17

Only small amount of activation possible
Maxillary retrusion common
Continued growth

Question 18

Simple interceptive treatment?

Answer 18

Incisor over the bite….

Question 19

Checklist for class 3 treatment?

Answer 19

Overbite:
- Need enough to retain correction
Space 
- Extra C's?
Interference from primary canines
Position of permanent canine - prevents movement of lateral incisor
Growth = relapse with class III

Question 20

What can permanent canines do?

Answer 20

May prevent movement so wait for canine eruption before correction
Resorb lateral if moved

Question 21

What does the prognosis for treatment of a class III depend on?

Answer 21

Skeletal pattern
Amount of overbite
Growth