Treatment of class III Flashcards
What is class III?
Lower incisor occludes in front of the upper incisor cingulum plateau
What does correction of class III depend on?
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
Aetiology of class III?
Mandibular protrusion = main cause
Maxillary retrusion
Both
Dento alveolar compensation in class III?
If teeth compensate for occlusal pattern - upper incisors proclined and lower incisors upright or retroclined
How to decrease an overbite?
Loss of overbite as tooth proclined - must retain tooth at end of treatment
How to treat a normal overbite in class III?
No lower extractions
Do not extract in upper arch
How to treat a moderate class III skeletal pattern?
Loss of overbite
Poor prognosis for stability
U and L fixed appliance
XLA in lower arch
How to treat a reduced overbite with mild skeletal class III? Reduced overbite with moderate to severe skeletal class III?
Accept skeletal pattern and align teeth
Moderate to severe = poor prognosis, align teeth and accept incisor relationship or surgery
Moderate or severe skeletal class III pattern treatment?
Surgery
OR moderate = upper and lower XLA
When to do early intervention?
Skeletal pattern - growth modification to bring maxilla forwards
-
-
-
-
How to move:
Mandible back?
Maxilla forwards?
Both?
Chin cup
Face mask
Class 3 functional appliance e.g. CBT
Chin cup features?
No evidence of mandible affected
Retroclines lower incisors
Possible TMD problems
How to wear face masks?
Worn full time 20 hrs a day for 4-6 months
What do frankel 3 appliances do?
Procline uppers
Retrocline lowers
Problems with class III functional appliances?
Only small amount of activation possible
Maxillary retrusion common
Continued growth
Simple interceptive treatment?
Incisor over the bite….
Checklist for class 3 treatment?
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
What can permanent canines do?
May prevent movement so wait for canine eruption before correction
Resorb lateral if moved
What does the prognosis for treatment of a class III depend on?
Skeletal pattern
Amount of overbite
Growth
