Functional appliances in skeletal class II are indicated when:
Maxilla is normal, mandible is retrognathic
Maxilla is prognathic
Mandible is retrognathic in a mature individual
When severe crowding is present
Moderate to severe skeletal class-II malocclusion division 1 cases due to a short or retrognathic mandible are ideally suited for functional appliance treatment.
Class II division 2 type of malocclusions may be treated with functional appliances after correcting the axial inclinations of maxillary anteriors.