National Institute of Dental and Craniofacial Research efficacy trials of bionator class II treatment: a review.

Reviewing publications from two North American functional appliance efficacy trials on Class II/1 malocclusions, we conclude that preadolescents show first molar correction in 13% of untreated cases, 38% of bionator-treated cases, and 50% of combined headgear/biteplane-treated cases. Also, bionator and headgear reduce ANB differences at nearly equivalent rates (degrees/year). Thirty-two percent of untreated patients show favorable reductions (>0.5 degrees/y), compared with 80% of patients treated by either bionators or headgear. Successful outcomes, however, are highly dependent on the severity of the malocclusion. Using either headgear or bionators, clinicians should expect successful Class II molar correction in over 57% of preadolescents presenting with half cusp molar discrepancies. When left untreated, 30% of such patients are reported to attain a Class 1 molar relation. But only 5% of cases presenting with greater than half cusp discrepancies are found to resolve themselves. The bionator appliance, though, corrects 30% of such cases, and combined headgear/biteplane treatment corrects 40%.