A comparison of the Herbst and Fränkel appliances in the treatment of Class II malocclusion.

This study investigated the treatment effects produced by two types of functional appliance, one primarily tooth-borne (the Herbst appliance) and one primarily tissue-borne (the FR-2 of Fränkel). Serial cephalometric radiographs from 45 patients who had been treated with the acrylic splint Herbst appliance and from 41 patients who had been treated with the FR-2 appliance were compared with serial radiographs of 21 untreated persons with Class II malocclusions. Treatment effects were identified through the use of a conventional cephalometric analysis. The results of this study indicated that both appliances had influenced the growth of the craniofacial complex in treated persons. Significant skeletal changes were noted in both treatment groups, with both groups showing an increase in mandibular length and in lower facial height, as compared with controls. Greater dentoalveolar treatment effects were noted in the group wearing the tooth-borne functional appliance than in those wearing the tissue-borne appliance.