Treatment effects of headgear biteplane and bionator appliances.

INTRODUCTION The purpose of this investigation was to evaluate the dentoalveolar and skeletal cephalometric changes produced by headgear (HG) biteplane and bionator appliances in subjects with Class II Division 1 malocclusion. METHODS The sample comprised 60 patients with Class II Division 1 malocclusion; 30 (15 boys, 15 girls; mean age, 10.02 years) were treated with the HG biteplane for a mean period of 1.78 years, and 30 (15 boys, 15 girls; mean age, 10.35 years) were treated with a bionator for a mean period of 1.52 years. For comparison, a control group of 30 untreated Class II children (15 boys, 15 girls) with an initial mean age of 10.02 years, followed for 1.48 years, was established. Lateral cephalometric headfilms were obtained at the beginning and at the end of the treatment or observation period. RESULTS The results showed that forward growth of the maxilla was restricted in the HG biteplane group. Bionator treatment, however, produced a statistically significant increase in mandibular protrusion. Both appliances provided increases in total mandibular and ramus lengths. There were no statistically significant differences in craniofacial growth direction. The mandibular incisors were tipped labially with bionator treatment and lingually in the HG biteplane group. The maxillary incisors were retruded with both appliances; there also were a significant increase in mandibular posterior dentoalveolar height and a restriction in the vertical development of the maxillary molars. CONCLUSIONS Class II treatment with HG biteplane and bionator appliances is efficient over the short term, with pronounced dentoalveolar movements and smaller but still significant skeletal effects. The stability of these results should be examined in a long-term study.