CEPHALOMETRIC EVALUATION OF 2 TREATMENT STRATEGIES FOR DEEP OVERBITE CORRECTION

This study compared the cephalometric changes achieved using fixed ver sus removable appliances to correct deep overbite in growing patients. Forty-five patients treated with cervical headgear/tandem mechanics a nd 50 patients treated with a bionator appliance were compared with 95 control subjects from the Bolton Study. Treatment differences were de termined using a cephalometric analysis that isolated vertical changes in overbite as the composite result of 6 variables: maxillary skeleta l change, tipping of the upper incisors, bodily movement of the upper incisors, mandibular skeletal change, lower incisor tipping, and bodil y movement of the lower incisors. The interaction of treatment type wi th facial type was also examined. In the headgear/tandem group, overbi te was corrected by a combination of intrusion of the upper incisors a nd increases in mandibular skeletal change. Treatment with the bionato r resulted in correction of the overbite by relative intrusion of the upper and lower incisors and increases in mandibular skeletal change. There were no significant interactions with facial type in the headgea r group. Gonial angle and lower tipping were influenced by facial type in the bionator group. These results demonstrate that fixed and remov able appliances produce both qualitative and quantitative differences in treatment response. Further studies are planned to create a rationa l decision tree that can be used to aid the clinician in the different ial diagnosis and treatment of deep overbite.