Cephalometric determinants of successful functional appliance therapy.

This retrospective study was undertaken to determine the presence of any features on a pretreatment lateral cephalogram that may be used to predict the success of improvement in the sagittal dental base relationship during functional appliance therapy in patients with a Class II skeletal pattern. Seventy-two patients judged to have been successfully treated with a functional appliance were selected for the study. Pre- and posttreatment radiographs were analyzed and the change in the ANB angle was used to determine the skeletal response to treatment. Within the total sample size of 72 patients, two groups were selected. One group of 13 patients who demonstrated a reduction in ANB angle of 3.0 degrees or more were identified as the skeletal group. A second group of 15 patients who demonstrated a change in ANB angle equal to or less than 0.5 degrees were identified as the nonskeletal group. Statistical analysis of these two groups revealed the presence of skeletal and dentoalveolar differences on the pretreatment lateral cephalogram. In the skeletal group, which responded with a favorable skeletal change, the mandible was smaller both in length (P < .01) and ramus height (P < .05) and the anterior and posterior lower face heights were smaller (P < .05). The cranial base was also smaller when compared with the respective lengths in the nonskeletal group.