The aim of this study was io compare the effects of four first premolar extraction and nonextraction treatment approaches on soft tissue profile configuration of subjects with excessive deep bite, vertically inclined incisors and characteristic deep bite soft tissue profiles. Before and after cephalograms and hand-wrist films of 23 (17 females, 6 maies) growing deep bite patients were assessed. 12 cases were treated by extraction of four first premolars, and 11 were treated by nonextraction fixed appliance therapy. Landmarks were digitized and measurements were made by use of a computerized cephalometric analysis program. Student’s t test was used to compare the treatment effects, whereas the associations between changes in soft and hard tissues were evaluated by means of Pearson's “r” correlation coefficients. Overbite and interincisal angle were reduced significantly in both groups, (p<0.001); and the group differences were not statistically significant. Regarding the soft tissue parameters, changes in the upper and lower lip position and sublabial curvature nevealed statistically significant differences between groups (p<0.05), in favour of nonextraction for lower lip position and in favour of nonextraction for lower lip position and in favour of extraction for sublabial curvature.

Keywords: Class II division 2, extraction, orthodontic treatment, x-ray cephalometry, soft tissue profile