The aim of this study was to evaluate the contribution of specific tooth movements in the correction of Class II division 1 cases with extraction of four first premolars. The present study comprised 17 subjects with ages ranging from 16 to 21 years. The patients were selected according to the following main criteria: Class II division 1 malocclusion with excessive overjet and SN-MP angle over 33 degress. All patients had their four first premolars extracted and were treated by Edgewise mechanics. High pull or combined headgear was applied as part of treatment planning. Vertical forces such as intermaxillary elastics were avoided during treatment. The average treatment period was 23 months. Lateral cephalograms were taken before and after the active treatment periods. According to findings of this study, four first premolars extraction did not seem effective on vertical dimension. Dental changes were more significant compared to vertical skeletal changes.

Keywords: Class II division 1, premolar extraction, vertical dimension