patients with Class Ⅱ division 1 treated with extraction of four first premolars by Begg appliance and Edgewise appliance. Methods The study was conducted using lateral cephalometric radiographs taken pretreatment, posttreatment and following- up. Thirty patients who had an Angle′s Class Ⅱ division 1 malocclusion were treated with first premolar extractions（19 by Begg appliance and 11 by Edgewise appliance）. Cephalometric radiographs were scanned and the data were analyzed according to the paired and unpaired t- test. Results The differences between the pretreatment and posttreatment periods were statistically significant for all the incisor and molar cephalometric variables（P0.05）. Conclusion There is no significant differences of hard tissue changes and stability between Begg appliance and Edgewise appliance.
