Comparison of treatment results between angle class III subgroup patients treated by maxillary protraction with fixed appliance and fixed appliance only

Objective To compare the treatment outcomes among different angle classⅢ subdivision patients treated by maxillary protraction with fixed appliance and fixed appliance only.Methods Twennty-eight classⅢpatients treated by maxillary protraction and fix appliance were collected from the orthodontic department,Peking University School of Stomatology during 1997—2000 and were divided into three groups according to different facial pattern.Three groups of comparative patients with same sex and age distribution treated by fixed appliance only were formed respectively.The differences of margins of 15 cephalometric measurements before and after treatment were analyzed by independent-samples t test. Results Better improvement of discrepancy of maxilla and mandiblc could be obtained in all the patients treated by maxillary protraction,yet the mechanisms of improvement were not the same.Compared with patients treated by single fixed appliance,better growth stimulation could he obtained in patients with retracted maxilla only.Conclusion Compared with patients treated by fixed appliance only,treatment outcomes were not the same among patients treated by maxillary protraction with fixed appliance.Yet the mechanisms of difference were not the same between patients with different facial patterns.