Conclusion: the rate of rootresorption of two methods are consistent, there's no relationship between the rootresorption of the teeth transportation distance or treatment time.
结论：两种治疗方法的牙根吸收率是一致的；牙根吸收率与牙齿移动距离和受力时间没有关系。
2
PURPOSE: The purpose of this study was to evaluate the effect of high pull J hook headgear(HPHG) on rootresorption of maxillary incisors during orthodontic treatment.
目的：评价标准方丝弓配合高位J钩对正畸治疗中牙根吸收的影响。
3
Results: There's no statistically significant difference between the rate of rootresorption of two methods, but there's statistically significant difference between the treatment time.