一步法和两步法关闭间隙对不同支抗影响的研究

The effects of en-masse retraction and two-step retraction on the anchorage variables

目的:研究安氏Ⅰ类错患者在间隙关闭过程中分别使用一步法或两步法对上颌支抗的影响。方法:选择安氏Ⅰ类中度拥挤,拔除4个第一前磨牙,侧貌较突的女性成人患者125人,按支抗及关闭方式分为4组,分别使用强支抗和中度支抗、一步和两步滑动法关闭间隙,对其治疗前后X线投影测量结果进行分析比较。结果:无论是强支抗还是中度支抗,两步法与一步法支抗丧失量无统计学差异。使用强支抗组磨牙近移量少,支抗丧失少(P<0.05)。结论:使用一步法或两步法关闭拔牙间隙,上颌第一磨牙前移量无显著差异。强支抗引起的磨牙近移量少于中度支抗。

Objective： To compare the anchorage loss of the maxillary posterior teeth and retraction of the maxillary anterior teeth be- tween en-masse retraction and two-step retraction of the anterior teeth in adult class I patients. Methods： 125 female adult patients with Class I malocclusion and lip protrusion were divided into 4 groups and treated by en-mass and two-step retraction with strong and medium anchorage, respectively. Cephalometric analysis was carried out before and after space closure stage. Data were statistically an- alysed. Results： There was no significant difference in anchorage loss of the maxillary posterior teeth between en-mass and two-step retraction groups strong and medium posterior anchorage groups （P 〉 0.05 ）. The anchorage loss of the upper posterior teeth was less in strong anchorage groups than that in medium anchorage groupa （P 〈 0.05）. Conclusion： En-masse retraction and two-step retraction are simlarly effective in the retraction of anterior teeth for space clusure, strong anchorage may produce less anchorage loss of the upper posterior teeth than the medium anchorage.