一步法和两步法关闭间隙对不同支抗影响的研究

目的:研究安氏Ⅰ类错(牙合)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.

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

Objective:To compare the anchorage loss of the maxillary posterior teeth and retraction of the maxillary anterior teeth between 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 analysed.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.