应用Time自锁托槽与传统托槽矫治牙列拥挤的临床比较研究

目的　比较使用Time自锁托槽与传统直丝托槽矫治上颌轻中度拥挤前后的牙弓宽度和上前牙凸度变化的差异。方法　选择46例轻中度拥挤的骨性Ⅰ类患者（女26例，男20例，13～16岁），治疗组23例，采用Time自锁托槽矫治技术，对照组23例，采用传统直丝托槽结扎矫治技术。分别测量矫治前后牙弓宽度和上前牙唇倾度，比较2种方法所致的牙弓宽度和上前牙凸度的变化，并进行统计学分析。结果　2组患者的前磨牙宽度和上前牙凸度在矫治后均增大，其改变量比较，差异有统计学意义(P＜0.05)；2组患者的尖牙宽度和磨牙宽度在矫治后也增大，但其改变量比较，差异无统计学意义(P＞0.05)。结论　自锁托槽在矫治牙列拥挤过程中较传统结扎托槽有更好的后牙弓扩展作用，但也会导致前牙的唇倾，故临床上可选择面型良好的轻中度拥挤患者进行非拔牙矫治。

Comparison of Time self-ligating bracket and conventional bracket on the correction of dental crowding

Objective To evaluate changes in dental arch width and the maxillary anterior teeth protrusion produced by Time self-ligating bracket and conventional bracket on the correction of mild and moderate dental crowding.Methods 46 patients with mild and moderate dental crowding and skeletal Ⅰmalocclusion were included in the study.23 subjects were treated with Time self-ligating bracket,and another 23 subjects with conventional bracket.Changes before and after treatment in the dental arch width and in the maxillary anterior teeth protrusion were determined between the two groups.Results There was significant increase in the premolar dental arch width and maxillary anterior teeth protrusion in the two groups,and no significant increase in the canine and molar dental arch width.Conclusions Compared with conventional bracket,Time self-ligating bracket on the correction of dental crowding could increase the posterior dental arch width,but could result in the increase of the anterior teeth protrusion.Therefore,Time self-ligating bracket could be used in the non-extraction patients with good profile and mild or moderate dental crowding.