两种关闭曲对安氏Ⅱ类1分类拔牙病例上切牙转矩影响的比较研究

Comparison the Torque of Upper Incisors Using two Closing Loops in the Treatment of ClassⅡ Division 1 Malocclusion

目的:比较在矫治安氏Ⅱ类1分类错过程中运用方丝弓矫治技术的垂直曲和T形曲关闭拨牙间隙后上颌切牙的转矩,为正畸临床实践提供参考。方法:采用前瞻性配对设计,选择24例安氏Ⅱ类1分类错拔牙病例,分别采用方丝弓矫治技术的垂直曲和T形曲关闭拔牙间隙,关闭间隙前后拍摄X线头颅定位侧位片,对两组上切牙转矩进行比较研究。结果:两组关闭间隙前后U1-SN和U1-NA角度均减小,T形曲组关闭间隙后U1-SN和U1-NA角度的减小值小于垂直曲组,差异有统计学意义。结论:T形曲比垂直曲更有利于产生持久的轻力,对安氏Ⅱ类1分类错拔牙病例上切牙的转矩存在更有效的控制。

Objective： To compare the effect of controlling the torque of upper incisors in the class Ⅱ division 1 malocclusion with extraction using vertical loop and T loop by means of Edgewise technique, in order to improve treatment technique level in clinic. Method： 24 of four first bicuspids extraction patients with class Ⅱ division 1 malocclusion were selected and divided into two groups for prospective paired t - test. Two - step vertical loop and T loop were used for space closures respectively. Cephalometric analysis was carried out before and after space closure stage in order to compare the torque of upper incisors in two groups. Result ：The angle of U1 -SN and U1 -NA both decreased significantly in two groups. The decrement was smaller in the group ofT loop. The difference was significant. Conclusion ：T loop is prone to make force more durable and softer, so it can control the torque of upper incisors better than vertical loop in the treatment of Class Ⅱ division 1 malocclusion with extraction.