直丝弓矫治器托槽底厚度的改进与临床验证

Improvement of bracket base thickness and clinical validation study of preadjusted appliance

目的对基于正常(牙合)中国人牙齿特征的直丝弓矫治器(Z1矫治器)的托槽底厚度进行改进,使其更薄,并对改进后的矫治器进行临床验证。方法利用AUTO CAD 2002计算机软件计算出邻面接触点弓形与弓丝弓形间的角度,加入托槽底的设计中,使整套矫治器的托槽底更薄。基于这种设计生产出Z2矫治器,同时设计出与该矫治器配套使用的弓形图。应用Z2矫治器对22例非拔牙病例进行常规正畸治疗,验证其消除第一序列弯曲的情况。结果在使用0.019×0.025英寸的平直不锈钢方丝两个月后,模型测量结果表明大多数相邻牙齿的邻面解剖接触点在(牙合)平面上投影的距离均数小于0.3 mm。结论 Z2矫治器排齐牙齿的总体效果较好,可以有效消除第一序列弯曲,对托槽底厚度的改进是有效的。

Objective To improve the bracket base thickness of the preadjusted appliance based on Chinese normal occlusion （Z1 appliance） and make it thinner; justify the improvement in clinical application. Methods The angulation between the archform obtained by each tooth crown center and the archform fabricated by the smooth curve connecting proximal contact points was calculated through AUTO CAD 2002 software, and then was built into the bracket base design. The bracket base thickness was reduced greatly. Z2 preadjusted appliance has been developed out on the basis of this philosophy, as well as the matching archform chart. In order to validate the efficiency of eliminating first order wire bending by Z2 appliance, 22 non-extraction cases have been treated with this new appliance. Results The result of models measurements indicated that average projective distance on occlusal plane between proximal contact points of adjacent teeth was less than 0. 3mm after the placement of 0. 019＂× 0. 025＂ stainless steel rectangular plain arch wires for 2 months. Conclusions Good effect of teeth alignment and effective elimination of first order wire bending could be achieved by Z2 appliance, which demonstrated the validity of improvement of the bracket base thickness.