槽沟尺寸对转矩控制影响的实验研究

目的研究在同一牙弓中牙齿存在相互作用的条件下，2种槽沟尺寸的托槽在转矩控制方面是否有差异。方法通过Typodont水浴实验，模拟临床矫治过程，测量结束弓丝为0.431 8 mm×0.635 0 mm不锈钢方丝时，使用0.558 8 mm×0.711 2 mm托槽和0.457 2 mm×0.635 0 mm托槽时上颌5┼5共10颗牙齿的唇舌向倾斜度。实验重复10次。通过计算机编程进行计算，将唇舌向倾斜度转换为上颌5┼5的转矩余隙角ψ。对2种槽沟尺寸托槽的ψ的绝对值进行配对t检验。结果2种槽沟尺寸的托槽在转矩控制方面的差异具有统计学意义，当结束弓丝为0.431 8 mm×0.635 0 mm不锈钢方丝时，0.558 8 mm×0.711 2 mm和0.457 2 mm×0.635 0 mm托槽转矩余隙角ψ的绝对值分别为6.140°±3.758°和2.608°±1.479°，2种托槽间转矩余隙角ψ的绝对值的均值相差3.532°，0.457 2 mm×0.635 0 mm托槽的转矩余隙角较小。在2种槽沟尺寸托槽的作用下，上颌左右尖牙ψ的绝对值分别为2.560°±2.605°、4.230°±2.817°、1.260°±0.747°和2.070°±0.663°，尖牙较其他牙位ψ的绝对值的差值要小。结论2种槽沟尺寸的托槽在转矩控制方面存在差异，弓丝尺寸相同时，0.457 2 mm×0.635 0 mm托槽可以更好地控制牙齿的转矩。槽沟尺寸对转矩控制的影响小于以往研究的理论计算值和材料学实验结果，可能是由于同一牙弓牙齿间的相互影响所致。

Influence of slot size on torque control

Objective To study the influence of two slot size brackets on torque control when teeth interacted in the same arch.Methods After the upper arch was aligned and leveled in Typodont study,the inclinations of upper teeth 5+5 were measured when 0.457 2 mm×0.635 0 mm OPA-K brackets and 0.558 8 mm×0.711 2 mm OPA-K brackets were filled with 0.431 8 mm×0.635 0 mm stainless steel wire.This experiment was duplicated 10 times.The inclin of each tooth were transformed to the absolute values of the torque play angle ψ by computing program,and paired- t test was used.Results The two kinds of slot size brackets were different with statistical significance on torque control.When the brackets were filled with 0.431 8 mm×0.635 0 mm stainless steel wire,the absolute values of the angle ψ in 0.558 8 mm×0.711 2 mm and 0.457 2 mm×0.635 0 mm slot size brackets were 6.140°±3.758° and 2.608°± 1.479° respectively,and the average difference of that between the two slot size brackets was 3.532°.The absolute values of the angle ψ in the upper left and right canine brackets were 2.560°±2.605°,4.230°±2.817°,1.260°±0.747° and 2.070°±0.663° respectively,and average differences between them were smaller than that in the other teeth.Conclusion There was difference between the two kinds of slot size brackets on torque control,and 0.457 2 mm×0.635 0 mm slot size bracket controls torque better when filled with the same size wire.In this study,the teeth interaction in the same arch probably caused the result that the difference of two slot size brackets on torque control was less than the study results of the theory calculations and material studys before.