FAS自锁托槽与传统自锁托槽的摩擦力对比研究

目的测量FAS托槽在两种不同调节状态下与正畸钢丝之间的摩擦力大小，并与DamonⅢ和SPEED两种传统自锁托槽进行对比。方法制作尺寸放大20倍的FAS、DamonⅢ和SPEED托槽钢制模型，同时制作放大20倍的钢制圆丝和方丝，采用拉力传感器测量托槽与弓丝间摩擦力的大小。实验中FAS托槽分为两种调节状态：垫片完全收入和与弓丝平面无压力状态相切后旋转0.5圈。结果在垫片完全收入的状态下，FAS托槽与直径8.128 0 mm的不锈钢圆丝之间的动静摩擦力与DamonⅢ和SPEED托槽均无统计学差异（P>0.05）；在使用9.144 0 mm×12.700 0 mm不锈钢方丝时，FAS托槽与方丝之间的动静摩擦力与DamonⅢ托槽无统计学差异（P>0.05），而低于SPEED托槽，且有统计学差异（P<0.05）。当垫片与弓丝平面无压力状态相切后旋转0.5圈时，FAS托槽与圆丝、方丝的动、静摩擦力均明显高于DamonⅢ和SPEED托槽（P<0.01）。结论FAS托槽可以有效调节摩擦力的大小，在无压力状态下，托槽与弓丝间的摩擦力与DamonⅢ托槽相似；在有压力状态下，可以有效锁定弓丝，防止弓丝滑动。

Comparison study of friction of FAS self-ligating bracket and traditional self-ligating bracket

OBJECTIVE: To measure the frictions between FAS bracket and stainless steel wire under different two conditions, and compare two traditional self-ligating brackets. METHODS: FAS bracket was a new-style self-ligating bracket with a friction adjusting system (FAS) to adjust the friction as the wires slide in the bracket. Firstly, FAS bracket 20 times of original size was made, then the frictions were measured respectively made by the steel round wires of diameters 8.128 0 mm or the steel square wires in size of 9.1440 mm x 12.7000 mm. It was divided into two adjusting states, and used the same method to measure Damon III and SPEED bracket in 20 times of original size. RESULTS: With the shim entirely drew in, all the frictions of the arch wire had no significant difference with the Damon III. When 8.1280 mm stainless steel round wire was used, SPEED bracket had no significant difference with FAS. When 9.1440 mm x 12.7000 mm square wire was used, they had significant difference (P < 0.05). On turning half a circle, all the frictions of the arch wire had significant difference with two tradition bracket (P < 0.01). CONCLUSION: The new-style FAS bracket can adjust the friction efficiently. Under no pressure state, the friction force is similar to Damon III. Under pressure state, FAS bracket locks the wires, and provides the sliding of wires.