陶瓷托槽与金属弓丝第二序列成角状态下摩擦性能的研究

目的研究陶瓷托槽与金属弓丝在第二序列成角状态下的摩擦力,探讨影响托槽弓丝间摩擦力的因素。方法进行托槽外观形貌的测量与观察,计算托槽与弓丝第二序列成角下的临界角,并设计带可调节罗盘的载物台,用MTS Tytron250微力试验机体外测试三种陶瓷托槽（A、B、C）和一种金属托槽（D）与0.016英寸不锈钢圆丝（SS）在第二序列成角分别为0度、2度、5度、8度时的最大静摩擦力和滑动摩擦力。结果与0.016英寸SS的摩擦力总体表现出B托槽〉C托槽〉A托槽〉D托槽的趋势,在四种成角状态下的最大静摩擦力随角度加大而增大,总体表现为0度到2度的摩擦力增加没有显著性,增大夹角后摩擦力增加量不同托槽间有差异：A托槽与弓丝在2度到5度成角状态下的摩擦力增加没有显著性,而5度到8度的摩擦力有显著增加;B托槽在2度到5度摩擦力有显著增加,而5度到8度摩擦力增加不显著;虽然2度到5度摩擦力增大没有显著性,但8度与0度状态下相比,C托槽与弓丝间的摩擦力有显著增加;D托槽在2度、5度、8度时摩擦力间差异无显著性。结论选用带金属槽沟的陶瓷托槽,增加陶瓷托槽边缘的圆钝程度等能减缓牙齿移动中托槽-弓丝成角引起的滑动阻力增加;使用传统陶瓷托槽要注意充分排齐。

Frictional resistance of ceramic brackets with stainless steel archwire in second-order angulation

Objective To study the frictional resistance between the brackets and the archwire in second-order angulations.Methods The measurement of frictional resistance of three imported ceramic brackets（A,B,C） and one metal bracket（D） with the 0.016 inch stainless steel archwire in four second-order angulations（0°,2°,5°,8°） was conducted with MTS Tytron250.Results The frictional resistance between different brackets and archwires has the tendency of B〉C〉A〉D.The frictional resistance increases with the increasing angulation： Frictional resistance of A with the 0.016 inch SS had no statistically increase below 5° angulation,but increased statistically in 8° angulation, compared to 5° angulation;the frictional resistance of B bracket with the 0.016 inch SS has a statistical increase in 5° angulation compared with 2° angulation.Although there is no statistical increase in 2° angulation,5° angulation, frictional resistance of C bracket with 0.016 inch SS,increased statistically in 8° angulation,compared to 0° angulation. And the contrast metal bracket had no statistical increase in 8° angulation.Conclusion Same material in contact area of bracket and wire,and round edge of ceramic bracket may reduce the frictional resistance between ceramic brackets and archwire in second-order angulation.To align and level the teeth thoroughly is critical in orthodontic treatment especially when traditional ceramic brackets are utilized.