Evaluation of friction in metal, ceramic and self-ligating brackets submitted to sliding mechanics

Abstract Objective With the purpose of evaluating the best results for a proposed orthodontic treatment, the aim of this research was to verify the frictional force between archwires and orthodontic brackets in sliding mechanics. Material and method Three different types of brackets were used: conventional metal, self-ligating metal and conventional polycrystalline esthetic type (n=10), totaling 30 brackets and .019 x .025 inches stainless steel rectangular wire. An acrylic plate was used. The wire was fixed to the brackets (conventional metal and conventional polycrystalline esthetic) with esthetic elastomeric ligation. The acrylic plate together with the 019 x 0.025 inches wire fitted to it was attached to the base plate of the Instron 4411 universal test machine so that it was positioned perpendicular to the ground. The bracket was drawn through the archwire segment at a speed of 5 mm / minute for a distance of 5 mm. For each type of bracket, ten tests were performed, with the bracket and archwire set being changed for each repetition. Data were analyzed by one-way Analysis of Variance (p <0.0001) and the Tukey Test (p <0.05). Result Convencional metal and self-ligating brackets presented similar friction (p>0.05), while ceramic bracket presented higher frictional resistance during sliding test (p<0.05). Conclusion It was concluded that the type of bracket influenced the frictional force value obtained, and better results were found when the metal and self-ligating brackets were used. The ceramic bracket presented a higher frictional force value.

摘要
目的 为评估拟实施正畸治疗的最优效果，本研究旨在验证滑动力学体系下弓丝与正畸托槽间的摩擦力。
材料与方法 本研究采用3种不同类型的托槽：传统金属托槽、自锁金属托槽及传统多晶美观托槽（每组n=10），总计30个托槽，并采用0.019×0.025英寸的不锈钢方丝。实验使用丙烯酸树脂板，将弓丝通过美观弹性结扎固定于传统金属托槽与传统多晶美观托槽上。将丙烯酸树脂板与装配完成的0.019×0.025英寸弓丝固定于英斯特朗4411（Instron 4411）万能试验机的底座，使其与地面垂直。以5mm/分钟的速度将托槽沿弓丝段滑动5mm。每种托槽开展10次测试，每次测试均更换托槽与弓丝组件。采用单因素方差分析（one-way Analysis of Variance，p<0.0001）与Tukey检验（Tukey Test，p<0.05）对数据进行统计学分析。
结果 传统金属托槽与自锁金属托槽的摩擦力水平无显著差异（p>0.05），而陶瓷美观托槽在滑动测试中表现出更高的摩擦阻力（p<0.05）。
结论 本研究证实，托槽类型对所测得的摩擦力数值存在显著影响；采用金属托槽与自锁金属托槽时可获得更优的测试结果，而陶瓷美观托槽的摩擦力数值更高。