陶瓷托槽槽沟形貌及滑动摩擦现象的观察

目的对四种托槽和两种弓丝滑动前后进行外貌和槽沟微观形貌的分析，探讨影响托槽与弓丝间摩擦力大小的因素。方法对四种托槽用立体显微镜对外观形貌及其与两种弓丝滑动前后扫描电镜的微观形貌进行观察，用微硬度测量仪测量四种托槽槽沟、托槽体部位的硬度。结果四种托槽形貌及滑动前后槽沟部位的微观形貌不同，硬度也有差异，硬度由小到大分别为A托槽的金属槽沟部位（F）213．72±57．33HV，D托槽305．76±46．65HV，B托槽1087．12±139．86HV，A托槽体部1111．26±182．52HV，C托槽1309．81±225．56HV。结论硬度和表面粗糙度是影响托槽与弓丝间摩擦力的因素。陶瓷托槽硬度大，表面粗糙，与金属弓丝间的摩擦力大。

Morphological observation and frictional phenomenon of ceramic brackets

Objective To study the structure factors influencing the frictional characteristics of the brackets and archwire. Methods Observation of the morphology of bracket and microstructure of the brackets＇ slots were conducted with stereo microscope and scanning electron microscope （SEM） before and after sliding along the archwires. Hardness measurement of four brackets were done with microhardness tester. The results were statistically analyzed with one-way analysis of variance and Student-Newman-Keuls multiple comparison test at the 0. 05 level of significance. Results Morphological observations showed a great variability in the bracket and bracket slot microstructure among the brackets tested, as well as before and after sliding. Vickers hardness of the brackets were as follows, metal slot of A（F） 213. 72±57.33, D 305.76±46.65, B 1087. 12±139.86, A 1111. 26±182. 52, C 1309. 81±225.56, which showed great variations among the brackets. Conclusions There were significant differences in the morphology, microstructure, and microhardness among the brackets tested, which might anticipate that hardness and roughness were two influencing factor for the friction between bracket and archwire. The rougher surface and higher hardness of the ceramic bracket caused the higher friction force.