不同肩台形态对前牙全瓷冠疲劳特性的影响

The influence of fatigue behavior for two different margin shapes of all ceramic crown of anterior teeth after cementation

目的:分析两种肩台形态设计对前牙全瓷冠疲劳特性的影响,为全瓷冠的临床设计、制作以及使用寿命的评估提供依据。方法:建立上中切牙及其全瓷冠的有限元模型。根据有限元获得的应力、应变结果,使用ANSYS Workbench 13.0软件下研究全瓷冠的循环疲劳特性。结果:载荷在90～130N范围内时,90°肩台在承受94.3N循环载荷时全瓷冠颈部肩台出现疲劳损坏,疲劳循环次数为1.95×107次;135°凹形肩台承受110N循环载荷时全瓷冠颈部肩台出现疲劳损坏,疲劳循环次数为2.18×107次。结论:在临床进行全瓷冠修复时应尽量采用135°凹形肩台设计,同时注意合理调整牙合力,从而提高全瓷冠的疲劳寿命。

Objective To study fatigue behavior for two different margin shapes of all ceramic crowns of anterior teeth under cyclic loading,and to establish clinical guidelines for the use and design of all ceramic crowns. Methods A 3-D finit element method model of teeth and crowns were established. The strength of two different margin shape of all ceramic crowns under cyclic loading in centric occlusio were investigated using computational techniques of the ANSYS Workbench 13.0 software. Results The all ceramic crowns with two different margin shapes were put under the pressure which ranges from 90N to 130N.The fatigue damage of 90shoulder margin of all ceramic crown caused bycyclic load of 94.3N, and the number of circle loading were 1.95x107 times.The fatigue damage of 135chamfer margin of all ceramic crown caused by cyclic load of 110N,and the number of circle loading were 2.18×107 times. Conclusion The 135°chamfer margin of all ceramic crown can be used in clinical application.The occlusal force should be adjusted properly in order to increase the longevity of all ceramic crowns.