微型种植体弯矩对骨界面应力分布影响的有限元分析

Three-dimension finite element analysis for the effect of bending moment of mini-implant on bone stress

目的探讨影响微型种植体骨界面应力分布的关键影响因素。方法设定在一侧下颌骨第二前磨牙与第一磨牙牙根间距离牙槽嵴顶4mm处为植入点,建立微型种植体三种植入方向模型,模型-Ⅰ:牙合向30°植入;模型-Ⅱ:垂直植入;模型-Ⅲ:近中30°植入。种植体载荷方向:水平向前、前上斜向、垂直向上、后上斜向及水平向后,记录骨组织内的Von-Mises应力分布。结果模型-Ⅱ的应力峰值在三个模型中最大。模型-Ⅰ中水平向前载荷应力峰值最大,垂直向上载荷应力峰值最小。模型-Ⅲ中水平向前与水平向后载荷的应力峰值相近,前上斜向与后上斜向载荷的应力峰值相近,水平向载荷应力峰值低于斜向载荷,垂直向上载荷应力峰值最大。结论种植体弯矩是影响骨界面应力分布的主要因素,载荷方向与种植体长轴夹角越小骨界面应力峰值越小。

Objective To investigate the effect of bending moment of mini-implant on the stability using threedimensional finite element analysis. Methods Three finite element models were established according to the insertion direction of mini-implant. Model 1, inserted 30° tilted occlusally; Model 2, vertically; Model 3, 30° tilted mesiolly. The mini-implants were loaded by force mesiolly, mesio-verticallly, vertically, distal-vertically and distally. The stress distribution under different conditions were recorded and analyzed. Results The peak stresses of Model 2 were the highest than the others. The peak stress by loaded mesiolly was the highest, the loaded mesiolly was lowest during Model 1. For the Model 3, the peak stresses of loading mesiolly and loading distally were similar, the peak stresses of loading mesio-vertically and loading distal-verticaly were similar, the peak stresses of loading mesiolly and distally were lower than loading mesiol-vertically and distal-vertically, the peak stress by loaded vertically was highest during five loading direction. Conclusion The bending moment of mini-implant is the main affecting factor on the stress distribution of bone interface. The angle between loading direction and axis of implant is smaller, the smaller stress peak value of bone interface.