桩冠修复中不同形式箍效应的三维有限元分析

Three-Dimensional Finite Element Analysis of the Various Forms of Ferrule Effect in Post Crown

:【目的】研究桩冠修复中不同形式的箍效应的应力分布特点 ,探讨箍效应的生物力学机制。【方法】运用CT扫描、图形数字化、SuperSAP有限元软件建立上颌中切牙烤瓷核桩冠三维有限元模型 ,模拟临床箍效应的 3种形式 ,通过静态加载分析牙本质受力情况。【结果】①牙本质应力分布呈现出从颈部向根中部逐渐增高的趋势 ;②不同的箍形式所产生的应力反应不同 ,核颈环降低应力峰值的作用最大 ,反转斜面的效果最小。【结论】在余留牙体高度较低时 ,核颈环形式的箍效应大于冠包绕牙体的形式 ,反转斜面形式无显著作用 。

Objective To investigate the stress distribution in various forms of ferrule effect in post crown, and to evaluate the biomechanics mechanism in post crown. Methods By CT scanning, graph digitizing and Super SAP software, the three dimensional finite element entity grid model was built, which was a maxillary central incisor restored with post and PFM crown. By imitating three types of ferrule effect under static loading, the dentin stress was analyzed. Results ①The stress distribution had an increasing tendency from tooth cervical part to root middle part. ②The stress reactions were different with the different ferrule patterns. The core collar had the best effect on decreasing peak stress, but contrabevel had the worst effect. Conclusion When the altitude of residual tooth is lower, the ferrule effect maintained by core collar wrapping cervical dentine is greater than that maintained by crown wrapping, but contrabevel has no effect.