The aims of this finite elemental stress analysis (FEA) study were to evaluate the effects of loading direction, crown coverage, and adjacent teeth on stress distribution in premolar tooth models restored using fiber-post restoration. Three 3D premolar tooth FEA models were created as follows: Model 1: sound tooth; Model 2: tooth-model including root filling, fiber-post and composite resin restoration; Model 3: tooth-model including root filling, fiber-post, composite resin core and ceramic crown. Three more models were created using Models 1, 2, and 3 with adjacent teeth (Models 4, 5, and 6). The Cosmoworks structural-analysis program was used for the stress analysis, which was based on the von Mises criterion. High stress concentrations were observed at the mesial side of the sound tooth models while the stresses were localized at both sides in the others. Loading with a nonzero inclination angle caused higher stress concentrations within the tooth structure than is other models with the normal/vertical loading. The presence of adjacent teeth strongly influenced stress distributions and concentrations in Models 4, 5, and 6, reducing the stress level. Meanwhile, crown restoration did not change the stress patterns.

中文翻译：

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加载方向，冠冠覆盖度和邻近牙齿对修复后的前磨牙应力的影响

这项有限元素应力分析（FEA）研究的目的是评估在纤维桩修复后的前磨牙模型中，加载方向，牙冠覆盖度和相邻牙齿对应力分布的影响。如下创建了三个3D磨牙前牙FEA模型：模型1：健齿；模型2：牙齿模型，包括牙根填充，纤维桩和复合树脂修复；模型3：牙齿模型，包括牙根填充，纤维桩，复合树脂芯和陶瓷牙冠。使用具有相邻牙齿的模型1、2和3创建了另外三个模型（模型4、5和6）。Cosmoworks结构分析程序用于基于von Mises准则的应力分析。在正常牙齿模型的内侧，观察到高应力集中，而在另一侧，应力集中在两侧。与其他具有法向/垂直载荷的模型相比，具有非零倾斜角的载荷导致牙齿结构内的应力集中更高。相邻牙齿的存在强烈影响模型4、5和6中的应力分布和集中程度，从而降低了应力水平。同时，牙冠修复并没有改变应力模式。