不同牙体高度箍结构前牙桩冠的三维有限元分析

目的 探讨桩冠修复中不同余留牙体高度及箍结构形式的应力分布特点和箍效应的生物力学机制.方法 模拟临床建立箍包绕不同牙体高度的上颌中切牙烤瓷核桩冠三维有限元模型,通过静态加载分析牙本质受力情况.结果 牙本质应力分布呈现出从颈部向根尖部逐渐增高的趋势.牙体预备形成箍结构修复后能减小牙根各部位应力值,减小程度依包绕部位和高度而变,箍结构包绕1 mm牙体高度能明显降低牙体颈部应力值,包绕2 mm牙体时应力降低反而不明显.结论 冠边缘包绕1 mm牙体可产生明显的箍效应,而包绕2 mm牙体修复时应根据牙体情况而定.

Three-dimensional finite element analysis of various tooth heights of ferrule effect in post crown

Objective To investigate the stress distribution in various tooth heights of ferrule effect in post crown,and to evaluate the biomechanical mechanism in post crown.Methods The three-dimensional finite element entity grid model was constructed,which was a maxillary central incisor restored with post and porcelain fused to metal crown (PFM crown).By imitating the various tooth heights under static loading,the dentin stress was analyzed.Results The stress distribution had an increasing tendency from tooth cervix to root,but it could be decreased by ferrule structures and the decrease degree accorded with the region and height of ferrule.The ferrule effect of the wrapping 1 cm coronal tooth could decrease the stress of the tooth cervix obviously but 2 cm decreased a little.Conclusion The crown wrapping 1 cm coronal can produce ferrule effect obviously and protect the tooth.We can choose to use crown wrapping 2 cm coronal to care the tooth condition.