牙本质微裂纹对牙体应力影响的三维有限元研究

发布时间：2018-11-01 15:19

【摘要】：目的基于三维有限元法研究根管预备过程中硬组织丧失和牙根微裂纹对上颌第二前磨牙的应力影响,为分析临床上根管治疗后患牙根折率增大的成因提供一定的参考。方法利用Micro-CT扫描上颌第二前磨牙,结合逆向工程软件建立完整牙体、仅有预备过程中组织丧失的牙体及预备后有不同牙根裂纹的预备后牙体3D模型,研究其在静态载荷下的应力情况。结果轴向力作用于完整牙体时,牙本质Von Mises应力集中分布于舌侧颈部;侧向力作用下,Von Mises应力集中分布于加力同侧牙根中上2/3处。轴向力和侧向力作用于预备后无牙根裂纹形成的牙体时,应力分布及应力值与完整牙体相比无明显变化。当牙根裂纹产生时,轴向力作用下应力值相对于预备前无明显变化,应力有向裂纹集中的趋势;侧向力作用下,应力峰值多增大明显,且应力多集中于裂纹局部。结论根管预备过程中的组织丧失对牙体应力情况无明显影响;牙根裂纹的产生会导致侧向力作用下应力值明显增大,且应力分布集中区域也多由牙体舌侧颈部转移至裂纹局部,牙根裂纹可能是导致根管预备后根折的重要因素。
[Abstract]:Objective to study the effect of hard tissue loss and root microcrack on the stress of maxillary second premolar during root canal preparation based on three-dimensional finite element method (FEM), and to provide a reference for analyzing the causes of the increase of root fracture rate after upper root canal therapy. Methods Micro-CT was used to scan the maxillary second premolars and reverse engineering software was used to establish the complete teeth. There were only 3D models of teeth with different root cracks in the process of preparation. The stress under static load is studied. Results when the axial force was applied to the intact tooth, the Von Mises stress of dentin was concentrated in the lingual neck, and the, Von Mises stress was concentrated in the upper 2 / 3 of the root of the same side of the tooth under the lateral force. When the axial force and lateral force acted on the teeth without root crack after preparation, the stress distribution and stress values had no significant change compared with the intact teeth. When the root crack is produced, the stress value under axial force has no obvious change compared with that before preparation, and the stress tends to be concentrated in the direction of crack, and the stress peak value increases obviously under lateral force, and the stress is mostly concentrated on the local crack. Conclusion the loss of tissue during root canal preparation has no significant effect on the stress of tooth. The root crack will cause the stress value to increase obviously under lateral force, and the stress concentration area will transfer from the lingual neck to the crack area. The root crack may be an important factor leading to the root fracture after root canal preparation.
【作者单位】：重庆医科大学附属口腔医院口腔疾病与生物医学重庆市重点实验室重庆市高校市级口腔生物医学工程重点实验室;
【基金】：重庆市渝中区科技计划项目(20140129) 2016年重庆高校创新团队建设计划资助项目重庆市高校市级口腔生物医学工程重点实验室资助项目(渝教科[2014]55号)~~
【分类号】：R781.05

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