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目的研究上颌中切牙根管治疗后少量缺损时,全冠和加桩全冠两种修复方式对剩余牙本质应力状况的影响。方法采用三维有限元法,用计算机建立上颌中切牙以及根管治疗后全冠和加桩全冠两种修复体的有限元模型,共3个。模拟正中牙合加载,选取指标为Von Mises应力、最大主应力,分析两种修复方式对剩余牙本质Von Mises应力和最大主应力的分布和峰值的影响。结果天然牙模型受力比较均匀,全冠修复和加桩全冠修复改变了天然牙的应力分布模式,但两个修复体模型应力分布一致,两种应力均在舌侧颈缘和根尖出现高应力区;两种修复体模型的两种应力峰值均较天然牙明显增大,与全冠修复时剩余牙本质的应力峰值相比,加桩全冠修复时牙本质Von Mises应力峰值降低16.25%,但是最大主应力增加了30.00%。结论根管治疗后上颌中切牙少量缺损全冠修复时桩是不必要的。
Objective To study the effect of two kinds of restoration methods of crown and crown on the residual dentin stress after root canal treatment of maxillary central incisor. Methods Three-dimensional finite element method was used to establish the finite element model of the maxillary central incisor, the full crown and the full crown after root canal treatment. The occlusal load was simulated. The Von Mises stress and maximum principal stress were selected to analyze the influence of the two repair methods on the distribution and peak value of residual dentin Von Mises stress and maximum principal stress. Results The stress of natural tooth model was more uniform. The crown restoration and the crown plus crown restoration changed the stress distribution patterns of natural teeth. However, the stress distribution of the two restoration models was consistent. Both stress appeared on the lingual cervical margin and apical root High stress zone. The two stress peaks of the two prosthesis models were significantly higher than those of the natural teeth. Compared with the stress peaks of the remaining dentin during the crown restoration, the dentinal Von Mises stress peak value decreased by 16.25 %, But the maximum principal stress increased by 30.00%. Conclusion After root canal treatment, the maxillary central incisor with a small amount of defects is not necessary for full crown restoration.