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目的通过三维有限元法研究不同形状纤维桩修复上颌中切牙弯曲牙根后牙本质及修复体的应力分布。方法应用MicroCT扫描结合Mimics、Geomagic、UG、Abaqus有限元分析软件建立柱形、锥形、双锥度纤维桩修复上颌中切牙弯曲牙根的三维有限元模型。模拟咬合,将载荷施加于模型舌侧面,方向与牙长轴成45°角,大小为120 N,分析牙本质及桩核冠的应力分布。结果3组模型应力分布趋势及应力值范围相同,最大应力主要分布在桩核交界处唇侧、全瓷冠颈缘唇侧,在牙根弯曲部位内侧牙本质层,柱形组VonMises应力峰值为20.34MPa,大于锥形组(16.42MPa)和双锥度组(16.29 MPa)。结论对弯曲牙根进行桩核修复时,不应过多去除弯曲部位的牙本质,且使用锥状和双锥度纤维桩优于柱形纤维桩。
Objective To study the stress distribution of posterior dentin and prosthesis with different shapes of fiber posts in the treatment of curved root of maxillary central incisor by three-dimensional finite element method. Methods The three-dimensional finite element model of the root of the maxillary central incisor restored with cylindrical, conical and double-taper fiber posts was established by using MicroCT scanning combined with Mimics, Geomagic, UG, Abaqus finite element analysis software. Simulated bite, the load was applied to the side of the model tongue, the direction of the long axis of the tooth at a 45 ° angle, the size of 120 N, analysis of stress distribution of dentine and post crown. Results The stress distribution trend and stress range of the three models were the same. The maximum stress was mainly distributed on the labial side of the post-core junction and the labial margin of the porcelain crown. The Von Mises stress peak value of the columnar group was 20.34 MPa, larger than the cone group (16.42MPa) and double taper group (16.29MPa). Conclusions In dentition repair of bent root, the dentin should not be removed excessively, and conical and double-taper fiber piles are better than cylindrical fiber piles.