有限元法在不同嵌体材料修复中的应力分析

Stress Analysis in Repair of Different Inlay Materials Using Finite Element Method

目的结合根管治疗后对下颌第一磨牙近中—合面—远中(MOD)实施不同材料的嵌体(Inlay)修复,得出不同荷载条件下的牙体组织应力水平及分布变化规律。方法建立右下颌第一磨牙MOD计算机三维有限元实体模型,模拟临床常用的金合金、复合树脂、陶瓷等材料对MOD采用嵌体修复,观察3种不同材料对MOD底部及牙颈部牙体组织的应力大小及分布变化。结果从两种条件下的应力分布趋势分析,舌向45°条件下,对于牙本质,金合金嵌体的应力最大,复合树脂嵌体的应力最小;而牙冠处的应力大小接近。在舌向加载条件下,对于MOD洞型底部和牙颈部来说,其颊侧应力区域较为集中,而舌侧应力集中度明显低于颊侧。结论复合树脂的应力最小;3种不同修复材料对牙体组织的应力分布相似,而且集中于MOD洞型底部及牙颈部位,前者的应力水平高于后者。当牙体组织龋损较为严重,或者波及较多牙面时,建议选择弹性模量与牙本质接近的复合树脂材料来进行嵌体修复,以更好的避免高应力集中导致牙体折裂的发生。

Objective According to implementing different materials inlay restoration of the mandibular first molar MOD after root canal recurrence, to analyse the stress level and distribution of tooth tissue in different loading conditions. Methods The right mandibular first molar MOD 3D finite element model was constructed. The clinical inlay restoration on gold alloy, composite resin, ceramics was simulated. The stress size and distribution on the bottom of the MOD and the tooth body organization of three different materials were observed. Results Based on the analysis of the stress distribution in two conditions, in tongue 45°, for the dentin, gold alloy inlay had the largest stress and composite resin inlay had minimum stress. For the bottom of the MOD cavity and the tooth neck, buccal side stress region was more concentrated. and lingual side stress was lower than buccal side. Conclusion The stress of composite resin is minimal. Dental tissues stress distribution of three different restorative materials is similar. and focuses on the MOD hole bottom and tooth neck. which is higher of the former stress level. When the dentin caries is serious or spreads many tooth surface. it is suggested that composite resin materials, whose elastic modulus are closed to dentin. should be selected for inlay restoration, which can avoid tooth fracture caused by the high stress concentration.