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目的比较不同桩核材料及漏斗深度对桩核冠修复漏斗状根管残根后的应力分布差异,寻找对残留牙体组织较少残根的最佳修复方法。方法建立桩冠修复上颌中切牙漏斗状根管残根三维有限元模型,设定漏斗状根管漏斗深度为0、2、4、6mm。成品桩为碳纤维桩,铸造桩采用镍铬合金材料,以VonMises应力、最大主应力为分析指标。结果桩冠系统修复漏斗状根管的残根后根部VonMises应力高应力区分布在唇舌侧,随漏斗的深度增加,高应力区范围逐渐扩大。与碳纤维桩相比,铸造桩修复后VonMises应力分布不均匀,各深度组的高应力分布区较同深度碳纤维桩组明显增大,应力集中明显,根尖及漏斗底处出现了应力集中。随漏斗深度增加,碳纤维桩根牙本质VonMises应力峰值增加了3.101MPa,增幅为10.3%,最大主应力峰值增加了2.958MPa,增幅为11.7%;铸造桩VonMises应力峰值增加了6.157MPa,增幅为22.6%,最大主应力峰值增加了5.486MPa,增幅为19.7%。结论漏斗深度及修复材料是影响根牙本质应力的重要因素。桩核冠修复漏斗状根管的残根设计时应尽量保存根唇舌向牙体组织,以增加牙根抗力,同时在桩核冠修复设计时应降低所受咬合力。在修复漏斗状根管的残根时,尤其是深漏斗状根管的残根时,推荐使用碳纤维桩。
Objective To compare the difference of stress distribution between the different post-core materials and the depth of the funnel on the post-core restoration of the funnel-shaped root canal, and to find out the best repair method for the residual root tissue with fewer residual roots. Methods The three-dimensional finite element model of root canal repair of maxillary central incisor was established, and the depth of funnel root canal funnel was set to 0, 2, 4, and 6 mm. The finished pile is carbon fiber post, the casting pile is made of Ni-Cr alloy material, and the Von Mises stress and the maximum principal stress are the analysis indexes. Results After the crown was repaired, the root of Von Mises stress was distributed in the labial area. With the increase of the depth of the funnel, the area of high stress area gradually enlarged. Compared with the carbon fiber post, the Von Mises stress distribution of the post-cast pile is not uniform, and the high stress distribution area of each depth group is obviously larger than the same depth of carbon fiber post group, the stress concentration is obvious, stress concentration occurs at the root tip and the bottom of the funnel. With the increase of funnel depth, the peak value of Von Mises stress of carbon fiber post root increased by 3.101 MPa, an increase of 10.3%, the maximum principal stress peak increased by 2.958 MPa, an increase of 11.7%; Von Mises stress peak of cast pile increased by 6.157 MPa, an increase of 22.6% %, The maximum principal stress peak increased 5.486MPa, an increase of 19.7%. Conclusion The depth of funnel and prosthetic material are the important factors affecting the stress of root dentine. Post-core crown restoration funnel-shaped root canal root design should try to save the root lip tongue to the tooth tissue to increase root resistance, while reducing post-core crown design should reduce the biting force. Carbon fiber piles are recommended when repairing the root of a funnel root canal, especially in the root of a deep funnel root canal.