切牙颈部穿髓型缺损唇、舌面入路的有限元分析

Three-dimensional finite element analysis of the upper cervical-defected incisor with labial access or lingual access

目的:应用三维有限元法比较颈部穿髓型缺损的切牙,在唇侧和舌侧不同开髓入路下的牙体受力情况,探讨唇侧入路在抗折力方面是否具有优势。方法:进行锥形束CT(cone-beam CT,CBCT)扫描,采用Mimics、Catia、Ansys软件建立上切牙模型,分别用唇、舌侧2种入路及直接树脂充填、纤维桩树脂修复、纤维桩全瓷冠修复3种不同修复方式,对其施加载荷,比较缺损部位及髓腔根管表面应力分布和最大von Mises值,采用Ansys10.0有限元分析软件对数据进行统计学分析。结果:在实验条件下,直接树脂修复时,唇、舌侧入路无明显区别;纤维桩复合树脂修复时,唇侧入路可以转移牙体应力集中部位,降低缺损处牙体折断几率而增加根折几率;桩冠修复可有效分散缺损处的应力集中,从而降低牙体从缺损处折断的几率。结论:对于颈部穿髓型缺损的切牙,直接树脂充填时,唇、舌侧入路均可采用;纤维桩树脂修复和桩冠修复时,分散了牙体应力的集中,而唇侧入路较舌侧入路更为明显。

PURPOSE： To evaluate the stress distribution of the cervical-defected incisor with labial or lingual endodontic access with finite element analysis（FEA）,and to explore the advantage of resistance in labial endodontic access.METHODS： 3-D finite element models of upper cervical-defected incisor were established using cone-beam CT（CBCT）,Mimics Catia,and Ansys software.The subjects were categorized according to the two endodontic accesses and three restorative ways,which were composite resin,glass fiber-reinforced composite resin and glass fiber-reinforced postcrown.All the models were loaded.The von Mises stress values and distribution were recorded and analyzed with Ansys 10.0 software.RESULTS： In this study,direct composite resin restoration showed no significant difference between the labial and lingual access.In glass fiber-reinforced composite resin,labial access could transfer the stress concentration area.It could reduce the incidence of fracture of the cervical lesion but increase the incidence of root fracture.Post-crown restoration could obviously reduce the incidence of fracture of the cervical lesion.CONCLUSIONS： When the cervicaldefected incisor is restored with composite resin,labial and lingual accesses can be considered.Labial access with glass fiber-reinforced composite resin or post-crown restoration is a good choice.Supported by National Key Clinical Discipline Construction Plan and Science and Technology Supporting Program from the Bureau of Science and Technology of Sichuan Province（2010SZ0118）.