口腔相关正畸方面有限元的应用

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研究用不同正畸丝对再种植牙齿松牙固定术中的应力分布: 三维有限元分析

Stress distribution in delayed replanted teeth splinted with different orthodontic wires: a three-dimensional finite element analysis

Fernando Isquierdo de Souza

Department of Dental Materials and Prosthodontics, Aracatuba Dental School, Unesp – Univ Estadual Paulista

Abstract

Aim: The aim was to evaluate the biomechanical behavior of the supporting bony structures of replanted teeth and the periodontal ligament (PDL) of adjacent teeth when orthodontic wires with different mechanical properties are applied, with three-dimensional finite element analysis. Materials and methods: Based on tomographic and microtomographic data, a three-dimensional model of the anterior maxilla with the corresponding teeth (tooth 13–tooth 23) was generated to simulate avulsion and replantation of the tooth 21. The teeth were splinted with orthodontic wire (Ø 0.8 mm) and composite resin. The elastic modulus of the three orthodontic wires used, that is, steel wire (FA), titanium–molybdenum wire (FTM), and nitinol wire (FN) were 200 GPa, 84 GPa, and 52 GPa, respectively. An oblique load (100 N) was applied at an angle of 45° on the incisal edge of the replanted tooth and was analyzed using Ansys Workbench software. The maximum (rmax) and minimum (rmin) principal stresses generated in the PDL, cortical and alveolar bones, and the modified von Mises (rvM) values for the orthodontic wires were obtained. Results: With regard to the cortical bone and PDL, the highest rmin and rmax values for FTM, FN, and FA were checked. With regard to the alveolar bone, rmax and rmin values were highest for FA, followed by FTM and FN. The rvM values of the orthodontic wires followed the order of rigidity of the alloys,that is, FA > FTM > FN. Conclusion: The biomechanical behavior of the analyzed structures with regard to all the three patterns of flexibility was similar.

摘要目的：通过三维有限元分析，评价不同力学性能的正畸钢丝对再植牙支撑骨结构和邻牙牙周膜(PDL)的生物力学行为。材料和方法：根据断层和显微断层数据，建立上颌骨前牙与相应牙齿（牙13-牙23）的三维模型，模拟牙21撕脱再植。用正畸钢丝(§0.8mm)和复合树脂夹板固定牙齿。钢丝(FA)、钛钼丝(FTM)和镍钛丝(FN)的弹性模量分别为200GPa、84GPa和52GPa。采用Ansys Workbench软件对再植牙切缘施加45°角的斜载荷（100 N）进行分析。获得了PDL、皮质骨和牙槽骨产生的最大（rmax）和最小（rmin）主应力，以及正畸导线的修正von Mises（rvM）值。结果：在皮质骨和PDL中，FTM、FN和FA的rmin和rmax值最高。对于牙槽骨，钢丝的rmax和rmin值最高，钛钼丝和镍钛丝次之。正畸钢丝的rvM值按合金刚度大小顺序为钢丝>钛钼丝>镍钛丝。结论：所分析的结构在所有三种柔韧性模式下的生物力学行为是相似的。