上颌骨复杂缺损3D打印精准重建支架的生物力学研究

Three-Dimensional Printed Scaffold for Complex Maxillary Defects by Accurate Reconstruction:A Biomechanical Study

目的提出一种用于修复上颌骨大面积骨缺损的3D打印植入体设计、优化、制造的个性化方案。方法基于患者CBCT和口腔扫描数据信息,首先进行植入体优化设计;采用有限元分析方法对植入体的结构迭代优化与材料选择。模拟植入体在口腔内的受力情况,得到植入体所受应力大小、传导方向与分布,据此对植入体结构进行优化。比较同种构型植入体在钛合金、钽金属、聚醚醚酮(polyetheretherketone,PEEK)3种不同材料下的最大等效应力、颌骨最大等效应力和钛钉总位移,确定植入体的打印材料。采用3D打印技术打印植入体,临床进行面部重塑和咬合重建。结果经过结构迭代优化得出植入体的最佳构型,并确定选择钛合金材料。将3D打印植入体应用于临床,完成了咬合重建。结论本研究描述的个性化方案具备临床可行性,适用于不同分类的上颌骨缺损病例。设计出的植入体尺寸精确、力学性能良好,不仅能恢复患者的颌面部外形,还满足了临床对颌骨缺损修复后咬合重建的需求。

Objective To propose a personalized design, optimization and manufacturing method of three-dimensional(3D) printed implants for repairing large area of maxillary defect. Methods Based on the patient’s cone beam computer tomography(CBCT) and oral scan data information, the implant design was optimized at first. The structure and material selection of the implant were iteratively optimized by finite element analysis method. The force of the implant in oral cavity was simulated, the stress magnitude, conduction direction and distributions of the implant were obtained, and the implant structure was optimized accordingly. Finally, the maximum equivalent stress of the implant and the mandible, as well as the total displacement of titanium screws with the same configuration under three different materials, namely, titanium alloy, tantalum metal and polyetheretherketone(PEEK) were obtained, so as to determine printing material of the implant. Finally, the implant was printed using 3D printing technology, and facial remodeling and occlusal reconstruction were completed in clinic. Results Through iterative optimization of the structure, the best configuration of the implant was obtained, and the titanium alloy material was selected. The 3D printed implants were used in clinic to complete occlusal reconstruction. Conclusions The method described in this study has clinical feasibility and is suitable for different types of maxillary defect cases. The designed implant is accurate in size and has preferable mechanical properties. It can not only restores the patient’s maxillofacial appearance, but also meets the clinical needs of occlusal reconstruction after maxillofacial defect repair.