Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, the Netherlands.
Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, the Netherlands.
J Mech Behav Biomed Mater. 2022 Aug;132:105291. doi: 10.1016/j.jmbbm.2022.105291. Epub 2022 May 26.
The reconstruction of large mandibular defects with optimal aesthetic and functional outcomes remains a major challenge for maxillofacial surgeons. The aim of this study was to design patient-specific mandibular reconstruction implants through a semi-automated digital workflow and to assess the effects of topology optimization on the biomechanical performance of the designed implants. By using the proposed workflow, a fully porous implant (LA-implant) and a topology-optimized implant (TO-implant) both made of Ti-6Al-4V ELI were designed and additively manufactured using selective laser melting. The mechanical performance of the implants was predicted by performing finite element analysis (FEA) and was experimentally assessed by conducting quasi-static and cyclic biomechanical tests. Digital image correlation (DIC) was used to validate the FE model by comparing the principal strains predicted by the FEM model with the measured distribution of the same type of strain. The numerical predictions were in good agreement with the DIC measurements and the predicted locations of specimen failure matched the actual ones. No statistically significant differences (p < 0.05) in the mean stiffness, mean ultimate load, or mean ultimate displacement were detected between the LA- and TO-implant groups. No implant failures were observed during quasi-static or cyclic testing under masticatory loads that were substantially higher (>1000 N) than the average maximum biting force of healthy individuals. Given its relatively lower weight (16.5%), higher porosity (17.4%), and much shorter design time (633.3%), the LA-implant is preferred for clinical application. This study clearly demonstrates the capability of the proposed workflow to develop patient-specific implants with high precision and superior mechanical performance, which will greatly facilitate cost- and time-effective pre-surgical planning and is expected to improve the surgical outcome.
对于颌面外科医生来说，用最佳的美学和功能效果来重建大的下颌骨缺损仍然是一个主要挑战。本研究的目的是通过半自动数字化工作流程设计患者特异性下颌骨重建植入物，并评估拓扑优化对设计植入物生物力学性能的影响。通过使用所提出的工作流程，设计并使用选择性激光熔化技术制造了由 Ti-6Al-4V ELI 制成的完全多孔植入物（LA 植入物）和拓扑优化植入物（TO 植入物）。通过执行有限元分析（FEA）预测植入物的机械性能，并通过进行准静态和循环生物力学测试对其进行实验评估。数字图像相关（DIC）用于通过将 FEM 模型预测的主应变与相同类型应变的测量分布进行比较来验证 FE 模型。数值预测与 DIC 测量吻合良好，预测的试件失效位置与实际位置吻合。在咀嚼负荷下，LA 植入物和 TO 植入物组的平均刚度、平均极限载荷或平均极限位移均无统计学差异（p<0.05）。在咀嚼负荷下（远高于健康个体的平均最大咬合力（>1000N））进行的准静态或循环测试中，未观察到植入物失效。鉴于其相对较低的重量（16.5%）、较高的孔隙率（17.4%）和更短的设计时间（633.3%），LA 植入物更适合临床应用。本研究清楚地表明，所提出的工作流程具有开发高精度和卓越机械性能的患者特异性植入物的能力，这将极大地促进成本和时间有效的术前规划，并有望改善手术结果。
