这项研究制定了针对患者的重建植入物的设计标准,并考虑了各种下颌连续性缺陷的外观和结构优化。不同的下颌骨连续性缺陷包括C(从左到右的犬科动物),B(从第一前磨牙到第三磨牙),和根据下颌骨图像定义的A(从第3磨牙到支)段。将有限元(FE)分析和加权拓扑优化方法相结合,以设计具有相应咬合条件的不同重建植入物内的内部支撑梁结构。使用增材制造(AM)重建的植入物和接骨板修复了五种连续性下颌骨缺损(单个B/C/AB以及BC和BCB段的组合),以通过生物力学疲劳测试确定合理的设计标准。根据材料力学和节段骨长度的结果,筛选出最差的下颌骨强度,厚度,和身高统计数据来自已建立的数据库,其中包含105名患者的下颌骨图像。加权优化分析结果表明,重建后的C内支撑梁的尺寸和位置,B,A+B植入物可以通过相应的骨长度参数化定义,宽度,和高度。FE分析发现,C中参数设计的植入物和原始核心实体植入物之间的重量变化百分比,B,A+B减少了54.3%,63.7%,和69.7%,分别。重建种植体和剩余骨的最大应力值没有明显降低,但远低于材料极限强度。生物力学疲劳测试表明,所有使用AM重建植入物的病例都可以通过250,000动态载荷。然而,髁头,骨板骨折,在使用骨板的情况下可以发现骨螺钉松动。这项研究为适用于AM的各种下颌连续性缺损的患者特定重建植入物制定了设计标准,以进一步临床使用。
This study developed design criterion for patient-specific reconstructed implants with appearance consideration and structural optimization of various mandibular continuity defects. The different mandible continuity defects include C (from left to right canines), B (from 1st premolar to 3rd molar), and A (from 3rd molar to ramus) segments defined based on the mandible image. The finite element (FE) analysis and weighted topology optimization methods were combined to design internal support beam structures within different reconstructed implants with corresponding occlusal conditions. Five continuity mandibular defects (single B/C/A+B and combination of B+C and B+C+B segments) were restored using additive manufacturing (AM) reconstructed implant and bone plate to confirm reasonable design criterion through biomechanical fatigue testing. The worst mandible strength was filtered based on the material mechanics and results from segmental bone length, thickness, and height statistics from the established database containing mandible images of 105 patients. The weighted optimization analysis results indicated that the sizes and positions of internal supporting beams within the reconstructed C, B, and A+B implants can be defined parametrically through corresponding segmental bone length, width, and height. The FE analysis found that the weight variation percentage between the parametric designed implants and original core solid implants in the C, B, and A+B was reduced by 54.3%, 63.7%, and 69.7%, respectively. The maximum stress values of the reconstructed implant and the remaining bone were not obviously reduced but the stress values were far lower than the material ultimate strength. The biomechanical fatigue testing indicated that all cases using the AM reconstructed implant could pass the 250,000 dynamic load. However, condyle head, bone plate fracture, and bone screw loosening could be found in cases using bone plates. This study developed a design criterion for patient-specific reconstructed implants for various mandibular continuity defects applicable for AM to further clinical use.