Mechanobiologically optimization of a 3D titanium-mesh implant for mandibular large defect: A simulated study

Recently, a novel 3D titanium-mesh scaffold with bone grafting material has been proposed to reconstruct the large defect of mandible. However, how to design and optimize the 3D scaffolds of mandible is still unclear. Therefore, the aim of this study was to investigate the optimization of 3D scaffolds for mandibular defect. Both the biomechanical behavior and mechanobiological property of scaffolds were considered in this study. Four configurations (regular hexahedron, cuboctahedron, regular dodecahedron, and diamond) and three strut diameters (0.2 mm, 0.5 mm and 0.8 mm) were divided into 12 groups. By employing Finite Element Analysis and bone "Mechnostat" theory, the optimal unit cell was selected from 12 scaffolds. Then, the original implant for mandible defects was designed with the optimal unit cell, and the final implant was optimized to promote osteogenesis and avoid mechanical failure under bi-lateral chewing bite (200N) and maximum force (worse-case) bite (800 N). The results illustrated a strong correlation between the configurations and the load transmission capacity, while mechanical failure highly depended on strut size and architecture. Regular dodecahedron with a strut diameter of 0.8 mm provided a good load transfer to bone tissue while resisting the mechanical failure. Ultimately, the optimized implant was constructed with regular dodecahedron unit cell, and the strut diameters of scaffold gradually varied according to the biomechanical analysis. The computational results indicated that the optimized implant can provide an excellent mechanical environment for bone regeneration, thus achieving a long-term stability and occlusal reconstruction with dental implant. This study is expected to provide a scientific basis for the design and optimization of 3D mesh scaffolds to reconstruct a mandibular functionally and aesthetically.