Patient-specific mandibular metamaterial implants with topology optimized microstructure

Mandibular reconstruction plates aim to restore function and esthetics after mandibular resection; however, achieving mechanical compatibility between implant and bone remains challenging. Solid titanium alloy plates induce stress shielding, compromising bone health and causing implant loosening. Metamaterial implants offer a solution but often exhibit highly non-uniform stresses within homogeneous microstructures due to complex loads. This study presents a personalized mandibular metamaterial implant with a topology-optimized microstructure that improves mechanical performance and reduces stress shielding. The design maps a gyroid lattice with inhomogeneous density onto the optimized topology, tailoring stiffness to loading conditions. Comparative analyses with a solid implant and a homogeneous gyroid design show that the topology-optimized implant reduces stress concentrations and transfers higher stresses to the mandible, enhancing fracture resistance and mitigating stress shielding. These results demonstrate that topology-optimized metamaterial microstructures can overcome key limitations of current personalized implants, potentially improving long-term survival and bone integrity. The proposed approach provides implant designs ready to be validated in a clinical trial and is applicable to other implantable devices. Overall, this work establishes a scalable framework for patient-specific reconstruction using load-tailored metamaterial designs.