3D-Architected Natural Tooth-Derived Scaffolds Reinforced by Graphene and Gradient Gyroid

This study aimed to develop a novel 3D-architected scaffold system using clinically discarded teeth as a renewable resource, integrating graphene-based mechanical reinforcement and biomimetic gradient Gyroid structural design to address the limitations of tooth-derived HA materials and achieve synergistic optimization of printability, mechanical performance, and biocompatibility. Clinically discarded teeth are processed into powders. Graphene is subsequently incorporated into the powder to prepare photocurable slurries, which are used to fabricate scaffolds via digital light processing (DLP) 3D printing. Four TPMS Gyroid structures are designed. The scaffolds are characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, mechanical tests, multiphysics simulations, and in vitro cytocompatibility assays. Integrated thermogravimetric analysis/fourier-transform infrared spectroscopy/X-ray diffraction analyzes, along with DLP printability assays, identified 500 °C as the optimal thermal treatment. The incorporation of 0.3 wt% graphene resulted in the most significant mechanical enhancement. Scaffolds with a low-porosity gradient exhibited the highest compressive strength (6.2 MPa) among all designs. Multiphysics simulations revealed improved uniformity in stress transfer. In vitro MTT assays showed all graphene-reinforced/gradient-structured scaffolds sustained >95% cell viability, with no significant cytotoxicity detected. These results demonstrate a sustainable route that upcycles clinical tooth waste into high-performance, 3D-printed HA scaffolds by coupling graphene-enabled reinforcement with graded topology, supporting personalized, load-responsive bone repair.