A functionally graded gyroid-type three-periodic minimal surface framework applied to implant-supported fixed complete dentures

Titanium alloy, particularly Ti6Al4V, is commonly used for constructing the framework of implant-supported fixed complete dentures (IFCDs) but exhibits poor specific strength and impact toughness. Three-periodic minimal surface (TPMS) porous structures have the advantages of high specific strength, lightweight, and shock and energy absorption. Therefore, the functionally graded TPMS porous structure was adopted to design the framework for IFCDs in this study. Nine types of TPMS-based lattice structures with radial gradient variations were designed. Finite element analysis and experimental results indicate that the relative density increases outward and the cell size decreases outward from the center. The B-I porous structure has the highest strength and impact toughness compared to other gradient porous structure types. Moreover, the IFCD framework, utilizing the B-I porous structure, exhibited a 50% reduction in weight compared to the solid framework. When compared to the hollow framework with the same weight, the B-I framework demonstrated a 42.81% lower maximum equivalent stress under normal chewing conditions without undergoing plastic deformation. Therefore, the B-I framework meets the mechanical performance requirements for daily chewing and exhibits superior mechanical properties over conventional structures.