A lightweight mechanical metamaterial framework produced via 3D printing for next-generation dental implants

Abstract

Lightweight mechanical metamaterials have attracted increasing attention due to their ability to achieve unusual mechanical properties through architectural design rather than chemical composition. In this study, a novel cylindrical metamaterial based on a gyroid triply periodic minimal surface (TPMS) architecture is proposed, selected for its high strength-to-weight ratio, smooth stress distribution, and fully interconnected porosity that are advantageous for load-bearing biomedical applications. A combined experimental and numerical approach was employed, where the finite element model was validated against quasi-static compression tests conducted on 3D-printed specimens (1.9 mm thickness, eleven unit-cells). The validated model achieved excellent agreement with experiments (R2 = 0.965), capturing the two-phase deformation behavior: an initial elastic regime followed by plasticity-driven global buckling initiating at the core between neighboring unit-cells. A comprehensive parametric study was then performed to investigate the effects of unit-cell wall thickness (1.1–2.7 mm) and number of unit-cells per circumference (3, 7, and 11) on the mechanical response. Results show that increasing the unit-cell count enhances stiffness and Specific Energy Absorption (SEA) but reduces the displacement at which buckling initiates. In contrast, increasing wall thickness simultaneously improves stiffness, peak load, SEA, and instability displacement, with SEA increasing by up to 201% from the thinnest to the thickest configuration. The highest performance was achieved for the 2.7 mm thickness with eleven unit-cells, yielding a peak load of 3679.9 N, stiffness of 4495.2 N/mm, and SEA of 3331.0 mJ/g. The tunable mechanical behavior and lightweight porous architecture position the proposed TPMS metamaterial as a promising candidate for further investigation in load-bearing biomedical applications.