ABSTRACT
Stress shielding has been a major concern with biomedical implants due to the vast elastic modulus difference between the host bone and the implant material. Titanium, which is the most widely used biomaterial, has an elastic modulus of 110 GPa; cobalt chrome has an elastic modulus of 240 GPa; similarly, stainless steel 316L has an elastic modulus of approximately 230 GPa, whereas the elastic modulus of human cortical bone is 20 GPa and that of cancellous bone is 3–5 GPa. Lattice/porous structures are used in biomedical implants to tailor the elastic modulus of the implant to match that of the adjacent bone resulting in a reduced stress shielding effect. The capability of manufacturing solid as well as lattice/porous structures of additive manufacturing (AM) has accelerated the acceptance of AM in biomedical implant applications. In this study, three different types of metal lattice/porous structures obtained through AM (Gyroid, Diamond, and Schwarz W) and their three different pore sizes (0.4, 0.5, and 0.6 mm) are investigated for tailoring the elastic modulus of a Ti6Al4V ELI (Extra Low Interstitial) material to match that of cancellous bone. Results showed a significant reduction in elastic modulus for all the studied lattice structure types.
