in vitro and in vivo Performance of Implants Using Additive Manufacturing vs. Commercially Available Implants

The study objectives were to evaluate the in vitro and in vivo performance of additive manufacturing (AM) Ti6Al4V ELI alloy compared to that of a commercially available dental implant. Two AM shapes with the solid or lattice structures on the solid substrate were used: in vitro test: disk shapes (10.0 mm/dia. 2.0 mm/thick) and in vivo test: AM shapes matching the overall geometry of a commercial implant (3.0 mm/dia. 8.0 mm/length). Six disk specimens were placed in direct contact with Balb/c 3T3 fibroblasts for 72 h. Cytotoxicity was assessed with adenosine triphosphate activity. Four implant-shaped specimens were placed in the femurs of three rabbits and retrieved after 6 weeks. Osseointegration was evaluated by push-out testing and histological analysis. Data were analyzed using one-way ANOVA (α = 0.05). Surface roughness (µm) of AM-solid, AM-lattice, and a commercial implant were 8.02, 9.00, and 1.46, respectively. Cytotoxicity was not statistically different compared to surface configuration and Teflon® controls (p > 0.05). Push-out test results were not significant between implants: the shear stiffness of commercial > AM-lattice > AM-solid (p > 0.05). Histological analysis demonstrated osseointegration without inflammatory responses in the surrounding bone tissue for all implants. While some processes and improvements are still required, AM remains a promising method for fabricating customized porous implants in the future.