Effect of heat post-treatment on Ti-6Al-4V full-arch fixed implant-supported frameworks manufactured by additive and milling processes: structural, biomechanical, and 3D finite element analyses.

Abstract

3D printing technologies for full-arch maxillary fixed implant-supported metallic frameworks manufacturing are a little unexplored in dental literature, due to the fact of their length and complex design. Therefore, the objectives of this study are: (1) to evaluate the marginal misfit, prosthetic loosening screw value and strain of maxillary Ti-6Al-4V full-arch fixed dental prostheses (FAFDPs) manufacturing techniques: milling, and 3D printing Direct Metal Laser Sintering (DMLS) and Electron Beam Melting (EBM), before and after the heat post-processing treatment; (2) to evaluate the effects of post-processing treatment on the samples surface/structure; (3) to evaluate metal-ceramic bond strength (ISO 9693- 1), before and after heat post-treatment; (4) to biomechanically evaluate the frameworks through finite element analysis (FEA). Thirty FAFDPs will be manufactured in Ti-6Al-4V (n=10) for each technique. Marginal misfit will be measured through single-screw test protocol, prosthetic loosening screw value will be evaluated after 24h, and stress through strain gauge analysis, before and after heat post-treatment. Additionally, structure analyses of each group will be assessed in specific samples via flexural strength and Vickers microhardness (n=15/group), as well as surface analyses of each group will be assessed in specific samples via scanning electron microscopy, energy dispersive spectroscopy, surface roughness, contact angle test, surface energy and X-ray electron spectroscopy (n=10/group). Metal-ceramic bond strength analysis of each group will be assessed in specific samples (n=16/group). For FEA, data regarding surface/structure analyses will be used (oblique loading of 150N in the posterior occlusal surface). Quantitative data will be statistically analyzed at a significant level of 5%.