Using Selective Laser Melting additive CAD/CAM technology (3D printing) for the fabrication of implant-supported partial fixed dental prosthesis: biomechanical, structural and electrochemical analysis

Abstract

The Selective Laser Melting (SLM) additive technique is a high technology method to fabricate prosthetic dental frameworks allowing for the direct 3D print of metal pieces. However, despite its advantages such as saving material that is lost by substractive methods, the technology remains unexplored in the dental literature. Analyses to confirm and support the use of additive technique in the clinical scenario for implant-supported frameworks are warranted. Therefore, the aim of this study will be verify if there is superiority of the SLM additive technology (experimental group) in relation to a commercial available subtractive Soft Metal Block (SMB) method (control group) to fabricate 3-unit fixed dental prosthesis frameworks (FDPs). The overcasting technique will be used as additional control group. The frameworks will be compared for the fit levels and stress transmitted to implant-supported system by the quantitative photoelastic and strain gauge stress analyses. Additionally, the structural and chemical behavior of each group will be assessed via Vickers microhardness, profilometry, flexural strength and modulus of elasticity, shear bond strength, and electrochemical stability in simulated oral environment. For the fit and stress evaluations, 3-unit implant-supported FDPs frameworks will be fabricated by SLM (experimental group), SMB (control group 1) and overcasting technique (control group 2). Additional specimens with specific dimensions will be used for the other analyses. The microhardness analysis will be performed by a microhardness tester at four points randomly distributed on the surface of each specimen. A profilometer will be used to evaluate the surface roughness. The shear bond strengths will be performed following the Schmitz-Schulmeyer method. The flexural strength will be tested by an universal test machine indirectly obtaining the modulus of elasticity of each evaluated technique. The electrochemical test will be conducted by a standardized method of three-electrode cells to evaluate the corrosion stability of each group. Quantitative data will be statistically analyzed at a significant level of 5%. (AU)