Surface characteristics and corrosion properties of Co-Cr dental alloys processed by laser-based methods

Abstract

Technological developments have led to the implementation of novel digitalized manufacturing methods for the production of metallic structures in prosthetic dentistry, less studied to date. The objective of the study was to assess the morphological characteristics and corrosion properties of selective laser sintered (SLS) and selective laser melted (SLM) cobalt-chromium (Co-Cr) dental alloys related to the surface processing and pH variations. For the experimental analyses metallic specimens made of Co-Cr dental alloys were prepared using SLS and SLM, as indicated by the manufacturers. The morphology and the topography of the samples were investigated by scanning electron microscopy and atomic force microscopy. Electrochemical measurements were made and the values for corrosion potential (Ecorr), corrosion current (icorr) and corrosion rate were calculated. The immanent advantages of additive technologies are accompanied by porosities resulted after the deposition of the fine metallic powder, especially for the SLM method. Considering the corrosion current density value a parameter which provides information on the kinetics of the corrosion process, SLS samples showed better performance under pH variations. Surface processing can result in an improvement in the corrosion performance also for extreme pH values. Given that the microstructure and corrosion behavior was significantly different, further differences in the clinical behavior of prosthetic restorations manufactured using SLS and SLM additive techniques are anticipated.