Study on the Surface of Cobalt-Chromium Dental Alloys and Their Behavior in Oral Cavity as Cast Materials

This study presents the correct processing of Co-Cr alloys as a method of preserving the properties of the materials as-cast, and therefore they can be safely placed in contact with the oral cavity tissues as resistance frameworks. The basic materials analyzed in this study were five commercial Co-Cr dental alloys with different components obtained in three processing steps. The analysis of the electrochemical behavior at the surface of the Co-Cr alloys was performed by electrochemical measurements: impedance spectroscopy (EIS), open circuit electrical potential (OCP), and linear polarization (LP). In terms of validation, all five alloys had a tendency to generate a stable oxide layer at the surface. After the measurements and the graphical representation, the alloy that had a higher percentage of tungsten (W) and iron (Fe) in composition showed a higher tendency of anodizing. After the application of the heat treatment, the disappearance of the hexagonal phase was observed, with the appearance of new phases of type (A,B)(2)O-3 corresponding to some oxide compounds, such as Fe2O3, Cr2O3, (Cr,Fe)(2)O-3, and CoMnO3. In conclusion, the processing of Co-Cr alloys by melting and casting in refractory molds remains a viable method that can support innovation, in the context of technology advance in recent years towards digitalization of the manufacturing process, i.e., the construction of prosthetic frameworks conducted by additive methods using Co-Cr powder alloy.

Automated summary

This study explores the correct processing of Co-Cr alloys to preserve their properties and safely use them in contact with oral cavity tissues. The electrochemical behavior of five commercial Co-Cr dental alloys with different compositions was analyzed, and their characteristics were determined. The study found that alloys with higher tungsten and iron content exhibited a stronger tendency for anodization, and new oxide compounds appeared after heat treatment. In conclusion, processing Co-Cr alloys through melting and casting remains a viable method that can support innovation in the context of digitalization of the manufacturing process.