Electrochemical characterization of novel Ag-based brazing alloys for dental applications

Objective. Taking into account that clinical data have proven the decomposition of Ag brazing alloys used in the production of orthodontic appliances the aim of this study was to develop new Ag based soldering alloys free of Cu and Zn. Methods. Four commercially available Ag brazing alloys were selected and their electrochemical properties were compared to the following experimental alloys: Ag12Ga, Ag10Ga5Sn, Ag20In and Ag7Sn. 112 disk shape specimens were prepared for each alloy and their electrochemical properties were evaluated by Open Circuit Potential (OCP), linear sweep voltametry (LSV), cyclic polarization (CP) and electrochemical impedance spectroscopy (EIS) in a NaCl 0.9% and a Ringer's electrolyte solution. Results. The experimental alloys combined higher OCP and E-corr with lower I-corr values. The impedance values of the commercial alloys were lower showing that any surface layers formed are not protective and steady compared to those of the novel ones. In conclusion experimental alloys demonstrated enhanced electrochemical properties. Significance. In and Sn showed a more beneficial effect on electrochemical properties compared to Ga and thus can be considered as a promising option for the development of a new family of Ag brazing alloys with increased biocompatibility. (C) 2019 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.