title: Corrosion and tarnish of dental silver-based alloys in 0.1% Na2S and Ringer's solutions. (Part 1) Electrochemical study.
abstract: The corrosion behavior of three silver-based alloys, Ag-Sn-Zn, Ag-In, and Ag-Pd-Cu, were investigated by potentiodynamic anodic polarization analysis and the polarization resistance method in 0.1% Na2S and Ringer's solutions. The corrosion activity of the Ag-Sn-Zn alloy was higher in Ringer's solution than in the 0.1% Na2S solution. In contrast, the corrosion rate of the Ag-Pd-Cu alloy was approximately 500 times higher in the 0.1% Na2S solution than in Ringer's solution. The results show that the generally accepted concept that tarnish is merely a surface discoloration due to the deposition of insoluble products is inadequate. The alloy discolors while being severely attacked in the presence of sulfides. For the Ag-In alloy, the corrosion activity in the 0.1% Na2S solution was as high as in Ringer's solution. These silver-based alloys exhibit different electrochemical activities in different solutions. The test solutions for corrosion tests must be carefully chosen for each alloy system through a screening test to replicate the predominant corrosion reaction proceeding in the oral environment.
authors.forename: K
authors.initials: K
authors.lastname: Endo
authors.forename: Y
authors.initials: Y
authors.lastname: Araki
authors.forename: H
authors.initials: H
authors.lastname: Ohno
mesh_terms: D003343:Corrosion; D003722:Dental Alloys; D007552:Isotonic Solutions; D000077331:Ringer's Solution; D012834:Silver; D013440:Sulfides
chemical_list: D003722:Dental Alloys; D007552:Isotonic Solutions; D013440:Sulfides; D012834:Silver; D000077331:Ringer's Solution; C033479:sodium sulfide