TARNISH OF CERTAIN DENTAL ALLOYS

¹ Department of Dental Materials, Indiana University School of Dentistry, Indianapolis, Ind.

An investigation was conducted to determine the role of various chemical elements in the tarnish of certain dental alloys.

1. X-ray diffraction patterns of clinically tarnished amalgam restorations indicate sulfide to be a dominating factor in the tarnish of amalgam alloys.

2. Amalgam specimens exhibited gross discoloration in sulfide solutions. Lesser degrees were noted in chlorides, synthetic saliva, and water.

3. The degree and rate of tarnish of the amalgam specimens did not appear to be influenced either by the residual mercury content or by the presence or absence of zinc.

4. Sulfur produced little tarnish on the gallium alloy, although heavy tarnish was incurred by storage in sodium chloride, hydrogen peroxide, and distilled water. It would thus appear that with this alloy, oxides or chlorides would be the principal constituents of tarnish.

5. A light tarnish of a low karat gold alloy was induced by sulfides. This alloy was not affected by other elements. High karat gold was not influenced by storage in any of the media used.