Journal of Dental Research, Vol 67, 1312-1315, Copyright © 1988 by International & American Associations for Dental Research Online Journals

ARTICLES

Mechanism of improved corrosion resistance of Zn-containing dental amalgams

N. K. Sarkar and J. R. Park
Department of Biomaterials, Louisiana State University, School of Dentistry, New Orleans 70119.

The aim of this study was to determine the mechanism of improved corrosion resistance of Zn-containing dental amalgams. Two Zn-containing conventional amalgams, their Zn-free counterparts, and three experimental amalgams (SnHg, ZnHg, and SnZnHg) were evaluated by the potentiodynamic polarization technique in 1% NaCl solution. The main difference between the two types of amalgams was found in their respective breakdown potentials at which passivity was destroyed. The breakdown potential of Zn-containing amalgams was about 200 mV more positive than that of the Zn-free amalgams. The improved stability of the Zn-containing amalgams has been attributed to the formation of a previously reported Zn stannate passive film which, according to the polarization data, is more resistant to the aggressive chloride ion than tin hydroxide that forms on Zn-free amalgams. The formation of Zn stannate was not found to affect the oxygen reduction reaction, the major cathodic reaction involved in the corrosion of dental amalgams.

This article has been cited by other articles:

				R. S. WALKER, A. G. WADE, G. IAZZETTI, and N. K. SARKAR Galvanic interaction between gold and amalgam: Effect of zinc, time and surface treatments J Am Dent Assoc, November 1, 2003; 134(11): 1463 - 1467. [Abstract] [Full Text] [PDF]