RESIDUAL MERCURY CONTENT OF AMALGAM RESTORATIONS AND ITS INFLUENCE ON COMPRESSIVE STRENGTH

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

It has been shown that the method employed here for mercury analysis of amalgam alloys is accurate for use with small and unpulverized specimens. Analyses of 27 amalgam restorations indicated that they are not homogeneous and that residual mercury in some critical areas often approaches 60 per cent. Residual mercury does vary with the original ratio and with the condensation pressure. With the two alloys used, although compressive strength was not altered appreciably by fluctuations in residual mercury content between the ranges of 50-55 per cent, there was a serious loss in strength when the mercury exceeded 55 per cent.