Correlation of dental amalgam crevice corrosion with clinical ratings.

In vitro corrosion behavior of gamma 2-containing and gamma 2-free dental amalgams was examined under crevice conditions which simulated the amalgam-tooth interface. By means of potentiostatic testing, current-density/time behavior and integrated anodic current were measured for 16 hr. All of the amalgams demonstrated crevice corrosion susceptibility. Crevice corrosion propagation for gamma 2-free vs. gamma 2-containing amalgams was characterized by lower acceleration and maximum rates during the most dynamic period. Integrated anodic current results were correlated with marginal breakdown ratings reported in two clinical investigations. Strong and significant coefficients were found between integrated current and marginal breakdown ratings when gamma 2-containing and gamma 2-free amalgams were correlated as a single group, but not when correlated separately.