Zinc release from dental restorative materials in vitro.

Zinc release from a range of dental restorative materials was measured in the absence and presence of dentin over a 2-week period. The presence of dentin was designed to simulate the residual dentin in vivo. There were considerable differences in both the levels and pattern of zinc release for the different materials. In several cases the concentrations exceeded the level which has been reported cytotoxic to cells in culture. With dentin, little zinc passed into solution, and high concentrations were measured in the dentin. This may explain the discrepancy between in vivo toxicity tests using zinc-containing materials and previous in vitro tests which have not included dentin in the test system.