The effects in vitro of zinc released from dental restorative materials

Summary. Zinc at the levels released from several dental restorative materials was toxic to both fibre-blasts and macrophages, and so appears to be an important factor in the cytotoxicity in vitro of these materials. The toxicity of zinc to fibroblasts was less at high and low pH, but alterations in pH caused a substantial reduction in cell numbers, accompanied by alterations in cell membrane permeability. With macrophages, zinc had a significant effect at all pH values tested and there was little alteration in cell numbers with pH. No evidence was found for the role of zinc in stabilizing either cell or lysosomal membranes. However, as in vivo zinc is readily adsorbed by dentine, it is unlikely to cause toxic effects.