Cytotoxicity of corroded and non-corroded dental silver amalgams

The cytotoxicity of one conventional and four non-γ₂-amalgams was studied in a cell culture system, using the Millipore filter method. Before testing set amalgam specimens were kept in distilled water or in artificial saliva at pH 4, 5 or 7 for up to 28 wk to produce a corrosion layer on the test surface. Non-corroded set amalgam specimens were also tested. None of the non-corroded, set amalgams showed any sign of surface accumulation of cytotoxic products whereas the corroded amalgams showed varying degrees of cytotoxicity. Generally, the non-γ₂-amalgams gave a more pronounced cytotoxic effect than the conventional amalgam. When the corrosion procedure was carried out at pH 7, the various non-γ₂-amalgams showed different degrees of cytotoxicity. It appears that the difference in cytotoxic effect between the non-γ₂-amalgams and the conventional amalgam as well as the differences among the various non-γ₂-amalgams could be related to variation in the retention of corrosion products deposited on the amalgam surface.