Corrosion of non-gamma 2-amalgams.

Eight different dental amalgams were studied in an in vitro corrosion test. Cylindrical test specimens were stored in weak lactic acid solutions at different pH for 1 month. The concentrations of mercury and copper in the solutions were measured and corrosion depths estimated. The results indicated that more copper was released from non-gamma 2-amalgams compared with conventional ones. The amounts of copper from these amalgams were not directly correlated to the concentration in the alloys. Mercury was released in much lower amounts than copper for all amalgams and seemed to originate from the gamma 1-phase. A low pH promoted the corrosion.