Mercury release, distribution and excretion from subcutaneously implanted conventional and high-copper amalgam powders in the guinea pig.

With both types of amalgam there was initial loss of material during healing of the implantation wounds. The rate of Hg release from the healed lesion was estimated by linear regression analysis of the content of implants when removed sequentially over 2 years. There were no significant differences between the amalgams, when expressed in absolute terms or as a percentage of the Hg content of the lesions immediately after healing, probably because gamma 1 (Ag2Hg3) phase breakdown was largely or solely responsible for Hg release with both materials. Hg levels in the blood, liver, renal cortex and faeces were all significantly lower with high-Cu amalgam which might be explained by the interference by Cu with Hg retention. There was no significant difference in urinary Hg excretion by the two groups of animals over the greater part of the study.