Copper in approximal plaque from conventional and non-gamma-2 amalgam restorations

Differences in copper concentrations found in plaque adjacent to conventional compared with copper-rich non-gamma-2 amalgam fillings were evaluated. Plaque was sampled at baseline and up to 2 months after polishing of two to four fillings of each type of amalgam in six patients. Copper concentrations of several hundred ppm were found, with higher values in plaque sampled from copper-rich amalgam. However, the copper release from the copper-rich amalgam probably has very little influence on plaque ecology owing to a relatively low copper ion activity because of stable copper complexes in plaque.