Effect of rubber dam on mercury exposure during amalgam removal

It was the aim of this investigation to treat 20 volunteers with maximally 5 amalgam fillings by the same comprehensive protocol in which all removals with (n=8) and without (n=12) rubber dam had been performed within a few m onths. Nine amalgam-related parameters indicated a close matching of both g roups before removal. In the group without rubber dam, mercury (Hg) levels in plasma increased significantly above preremoval values at days 1 and 3 a fter removal, they decreased significantly below preremoval values at day 3 0 in the rubber-dam group and at day 100 in both groups. Excretion rates di d not increase significantly in either group, but decreased significantly a t day 100 in the protected group. Peak plasma-Hg was 0.6 ng/mL on average a t day one and decreased with halftimes of 3 and 43 d in subjects protected by rubber dam. The results indicated that concentrations of total mercury i n plasma responded rapidly to changes in the amalgam status and reflected t he actual absorption most reliably. Notably, plasma-Hg levels were sensitiv e enough to detect a transient attenuation of the additional exposure by us ing rubber dam during the removal of only a few fillings. However, being sm all in magnitude and lasting 100 d at best, the rubber-dam effect had minor toxicological relevance.