SYSTEMIC TRANSFER OF MERCURY FROM AMALGAM FILLINGS BEFORE AND AFTER CESSATION OF EMISSION

In 29 volunteers with a low amalgam load, the number of amalgam-covere d tooth surfaces and the occlusal area of the fillings were determined . Concentrations of total mercury were measured in plasma and erythroc ytes as well as in urine together with the excretion rate, Absorbed da ily doses were estimated from intraoral Hg emission by two separate me thods. The transfer of Hg from the fillings via the oral cavity and bl ood to urinary excretion was evaluated according to the most represent ative combination of parameters, This consisted of urinary excretion ( 1), Hg concentration in plasma (2), absorbed dose (3), and occlusal ar ea (4). Pairwise correlation coefficients were 0.75 for parameters 1 v s 2 and 2 vs 3 and 0.49 for parameters 3 vs 4. Within 9 days after rem oval of the fillings, a transient increase was observed in plasma Hg l evels only. This was reduced in those volunteers to whom a rubber dam had been applied during removal. Peak plasma Hg was 0.6 ng/ml on avera ge and decreased with halftimes between 5 and 13 days. A significant d ecrease in Hg excretion was noted not before 100 days after removal, B eing relatively insensitive to dietary mercury, the determination of t otal mercury in plasma and of its urinary excretion rate appears, unde r practical aspects, most suitable for the investigation of Hg uptake from amalgam. (C) 1998 Academic Press.