Study of the short-term release of the ionic fraction of heavy metals from dental amalgam into synthetic saliva, using anodic stripping voltammetry with microelectrodes

The present paper describes a fast and reproducible procedure, employing differential pulse stripping analysis technique with graphite microelectrodes, for the quantitative evaluation of the ionic fraction of heavy metals (namely Hg, Cu, and Zn) released from dental amalgams into synthetic saliva during 6-90 h contact between amalgam and saliva, after completion of the dental restoration (short-term release). The Zn2+ concentration was evaluated by linear calibration, whereas Cu2+ and Hg2+ contents were estimated by the standard additions method. While the concentration of Zn2+ ion does not increase significantly anymore after a 6-h contact (values from 288+/-12 to 346+/-12 mug dm(-3) at time of contact from 6 to 90 h, respectively), in the same time interval the concentration of both Cu2+ and Hg2+ ions progressively increases (from 38+/-6 to 197+/-4 mug dm(-3) and from 15+/-3 to 101+/-2 mug dm(-3), respectively). The results of the release tests reveal that Hg concentration is at the highest level of risk (HBM III), as identified by the three human biomonitoring categories suggested by the Institut fur Wasser-, Boden- und Lufthygiene des Umweltbundesamtes (Germany) for the estimation of potential harmful effects on health due to exposure to heavy metals. (C) 2002 Elsevier Science B.V. All rights reserved.