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 2889/12 to 3469/12 mg dm3 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 389/6 to 1979/4 mg dm3 and from 159/3 to 1019/2 mg dm3, 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 fu¨ r Wasser-, Boden- und Lufthygiene des Umweltbundesamtes (Germany) for the estimation of potential harmful effects on health due to exposure to heavy metals.