Factors affecting estimation of dental amalgam mercury exposure from measurements of mercury vapor levels in intra-oral and expired air.

Several investigators have attempted to assess the extent of mercury exposure from dental amalgam restorations through the use of mercury vapor measurements of intra-oral or expired air. The sampling times and flow rates of the mercury vapor analyzers used in intra-oral measurements are not comparable with physiological inhalation times or flow rates of air through the mouth during inhalation. Analysis of the assumptions and measurement techniques employed in previous attempts to estimate mercury exposure from amalgam restorations shows that adequate compensation had not been made for these measurement parameters. Calculation of the mercury vaporization rates responsible for the mercury vapor concentration values previously reported enabled the daily dose of mercury to be estimated for subjects with various numbers of amalgam restorations. The corrected estimates for daily dose of mercury from amalgam restorations are a factor of sixteen lower than those previously reported.