Mercury excretion and occupational exposure of dental personnel

At the annual congresses of the Norwegian Dental Association in 1986 and 1987 surveys were conducted to assess the significance of potential sources of mercury exposure. Morning urine samples and questionnaires were collected from 672 participants in 1986 and 273 participants in 1987. The mean values of the urinary mercury excretion were 39 nmol/L (SD = 29) in 1986, and 43 nmol/L (SD = 36) in 1987. The excretion values were correlated to the answers on questionnaires supplied from each participant. The data was analyzed using ANOVA, multiple classification analyses, and Pearson correlation. The correlations between environment and practice characteristics and the mercury excretion values reconfirm in general results from previous investigations. In addition, the data indicate that urinary mercury excretion may be gender dependent and that the restorative status of the participants contribute to the daily mercury exposure. Moreover, the excretion correlates not only to the number of placed restorations per week, but also to the number of polished and replaced amalgam restorations per week. Participants working in environments with wooden floors had significantly higher mean mercury values than other dental personnel. Elevated mercury values were also observed for participants working in clinics with installed amalgam separators or other filtering devices. The possibility that the storage of collected scrap amalgam and mercury from the filtering devices increases the mercury vapor in the work environment warrants further investigation.