Occupational Exposure to Mercury and Urinary Mercury of Dental Personnel

Mercury toxicity from dental amalgam fillings is today a matter of debate in several countries. Objectives: The aim of the study was to evaluate the mercury (Hg) in urine of dental personnel compare to non exposure subjects. Methods: A cross-sectional study was conducted in a group of dental personnel who lived in Phung-Nga province of Thailand. The urine samples were collected from 76 dental personnel who exposed to dental amalgam and 16 non exposure subjects for comparison. Cold-Vapor Atomic Absorption Spectrometry was used to measure the urinary Hg. The subjects were asked to complete the questionnaire that designed to provide information about the parameters that influenced their occupational exposure to mercury. Results: The mean urinary mercury concentration of the dental personnel and control subjects were 2.27 ± 5.3(range 0-37.3) and 0.69 ± 0.92(range 0-3) µg/g creatinine respectively. Dental personnel had an average urinary Hg level higher than control subjects, but this difference was not statistically significant (Mann-Whitney U test, p =.59). There were 10.53% of the dental personnel had urinary mercury level above 5 µg/g creatinine, compared to 0% of control group. The result of questionnaire revealed that dental personnel used precapsulated dental amalgam in their clinical practice. The mean number of amalgam fillings placed in a week was 3.15 ± 1.74 fillings (range = 0-5). The daily working hours in dental clinic was 7.73± 2.81 hours (range = 0 to 12). Conclusion: There was no significant difference of urinary mercury between dental personnel group and control group.