Mercury in dental practice. II. Urinary mercury excretion in dental personnel.

Urinary mercury levels (HgU) have been measured in the first morning urine samples from 505 dental personnel in the county of Västerbotten in northern Sweden, and from 41 controls, randomly selected wives and husbands to the examined dentists. Information concerning personal factors and working routines were gathered from questionnaires. The HgU values were higher for dental personnel than for the control group but were consistently very low and were for all examined subjects below the proposed occupational exposure limit for HgU for subjects exposed to mercury vapor (approximately equal to 28 nmol/mmol creatinine). Dental nurses had the highest HgU values, higher in Private Dental Care than in Public Dental Care. The levels of mercury vapor in the workroom air influenced the HgU in a statistically significant way only for male dentists in Public Dental Care. Symptoms which might be caused by exposure to mercury were more common among dental personnel than in the control group, but no statistically significant correlations could be found with HgU values. There was a statistically significant correlation between the number of amalgam surfaces and the HgU values in the control group.