[Exposure to mercury in public dental clinics in Oslo--an occupational hazard evaluation].

To evaluate the occupational hazard in use of mercury by dentists, the work environment and procedures of 22 dentists and their 33 assistants were surveyed. Determinations were made of a) the mercury vapour concentrations in the offices b) the urinary excretion of mercury by the 55 persons concerned c) the mercury concentration in blood. In three of the offices surveyed, mercury vapour concentration exceeded the threshold limit value of 0.05 mg/m3, implying a lack of care in handling mercury. Urinary mercury contents of one dentist and four dental assistants exceeded 0.05 mg/l i.e. the upper "normal" value for a population with no known exposure to mercury. The manner in preparation and handling of the amalgam were considered to be the predominant comtamination factor.