Occupational exposure to metallic mercury in the dentist's office of a public primary health care clinic in the city of São Paulo

Abstract

This paper discusses occupational exposure to metallic mercury among dentists and dental assistants, focusing on biological evaluation, effects on heaith, and environmental evaluation. Methods included visits to the clinic, hazard maps, urinary and environmental mercury measurements, and evaluation of health status. Results for the environment and work processes showed that mercury vapor concentrations impregnating surfaces and piping varied from 0.001 to 0.051 mg/m3 in air; occupational exposure with 62.5% of health workers having HgU ranging from 10 to 49 mg/l and 37.5% having HgU below 10 mg/l in 1994, while workers' previous measures (from 1992) were lower in every single case; an outflow of mercury and inadequate amalgamation due to a faulty amalgamator, the need for using a piece of chamois to obtain a homogeneous amalgam and remove excess mercury; the existence of combined hazards in the environment, and that all workers had been exposed since 1992. Results for workers' health showed a prevalence of symptoms from lesions to the central nervous system; central nervous system signs; and that mild-to-moderate chronic poisoning was found in 62.5% of workers.