Assessment of occupational exposure of dental professionals to mercury in dental offices of a public primary health care in maringá, paraná state, Brazil

Abstract

In order to evaluate the occupational exposure of dental professionals to metallic mercury in dental offices of a public primary health care in the city of Maringá, Brazil, samples of blood and urine were collected from 149 dental professionals (group exposed), and 51 healthy adults similar for age and gender of the exposed group (control group) in September and October, 2008. Urinary mercury was determined using atomic absorption spectrophotometry, urea and creatinine in blood and urine by UV/VIS spectrophotometry and analysis of physical, chemical and microbiological characteristics of the urine by reactive bands. The program 'Statistic' version 7.1 and the software R version 2.6.2 were used for the statistical calculations. Urinary mercury was 2.08 ± 2.11 μg g-1 creatinine in workers exposed to mercury and 0.36 ± 0.62 μg g-1 creatinine in the control group (p < 0.05). Urinary levels of mercury were below the maximum allowed by the biological index established in Brazil (35 μg g-1 creatinine); 11% of these professionals (n = 16) had mercury levels above the reference value (5.0 μg g-1 creatinine), whereas the maximum value found was 13 μg g-1 creatinine. The dental professionals of public primary health care in the city of Maringa was exposed to metallic mercury at levels 5.8 times higher than the non-exposed subjects.