Mercury levels in hair samples of dentists: A comparative study in Sri Lanka.
Elemental mercury is widely used in dentistry as dental amalgam. Hair samples constitute preferred biomarkers to determine the index of mercury exposure. In the absence of any published studies, the aim of the present study was to ascertain the level of mercury in a selected sample of dentists and controls in Sri Lanka. Hair samples (.7 g) from dentists working in and around the Colombo district in Sri Lanka (n = 50) and controls (n = 50) were digested with sulfuric acid-potassium permanganate solution, and reduced to metallic mercury with stannous chloride. Digested samples were analyzed for mercury using an atomic absorption spectrophotometer. The average mercury contents of the test and control samples (n = 50 each) were 5.36 ± 2.64 ppb and 3.1 ± 1.99 ppb, respectively. Based on the estimated ratio of mercury in hair to blood in humans as 250:1, the average content of mercury in the blood of the two groups could be .02 ppb and .01 ppb, respectively. The number of years in dentistry and number of amalgam restorations performed within 1 week were not correlated with the hair concentration of mercury. As the values of both groups were well below 10 ng/mL (10 ppb), within the concentrations considered as normal, mercury use was not considered an occupational hazard for dentists.