Mercury Exposure Levels in Children with Dental Amalgam Fillings

Objectives: Mercury combined with other metals to form solid amalgams has long been used in reconstructive dentistry but its use has been controversial since at least the middle of the 19th century. The exposure and body burden of mercury reviews have consistently stated that there is a deficiency of adequate epidemiological studies addressing this issue. Fish and dental amalgam are two major sources of human exposure to organic (MeHg) and inorganic Hg respectively. Materials and methods: A total of 150 subjects aged between 9 and 14 years were divided into two groups of 75 subjects each depending on their diet, i.e. seafood or nonseafood consum-ing. Each category was subdivided into three groups based on number of restorations. Scalp hair and urine samples were collected at baseline and 3 months later to assess the organic and inorganic levels of mercury respectively by atomic absorp-tion spectrophotometer (AAS). Results: The mean values of urinary mercury (inorganic mer-cury) in the group of children with restorations were 1.5915 µg/l as compared to 0.0130 µg/l in the groups with no amalgam restorations (p < 0.001) (Wilcoxon sign rank test and paired t-test). The hair mercury levels (organic mercury) varied signi-ficantly between the fish-eating group and nonfish-eating group, the average values being 1.03 µg/l and 0.84 µg/l res-pectively (p < 0.001) (Mann-Whitney U-test and paired t-test). Conclusion and significance: The notion about the mercury being released from the amalgam restorations as a sole expo-sure source needs to be put to a rest, as environmental factors collectively overpower the exposure levels from restorations alone