Mercury exposure due to environmental factors and amalgam restorations in a sample of North Carolina children

Purpose: Dental amalgam restorations provide a potential source for mercury (Hg) exposure in children. This study explored the possibility that Hg levels in dentin of exfoliated primary maxillary canines could detect cumulative Hg exposure from amalgam restorations in a sample of North Carolina children. Methods: Twenty-seven exfoliated maxillary canines from 33 children, without restorations or caries, were assayed for dentin Hg concentration ([Hg]). Urine samples were obtained from 21 subjects and assayed for [Hg] and diet surveys for seafood ingestion were completed for 26 subjects. A surface/month exposure index (SMEI) was compiled from dental records to quantify each child’s cumulative exposure to amalgam restorations. Results: Results showed that dentin [Hg] ranged from undetectable levels to 15.7 ppm with a mean of 3.7 ppm. The SMEI scores ranged from 0‐638 with a mean of 95. Ten subjects had low SMEI scores of 0‐3, nine had scores 4‐100, and eight had scores higher than 100. No statistical correlation was found for SMEI scores and dentin [Hg]. Urine Hg levels were found to be negligible and no relationship was found between urine [Hg] and reported ingestion of seafood or SMEI scores. Conclusions: Hg exposure in this sample of children was low and additional exposure from amalgam restorations could not be detected by the methods used in this study. (Pediatr Dent 21:114‐117, 1999)