Polychlorinated dibenzo-p-dioxins and dibenzofurans via mother's milk may cause developmental defects in the child's teeth.

Previous studies have shown developmental dental defects in rhesus macaques and rats experimentally exposed to dioxin. Now it was investigated if dioxin exposure from mother's milk in a normal breast-fed child population correlated with enamel hypomineralization of teeth that mineralize during the first 2 years of life. We studied 102 6-7-year-old Finnish children breast-fed for an average of 10.5 months. Milk samples were collected when the child was 4 weeks old. The concentrations of 17 most toxic polychlorinated dibenzo-p-dioxin and furan congeners were determined. The total exposure to dioxins was calculated from the concentrations in milk and the duration of breast feeding. Hypomineralization of the target teeth was found in 17 children. Both the frequency and severity of the lesions correlated with the total exposure. The results suggest that at the prevailing levels in human milk, dioxin may be an important cause of hypomineralization in the developing teeth of children.