Neurodevelopmental outcomes at 5 years in children exposed prenatally to maternal dental amalgam: The Seychelles Child Development Nutrition Study

Abstract

Limited human data are available to assess the association between prenatal mercury vapor (Hg0) exposure from maternal dental amalgam restorations and neurodevelopment of children. We evaluated the association between maternal dental amalgam status during gestation and children’s neurodevelopmental outcomes at 5 years in the Seychelles Child Development Nutrition Study (SCDNS). Maternal amalgam status was determined prospectively in a longitudinal cohort study examining the associations of prenatal exposure to nutrients and methylmercury (MeHg) with neurodevelopment. A total of 236 mother-child pairs initially enrolled in the SCDNS in 2001 were eligible to participate. Maternal amalgam status was measured as number of amalgam surfaces (the primary metric) and number of occlusal points. The neurodevelopmental assessment battery was comprised of age-appropriate tests of cognitive, language, and perceptual functions, and scholastic achievement. Linear regression analysis controlled for MeHg exposure, maternal fatty acid status, and other covariates relevant to child development. Maternal amalgam status evaluation yielded an average of 7.0 surfaces (range 0–28) and 11.0 occlusal points (range 0–40) during pregnancy. Neither the number of maternal amalgam surfaces nor occlusal points were associated with any outcome. Our findings do not provide evidence to support a relationship between prenatal exposure to Hg0 from maternal dental amalgam and neurodevelopmental outcomes in children at 5 years of age.

Dental associations with blood mercury in pregnant women

“…This has been tested in two birth cohort studies. (i) In the Seychelles, a detailed study showed no effect of the number of amalgams in pregnancy and child motor development at 9 and 30 months or neurodevelopment at age 5 years; there were no adverse associations with educational achievement, language or other cognitive outcomes at 5 years old. (ii) An analysis of the ALSPAC cohort demonstrated no relationship between speech and language development at 15 months and any measure of prenatal DA exposure.…”

Prenatal exposure to dental amalgam and pregnancy outcome

“…Studies on fetal mercury exposure from amalgam fillings have focused on possible effects on neurodevelopment. It is also of interest to include other birth outcomes in studies dealing with prenatal mercury exposure.…”

Prenatal chemical exposures and child language development

“…In both the Seychelles main and follow-up cohorts, no associations were found between maternal amalgam history and expressive or receptive language as measured by the PLS (Watson et al, 2011; Watson et al, 2013). In the follow-up cohort, there was also no association between maternal amalgam history and verbal knowledge as measured by the Kaufman Brief Intelligence Test at 5 years of age (Watson et al, 2013). …”

“…The follow-up cohort was established to assess the effects of prenatal MeHg exposure, while controlling for the beneficial influence of a diet high in ocean fish. Researchers have also assessed the association between maternal dental amalgam (which contains a less toxic form of mercury) and neurodevelopmental outcomes in the Seychelles cohorts (Watson et al, 2011; Watson et al, 2012; Watson et al, 2013). Discussed here are results from the Seychelles, Faroe Islands, and other cohort studies that have assessed prenatal MeHg exposure and neurodevelopment.…”