Prenatal exposure to dental amalgam

Background.

Dental amalgams contain approximately 50
percent metallic mercury and emit mercury vapor during the life of
the restoration. Controversy surrounds whether fetal exposure to
mercury vapor resulting from maternal dental amalgam
restorations has neurodevelopmental consequences.

Methods

The authors determined maternal amalgam restoration
status during gestation (prenatal exposure to mercury vapor [Hg0])
retrospectively in 587 mother-child pairs enrolled in the Seychelles
Child Development Study, a prospective longitudinal cohort study of
the effects of prenatal and recent postnatal methylmercury (MeHg)
exposure on neurodevelopment. They examined covariate-adjusted
associations between prenatal maternal amalgam restoration status
and the results of six age-appropriate neurodevelopmental tests
administered at age 66 months. The authors fit the models without
and with adjustment for prenatal and recent postnatal MeHg
exposuhttp://beta.blogger.com/img/blank.gifre metrics.

Results

The mean number of maternal amalgam restorations
present during gestation was 5.1 surfaces (range, 1-22) in the 42.4
percent of mothers who had amalgam restorations. The authors
found no significant adverse associations between the number of
amalgam surfaces present during gestation and any of the six
outcomes, with or without adjustment for prenatal and postnatal
MeHg exposure. Results of analyses with the secondary metric,
prenatal amalgam occlusal point scores, showed an adverse
association in boys only on a letter- and word-identification subtest
of a frequently used test of scholastic achievement, whereas girls
scored better on several other tests with increasing exposure.
Conclusions. This study’s results provide no support for the
hypothesis that prenatal Hg0 exposure arising from maternal dental
amalgam restorations results in neurobehavioral consequences in
the child.