No Neurological Effects From Dental Amalgams

Environ Health Perspect 2003 May;111(5):719-23
Mercury derived from dental amalgams and
neuropsychologic function.
Factor-Litvak P, Hasselgren G, Jacobs D, Begg M,
Kline J, Geier J, Mervish N, Schoenholtz S, Graziano J.
Department of Epidemiology and Department of
Environmental Health Sciences, Mailman School of
Public Health, Columbia University, New York,
New York, USA.

There is widespread concern regarding the safety
of silver-mercury amalgam dental restorations,
yet little evidence to support their harm or safety.
We examined whether mercury dental
amalgams are adversely associated with cognitive
functioning in a cross-sectional sample of
healthy working adults. We studied 550 adults,
30-49 years of age, who were not occupationally
exposed to mercury. Participants were representative
of employees at a major urban medical
center. Each participant underwent a neuropsychologic
test battery, a structured questionnaire, a
modified dental examination, and collection of
blood and urine samples. Mercury exposure was
assessed using a) urinary mercury concentration (UHg);
b) the total number of amalgam surfaces;
and c) the number of occlusal amalgam surfaces.
Linear regression analysis was used to estimate
associations between each marker of mercury
exposure and each neuropsychologic test,
adjusting for potential confounding variables.
Exposure levels were relatively low. The mean UHg
was 1.7 micro g/g creatinine (range, 0.09-17.8);
the mean total number of amalgam surfaces was
10.6 (range, 0-46) and the mean number of
occlusal amalgam surfaces was 6.1 (range, 0-19).
No measure of exposure was significantly associated
with the scores on any neuropsychologic
test in analyses that adjusted for the sampling
design and other covariates. In a sample of healthy
working adults, mercury exposure derived from
dental amalgam restorations was not associated
with any detectable deficits in cognitive or fine motor
functioning.