NOTE: 1 µg = 1 microgram = 1 x 10-6
grams
The U.S. Environmental Protection Agency safety
limits for mercury vapor exposure are 10 µg per day.
Numerous studies have shown that mercury amalgam
fillings release anywhere from 1 to 29 µg/day, 3 times
the limit. The rate of mercury release from dental
amalgam is dependent upon several factors including the
number of amalgam restorations, the composition of the amalgam (high vs. low copper
amalgam), the location (occlusal vs. nonocclusal teeth),
and the amalgam surface area.
For more information on the release of mercury from
dental amalgam fillings as well as the contribution of
dental amalgam to the mercury body burden, please see Release
of Mercury from "Silver" Dental Amalgam
Mercury concentrations in urine
and whole blood associated with amalgam exposure in a US
military population.
Kingman A, Albertini T, Brown LJ.
J Dent Res 1998 Mar;77(3):461-71
http://www.ncbi.nlm.nih.gov/entrez/PubMed_uids=9496919=Abstract
Oral Health Promotion, Risk Factors and Molecular
Epidemiology Branch, National Institute of Dental
Research, Bethesda, Maryland 20892, USA.
Minute amounts of mercury vapor are released from
dental amalgams. Since mercury vapor is known to be
associated with adverse health effects from
occupationally exposed persons, questions regarding the
margin of safety for exposure to mercury vapor in the
general population continue to be raised. To address
this issue, one needs information regarding exposure to
mercury vapor from dental amalgam fillings and its
possible consequences for health in the general
population. The NIDR Amalgam Study is designed to obtain
precise information on amalgam exposure and health
outcomes for a non-occupationally-exposed population of
US adults. One hypothesis was that in a generally
healthy population a significant association between
amalgam exposure and Hg levels in urine and/or whole
blood could be detected. The cohort investigated was an
adult military population of 1127 healthy males. Their
average age was 52.8 years, and their ages varied from
40 to 78 years. Ninety-five percent of the study
participants were white males, and slightly over 50% had
some college education. Five percent were edentulous.
The dentate participants, on average, had 25 natural
teeth, 36.9 decayed or filled surfaces (DFS), and 19.9
surfaces exposed to amalgam, with amalgam exposure
varying from 0 to 66 surfaces. Their average total and
inorganic urinary mercury concentrations were 3.09
microg/L and 2.88 microg/L. The average whole-blood
total and inorganic mercury concentrations were 2.55
microg/L and 0.54 microg/L. Significant
correlations were detected between amalgam exposure and
the total (r = 0.34, p < 0.001) and inorganic 0.34 (r
= 0.34, p < 0.001) urinary mercury concentrations on
the original scale. Stronger correlations were found for
total (r = 0.44, p < 0.001) and inorganic (r = 0.41,
p < 0.001) urinary Hg on the log scale, as well as
for creatinine-corrected total (r = 0.43, p < 0.001)
and inorganic (r = 0.43, p < 0.001) urine
concentrations. In whole blood, statistically
significant, but biologically weak, correlations were
detected for total (r = 0.09, p = 0.005) and inorganic
(r = 0.15, p < 0.001) Hg concentrations,
respectively. Based on these cross-sectional
data, it is estimated that, on average, each ten-surface
increase in amalgam exposure is associated with an
increase of 1 microg/L mercury in urine concentration.
Dental
Information 
