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are likely to include variants that contribute to to replace amalgam fillings with less toxic Mercury
susceptibility. Candidate genes are involved alternatives must evaluate dentists’ use of ad-
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not only in methylation and detoxification, but equate protective measures. The International levels in
in vitamin and mineral (i.e., enzyme cofactor) Academy of Oral Medicine and Toxicology amniotic
absorption, transport and metabolism. Unfor- (IAOMT), a professional dental organization, fluid, cord
tunately, policy makers, health authorities and has developed a protocol and training program
the dental industry have yet to consider the issue that attempts to minimize the exposure to mer- blood,
of genetic susceptibility. Indeed, for millions of cury vapor to the patient, dentist and staff during placental
children and adults covered by subsidized dental amalgam removal. In women of childbearing tissue and
programs (including military family dental care age, removal of amalgam should be timed so
and Native American services), amalgam is still as to avoid the twelve to eighteen months pre- breast
virtually the only option for dental restorations. ceding conception as well as pregnancy and milk are
In 2009, despite much scientific evidence to breastfeeding. significantly
the contrary, the U.S. Food and Drug Admin-
istration (FDA) reiterated the safety of dental DIETARY FISH associated
amalgam. As of 2016, public interest groups Natural releases of mercury from the in a dose-
are challenging this “final amalgam rule” in Earth’s crust and the oceans account for 60 to 70 dependent
federal court. Issues to be litigated include percent of the annual releases of mercury to the
whether amalgam is deemed an implant, which atmosphere. The remaining 30 to 40 percent is manner with
would require manufacturers to provide proof attributable to human activities. Once released the number
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of safety, and whether the toxicity warnings that into the atmosphere through either natural or hu- of maternal
are given to dentists via labeling requirements man activities, mercury is deposited in soil and
should also be given to patients. Norway, Den- water, where it enters the food chain. Mercury dental
mark and Sweden have banned dental amalgam, accumulates in fish, particularly large, long- amalgam
and as of May 2015, a scientific committee of lived ocean fish. fillings.
the European Commission recommends that Mercury levels in fish vary widely by
non-mercury alternatives be used in fillings for species and by individual, ranging from less
pregnant women and children. than 0.1 part per million (ppm) for salmon and
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In fact, fetal neurons are more sensitive to sardines to more than 1 ppm for some samples
the toxic effects of mercury than any other cell of tilefish, shark, swordfish and king mack-
type. Mercury from the mother’s body readily erel. A typical 3.5-ounce (one-hundred-gram)
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crosses the placenta and accumulates in the serving of fish could contain anywhere from a
fetus, as revealed in postmortem human and few to more than one hundred micrograms of
animal studies. In tissue culture, clear effects mercury. Tuna contains moderate levels, which
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on nerve growth arise at mercury concentra- vary by species. The FDA sets an action level
tions equivalent to those found in newborns for mercury contamination in commercial fish
of amalgam-bearing mothers with no other of 1 ppm. This means that federal officials are
known exposures. Furthermore, mercury levels allowed to confiscate products that exceed this
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in amniotic fluid, cord blood, placental tissue threshold—but it does not mean that they actu-
and breast milk are significantly associated in ally do so.
a dose-dependent manner with the number of Due to natural releases of mercury, hu-
maternal dental amalgam fillings. Human mans have always encountered some mercury
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and animal studies show increased rates of in certain fish. As long as the body’s natural
miscarriage, neonatal death, low birth weight defense systems are working, one can con-
and developmental disorders associated with sume mercury-containing fish in moderation.
mercury exposure. In healthy individuals, intestinal metallothio-
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As if the cumulative effects of ongoing neins (a class of metal-storage molecules that
amalgam exposure were not enough, unsafe can be cumulatively damaged by mercury) can
amalgam removal also can cause acute expo- sequester ingested mercury and slowly allow
sures to mercury vapor. Thus, patients wishing its excretion. Selenium, discussed below, also
SPRING 2018 Wise Traditions 17