The safety of silver fillings has been debated since the early 1800s.
Dental amalgams are composed of several metals, including liquid mercury and an alloy consisting of silver, tin and copper. According to the FDA, approximately 50 percent of the dental amalgam is elemental mercury by weight. Dental amalgam fillings are also called "silver fillings" because of their appearance. They're used to fill cavities in teeth. The safety of dental amalgams has been debated ever since they were first introduced in the early 1800s.
Mercury Vapor
Elemental mercury releases low levels of mercury vapor that can be inhaled. According to the World Health Organization (WHO), the average person in the industrial world, with an average number of amalgam fillings and no exposure to mercury at work, absorbs between 3 and 17 micrograms per day, with an average of 10 micrograms coming from their amalgams. The Environmental Protection Agency limits the amount of non-occupational exposure to inorganic mercury to 4.8 micrograms per day. The Dept. of Health and Human Services has a limit of 3.2 micrograms per day.
Dangers
Exposure to high levels of mercury vapor is associated with problems in the brain and kidneys. Other possible risks, according to the International Academy of Oral Medicine & Toxicology (IAOMT), include autoimmune reactions, kidney problems, a resistance to antibiotics among intestinal flora and a possible connection to Alzheimer's disease.
Experiment
According to IAOMT, a large body of scientific literature shows mercury from dental amalgams spreads around the body. In one experiment at the University of Calgary Medical School, pregnant sheep were given 12 amalgam fillings filled with radioactive mercury. Researchers collected samples of maternal and fetal blood, amniotic fluid and maternal feces and urine. The researchers found that the amalgam-derived mercury appeared in maternal and fetal fluids within two days of placement. After one month, the concentration of mercury remained steady for the rest of the 140-day course of the experiment, which implied there was ongoing exposure from the fillings.
FDA
As of 2010, the FDA regards dental amalgam fillings to be safe for adults and children ages 6 and older. According to the FDA, mercury levels released by dental amalgam fillings aren't high enough to cause harm. However, the FDA classifies dental amalgams as class II, moderate risk, and recommends that product labels warn dental professionals to use adequate ventilation when handling amalgams. In addition, they suggest that labels include a statement about the scientific evidence on the benefits and risks of dental amalgams. In December 2010, the FDA will hold public hearings to reconsider the safety of dental amalgams.
Allergies
In 1972, the North American Contact Dermatitis Group said that 5 to 8 percent of the US population demonstrated an allergy to mercury by skin patch testing. When using antibody-antigen flocculation tests on blood serum, the figure was more than 90 percent. Allergic people can develop mouth sores in response to dental amalgams, and should not get dental amalgams, according to the FDA.
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