Mercury fillings have been around since around 1890. In the early 1900s, German chemist, Alfred Stock warned of mercury toxicity from the fillings. So the mercury fillings and the controversy surrounding them are not new. Mercury fillings contain 50 parts mercury, 35 parts silver and 10 parts tin, copper and zinc. In spite of the propensity of the dental profession to call amalgam fillings “silver”, more than 50% of the material in them is mercury, which is toxic.

Dental Teeth Filling Dentists Xray ScanThe American Dental Association has long held the belief that amalgam fillings became inert after a few days and were safe. Currently the ADA recognizes that there is some absorption from amalgam fillings, but they are still safe. The FDA recommends not placing mercury fillings in children under the age of six. The FDA has produced a lengthy report (posted on its website) that discusses the amount of mercury absorbed from fillings, the effects of mercury toxicity and methods of testing. The report cites a study performed at the University of Tubingen Health Clinic, involving 20,000 subjects with mercury fillings. On average the amount of mercury found in saliva was 11.6 mcg/L; gum chewing could triple that figure. Also, those subjects with multiple fillings tended to have higher levels. Some subjects had extremely high levels, with 1% having more than 200 mcg/L and 10% having more than 100 mcg/L.

According to research appearing in the Journal of Dental Research (1992;71(AADR Abstracts);284/1424) found that polishing fillings increased the mercury released from the fillings. A filling with a surface area of 25 square millimeters released over 3x more mercury vapor after being polished.

A study appearing in the Archives of Environmental Health (May/June, 1996;51(3):234-241) evaluated the amount of mercury in blood, hair and Extracted teeth with details of cariesbreast milk in 30 Swedish women six weeks after giving birth. Researchers found that the amount of inorganic mercury in the blood and breast milk correlated with the number of mercury fillings. The exposure of infants to mercury from breast milk was found to be about half of the tolerable daily intake for adults recommended by the World Health Organization.

Research appearing in Biological Trace Element Research (1997;56:143-152) looked at mercury absorption from amalgams in pregnant sheep. Three ewes were given 12 mercury amalgams, containing radioactive mercury, while three other ewes (not given amalgam fillings) acted as controls. The lambs born of the ewes with the fillings had mercury (which was found primarily in the liver). Breast feeding provided the newborn lambs with additional mercury, found primarily in the kidney. Mercury crosses the placenta and into the fetus. Mercury also crosses into the breast milk.

Cadavers were examined in research appearing in the Journal of Prosthetic Dentistry (1987;58(6):704-707) to find the relationship between the number of amalgam fillings and the presence of mercury in nerve tissue. The data showed a positive correlation between the number of fillings and the amount of mercury found in brain tissue.

Clearly there is a relationship between mercury fillings and the absorption of mercury into the body. Also, the amount absorbed seems to vary between patients, but there is a correlation between the number of fillings and the amount of mercury absorbed. Mothers can pass the mercury on to the fetus. There currently is controversy surrounding the presence of mercury in vaccines and the increase in autism. Some experts make much of the fact that autism did not exist before the advent of vaccines in the 1940s. It might be worth noting that, although mercury amalgams have been around for 150 years, their use became widespread in the 1930s. If there is a connection between autism and mercury toxicity, it may be worth looking into mercury fillings.