Despite presence of a toxin, the American Dental Association says amalgam fillings are safe
By Abe Proctor Of The Skanner
The fillings that are installed in the mouths of low-income kids during an annual dental health day — and in the mouths of millions of other Americans every year — are unsafe, two local activists said.
Amalgam fillings — commonly referred to as “silver” fillings — are given to hundreds of Portland kids every year during Give a Kid a Smile Day, a program put on by local affiliates of the American Dental Association and corporate and nonprofit sponsors. They are also the most common fillings in dentists’ offices around the country and have been in use for more than 100 years. The fillings are composed of approximately 50 percent mercury, a known neurotoxin and considered among the most toxic non-radioactive elements on Earth.
The American Dental Association, however, maintains that amalgam fillings are safe. Its official statement on dental amalgam — posted on its Web site, ada.org — claims that the other metals in the fillings bind with mercury in such a way as to render the fillings “into a hard, stable, safe substance.”
Mercury is associated with a range of disorders, including autism, epilepsy, fibromyalgia and multiple sclerosis, as well as certain cancers, heart and kidney problems, muscular and respiratory ailments and changes in vision and hearing. In pregnant women, exposure to elevated mercury levels can result in fetal abnormalities.
“We are concerned about mercury in tuna, and there are now advisories that pregnant women should limit their tuna consumption because they shouldn’t expose their unborn child to mercury,” said Caroline Skinner of Mothers Against Mercury Amalgam — MAMA — an organization of women concerned about exposure to mercury through dental fillings.
“If mercury is being placed in the human mouth, shouldn’t we be concerned about that, too?”
Amalgam fillings are composed of roughly half liquid mercury (43 percent to 54 percent) and half a mixture of other materials, including silver, tin and copper (57 percent to 46 percent), according to the Centers for Disease Control and Prevention. Many dentists favor its use because of its malleability and its cost-effectiveness when compared to alternate materials such as gold or pure silver.
Jack Ferracane, Ph.D., chair of restorative dentistry at Oregon Health &Science University — one of the sites of the annual Give a Kid Smile Day believes that amalgam fillings are safe.
“It’s been in use for a long time,” he said. “Mercury is a poison, but it’s always a question of dosage. The amount of mercury released by amalgam fillings doesn’t pose a health risk.”
Ferracane added that many studies have been conducted in an attempt to link amalgam with mercury-induced ailments, but that none have conclusively proven a health risk.
OHSU’s Prashant Gagneja, D.D.S. — who coordinated this year’s Give a Kid a Smile Day event — also stands behind the safety and ease of amalgam fillings. However, he said that fewer amalgam fillings were installed during this year’s event than in previous years, with more patients — and their parents — opting for composite fillings instead.
“In pediatric dentistry … amalgam is easier and faster to place on the child,” Gagneja said, adding that composite materials have grown in popularity because they are far less visible in the mouth than amalgam. “For children, we are tending to use more composite, not because we’re concerned about amalgam’s toxicity — because I think it’s pretty safe — but because of aesthetics.”
Gagneja said he thinks that concerns about amalgam’s health risks are “overblown.”
“Once the amalgam sets, there’s hardly any free mercury in it,” he said. “The free mercury that everybody talks about as causing health problems is so little in the filling itself … it doesn’t cause health problems. … Mercury itself is toxic, I highly agree with that, but with the fillings themselves, I don’t think the assumption (of mercury poisoning from amalgam fillings) holds up.”
The American Dental Association admits that a minute amount of mercury (one to three micrograms) is released into the mouth from a single filling every day as a result of chewing and grinding but that this level of exposure does not constitute a health risk.
“(Dental patients) should feel very secure that the many organizations responsible for protecting the public’s health have said time and time again that amalgam fillings are safe,” the site said. “Those organizations include the World Health Organization, United States Public Health Service, the National Institutes of Health and the Food and Drug Administration.”
The site provides a link to a World Health Organization report that reads, “At present, there is scant evidence that the health of the vast majority of people with amalgam is compromised.”
However, the same report goes on to say that a lack of definitive research on amalgam leaves the question of its toxicity effectively unresolved: “Nonetheless, the possibility that this material … could pose health risks cannot be totally ruled out because of the paucity of definitive human studies.”
Further, the report states that the lack of data on amalgam’s toxicity necessitates the launch of a research program on the subject.
Despite the American Dental Association’s assurances, Skinner is among a growing number of citizens concerned about the routine and widespread use of a toxic substance in the human body. Among them is the National Association for the Advancement of Colored People, which in 2001 voted to support The Mercury in Dental Fillings Disclosure and Prohibition Act.
The bill, written by Reps. Diane Watson, D-Calif., and Dan Burton, R-Ind., was introduced to Congress in 2003 as HR 1680 and calls for full disclosure of the presence of mercury in fillings and protection for women and children against the fillings’ installation. The bill has since been referred to the House Subcommittee on Health.
In California, Assemblyman Dan Horton, D-Los Angeles, chair of the state Legislature’s Black Caucus, wrote a bill ending the practice that mandated that amalgam fillings be installed in the mouth of any low-income child receiving a subsidized filling. The bill was signed into law in 2003 by Gov. Gray Davis before he left office.
Sandy Duffy, also a member of MAMA, said that if dental patients are concerned about mercury exposure, they should insist upon mercury-free fillings. Many dentists, she said, make a point of advertising that they run mercury-free offices.
Duffy cited a University of Washington study that found high incidences of neurological problems among dentists with elevated mercury levels in their urine.
“The federal government’s definition of ‘safe levels’ of mercury is just too high,” she said. “If dentists and patients are developing problems due to mercury, then it needs to be abandoned. Mercury is at least 40 times more toxic than lead, and we would never start packing lead in kids’ mouths.”
According to the World Health Organization, the primary source of mercury exposure to the general population is through amalgam fillings. A toxicology profile for mercury prepared by the Agency for Toxic Substances and Disease Registry in 1999 stated that “children may have greater exposure and greater risks from mercury.”
The federal Environmental Protection Agency lists mercury as a serious environmental toxin and, in addition to its recommendation that people limit their consumption of tuna because of elevated mercury levels, has recommended that coal-burning power plants take steps to reduce their mercury emissions. Mercury is in the process of being phased out from use in thermometers, vaccines, electrical switches and blood pressure machines due to its toxicity.
“When a mercury filling is removed, it’s classified by law as hazardous waste,” Skinner said. “Why is it not hazardous when it’s put in?”
