By David Wahlberg - Staff
Atlanta-Journal
http://www.ajc.com
December 9, 2004
Mercury in dental fillings has not been proved to cause kidney, brain or immune system damage, as critics charge, says a report funded by the National Institutes of Health.
But the report is being released today under controversy. The NIH is investigating whether its dentistry institute improperly awarded the research contract, allegedly to uphold the American Dental Association's stance that mercury fillings are safe.
The Life Sciences Research Office, a Washington-based nonprofit group, conducted the research on behalf of the National Institute of Dental and Craniofacial Research.
The review of 300 studies over the past eight years said that the mercury absorbed from fillings is not known to cause health problems alleged by critics, such as Alzheimer's disease, Parkinson's disease, multiple sclerosis or kidney dysfunction.
Other countries, including Austria, Canada, Denmark, Germany and Sweden, have banned or discouraged mercury fillings, especially in children and pregnant women. Some Americans have had their mercury fillings replaced with plastic ones.
Mercury filling critics, including at least one U.S. senator, say the dental institute issued the contract without proper bidding. Dr. Elias Zerhouni, NIH director, this summer launched an internal investigation that continues, a spokesman said.
Lawyer Charles Brown of Consumers for Dental Choice contends the institute is controlled by dentists who favor mercury fillings and ought not be in charge of such research. His group, along with Sen. Frank Lautenberg (D-N.J.), complained to the NIH, questioning the dentists' motives. Neurologists, not dentists, should lead the way, Brown said.
"It's not about whether the fillings stick properly to the tooth," he said. "It's about whether they cause brain damage to children."
But Lawrence Tabak, the institute's director, said the report was conducted fairly and independently. "To suggest that there is a conflict of interest in dentists' participating in research in this area makes no more sense than saying that oncologists should not participate in research on cancer treatment," he said.
The Life Sciences Research Office said its experts included toxicologists, immunologists and pediatricians --- and no dentists --- to ensure "a fresh and unbiased approach."
Mercury fillings have been around for more than a century, but the debate over possible health effects largely erupted a decade ago. Many dentists refer to the fillings as "silver," but they are an amalgam of half mercury and the other half a mixture of silver, copper, tin and zinc.
Even supporters agree that the fillings release mercury vapor into the body, but in nonharmful trace amounts. Critics say mercury is a known neurotoxin and that plastic fillings are a safe alternative.
"Regardless of the dose, you end up over time with an accumulation of mercury in two critical organs, the kidneys and the brain," said San Diego dentist David Kennedy of the International Academy of Oral Medicine and Toxicology.
But Rod Mackert, a dentistry professor at the Medical College of Georgia and an American Dental Association spokesman, said mercury fillings emit 1 to 3 micrograms of mercury a day, compared with the 5 to 6 micrograms people take in daily through food, water and air. "The levels absorbed . . . are far below those that would cause even the most subtle changes in the most sensitive individuals," he said.
Mackert said plastic fillings may also leak hazardous substances into the body, such as xenoestrogens, which can disrupt cell activity. "All materials have their baggage," he said.
The new report finds no general evidence of health hazards, but it says people with mercury allergies should avoid the fillings and that the use of nicotine chewing gum could increase the amount of mercury vapor released.