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FDA Advisers Reject Safety Report on Dental Fillings

Mercury-containing amalgams need further study, they contend

THURSDAY, Sept. 7, 2006 (HealthDay News) -- Federal health advisers have rejected a government report suggesting that mercury-containing amalgam dental fillings are safe, saying instead that further study is needed.

The U.S. Food and Drug Administration advisory panel's decision is not a declaration that the widely used fillings are unsafe, the Associated Press reported late Thursday. However, in a 13-7 vote, the panel said a large federal review of data fails to clearly and objectively present the current body of knowledge on the subject.

In a second vote, also 13-7, the panelists said the report's conclusion that amalgam fillings are safe is not reasonable, according to the AP.

The announcement came after FDA committee meetings held Wednesday and Thursday --the first public hearings in more than a decade on the safety of these fillings.

The FDA is not compelled to act on the advice of its advisory committees, although it frequently does.

Dental amalgam contains elemental mercury combined with other metals such as silver, copper, tin and zinc. The fillings, about 50 percent mercury, have been used for generations to stabilize decaying teeth. Dental experts contend that when mercury is bound to the other metals it's encapsulated and doesn't pose a health risk. Consumer groups, however, contend that mercury, a known neurotoxin, does leak out in the form of mercury vapor and then gets into the bloodstream.

According to the American Dental Association (ADA), the use of amalgam is declining. In 1990, dental amalgams made up 67.6 percent of all dental restorations, by 1999 45.3 percent and, in 2003, an estimated 30 percent. Cavities that previously would have been treated with dental amalgam are now mostly filled with a resin composite.

Several European and other countries, including Canada, Norway, Sweden, Britain, Germany and Denmark, currently advise dentists against using mercury fillings in pregnant women.

The ADA, however, said the recommendation was made despite there being no scientific evidence of systemic health problems or toxic effects.

The ADA maintains its position that dental amalgam should remain an option for patients.

"Our position is one of looking at the scientific evidence and believing it's safe and effective and that dentists and patients should have the option," said Dr. Ron R. Zentz, senior director of the ADA Council on Scientific Affairs.

Zentz pointed, in particular, to two studies (the Children's Amalgam Trials) published in the April issue of the Journal of the American Medical Association. Those trials compared the use of amalgam to composite dental fillings in children.

The studies found no differences in IQ, memory, attention, kidney function or other measures between children with amalgam fillings and children with composite fillings.

The fillings may even be superior to other materials in certain instances, such as in the back of the mouth where the forces and stress on the fillings are stronger, Zentz said.

According to the Associated Press, officials at the FDA also asked committee members to carefully review findings from an internal agency "meta-analysis" of 34 recent studies. That review found "no significant new information" that might change the FDA's conclusion that amalgam fillings pose no harm to the vast majority of patients.

Earlier on Thursday, one consultant to the panel said the review fell short. "Just by looking at this paper, we are in a sense really limiting ourselves. I am not convinced we are doing justice to the topic at hand," Vanderbilt University professor of pediatrics and pharmacology Michael Aschner told the AP.

Several groups are vehemently opposed to the use of these fillings.

On Sept. 5, a consortium of organizations including Consumers for Dental Choice, the Mercury Policy Project and the International Academy of Oral Medicine and Toxicology filed a petition to the FDA to immediately ban mercury fillings for pregnant women so as to protect their unborn children. The FDA has six months to respond to the petition.

"We're doing this primarily as a precautionary measure to protect unborn children from unnecessary exposure to mercury," said Michael Bender, director of the Mercury Policy Project, located in Montpelier, Vt. "We're very concerned that our government is not doing what it should to protect the unborn."

"Why isn't the FDA joining Health Canada and the other countries in banning the placement in expectant mothers?" he continued. "FDA silence over mercury is the same kind of silence our government once had for tobacco."

Still, any ban could have consequences. A study by dentist Howard Bailit and colleagues at the University of Connecticut found that a ban on amalgam fillings would boost costs, cut down on cavities filled and hurt America's oral health.

"Our recommendation is, do not ban the use of dental amalgams," Bailit told the Associated Press.

More information

To learn more about amalgam fillings, visit the U.S. Centers for Disease Control and Prevention.

SOURCES: Ron R. Zentz, D.D.S., senior director, American Dental Association Council on Scientific Affairs; Michael Bender, director, Mercury Policy Project, Montpelier, Vt.; ADA statement; International Academy of Oral Medicine and Toxicology, news release; Sept. 7, 2006, Associated Press
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