WebMD Medical News
Louise Chang, MD
Dec. 15, 2010 -- An advisory panel today recommended that the FDA examine all relevant evidence in reviewing its 2009 ruling that mercury-containing fillings known as dental amalgams are safe.
The agency needs to look at “not just certain studies but all scientifically sound studies,” said panel member Judith Zelikoff, PhD, of the Institute of Environmental Medicine in Tuxedo, N.Y.
At issue over the two-day meeting, which concluded today, were questions raised about how the agency reached its decision in July of last year. In four petitions, members of consumer and dental groups criticized the FDA’s decision-making progress, arguing that the agency had used flawed and insufficient data to draw conclusions about safety.
The panel, which generally held that amalgams are safe for most people, did agree that there is not enough data to rule out the possibility that a small but significant number of people might be at risk from exposure to mercury in the fillings.
Existing studies “provide compelling evidence that there is no effect level for the general population,” said panelist Susan Griffin, PhD, of the EPA, “but there does appear to be a very sensitive subpopulation.”
Several such people testified during the open hearing portion of today’s meeting.
“I was a dental assistant for 24 years, now I get $700 a month in disability payments,” said Karen Burns, who told the panel that exposure to mercury in the workplace had led to crippling, career-ending symptoms. Her story was echoed by several other public speakers who also told the panel that they or family members had suffered from mercury poisoning.
High levels of exposure to mercury can cause brain and kidney damage. Memory and hearing loss are symptoms associated with mercury poisoning, as are tremors, irritability, mood swings, insomnia, and headaches.
“My brain started vibrating inside my skull as if it were trying to get out,” Marie Flowers told the panel of her experiences after amalgams were implanted in her mouth. Flowers spoke on behalf of Dental Amalgam Mercury Solutions, a group formed to educate the public on what it considers the risks of mercury-based fillings.
Several dentists, and one dental student, spoke in support of dental amalgams and the FDA’s ruling that declared them safe.
“In the absence of new evidence, no reason to reconsider the decision that was made last year,” Andrew Read-Fuller, a fourth-year dental student at UCLA, told the panel.
The panel spent most of the afternoon discussing questions posed to it by the FDA. The agency sought to learn from the assembled experts how best to measure mercury exposure, how to determine what, if any, level of mercury exposure can be considered safe, and how to weigh the evidence.
Their conclusion: A lot more needs to be learned before any decision can be made. Speaking about how to best to measure the amount of mercury that people with amalgams are exposed to, the panel’s chair cautioned that any model that they came up with would be provisional until sufficient data had been collected.
“It’s going to be a moving target,” said Marjorie K. Jeffcoat, MD, of the University of Pennsylvania.
The panel also talked at length about the limited data on risks to pregnant women and their unborn children, as well as to children under the age of 6. Despite the lack of evidence, panelist and pediatrician Suresh Kotagal, MD, of the Mayo Clinic, was very firm in his conclusions:
“There is no place for mercury in children. The bottom line is, do no harm. We have to start with that and take it from there.”
SOURCES:Dental Products Panel, Medical Devices Advisory Committee Meeting, Dec. 15, 2010, Gaithersburg, Md.Agency for Toxic Substances and Disease Registry: “ToxFAQs for Mercury.”Environmental Protection Agency: “Mercury Health Effects.”
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