Mercury filling faces controversy again

A joint panel of outside experts Thursday rejected a FDA report that concluded dental fillings used by dentists to fill in patient's cavities are safe, saying further study of the mercury-laden mixture is needed.

A mercury amalgam that has stirred controversy since dentists started using it to fill cavities in the 1800s is once again facing the disagreement on its use. Mercury, which is toxic to humans, is mixed with other metals to form the amalgam. The metal can cause neuro-developmental deficits in children and motor problems in adults at high doses. Dental experts have long believed that fillings do not expose most patients to meaningful mercury levels.

A pair of federal reports in 1993 and 1997 concluded that mercury fillings causes no serious health risks to patients. A draft FDA report issued this week supported those conclusions, stating that no new information has come to light to prove them to be false.
In a 13-7 vote yesterday, the federal panel said the report did not objectively and clearly present the current state of knowledge about the fillings.

However, the panel did not go so far as to state the mercury-laden amalgam a danger and just recommended that more study is needed because of the risk it poses to some groups.

The US health safety agency, Food and Drug Administration (FDA) had asked the panel of outside advisors to weigh the report, a review of 34 recent research studies.

"For the general population, amalgams are safe. There is evidence of that," said Karl Kieburtz, a University of Rochester professor and chairman of one of the two panels brought together by the FDA. Still, Kieburtz and other panelists said remaining uncertainties about the risk the fillings may pose to some groups urged further study.

Especially, research is needed on the effect of dental mercury on children, the fetuses of pregnant women with fillings and others whose bodies may absorb, distribute, process and eliminate mercury differently, panelists including Kieburtz said.

"There are too many things we don't know, too many things that were excluded," said Michael Aschner, a professor of pediatrics and pharmacology at Vanderbilt University and a panel consultant, who cast two "no" votes.

A study of 534 children published in the Journal of the American Medical Association (JAMA) in April found no appreciable effect of amalgam fillings on IQ scores. On contrary several European studies suggesting high mercury levels in some filling wearers have gained increased scrutiny from regulators there.

Influenced with the further study proposal, Dr. Norris Alderson, the FDA's associate commissioner for science, told the panel, "We are going to take the recommendations, your comments, and we will start evaluating the next steps, with the white paper and this whole issue of dental amalgam."