Printable format	E-mail article:	Search news:

By Craig Palmer

Gaithersburg, Md.—A U.S. Food and Drug Administration literature review concludes that "the peer-reviewed scientific information published since 1997 does not substantially change comprehension of the health risk of mercury in dental amalgam compared to previous analyses performed by the U.S. Public Health Service."

"Mercury exposure from dental amalgam is not believed by USPHS agencies and WHO (World Health Organization) to represent levels associated with adverse health effects in humans, including sensitive populations," said the FDA white paper on the literature review.

Experts: Drs. Ismail (left) and Zentz reaffirmed the ADA's position that amalgam is a safe and effective restorative option. (Photo by Bill Geiger)

But joint government advisory panels meeting Sept. 6-7 challenged the literature review as insufficient and called for further benefit-risk research on dental amalgam products regulated by the FDA as devices. FDA convened the dental products panel of the medical devices advisory committee and the peripheral and central nervous system drugs advisory committee in joint session to advise the agency and told the panelists, "You're the experts; help us."

ADA witnesses at the occasionally emotional public hearings reaffirmed the Association's position that dental amalgam is a safe and effective cavity-filling material and said patients should have a choice of restorative options. "If substantial scientific evidence showed that dental amalgam posed a threat to the health of dental patients, we would advise dentists to stop using it," said Dr. Ronald R. Zentz, senior director of the ADA Council on Scientific Affairs.

"Dental amalgam remains a valuable restorative option for dentists and their patients," Dr. Zentz told the FDA advisers. "At present, there is no direct restorative material that works as well as amalgam for large fillings in the back teeth, in very deep fillings, or in fillings below the gum line. Alternatives are often less effective in these situations."

Current scientific evidence does not support an association between dental amalgam and any adverse health effect except for a small number of documented cases involving individuals who were allergic to one of its components, said Dr. Amid Ismail, who chairs the ADA Council on Scientific Affairs. "The ADA is concerned that efforts to eliminate use of dental amalgam will create unwarranted public anxiety, increase disparities and eliminate viable treatment options."

In other Association testimony, Milton Marshall, Ph.D., said his review of the scientific literature supports research that demonstrates "the lack of an association between elemental mercury in dental amalgam and adverse health effects other than a mild, localized allergic response in some individuals. As a toxicologist, my opinion is that the overwhelming body of scientific evidence supports the safety of dental amalgam and there are not adverse effects in children or in adults after long-term exposures other than a mild, localized allergic response in some individuals."

Dental restorative information for patients and dentists is available online at ADA.org, and in various print materials such as the ADA patient brochure entitled, "Choice for Restoring Your Smile," and an ADA-developed chart comparing dental restorative materials. The dental materials chart has been described and offered as a resource for congressional hearings and regulatory agencies including the Food and Drug Administration.

The FDA advisory panels also took testimony from other dental and dental insurance organizations and from individual dentists. Rep. Diane Watson (D-Calif.), who sponsors legislation to phase out use of dental amalgam, and consumer groups opposing use of dental amalgam also testified at the hearings. The FDA also heard testimony on the economic effects of a ban on dental amalgam. A transcript of the proceedings will be posted at the FDA Web site, although the agency gave no indication of when. Hearing materials and the public docket on this proceeding are posted at the FDA site . The advisory panels included dentists, physicians, epidemiologists, pharmacists, toxicologists and other professionals. The panels also included non-voting consultants in their deliberations.

At the end of the day, the advisory panels made no recommendations to the Food and Drug Administration and made a point of it. "There are no official recommendations," Karl D. Kieburtz, M.D., chair of the drugs advisory panel, said in concluding the hearings. "The charge was to comment on the FDA white paper (on the literature review). The vote was the vote. The next step is up to the FDA." Dr. Richard Burton, oral and maxillofacial surgery professor at the University of Iowa College of Dentistry, chaired the dental products panel. They co-chaired and shared direction of the hearings.

Panelists were asked if the FDA white paper/literature review "objectively and clearly" presents the current state of knowledge about the exposure and health effects related to dental amalgam and if the white paper conclusions were "reasonable." By consecutive 13-7 votes, they said no.

The FDA public docket remains open through Nov. 9 for public comments related to the subject of the meeting. The joint committee was charged with review and discussion of peer-reviewed scientific literature on dental amalgam and its potential mercury toxicity, specifically as it relates to neurotoxic effects. The notice was published in the April 3, 2006, Federal Register, a daily publication of regulations and legal notices issued by federal agencies.