Mercury ... fillings ... deja vu

My colleague Don Sapatkin, who covers public health and has reported on controversy over the material used to fill cavities, summarizes yet another twist in the story:

Are dental fillings that contain mercury safe?

The tug of war on silver-colored fillings got another tug when the Food and Drug Administration announced last week that it will convene an advisory panel on Dec. 14-15 to examine several scientific issues surrounding what is known as dental amalgam.

The FDA maintained for years that the fillings posed no concerns. An advisory committee in 2006 rejected an FDA report on the topic, saying that scientific knowledge at the time was not conclusive enough to declare dental amalgam safe.

Then, in June 2008, the FDA officially reversed course as part of a settlement with consumer advocates."Dental amalgams contain mercury, which may have neurotoxic effects on the nervous systems of developing children and fetuses," the FDA said on its Web site.

In July 2009, in a regulatory step that formally classified the previously separate fillings and their ingredients as a single device, the agency removed that and related cautions – and once again said that there was no evidence of risk to patients. That decision prompted the challenges that resulted in the upcoming review.

Use of dental amalgam has been gradually declining, with half or more cavities now filled with resin composites that look more natural but also cost more and may be harder to work with in certain situations.

The American Dental Association has consistently argued that the form of mercury in silver-colored fillings is safe, and that putting restrictions on their use could cause more poor people to skip dental care. Anti-amalgam groups such as the International Academy of Oral Medicine & Toxicology have argued that the mercury can cause neurological damage and that fillings containing it should be banned or at least restricted in young children, women of childbearing age and people with various conditions that could put them at risk.

IAOMT is one of the groups that petitioned the FDA to re-examine the issue after the agency's decision last year.

In agreeing to undertake a review, the agency said the "panel meeting will focus particularly on the potential risk to vulnerable populations, such as pregnant women, fetuses, and young children." Public comments will be accepted through Dec. 3.

Independent of the federal actions, Philadelphia City Council last year required all dentists to begin distributing an "information sheet" that outlines pros and cons on the issue to their patients, with signatures from both dentist and patient. The information sheet was written by the city Board of Health in a process that brought heated debate from local affliates of the national groups on both sides of the issue.

The board agreed to revisit the issue after one year and began hearing comments a few months ago. Anticipating the latest FDA review, however, the board decided last month to table any reconsideration until after the federal government rules. The previously approved information sheet must still be distributed and signed.