Q & A Library

Mercury amalgam fillings have been around for more than 150 years and have been generating controversy from the start. The amalgam is inexpensive, versatile, durable, and easy for dentists to work with. But over the years, repeated concerns have been raised that toxic mercury vapor escaping from fillings poses all kinds of health problems.

There is no question that mercury vapor is toxic, but its release from amalgam fillings is slow, and studies here and abroad have found no evidence to show that it amounts to a public health risk. Most release occurs when fillings are put in, making it more hazardous for the dentists who work with amalgam regularly. The only documented problems that have been traced to the fillings are rare, local side effects or allergic reactions.

In 1993, the U.S. Public Health Service (USPHS) published a report on the safety and use of dental amalgam and other materials commonly used to fill cavities that found no evidence of harm - but also failed to show that the material is entirely safe. Since then, USPHS scientists have analyzed some 175 peer-reviewed studies submitted in support of citizens' petitions received by the FDA. The scientists concluded that none of the studies supported claims that people with dental amalgam restorations will experience problems that include nerve, kidney, or developmental effects (other than rare allergic or hypersensitivity reactions).

Although health authorities continue to study this issue, the FDA reports that the use of dental amalgams in the United States is declining. Pediatric dentists are now using mercury-free, resin (plastic), tooth-colored materials that are bonded to teeth. Sadly, these do not last as long as amalgam. And amalgam remains the best material available for large cavities in rear teeth and cavities below the gum line.

Given the lack of evidence supporting claims that dental amalgams cause health problems, I wouldn't worry about any fillings you may have. When they break down, you can replace them with non-mercury-containing material. But make sure the dentist who removes them takes precautions to protect you from inhaling mercury vapor during the process.

Andrew Weil, M.D.