By David A. Albert, D.D.S., M.P.H.
Columbia University College of Dental Medicine

As consumers, we want to know whether the products we use are safe. If something has been used for many years, we often assume it is safe. This is true in oral health care as well as other areas. Yet questions are being raised about one product that has been used for more than 100 years — amalgam tooth fillings. These fillings contain mercury.

The U.S. Food and Drug Administration (FDA) updated its website on June 3, 2008, to say that dental amalgam may have toxic effects on the nervous systems of developing fetuses and children. An FDA advisory panel concluded that there was not enough information to warn pregnant women and children not to get amalgam fillings.

As its name implies, dental amalgam is an amalgamation (mixture) of several metals. They include silver, mercury and copper. The controversy over safety applies to the use of mercury. Mercury is a known toxin to nerve tissue, particularly in the developing brains of children. Some people also are allergic to products that contain mercury.

Scientists have tried to find out if an amalgam filling releases enough mercury to cause harm. Mercury may be released when the filling is put in and when you chew.

The National Institutes of Health funded two studies on this topic. They were published April 19, 2006, in the Journal of the American Medical Association. They showed more mercury in the urine of children who received amalgam fillings than in children who received resin fillings. However, the children with the amalgam fillings did not have a decrease in IQ or memory. They also did not have a higher rate of kidney problems.

In 2009, the FDA reaffirmed that amalgam fillings are safe for adults and children ages 6 and above. Clinical studies in these groups have found no link between dental amalgam fillings and health problems.

Limited research is available about the potential effects of dental amalgam fillings on the following groups:

• Children under the age of 6
• Pregnant women and their developing fetuses
• Babies of breastfeeding mothers

If mercury is known to be dangerous to humans, why do we use it in dental fillings? Why do so many of us have it in our mouths? If you have dental amalgam fillings, should you have them removed and replaced with other materials?

Previous well-designed studies have not found harmful health effects from the use of dental amalgam. In 1998, the American Dental Association's Council on Scientific Affairs reviewed all relevant studies and literature. The council reported that "based upon available information, amalgam continues to be a safe and effective restorative material." The U.S. States Public Health Service has come to similar conclusions. Many countries have policies similar to that of the United States. In Sweden, dental amalgam fillings have not been permitted since 1995.

As a consumer, what choice should you make? The answer, in my opinion, is to use caution. For example:

• If you are pregnant, do not have amalgam fillings placed or removed. Removal releases mercury.
• If your child needs a filling, consider other materials. Discuss the options with your dentist.
• If you have an allergy to mercury or impaired kidney function, ask your dentist to avoid using amalgam fillings.

New materials offer the dentist more options for fillings. These include dental composites and glass ionomer. As a dental consumer, you should ask questions about the type of filling to be used.

Old amalgams in good condition should not be removed. When fillings are removed, it is possible for a tooth to fracture or break. This can lead to larger fillings, root canal therapy or extraction of the tooth.

The lifespan of a filling is limited. Your dentist should evaluate any amalgam filling that you have had more than 10 years. It may need to be replaced. However, if it is intact and functioning well, it should be left in place.

The use of dental amalgams has been decreasing. The reasons include a decrease in the number of cavities and increased use of other dental materials. This trend probably will continue, even as research continues on the safety of amalgam.

David A. Albert, D.D.S., M.P.H., is an associate professor and associate director of community health at the Columbia University College of Dental Medicine. He also holds an appointment in the Joseph Mailman School of Public Health at Columbia University. He maintains a practice within the ambulatory care network of the Columbia DentCare program in the community of Washington Heights/Inwood in Northern Manhattan.