Expert Panel Finds Little Peril From Mercury in Tooth Fillings

Dental patients are in little danger of being harmed by tooth fillings that contain the poisonous metal mercury, a federal panel of experts said Wednesday.

The panel said that that type of filling, called silver amalgam, does release mercury vapor into the mouth over many years. But it said the amount of mercury is so small that it poses no known danger.

“Very few patients are at risk of developing reactions from dental fillings,” said Dr. William D. McHugh, chairman of the panel, which was set up by the National Institutes of Health. “There is no substantial evidence that side effects are significant.”

McHugh, a University of Rochester professor, said that, based on the committee’s findings, “there’s no reason for anyone to avoid the use of amalgam fillings if a dentist recommends it.”

About 200 million tooth restorations are performed annually in the United States, with dentists using silver amalgam in many of them.

The NIH organized the panel after a controversy arose about the risk of mercury poisoning from silver amalgam. Officials said there have been isolated reports of patients who seemed to have symptoms of mercury poisoning, and a television program that explored the problem raised new concerns.

Additionally, some dentists have encouraged patients to have their silver amalgam fillings removed and replaced with other materials.

McHugh said at a news conference that there was no valid scientific evidence to suggest that removing silver amalgam fillings was a good idea.

“I would have no concern about using the material,” he said. “I had two amalgam fillings just last week.”

Silver amalgam is composed of silver, tin, copper and other metals mixed with mercury to make a metal alloy that is used to fill cavities. Variations of the mixture have been used by dentists for more than 150 years.

In recent years, the amalgam has come under close scrutiny by the Food and Drug Administration and by a committee of the American Dental Assn.

McHugh said that preparing the material once represented a real hazard to dental practitioners because it was mixed by hand, using free-flowing mercury, in dentists’ offices. After mixing the material, McHugh said, dentists would squeeze it through cloth to extract excess mercury. More mercury was released, he said, when the material was placed in a patient’s tooth.

“There was mercury everywhere,” McHugh said.

Now, he said, the material is premixed and packaged in small plastic capsules. The amalgam has lower levels of mercury and less of it typically is used in tooth fillings.

Other types of dental material, such as plastics, composites and types of glass, also were examined by the committee.

In its report, the panel said there could be “potential health risks” with virtually any tooth restorative material, but it concluded that “there is no scientific evidence that currently used restorative materials cause significant side effects.”