Long-standing questions over the safety of mercury-containing dental fillings may be answered within a year.

The latest salvo in the decade-old battle over mercury amalgams occurred earlier this summer when the Food and Drug Administration agreed to settle a lawsuit brought against it by opponents of the dental material. Under the agreement, the FDA must decide by July 2009 how it will regulate mercury amalgams and what warnings dentists should give patients about the filling's use.

Moms Against Mercury and other plaintiffs filed suit against the FDA in 2006 in an effort to push the federal government into formally classifying encapsulated mercury amalgams, which would require an analysis of their risk and make them subject to certain controls. Anti-mercury advocates hope this action will lead to elimination of amalgam use.

As part of the legal settlement, the FDA also agreed to change the safety information on its Web site regarding mercury amalgams, noting for the first time that they may be harmful to certain individuals.

"Dental amalgams contain mercury, which may have neurotoxic effects on the nervous systems of developing children and fetuses," the agency states.

It goes on to say that "[p]regnant women and persons who may have a health condition that makes them more sensitive to mercury exposure, including individuals with existing high levels of mercury bioburden, should not avoid seeking dental care, but should discuss options with their health practitioner."

Evolving position

The FDA's new cautionary statements reflect evolving thinking by dental experts on mercury amalgams, according to Jed Jacobson, senior vice president of professional services and chief science officer at Delta Dental of Michigan, Ohio and Indiana. Jacobson is a former researcher who has closely followed the mercury amalgam controversy.

"Many people have misinterpreted this as the FDA reversing or at least backsliding on its position. That is not the case," he says. "They're saying amalgams may cause problems, not that they do.

"The FDA and the American Dental Association state that amalgams are safe, with possible exception," he continues. "Since 2002, we've been trying to identify those exceptions, if any, and inform the public."

In 2002, the FDA proposed reclassifying mercury amalgams as Class II medical devices but never issued a final rule. The purpose of the mercury opponents' lawsuit was to force the agency to do so, since "Class II" indicates that a product carries some element of risk and is subject to certain controls.

When it initially proposed Class II status for amalgams, the FDA suggested that controls include materials testing to confirm strength and determine the amount of mercury vapor released by the devices and cautionary labeling for dentists and patients. The agency asked for additional public comment on these issues in June; the comment period ended in mid-July.

Removal not recommended

The FDA is not recommending that amalgam fillings be removed, saying that the decision is between the patient and the dentist.

"If you are concerned about the possible health effects of amalgam fillings, you should talk with your qualified health care practitioner," the agency states. "Dental amalgam fillings are very strong and durable, they last longer than most other types of fillings, and they are relatively inexpensive. You may want to weigh these advantages against the possibility that dental amalgam could pose a health risk, until further information is conveyed through the rulemaking or otherwise." Some unscrupulous dentists may try to take advantage of the latest publicity on mercury amalgams and attempt to scare patients into exchanging them for other fillings. "For those dentists inclined to pray upon public, this might be [an opportunity]," agrees Jacobson. "But they would be abusing the FDA's cautionary note. Dentists who remove amalgams unnecessarily would invite the careful review of third-party carriers and the attention of the ADA."

Environmental concerns

In fact, the dental industry has been moving away from using amalgams, "not because of safety concerns, but because of environmental issues," Jacobson notes. The Clean Water Act of 1972 set a new standard for wastewater, including the amount of mercury allowed in it. To meet the CWA requirements, municipalities passed regulations restricting the amount of mercury that dental offices may add to the local wastewater system, he explains.

"Dental offices are being compelled to buy equipment to collect excess mercury-containing amalgam. Consequently, many dentists are saying we won't use mercury amalgams anymore. Fifty percent to 60% of posterior, or back, fillings, where amalgams were most often used, now are being done with composite or 'white material.'"

At Delta Dental, which covers 50 million plan members in 50 states, there has been no increase in inquiries about the safety of mercury amalgams as a result of the recent publicity on the court settlement, Dr. Jacobson reports.

"We've been dealing with this for over 10 years. We get at least one call a day from a plan subscriber or dentist wanting to know where we stand on amalgams and whether we'll pay for them. "We cover amalgams and composites and leave the decision on which to use in the dental office between dentist and patient. Both [fillings] work; mercury amalgams last a little longer. Until one proven is proven to be safer, we consider them equally effective."

Further reading

• "Questions and Answers on Dental Amalgams," www.fda.gov/cdrh/consumer/amalgams.html.
• Brief of Appellants, Moms Against Mercury vs. the Food and Drug Administration, December, 2006, www.toxicteeth.org/Brief-MAM-FDA.pdf
• "FDA: Possible risk from dental fillings," Daniel J. DeNoon, WebMD, www.webmd.com/oral-health/news/20080605/fda-dental-filling-risk-possible