Amalgam wars: Part I

Michelle Uss credits her dentist for giving her back her life -- but not because he stopped an infection from spreading or spotted an incipient tumor. Rather, Mark Breiner, D.D.S., removed nine silver amalgam fillings from her mouth, replacing them with composite resin. That procedure, said Uss, a 50-something Milford-Connecticut resident, cured her crippling fatigue. "By the next day, I felt 100% better."

Uss' story is a common one for Dr. Breiner. For more than 30 years, he has been replacing amalgam for patients who complain of an array of symptoms, including arthritis and depression. "I’ve seen thousands of patients improve when they remove this toxic material from their mouth," said Dr. Breiner, author of "Whole Body Dentistry" and founder of a clinic by the same name in Trumbull, CT.

Under orders from the Connecticut Department of Public Health -- which threatened to revoke his license -- Dr. Breiner has his patients sign statements saying there's no evidence that amalgam fillings will harm them. But he enlisted the American Civil Liberties Union in a successful lawsuit so he can write articles against amalgam.

Dr. Breiner is part of an international campaign against amalgam fillings. Organizations such as Consumers for Dental Choice (in which Dr. Breiner serves on the board) and the International Academy of Oral Medicine and Toxicology maintain active antiamalgam Web sites, send out news releases, and lobby governments. And they're being heard in high places; on November 14, both organizations testified in support of a bill introduced by Rep. Diane Watson (D-CA) that would ban amalgam fillings in children and pregnant or lactating women.

But these groups hardly have the public forum to themselves. On the other side sit established bodies such as the American Dental Association, U.S. Public Health Service, the Centers for Disease Control and Prevention, and the U.S. FDA.

The ADA in particular works actively to convince the public that amalgam fillings are perfectly safe; in October the organization announced it was working on a pamphlet to accompany its Web articles on the topic. "We have to reassure patients and discuss scientific evidence that shows that amalgam is safe," said Rodway Mackert, D.D.S., Ph.D., a professor of oral rehabilitation at the Medical College of Georgia’s School of Dentistry and a spokesman for the ADA.

So who's right? Why won't this decades-old controversy die? And what should dentists tell nervous patients about the mercury in their mouths?

Mad as a hatter

One reason the issue is so difficult to resolve is that scientific evidence has stacked up on both sides. Research has shown over and over that amalgam fillings emit minute amounts of toxic mercury vapor that can find its way into the human body. But no one has proved a correlation between having amalgam fillings and any sort of illness. In fact, last year the Journal of the American Medical Association (JAMA) published two randomized, prospective clinical trials carefully aimed at detecting just such a connection. They found no cause for concern.

David Bellinger, Ph.D., M.Sc., an author of one of the JAMA studies, can understand why the public -- and many dentists -- remain confused. "It does seem like a nutty idea to put a heavy metal in your mouth," said Bellinger, a professor of environmental health in the Harvard School of Public Health.

The seemingly nutty idea dates back hundreds of years. No other metal is liquid at room temperature, a property that earned the element the nickname of "quicksilver." This attribute also accounts for its popularity among early metal workers; it can easily combine with other metals to form amalgams. In nature, mercury is chemically tied to sulfur, where it does no harm. Once workers release it from these bonds, the metal can kill.

In the air, elemental mercury vapor passes through the lungs into the bloodstream. In water, microorganisms convert elemental mercury to methylmercury. This compound, found in fish, can pass through the gastrointestinal tract into the bloodstream. Via either route, mercury can enter and damage other organs, including the brain.

One of the most familiar examples is the "Mad Hatter" character in the children’s classic, "Alice in Wonderland." Author Lewis Carroll didn't coin the term; it entered the late 18th century to mid-19th centuries when hat factory workers often babbled nonsense and behaved irrationally. These signs, along with tremors, psychosis, and hallucinations, stemmed from inhaling vapors of mercury, which helped soften material used for making hats.

Dentists of that period may have risked similar symptoms when they mixed their own amalgam for fillings. The process involved measuring the correct amount of mercury and using a mortar and pestle to blend in powdered metallic alloy, said Karl-Johan Söderholm, D.D.S., Ph.D., professor of materials science and engineering at the University of Florida.

"They tended to use a cloth to squeeze out the excess mercury that hopefully fell into a cup, but sometimes landed on the floor," Dr. Söderholm said. "If anyone had come into a dental office back then and measured mercury, they would’ve seen very high levels." Since then, mixing machines and prepackaged amalgam have eliminated direct contact with liquid mercury.

Research has shown that contemporary dentists and their assistants still carry more mercury in their bodies than most people and that they are more likely to suffer memory problems and kidney dysfunction. But most research, including a 2001 British study in Occupation and Environmental Medicine, showed no correlation between the level of mercury in their bodies and these disorders, which could mean that some other substance is causing the problems.

The use of silver amalgam in dentistry dates back as far as 7th century China, but the material didn't find its way into Westerners' teeth until the 19th century, according to The Excruciating History of Dentistry: Toothsome Tales & Oral Oddities from Babylon to Braces (St. Martin’s Press, 1998). By then, mercury's toxic properties were well known and on both sides of the Atlantic amalgam fillings swiftly became controversial.

As early as 1835, American dentists organized into groups that forbade members to use amalgam. The advantages of amalgam, however, were far too great for many dentists to pass up. Because it was much cheaper than gold, which was then the standard material for fillings, dentists could extend their services beyond those wealthy enough to afford the precious metal. Amalgam is also more malleable than gold, sparing the dentists' effort and patients' pain.

And with experimentation, the material got more and more useful. To the silver-mercury mix, dentists added tin, which prevented fillings from expanding in the patients' teeth. By 1895, today's formula was more or less standardized: 50% mercury, 35% silver, 9% tin, 6% copper, and a trace of zinc. Membership in the American Society of Dental Surgeons, the main antiamalgam group, declined to the point that the organization disbanded in 1856. Three years later, the ADA rose in its place. And from the beginning its leaders took a stand in favor of the controversial material.

Seal of acceptance

Some critics say the organization never had an impartial perspective."There's no question that the ADA was founded as the group that used amalgam," said Charlie Brown, national counsel of Consumers for Dental Choice. He accuses the ADA of bias because it charges amalgam product manufacturers for the right to carry its Seal of Acceptance. "It’s a massive money maker for them," he said.

That's hogwash, responds Clifford Whall, D.D.S., director of the ADAs Seal of Acceptance program. The ADA didn’t begin requiring fees until 1995, when it began to ask $500 for every product submitted for evaluation, said Dr. Whall, who has held his post since 1981. Once accepted into the seal program, companies pay $100 per year to support the program and retesting every five years.

"Most of the amalgam products were already in the seal program before we had any fees," he said. "We’re trying to promote good oral healthcare; that’s our sole reason for running the seal program."

Today, amalgam remains in the toolbox of most dentists for the same reasons that first put it there: amalgam is nearly half the cost of other materials and it lasts much longer. Composite resin "is more expensive to replace and more expensive over the life of the tooth," ADA spokesperson Dr. Mackert said. Some insurance companies won't reimburse patients the entire cost of composite resins, arguing that amalgam is a better alternative.

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Laura Lane has bared her fangs for the nearly 10 years spent in journalism. She first sank her incisors into newspapers and then moved on to the molar-grinding dot-com world. She has written for the Dallas Morning News, Harvard Women's Health Letter, Shape magazine, and WebMD, as well as a variety of trade publications. She earned a B.S. in biology from the University of California, Los Angeles, and a M.S. in biological sciences from Stanford University.