Debate Over Dental Fillings

The debate over whether mercury in dental fillings can leach out and cause a wide range of health problems — from multiple sclerosis and cancer to Alzheimer's disease — refuses to die down.

The mercury in dental fillings is an amalgam, or blend, of copper, silver, and mercury that has been used for more than 150 years. Silver dental fillings contain very small amounts of inorganic mercury, which is not easily absorbed by the human body, according to the American Dental Association (ADA) and other public health groups.

The ADA's position that dental amalgam is a safe and effective material to fill cavities is supported by the U.S. Public Health Service, the European Commission and the World Health Organization, and many studies. In late 2004, a group called the Life Sciences Research Office Inc. reviewed seven years worth of scientific studies and concluded that there is insufficient evidence "of a link between dental mercury and health problems, except in rare instances of allergic reactions."

However, Austria, Canada, Denmark, Germany, and Sweden have banned or discouraged mercury fillings, especially in children and pregnant women.

How Easily Is Mercury Absorbed?

"The mercury in fish is methyl mercury and is much more easily absorbed by the gastrointestinal tract, whereas elemental mercury from an amalgam is almost not absorbed," says ADA spokesman J. Rodway Mackert, DDS, a professor in the School of Dentistry at the Medical College of Georgia in Augusta. And if it's not absorbed, it can't cause any problems, he says.
But "people feel passionately and won't take no for an answer," Mackert says. "Its perplexing. I thought that a number of times after studies came out showing silver fillings were safe, people would begin to realize that the mercury used in amalgam fillings doesn't cause problems and they would drop it."

According to Mackert and the ADA, there is certainly no reason to avoid amalgam fillings. "I have them and my wife and kids do too," he says. "In fact, a survey done asked dentists what type of filling they prefer in their own mouth and amalgams were preferred in their back teeth because they last longer."

Silver Fillings Vs. Porcelain Fillings

Silver fillings are not exactly attractive, which is why most dentists prefer white or porcelain fillings in the more visible part of their smile, he notes.

"We are always improving the white filling," he says. "They don't last quite as long, but are still very durable and a lot of people like them because they look like a real tooth," he says.

They haven't really caught on because "silver is so easy to use," says Nicholas Davis, DDS, president of the American Academy of Cosmetic Dentistry. "We can put it in the mouth when the mouth is wet and it doesn't take an advanced technique, so it's easy to fall back on," he says, adding that it's harder to use the newer white fillings, which are technique sensitive.
Still, "mercury is a poison, but so is fluoride, and fluoride in the right concentration will keep teeth from decaying," he says, likening the mercury controversy to the equally heated debate over the fluoridation of the public water system. The problem with the latter, some say, is that excess fluoride can lead to dental fluorosis, in which the teeth become stained yellow or brown or flecked with white spots and can be toxic to other parts of the body.

Removing Silver Fillings

As far as mercury in fillings goes, "If I had immune problems or anything that would make me subject to getting an infection, I would do anything I could to boost my immune system and decrease my chance of infection including purging all metals from my mouth," Davis tells WebMD. But "for the general public, mercury in fillings is not that much of a problem."

Davis often advises patients to consider having silver fillings removed if they are large fillings that can make the tooth weak over time. "I recommend that my patients do it over several years," he says, by removing and replacing one quarter of the mouth at a time. "Over time, your whole mouth will be upgraded."

"Just like you find with fluoridation, [some people] feel no matter what anybody says about this procedure they are wrong and there is a problem," says Erie, Pa.-based dentist William Glecos, DDS. Glecos is a past chairman of the environmental task force for the Pennsylvania Dental Association.
Dental amalgam is about 50 percent liquid mercury and 50 percent a combination of alloy powder (metals composed of silver, tin, copper and others). "The mercury is what binds all the other powders together," Glecos says. "Even if you remove these fillings and they leach into the waste water, just 0.006 percent of mercury in amalgam will leak out," he says.

The main pluses of amalgam fillings are that "they are economic and tend to be very durable and can be used in situations that are not ideal," Glecos says. "One of the problems with the white fillings are that they are very sensitive and need a certain environment to be used; they are also very costly and not as durable," he says.

The View Of Mercury Opponents

This doesn't mean too much to public health advocate Freya Koss, the development director of Consumers for Dental Choice in Wynewood, Pa. She is also director of development for the Pennsylvania Coalition for Mercury Free Dentistry. It is Koss's mission to alert the public to the dangers of mercury in fillings.

Close to a week after a dental visit several years ago, Koss was struck with double vision — seemingly out of nowhere. Her dentist had drilled out some old mercury fillings and replaced them with a new batch. After visiting several specialists and undergoing a battery of tests, a doctor told her that based on the results, she either had MS or lupus.

But Koss refused to take this diagnosis lying down. "I had a light bulb moment on the Web, when I read a woman's story about similar symptoms brought on by mercury poisoning," she says. "I wasn't crazy. I wasn't alone."

After having the fillings carefully removed and going on a detox plan rich in antioxidants, Koss began to feel better slowly. Her symptoms continued long after she identified the cause. In fact, she had a drooping eyelid for 3.5 years.

"The symptoms of mercury poisoning are insidious, and you can have a variety of symptoms through the years," she tells WebMD.
"Do research and find out what tests are being used to determine mercury poisoning," she says. "And make sure you find a mercury-free dentist who follows the protocol for safe amalgam removal. Be your own advocate."

Who Is Debating?

Koss and others contend that the debate over mercury in fillings is being run — and won — by dentists, but instead should actually be led by neurologists. They point to a vested economic interest of the ADA in the amalgam.

Those who oppose mercury in fillings also say there is research suggesting that prenatal mercury exposure from fillings has been equated with epidemic levels of childhood learning disabilities, neurological illnesses, and autism. They also say that exposure has been linked to adult illnesses including MS, lupus, Parkinson's disease, Alzheimer's disease, and autoimmune, gastrointestinal, and mental illness.

According to the FDA and other organizations of the U.S. Public Health Service (USPHS) who continue to investigate the safety of amalgams used in dental restorations (fillings), no valid scientific evidence has shown that amalgams cause harm to patients with dental restorations, except in the rare case of allergy.

Alternatives Abound

Many alternatives to silver fillings exist.

"The wave of the future, at least cosmetically speaking, is porcelain fillings," Davis says. "I have placed porcelain fillings that look so real that other dentists have ground them out and put silver fillings in there. They can be so lifelike it's very difficult to tell if there is a filling in there."

Plus, porcelain can't decay, he adds. Porcelain fillings are, however, more expensive and less durable then their amalgam counterparts.

Another option is a resin, which mixes plastic and fine glass particles. "While resins can fill a hole, they don't hold up over time, but they are great for small cavities where you can remove the decay and replace minor areas."

Sources: J. Rodway Mackert, DDS, professor, School of Dentistry at the Medical College of Georgia, Augusta. Nicholas Davis, DDS, president, American Academy of Cosmetic Dentistry. Freya Koss, development director, Consumers for Dental Choice, Wynnewood, Pa. FDA.

By Denise Mann, MS
Reviewed by Brunilda Nazario, MD
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