Tooth Aches
Mounting evidence suggests something the dental establishment doesn't want to hear -- your fillings may be making you sick

By Mark K. Anderson for the Advocate

Mercury is one of the most toxic substances on the planet. Ingesting a drop of it will get you a trip to the emergency room. A thimble-full will kill. A half-gram of mercury in a 10-acre lake is enough to warrant a fish advisory. In 1994, Minnesota banned running shoes with lights in their heels because the shoes contained a half-gram of mercury, and that was deemed too hazardous to consumers. The average "silver" dental filling contains a half-gram of mercury!

Too hazardous for footwear or a 10-acre lake yet safe enough to be implanted in human mouths? It's quite a paradox -- one that has researchers around the world at loggerheads with dental trade organizations like the American Dental Association. The latter claims researchers are needlessly scaring patients with unfounded speculations, while the former assert that silver amalgam fillings are responsible for millions of cases of chronic, long-term mercury poisoning that have been misdiagnosed as anything from Chronic Fatigue Syndrome to Alzheimer's Disease to Multiple Sclerosis to senility.

This is not a new controversy. Yet with an ever-accumulating baseline of scientific studies that continue to converge on the conclusion that the mercury in amalgams is hazardous to the public health, where are the media and where is the government? If a handful of studies connecting asbestos to lung cancer were sufficient to remove it from the market, why don't the American regulatory agencies governing amalgams act with similar resolve?

The answer, not surprisingly, may have more to do with politics and money than with science and the public interest.

Silver amalgam fillings were pioneered in the early 19th century. To make the first amalgam, a British chemist in 1812 mixed coin shavings with mercury (added so the filling would harden without shrinking) for a "silver paste" he used in tooth restoration. It was a revolutionary innovation, since gold was previously the only metal that was tough and durable enough for the job but could still be installed without harming the patient. However, gold was, as it is today, a prohibitively expensive metal, beyond the budgets of most cavity-getters.

Silver and mercury, on the other hand, are cheap. And that economic edge meant modern mouths could be fitted with affordable metal implants whenever tooth decay struck.

Almost from the beginning, though, some dentists began advocating a ban on amalgams, for fear of inadvertently poisoning their patients.

Mercury has been known as a deadly poison for millennia. And during the 19th century, symptoms of mercury poisoning were in abundance for those who cared to look. Hatters, for instance, regularly used mercury on hat felt to make the material more pliable. In the process, many hatters inhaled toxic levels of mercury vapor and developed extreme cases of mercury-induced dementia. Lewis Carroll's "Mad Hatter" from Alice's Adventures in Wonderland offers a comic glimpse at these mercury victims.

But the presence of a known poison in tooth restorative material wasn't enough to sway popular opinion away from amalgams. By the mid-19th century, most of the previously mercury-free dentists had either left the business or opted for the expanded customer base that amalgams provided.

In the ensuing century and a half, the mercury has continued to flow, to the point that some three-quarters of the industrialized world are now estimated to have at least one silver-mercury amalgam filling in their mouths.

That fact alone is manna to the ADA. According to a 1990 Journal of the American Dental Association, "The strongest and most convincing support we have for the safety of dental amalgam is the fact that each year more than 100 million amalgam fillings are placed in the United States. And since amalgam has been used for more than 150 years, literally billions of amalgam fillings have been successfully used to restore decayed teeth."

Perhaps from a public relations standpoint, the ADA's response was a clever move. But in the words of Dr. Michael Ziff, executive director of the International Academy of Oral Medicine and Toxicology, "The ADA's position is not scientific; it's not analytical; it's not even ethical." Or as Dr. Fritz Lorscheider of the University of Calgary Medical School says, "The ADA is on thin ice, because they're trying to counter medical research evidence with dental opinion."

What is the medical research evidence?

For starters, it has been well established scientifically for more than a decade that mercury does not remain inert and "locked-in" to the filling, as the ADA and amalgam proponents had been claiming for more than a century. (The ADA has since backed off that claim. Now it says that amalgams release a measurable but inconsequential amount of mercury.)

The average individual with amalgam fillings is now estimated to breathe in anywhere from 1 to 29 micrograms of mercury per day. Some individuals breathe in even more -- approaching 100 micrograms per day -- due to the number of fillings, gum chewing, chronic tooth grinding during sleep, food chewing patterns, food acidity and other factors.

As a comparison, in 1994 the U.S. Public Health Service deemed 0.28 micrograms of mercury vapor per day as the Minimal Risk Level -- or the amount above which one risks harm from mercury vapor. But even according to pro-amalgamists, who have conceded that people with amalgams typically breathe in between one and three micrograms of mercury a day, people with amalgams may be risking long-term health problems. OSHA has shut down factories for less.

Autopsy studies in Sweden, Germany and the United States have also established that people with amalgams have significantly more mercury in their brains and kidneys than those without, and the mercury concentration increases with the number of amalgams. Furthermore, the World Health Organization has stated that amalgam fillings constitute the majority of mercury exposure for people with amalgams -- more than every other mercury source combined. This finding has been independently verified by the national insurance program Health Canada and by the National Institutes of Dental Research.

And still the ADA remains steadfast -- a flabbergasting fact to somemedical researchers. "What's puzzling is their adamant stance in going to the wall even when the medical evidence is so overwhelming," said Lorscheider.

Or in Ziff's words, "Mercury has been demonstrated as one possible cause of Alzheimer's Disease, and the World Health Organization says that people with amalgams get more mercury from their fillings than from all other sources combined. Two plus two equals what? According to the ADA, it equals zero."

However slow their progress in the United States, the anti-amalgamists have had more success in Canada and Western Europe. Germany and Austria, for instance, both have restricted the use of amalgams in children, women of childbearing age and patients with kidney problems. In addition, the German company Degussa, one of the world's leading manufacturers of dental fillings, has dropped its amalgam line entirely, and the Austrian government has set a goal of banning all amalgams by the year 2000.

Austria won't be the first, either. Sweden has already banned the filling for children. As of next month, Sweden will be the first country in the world to ban silver-mercury amalgam fillings outright.

And Canada may not be far behind, although the Canadian Dental Association and other pro-amalgam forces haven't given up the fort yet.

Less than a year ago, Health Canada held a stakeholders' meeting that put the issue to a vote. The amalgamists won. The following day, though, the Montreal Gazette quoted a less-than-triumphant leader of the pro-amalgam faction: "The odds are good that the anti-amalgamists will reign triumphant over the traditionalists," he said. "Maybe you shouldn't write this, but I think it's a war we're going to lose pretty soon. It's political pressure. By telling and telling about it, by reading it in the newspapers, I think the momentum is there for us to lose that war and go on to other materials."

In the United States, the war has to date been fought with few positive results. Newsweek ran an article on the subject in October of 1990 and 60 Minutes followed Newsweek's lead in December. But the mainstream American media have since been grossly silent on amalgams and mercury toxicity.