Dental amalgam under the microscope

Dental amalgam under the microscope

By Daniel McCann

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http://www.altcorp.com/DentalInformation/amalgamdebate.htm

As far as professors Murray Vimy and Boyd Haley are concerned, the debate's settled. The data are in and the results are indisputable: Mercury vapor from dental amalgam is a toxin that's been linked to a host of illnesses—from Alzheimer's disease to renal dysfunction to disabled immune systems and more.

"From a scientific standpoint, the issue's over," says Vimy, a dentist and professor of endocrinology and metabolism at the University of Calgary, Alberta, Canada. "Dentistry should just stop using this stuff."

Not so fast, say plenty of other researchers. These investigators question the science behind such categorical conclusions as they point to their own studies that show different results.

"In 20 years of research nobody has been able to demonstrate that there are adverse health effects from amalgam fillings," says J. Rodway Mackert, professor of dental materials at the Medical College of Georgia dental school. "Just to say something is toxic doesn't really tell us much because we know that even things that are essential to our health, such as vitamin A, are toxic in higher doses."

And on the debate rages. Ever since researchers found that mercury vapor escapes from amalgam fillings more than 20 years ago, scientists have been working to unravel the discovery's implications. They've since learned that mercury travels to different areas of the body, but disagreement abounds on such issues as just how much vapor is released and absorbed by the human body, and to what effect.

In 1991, largely as a result of the ongoing debate, the U.S. Food and Drug Administration launched a two-year study of the conflicting data. Its findings, released in 1993 (and reaffirmed in 1995 and 1997) endorsed the continued use of dental amalgam. "Available data," says the agency, "are not sufficient to indicate that health hazards can be identified in non-occupationally exposed persons."

Some evidence presented to the agency purporting to show problems with dental amalgam proved weak, say FDA officials. "I think a lot of the people who have severe concerns [about amalgam] have produced anecdotal literature, which is very hard to evaluate," says Dr. Susan Runner, director of the FDA's Center for Devices and Radiological Health. "When people say they're cured of something by having their amalgams taken out, there are so many factors that can come into play."

For instance, she continues, scientists scrutinizing anecdotal evidence might reasonably ask: Did individual sensitivities come into play? What was the exact sequence of what happened? Was there an independent diagnosis of what occurred? "It's very difficult to make decisions based on something that's not controlled and lacks sufficient data," says Runner.

She also cites problems with some "very limited animal studies" that were used to explain how dental amalgam harms people. "Those are very difficult to evaluate in terms of what the [human] effect is," she says.

Yet the FDA doesn't dismiss critics of amalgam out of hand. In fact, the agency acknowledges the need for further scrutiny of the material. In its 1993 report, the FDA noted, "the potential for effects at levels of exposure produced by dental amalgam restorations has not been fully explored."

Just what those levels of exposure are varies according to the research. Variables such as different testing methods and analyses, along with patients' diet and gum-chewing habits can deliver diverse results.

The FDA noted that research into the "human uptake of mercury from amalgam fillings" showed results ranging between 1.24 to 29 micrograms a day. After adjusting for test differences, estimates fell to less than 5 micrograms a day, the agency reported. In a study published in the World Health Organization's 1997 publication "Dental Amalgam and Alternative Direct Restorative Materials," Mackert reported that it would require about 500 amalgam surfaces to reach the point set by WHO (30-100 ug mercury/g creatinine) where "particularly sensitive individuals" might develop subtle toxic effects such as "defects in psychomotor performance, objectively detectable tremor and evidence of impaired nerve conduction velocity."

But for scientists such as Vimy, there's no safe level of absorbed mercury. "Mercury is a poison; if one atom is poisonous, a million atoms are poisonous. Obviously," he continues, "the more you're exposed to, the worse it is."

In 1991,Vimy and other researchers published a study in the Journal of American Physiology ("Mercury from Dental 'Silver' Tooth Fillings Impairs Sheep Kidney Function," Am J Physiol 1991; 261: R1010-R1014) that investigated mercury's poisonous effects on sheep. Researchers placed 12 occlusal fillings in each of six female sheep and two glass ionomer restorations in two control sheep. Before surgery and at 30- and 60-day intervals after amalgam placement, scientists checked the animals' renal function.

They then evaluated how effectively the sheep cleared a substance called inulin, a chemical not metabolized by the body. They found that plasma inulin clearance fell by about 60 percent after 30 days and remained so at the 60-day checkup. Among the control sheep, baseline clearance stood unchanged after 30 days. They concluded that the amalgams damaged the animals' renal function.

But the study drew quick criticism. In a letter to the editor of the journal, professor Richard Malvin from the University of Michigan's department of physiology and other scientists cited numerous flaws in Vimy's research methods and analysis. In particular, Malvin and the others wrote, "in these experiments, as the clearance of inulin decreased with time, the clearance of urea increased with time to the point that it actually exceeded the inulin clearance. This is a physical impossibility."

Also, Malvin recalls today, "they measured two enzymes that did not change [y-glutamyl transpeptidase and alkaline phosphatase]. And that's evidence of good kidneys, not bad kidneys." In addition, Malvin says the study's controls were inadequate. "They should have had six control sheep, not two. And they [the controls] had only one post-amalgam measurement, at 30 days. That's totally insufficient."

Vimy responds, "our findings are consistent with the bulk of the published data on the renal effects of low doses of mercury from sources other than amalgam. The other mercury sources show similar effects in humans and other mammals."

Some of the more recent questions about dental amalgam have centered on its possible neurological effects. Anecdotal reports of people with multiple sclerosis undergoing complete remissions after having their amalgams removed have been followed by hypotheses linking the fillings to Alzheimer's disease, autism and Parkinson's disease. Yet none of the national organizations founded to research and find a cure for the respective diseases subscribe to the dental amalgam theory.

In 1997, professors James Pendergrass, Murray Vimy, Boyd Haley and others published a paper ("Mercury Vapor Inhalation Inhibits Binding of GTP to Tubulin in Rat Brain: Similarity to a Molecular Lesion in Alzheimer Diseased Brain," NeuroToxicology 1997; 18[2]: 315-324) in which they concluded that mercury vapor so altered the brain chemistry of rats that it created lesions similar to those found in humans with Alzheimer's disease.

Two years later, in 1999, Dr. Stanley Saxe published an article in the Journal of the American Dental Association ("Alzheimer's Disease, Dental Amalgam and Mercury," JADA 1999; 13(2): 191-199), that showed contrary results. Saxe and other researchers had focused their study on 101 Roman Catholic nuns, 68 with Alzheimer's disease and 33 controls. At autopsy, the researchers examined the brains of the sisters in each group. In their conclusion, they wrote; "We found no significant difference in brain [mercury] levels between subjects with AD and control subject. Our results do not support the hypotheses that dental amalgam is a major contributor to brain [mercury] levels. They also do not support the hypothesis that [mercury] is a pathogenetic factor in AD."

Professor Boyd Haley, one of the authors of the 1997 NeuroToxicology study on mercury vapor and lesions in rat brains, is a strong proponent of the dental amalgam-AD link. "What I've focused on is trying to find what toxic exposure [to mercury, including dental amalgam] increases a person's chances of getting Alzheimer's," says Haley, professor and chair of the department of chemistry at the University of Kentucky.

Haley contends that the Saxe study falls short of solid science. The key issue, he says, is the amount of mercury found in the subjects' olfactory tissues. He points out that the controls had more than double (88.9 nanograms per gram) the mercury than the AD subjects (41.7 nanograms per gram). Since the olfactory tissue is outside the blood-brain barrier, Haley continues, "that indicates that the controls were more exposed to mercury in the short time before they died than were the AD patients.

"He (Saxe) was supposed to match [both groups in terms of] having the same amount of mercury exposure. If you can assume that most of the mercury came from the amalgams, how can you explain the controls having more mercury in the olfactory bulb? So you really have to question the rest of the data."

Saxe concedes that a few of the study's 33 control subjects had higher amounts of mercury, and at first glance it might appear that the data is wildly out of kilter. But on closer inspection, he continues, the statistical analysis (which takes into account standard error and probability factors) demonstrates that there was no statistical difference between the control group and the people with AD.

The desire to answer further questions about the safety of dental amalgam—and resolve conflicting data—prompted the National Institute of Dental and Craniofacial Research in 1996 to launch two prospective, longitudinal, randomized clinical trials. With sites in New England and Portugal, each of the independent investigations involve about 500 schoolchildren with no history of restorations. All the children tested normal for intelligence, and baseline measurements included visual-motor ability, memory, learning ability, kidney and renal function and mercury levels in blood, urine and hair. Children with decay have been randomly assigned to receive either silver fillings or composite restorations. During the course of the 10-year trials, researchers are scrutinizing the children for any changes in baseline measures. As of late June 2002, the NIDCR reports that there have been no adverse effects among the children.

Yet some opponents of amalgam put little faith in the NIDCR study. In a May 2001 letter to U.S. Congressman Dan Burton (R-Ind.), chairman of the Committee on Government Reform, Boyd Haley wrote: "Do we really think that the NIDCR and associated ADA personnel are going to deliver up a conclusion to American parents saying, 'we put a mercury containing toxic material in your child's mouth that lowered his/her IQ and made him more susceptible to neurological problems in comparison to the children whom we selected to not get exposed to this toxic material'?" Haley added that "the results presented from this study will likely follow previously ADA-supported research, i.e., no significant results."

In its defense, the NIDCR answers that "Neither the NIDCR nor the ADA has any influence on the outcome or reporting of the children's amalgam trials. From the outset, the NIDCR says, the request for applications on the proposed trial was open to all interested parties, and an independent peer review board scrutinized each entry. "The reviewers," the NIDCR continues, "included experts in behavior and cognition, IQ, heavy metal toxicology, neurology, bio-statistics, clinical trials design/execution [and] biomedicine, including urology and immunology."

Evaluation of investigations is the responsibility of an independent data and safety monitoring board, says the NIDCR. The agency adds that "the data from the studies belong to the investigators who are free to publish them without any restrictions from NIDCR."

Among of the NIDCR's investigators in the children's studies is James Woods, research professor of environmental health, toxicology program, at the University of Washington, Seattle. Woods has been studying mercury for nearly 30 years and is considered an authority in the field, by both supporters and opponents of dental amalgam.

"I think it's fair to say that certainly we do not know if there's any level of elemental mercury exposure that is safe," says Woods. Neither do we know for sure, he adds, whether current exposure levels are a public health or clinical concern. And he's convinced that the current NIDCR trials will prove pivotal. "We hope and fully expect, in fact, that the studies being conducted in children will resolve this issue and that the answer to that question should be known within the next three to four years at the most."

Why the amalgam debate just won't go away

What with one claim or another questioning the safety of dental amalgam every few years during the past two decades, small wonder at least two congressmen now want to abolish the country's most economic and durable restorative material. If the allegations aren't true, why would anyone continue the debate for so many years? A closer look at what motivates four anti-amalgamist leaders attempts to answer these questions.

By Dennis Spaeth

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Despite the religious fervor at times generated by the mercury amalgam debate, particularly now as the controversy appears destined for a courtroom showdown, don't expect a 1925 "Monkey Trial" where the likes of Clarence Darrow and William Jennings Bryan wrestle with the origins of the human race. As much as some involved may think the amalgam debate reaches such lofty heights, several pending lawsuits questioning the safety of dental amalgam promise nothing more than a forum for both sides to once again air their arguments. And, if history is any judge, a decision favoring one side or the other won't mean an end to the controversy; somehow it will survive and evolve.

From the science and common sense arguments tracing back some 20-plus years to the legislative and legal tactics of today, the anti-amalgamists may appear to go down in defeat after resurrecting the debate every few years, but they never go away. They regroup. They conduct more research. They form a coalition and seek legal counsel. And, what's more, they call on the American Civil Liberties Union to defend their freedom of speech.

With the ACLU seemingly on their side and a few other apparent victories in the past year or so, common sense would seem to suggest that there's some truth in what the anti-amalgamists claim. Otherwise, how could they sustain the debate for so long?

Unfortunately, both sides of the debate lay claim to common sense.

Dental amalgam has been placed in millions of mouths in the past 150 years, say those who insist amalgam is safe. Where is the epidemic of Alzheimer's disease and any number of other illnesses allegedly linked to the mercury vapor that comes from dental amalgam? Surely, if there were any truth to any of these claims, dentists and their staffs would be hardest hit—yet there is no epidemic of these diseases among them.

Then again, mercury is a toxin. It is poison. And dental amalgam does emit a small amount of mercury vapor—anywhere from about 1 to 43 micrograms per day, depending on whose measurements you choose to believe. But the anti-amalgamists wonder who in their right mind would expose themselves to any level of poison.

Any toxicologist will tell you, however, that the dose is the poison. So, if you truly apply common sense, the question patients must ask themselves is whether they're willing to risk a low level of mercury vapor exposure in order to receive the most clinically effective restorative material aside from gold, which is cost-prohibitive for millions of patients. Granted, patients have options. They could ignore the problem and eventually lose the tooth or, if they can afford it, opt for a composite resin, which is less durable and a bit more expensive than amalgam.

Given that federal public health agencies insist that dental amalgam is safe despite the low levels of mercury vapor exposure, then choosing dental amalgam would seem to win the common-sense argument.

Of course, this is where the anti-amalgamists cite their own scientific studies, which they say question the safety of amalgam and link it with a multitude of diseases.

Each time federal public health agencies review the research from the anti- amalgamists, however, the conclusion is always about the same: No scientific study has yet to show a cause-and-effect relationship between the mercury in dental amalgam and any disease. Neither has any study yet shown any adverse effects whatsoever from the mercury in dental amalgam (except for rare allergic reactions).

So, seemingly getting nowhere with their common-sense argument or scientific claims, the anti-amalgamists now have added a new wrinkle or two. They allege that the American Dental Association and dental boards infringe on a dentist's right to discuss the dangers of amalgam with patients. They also claim there is a conspiracy spearheaded by the ADA to keep the truth about amalgam from the public and from you; that the ADA and its member dentists have an economic interest in the continued use of amalgam, and that the ADA somehow placed its members in control of those government-run scientific reviews so that they could ensure a conclusion that amalgam is safe.

These views are spelled out in one form or another in a flurry of recent personal-injury lawsuits seeking damages for injuries allegedly caused by the mercury in amalgam, a few class-action cases with a similar bent, the introduction of legislation in several states that would require dentists to disclose to patients the alleged dangers of amalgam and a congressional bill that would abolish the use of mercury in amalgam by 2007.

In November 2001, Rep. Diane E. Watson (D-Calif.) introduced the bill in Congress that would abolish the use of mercury in dental amalgam. With the introduction, she included a press statement that hinted at the very conspiracy the anti-amalgamists suggest.

Why does the congresswoman choose to ignore the statements by her own government public health agencies that say amalgam is safe? Her press secretary, Bert Hammond, put it this way, "Well, the government has put out a lot of studies that have said this and that, that are not necessarily totally factual. Just because the government says it, doesn't mean we have to believe it."

In essence, there is no new argument here, just another study and a new conspiracy theory reminiscent of the anti-amalgam message spread by Dr. Hal Huggins, whose evangelism didn't end with the loss of his dental license in 1996. But one more study and a conspiracy theory doesn't explain why the debate has emerged yet again, or why it's reached Congress. The credit for that can only be attributed to the perseverance of the anti-amalgamists themselves, particularly the leaders of the movement.

Just what motivates them to continue? Dental Practice Report put that question to four anti-amalgamist leaders. Though they appear to be staunch believers in their cause, most of them seem to have at least as much economic interest in fighting this debate as they say the ADA does in giving its Seal of Acceptance to dental amalgam (about $5,000 a year, according to the ADA).

Though the four individuals selected for this story are by no means the only leaders in this debate, they are among the most prominent. And, as the following vignettes show, each of these leaders plays a unique role in this ongoing drama.

• The litigator—Shawn Khorrami, a California attorney who is the lead litigator behind several lawsuits against the ADA, some state dental associations and a host of dental amalgam manufacturers.
• The scientist—Boyd Haley, a professor and chairman of the chemistry department at the University of Kentucky.
• The lobbyist—Charles Brown, a lobbyist and an attorney who serves as national counsel of Consumers for Dental Choice, a coalition of anti-amalgam groups.
• The evangelist—Dr. Hal Huggins, who has reached an untold number of dentists, physicians and patients since he began spreading his anti-amalgam message in 1974.

The litigator

With a growing number of lawsuits filed against the American Dental Association, various state dental associations and a host of dental amalgam manufacturers all in the past year or so, little wonder the attorney behind these suits has become something of a central figure in the latest round of the amalgam debate.

As the litigator representing a number of anti-amalgam organizations and patients, California attorney Shawn Khorrami is accusing the profession of conspiring to keep the truth about amalgam from the public. For his trouble, the ADA earlier this year retaliated by suing Khorrami for alleging that the association masterminded a conspiracy to keep the truth about the dangers of amalgam from the public.

Parties on both sides of the debate suggest that either the class-action suits, which are still wending their way through one legal maneuver after another, or the defamation case will lead to a scientific debate in court. That the epicenter of this legal battle seems to be in California is no coincidence; it's the only state in the country where the anti-amalgamists have been able to attain some measure of success in court thanks to a plaintiff-friendly environmental protection law and an attorney who's "ready to give up everything" to win. Enter Khorrami.

After graduating cum laude from Pepperdine University School of Law in 1995, Khorrami established a Los Angeles-area law office focused on environmental law and the enforcement of California's Proposition 65. Otherwise known as the Safe Drinking Water and Toxic Enforcement Act of 1986, Proposition 65 in part requires businesses to warn the public if a product exposes any individual to a chemical known to cause cancer or reproductive toxicity. Critics of the state law say it spawned a subculture of lawyers variously known as Proposition 65 enforcers and bounty hunters, so named because they seek out products without a warning, file suit against the manufacturer and wrangle a settlement. Companies more often than not settle because defending against such claims requires defendants to prove the chemical at issue in their products would not cause harm to any individual at one one-thousandth of the level where no observable effect can be detected in humans. It's called the "thousand-fold safety of margin."

While Khorrami's firm has filed more than 80 notices of alleged violations—about one a month since the practice opened its doors—that's not necessarily an inordinate number, according to the California attorney general's office. Some firms have filed far more notices, which simply inform a company of a plaintiff's intent to bring a private action against the company under Proposition 65.

Though Khorrami is a relative newcomer to the amalgam debate, he first began investigating the health ramifications of mercury when he brought Proposition 65 actions against tuna fish manufacturers in 1997. The actions did not result in warnings that tuna fish contains trace amounts of methyl mercury. Khorrami instead negotiated an undisclosed cash settlement from the manufacturers and an agreement that they would more rigorously test the mercury level in tuna before canning, thereby excluding tuna with unusually high amounts of mercury.

As a public health issue, explains an attorney familiar with the negotiations, the feeling was that a warning on tuna cans would cause more harm than good to the overall health of the public. Tuna is a cheap way to get protein, and a mercury warning may cause many consumers to forego tuna. Therefore, it was considered in the best interests of the public to reduce the amount of mercury in each can by weeding out the tuna with the highest amount of mercury content.

Khorrami, however, doesn't see it that way when it comes to the mercury in dental amalgam.

"Dental use seems to be the most egregious type of situation that I've seen," he observes. While Khorrami admits he's not looked into all the scientific studies on the issue, he says he's convinced that the mercury in dental amalgam is dangerous.

"Based on what I've seen and the experts I have talked to, and in some cases the consultants I've retained, there's no doubt in my mind that mercury shouldn't be used for various reasons." For one thing, he adds, mercury amalgam isn't necessary because there are other restorative materials dentists can use in its place, such as composite resins.

So, rightly or wrongly assuming composites can serve as a replacement for amalgam in all situations, Khorrami and other anti-amalgamists argue that the ADA, state dental associations and dentists everywhere should practice full disclosure—tell patients about the potential dangers of the mercury in amalgam—even if it means patients who can't afford any other restorative material may forego treatment.

To some extent, Khorrami and other attorneys enforcing Proposition 65 have made progress toward full disclosure in California. An action brought by the Environmental Law Foundation against a number of dental amalgam manufacturers and distributors was settled in late 2000 for $350,000 and an agreement to include warnings on the labels for their products as well as on the materials safety data sheets, according to Stanley Landfair, who defended many of the dental companies named in the Environmental Law Foundation complaint. Plus, the companies had to create a fund that would pay for the annual distribution of Proposition 65 warning materials to all dentists who are licensed in California.

"Any warning signs that are posted in dental offices (in California) most likely came from this settlement," reports Landfair. A partner in McKenna Long & Aldridge, LLP, Landfair is the firm's practice group leader for Proposition 65 actions.

Picking up where the Environmental Law Foundation left off, Khorrami filed Proposition 65 actions against a series of dental offices to force dentists to post the warnings. The case is nearing a settlement, notes Khorrami, and one of the items under discussion is a warning sign in dental offices.

Perhaps buoyed by the success of Proposition 65 actions against amalgam manufacturers and distributors, Khorrami began filing a series of personal-injury and class-action suits last year. While none of the class-action suits have been certified as such by the courts and no personal-injury suit involving dental amalgam has ever been successful, Khorrami remains confident. He points to new science and the fact that he's citing a specific injury in each of the suits.

Specifically, Khorrami notes new studies that show rat brains exposed to low levels of mercury can mimic the signs of Alzheimer's disease found in human brains. Two separate studies that have shown this alleged link, however, were conducted by clear anti-amalgamist researchers, including Boyd Haley. "That's not something that's been looked at much before, the fact that mercury remains in the body," suggests Khorrami.

On the contrary, the National Institutes of Health initiated a long-term study of its own to determine the truth of the allegations suggested by anti-amalgamist researchers. The study has been looking at the impact of amalgam on children for a number of years and the NIH recently decided to extend it. Though no results have been released or published from the children study, an adverse health effect found at anytime along the way must be reported, an NIH spokesperson noted. "To date," says the NIH representative, "no adverse effects have been reported during the dental amalgam study in children."

But Khorrami isn't relying on new science alone in the personal-injury suits; he's sure that California's Proposition 65 law will carry some weight. "Proposition 65 is the standard we should be using," he insists. "What you have to prove inside a lawsuit is that a particular chemical or exposure caused a particular injury. Yeah, that's a different standard, but the fact of the matter is I believe that if under Proposition 65 you have a violation, you have a seriously problematic product."

While Landfair views Khorrami as a good lawyer, he questions the weight Proposition 65 will carry in personal injury lawsuits. "I think the plaintiff's community has been encouraged by Proposition 65," observes Landfair. "And these claims have prospered in an environment where the law is skewed in favor of the plaintiff. They have seen all these manufacturers and distributors of these materials enter into very significant settlements."

Landfair suspects that their success under Proposition 65 may have offered some false encouragement that these same companies would settle a similar case outside of the Proposition 65 realm. There's also the possibility of a huge payoff, he suggests, noting that "they're looking at the tobacco (settlement) model." That's why, Landfair adds, you see a claim of conspiracy against the ADA. "It's a big, dark, evil world—if you ring that bell once before a jury, there is an unlimited pool of plaintiffs out there. Every plaintiff's lawyer would like to be the first one there with the next set of tobacco, gun or asbestos cases."

Landfair notes that Khorrami's lawsuit against dental amalgam manufacturers—filed at about the same time as similar cases against the ADA and CDA in June 2001—was dismissed without prejudice.

Khorrami, who is working the amalgam cases on a contingency basis, balks at the notion that he's in the amalgam debate solely for the big payoff.

"I don't think anybody involved with toxics is sitting there pondering some gigantic settlement," Khorrami says. "From the plaintiff's side," he continues, "it is absolutely the worst, most costly and chancy type of litigation. You have to be ready to give up everything in order to get there. If the case ever comes to fruition, I would recover fees." Asked if he would, in fact, do better than recover fees, such as possibly win a billion-dollar settlement as with the tobacco industry, Khorrami says that's a "big if."

At the moment, he adds, he's only concerned with the money being made by the ADA. Even if they only make a dollar from amalgam manufacturers through the association's Seal of Acceptance program, that's an economic interest.

In the class-action suits filed by Khorrami, the ADA is accused of conspiring to prevent patients from obtaining accurate information about mercury amalgam. For one thing, the association "deliberately intended to disguise mercury amalgam fillings as silver.

"This deception takes the form of concealment, openly false representations, and an outward aggression toward those who do not agree with the defendants," the suit alleges.

As further proof of this, Khorrami cites the ADA's defamation suit filed against him. Despite the suit, however, Khorrami seems outwardly calm about the pending case. "I have nothing to worry about," he says.

The scientist

Boyd Haley, Ph.D., professor and chairman of the chemistry department at the University of Kentucky, is happy the ADA is suing Khorrami for defamation because now the association has to go to court and discuss the issues.

"I want to see them put their expert witnesses on the stand," says Haley, "and then you walk up and lay 100 papers in front of them that talk about mercury toxicity and talk about mercury coming out of amalgam fillings."

To Haley, the great amalgam debate is simple: Mercury is toxic. Keep it out of the mouth. End of story.

"Can I prove that chronic exposure causes any one specific disease? Well, that takes a long time to do that kind of research. It's hard to prove that," says Haley, who even some of his critics say has earned a solid reputation as a researcher. He's received millions in funding from the National Institutes of Health between 1975 and 2000 for various research projects that led him to develop photoaffinity labeling with nucleotides.

It was his work with photoaffinity labeling while researching Alzheimer's disease that drew him to the amalgam debate in about 1992. Shortly after publishing a study that found mercury caused aberrancies in rat brains similar to those found in human brains with Alzheimer's disease, he came under attack by the dental profession.

"Then I started being called a quack and a crackpot," he recalls. "And that's what really got me irritated, because I was being very cautious."

Haley, for instance, doesn't say removing amalgam will cure any disease. On the other hand, he does suggest that doing so would reduce a person's exposure to mercury and that would take "an oxidated stress off of the body—a very significant one."

He admits that he's suggested to people with one disease or another that he would have his amalgam removed if he had the same problem. "When they do, they get better," he notes.

When his wife, Sandra, had her amalgam removed, he says her energy level increased.

Anecdotal evidence aside, Haley simply can't understand the ADA's position on amalgam, which is that it is safe and no scientific evidence exists that shows any cause-and-effect relationship between mercury in dental amalgam and any disease. "If you say wait until you prove that this toxic material is really reaching a concentration to harm a significant number of human beings," says Haley, "it seems to me that that's kind of a heartless way to look at protecting the public."

Like Khorrami, Haley discounts the NIH amalgam study on children designed to address the very questions Haley and others like him have raised. He says he is suspect of the National Institute of Dental and Craniofacial Research and its role in that study.

While Haley could not decide who should do such a study, he is emphatic that the ADA should admit it has made a mistake and change it, instead of belittling people who have done research.

"I have a good reputation," Haley adds. "I've published too much that everybody has repeated, and I haven't had to write a retraction ever in my life that I did anything that wasn't right."

What's more, he continues, he published a paper in 1992 that suggested glutamine synthetase was a possible diagnostic marker for Alzheimer's disease. Last March, Haley says, other researchers published a study that found that to be the case. "The increase of the release of that enzyme from the brain tissue and the inhibition of it is due to mercury toxicity.

"So I have a history of being right when I talk about things. I'm very careful."

In the years since publishing that first paper suggesting a link between mercury and Alzheimer's disease, Haley says he's tried to share the information with the appropriate government agencies and the ADA, hoping that they would then take care of the alleged amalgam problem. "But you write letters and they don't even respond to them.

"So now I've become more of an activist because I have lost total respect for the dental branch of the Food and Drug Administration and for the ADA," he continues. "If they were honest people, they'd invite me to a talk and beat me up."

As for the government reviews of the science questioning the safety of amalgam, Haley discounts them because he says they were conducted by a committee consisting largely of dentists and material scientists.

If anyone believes anything the government says anymore, then Haley is mistaken. One of the U.S. Public Health Service reviews evaluated 175 citations related to the potential adverse effects of mercury in dental amalgam. "The citations represented an assortment of literature, including peer-reviewed publications, non-refereed publications, untranslated foreign documents, print media articles and letters to the editor," according to the FDA. Scientists from the Office of Science and Technology "performed a triage of the citations" so that evaluation could focus on studies that met a set of criteria established by the review group.

"This process resulted in 57 articles, which were reviewed by scientific experts from FDA, CDC and NIH representing disciplines of general toxicology, neurotoxicology, immunotoxicology, epidemiology, dental materials and clinical dentistry," the FDA reports. "These experts commented on the strengths and weaknesses of each paper, the appropriateness of methodologies, control groups and statistics, and whether the conclusions were supported by the data. The conclusions drawn by these experts were overwhelmingly unanimous. None of the reviewers suggested that any study under review would indicate that individuals with dental amalgam restorations would experience adverse health effects."

All lies, according to Haley. To counter such alleged misinformation, Haley collected a myriad of anti-amalgamist studies, papers and other information and posted all of it to the Web site of ALT Inc., a company he co-founded in 1997 that, among other things, sells nucleotide photoaffinity probes to researchers.

"I put that mercury stuff on (the Web site) because I got damned tired of the ADA saying there's no science," he says. "It's just something I feel compelled to do because I have a real distaste for people who lie. And the ADA right now is lying to Congress telling them that this is just junk science."

That these reviews can discount the research by anti-amalgamists and that the ADA refers to it as "junk science" is particularly disturbing to Haley. And he plans to retaliate, suggesting that he has considerable influence among the anti-amalgamists to organize a massive letter-writing campaign to Congress. "Even I'm surprised at how much clout I have, not that I have a lot of money or anything, but people think that I'm a very honest person and I pride myself on that. I'm going to make sure Congress gets flooded with a very short request from voters." He wants political leaders to go to Medline on the Internet and type in "mercury toxicity" and "amalgam" and see how much of the resulting list of research links looks like junk science.

Like Khorrami, Haley seems convinced that the ADA would discredit any science questioning the safety of amalgam because of the association's economic interest in amalgam. Aside from the money manufacturers pay to have their amalgam products considered for the ADA Seal, Haley claims that dentists earn more by using amalgam than they could by switching to a composite resin, despite the fact that composite resin restorations clearly are more expensive to patients. Amalgam, he says, has a higher profit margin because dentists can produce more amalgam restorations in a day than they can composite resin fillings.

As quick as he is with theories about the economic interests of the ADA and dentists, Haley is even quicker to disavow any financial interest of his own in the ongoing amalgam debate. When asked about the products he sells through the ALT Inc. Web site, Haley insists that "you won't find one thing on there that we sell that makes money off of mercury."

But he does make some money on the message that amalgam is dangerous. The site sells videotapes of various presentations from an ALT-sponsored conference. Several of Haley's presentations on mercury toxicity are available for purchase on the site.

In addition, the ALT site also sells Toxicity Prescreening Assays (TOPAS) to dentists. As the site notes, TOPAS allows dentists "to quickly distinguish between current disease activity and old damage (deep pockets), something not possible with simple periodontal probings." In short, the test reportedly can measure the amount of toxic thiols produced by periodontal disease bacteria.

And, according to a paper authored by Haley, "the reaction of oral mercury from amalgams and the reaction of this mercury with toxic thiols produced by periodontal disease bacteria very likely enhances the toxicity of the mercury being released."

Though this statement would seem to indicate that the TOPAS device could be used by dentists to illustrate to patients the severity of their mercury toxicity exposure, Haley dismissed the notion. "This is something that would escape any but the brightest of them (dentists)," he says.

But, he adds, "there is no doubt" that the thiols produced by periodontal disease bacteria and measured by TOPAS could be used to indicate to a patient that his or her mercury vapor exposure will be more severe.

Haley notes, though, that the site really doesn't make any significant income from the videotapes or TOPAS. The main income is from the sale of photoaffinity nucleotide analogs to researchers.

The lobbyist

A federal law abolishing the use of mercury in amalgam is the best thing that could happen to the American Dental Association, says Charles Brown, a partner in the Washington, D.C., law firm of Swankin & Turner.

If a bill introduced in Congress last November by Rep. Diane Watson (D-Calif.) passes, dentists would have to phase out the use of mercury amalgam by 2007. As far as Brown is concerned, that bill would give the ADA "a nice exit strategy."

Should the Watson bill succeed, however, that would seem to strengthen the class-action lawsuit attempting to hold the ADA liable for alleged injuries caused by the mercury in amalgam. That puts Brown in a pivotal role in the debate. Brown, who serves as co-counsel alongside California attorney Shawn Khorrami in that lawsuit, also is a registered lobbyist in Congress working for passage of the Watson bill.

And Brown warns the ADA that without the "easy out" offered by the Watson bill, the very existence of the association could be in jeopardy.

If dentists don't stop using amalgam, Brown suggests, "a lot of people are going to get sick and a lot of dentists are going to get sued." While dentists may have been able to claim ignorance of the problem as recently as last year, he says, they can no longer keep putting mercury in their patients and say they had no idea it was unsafe. "They cannot confine themselves to reading the ADA journal and refuse to read anything else and then say, 'how could I have possibly known?'"

When the ADA acknowledged some 10 years ago that amalgam emits a small amount of mercury vapor, he adds, that should have been the end of amalgam use. Instead, Brown charges, "they have taken the approach that the public health is not important, that the important thing is protecting themselves. So they've disregarded the health of the patients, the health of their own members. And in that sense the tobacco analogy is a very good analogy. The tobacco industry knew it was wrong."

To Brown, there is no question that there has been a conscious effort by the ADA to keep the truth about amalgam from patients and dentists. "For one thing," he says, "they use the words 'silver fillings' in their brochures. That's a conscious effort to hide the word 'mercury.'

"And they have a gag rule," which Brown says is a conscious effort to prevent dentists from discussing the dangers of amalgam with their patients.

The so-called gag rule is an advisory opinion from the ADA Principles of Ethics and Code of Professional Conduct. Included under the section discussing the principle of veracity, the advisory opinion reads: "Based on available scientific data the ADA has determined that the removal of amalgam restorations from the non-allergic patient for the alleged purpose of removing toxic substances from the body, when such treatment is performed solely at the recommendation or suggestion of the dentist, is improper and unethical. The same principle of veracity applies to the recommendation concerning the removal of any dental restorative material."

What that means, says ADA General Counsel Peter Sfikas, is that it is "perfectly fine" for a dentist to discuss with a patient the advantages and disadvantages of each of the dental restoratives the dentist may consider for treatment. What the advisory opinion is designed to do, adds Sfikas, "is prevent a dentist from telling someone who has a very serious illness such as multiple sclerosis that by taking out the amalgam fillings this person would be cured. It's really trying to prevent someone from preying on the fears of people who have serious medical conditions."

Such explanations aside, if there is a conspiracy masterminded by the ADA, it would follow that the public health agencies that also suggest that amalgam is safe are in on it. Brown disagrees, and he says he's not as critical of the government's role because the government agencies are all over the place. "I don't try to make a statement about the government because it's too big," he adds. "There are too many agencies to say. You'd have to start looking into each agency."

But that hasn't stopped him from going after state dental boards in his role as national counsel with Consumers for Dental Choice, a coalition of anti-amalgam groups. A Yale Law School graduate and a former attorney general of West Virginia with a particular interest in antitrust matters, trade regulation and consumer protection, Brown took on Consumers for Dental Choice as a client when the coalition formed in 1996. Among the groups represented by the coalition are Dental Amalgam Mercury Syndrome Inc., the International Academy of Oral Medicine and Toxicology, the American Academy of Biological Dentistry and the Holistic Dental Association.

According to its Web site, Consumers for Dental Choice "supports education of dentists on the removal of amalgams to ensure safe

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