Fillings regulation may sound dull. But for the dental business, the debate over mercury-containing fillings is just as divisive and loud as societal arguments about gun control, the Vietnam War or scoring figure-skating contests. It's the Protestant revolt -- questioning a basic practice of dentistry for more than 150 years.

The more extreme members of each side accuse the other of trying to defraud the public to make a fast buck. The debate has led to lawsuits, a pending federal bill and the firing of California's entire state dental board.

"Man, it's a really hot issue," said Fred Berman, director of a toxicology resource center at Oregon Health & Science University. "There's certainly enough controversy and enough people on both sides of the issue. Sorting it out is the problem."

The great majority of dentists, backed by the Oregon and American dental associations, say silver amalgam fillings are safe except for a very small group of people with mercury allergies. The bulk of scientific research backs that position. Last month, the Food and Drug Administration released a review of research on fillings that said "no valid scientific evidence has ever shown that amalgams cause harm to patients."

"All the mainstream scientific literature that I've read indicates that the silver filling -- even though it contains about 50 percent mercury and even though it does leach mercury vapor in small amounts -- has no negative effect on human health," said Gordon Empey, dental director for Multnomah County Health Department.

But a vocal minority of dentists and patients, called "anti-amalgamists," think silver fillings pose serious health risks. They point out that amalgam fillings are half mercury by weight and that mercury is a toxic metal. They also note that a few nations, including Canada and Germany, have advised pregnant women and young children to use other types of fillings.

"There's a strong and growing number of dentists who are opposed to using mercury," said Charlie Brown, a Washington, D.C., lawyer with Consumers for Dental Choice, an anti-amalgam group that Brown said grew out of "a national victims' group of people who have gotten sick from mercury in their mouth."

A rule barring fraud What the nine-member dental board will consider today is a 1990 rule that says "it is a fraud and a violation of the Dental Practice Act for a dentist to advocate to a patient the removal of" properly working amalgam fillings, just to substitute a filling material that doesn't contain mercury. Fraud is grounds for the board to remove a dentist's license to practice.

The board passed that rule to keep dentists from selling expensive filling-replacement procedures by claiming they would cure diseases, said Jo Ann Bones, the board's executive director. Some anti-amalgamists claim that the silvery fillings cause ills -- including asthma, depression, diabetes, multiple sclerosis and Lou Gehrig's disease -- and say that removing the fillings can cure those diseases. There is almost no scientific evidence to support such claims.

But the board's rule has a serious flaw, according to Sandra Duffy, a Lake Oswego lawyer leading today's effort to kill the regulation. By governing what dentists can say, not what they do, it is "an unconstitutional abridgment of free speech," she said.

The board never investigated or disciplined any dentist for violating that rule. But at least a few Oregon dentists said they feel it limits their speech.

"I have always been fearful to tell the patients that mercury is not good for you," said Amy Khajavi, a Portland dentist who doesn't use mercury fillings and who plans to speak at today's hearing. Khajavi said she has never heard from the board about her views. "Nobody has approached me directly saying, 'Don't do that.' But there was the fear that my license could be jeopardized."

Free speech At Duffy's urging, the American Civil Liberties Union sent a letter to Attorney General Hardy Myers saying the policy violates Oregon and U.S. free speech protections. The ACLU also said the board adopted the rule without following the right legal process, including a public hearing.

The ACLU could get an easy win. Bones said the board's lawyer already told members that they either need to reword or rescind the rule to address those worries. The lawyer will recommend rescinding the rule this afternoon, she said. That's mostly because the board does not "recommend what materials dentists should use," Bones said. She added that "there was no intention for that to be a gag order."

Bones said the board could still discipline a dentist who convinces patients to replace perfectly good amalgam fillings by making bogus health claims. To do that, the board would have to have a complaint and determine that the dentist was not following "acceptable patient care," as defined by standard dental teaching and practice. "The bottom line is, would any reasonable dentist have done this," Bones said.

The ACLU would be satisfied with that, said Julia Markley, the lawyer who wrote Myers. The group is worried about a policy limiting speech, not necessarily limits on actions.

"I would hope the Board of Dentistry would protect our health and prohibit dentists from doing certain things," Markley said.

A matter of discipline But rescinding the rule while still considering discipline for dentists who do pull and replace amalgam fillings would not satisfy anti-amalgamists, Brown said. If that happens, he said, there will still be a de facto rule against replacing amalgam for health reasons, and he'll urge the ACLU to pursue a lawsuit.

Brown added that he hoped to get the ACLU interested in the issue in other states. It's part of a broader campaign against mercury fillings. That effort's most notable success has been in California, where the legislature dissolved the state dentistry board last year after it delayed issuing a warning about the health pros and cons of amalgam.

The legislator who led that effort, Diane Watson, is now a member of the U.S. House. She has drafted a bill that would phase out the use of amalgam fillings entirely over five years, an idea that heartens Brown's group.

"We now feel we can move to our top goal, which is to abolish mercury dental fillings," he said. You can reach Andy Dworkin at 503-221-8239 or by e-mail at andydworkin@news.oregonian.com.