There is a substance in the mouths of millions of people that can cause inflammation of the lungs, tremors, coughing up blood and - in some cases - death.

That substance is mercury, and it is just one component of amalgams, the silver fillings used by dentists.

A joint panel of Food and Drug Administration advisers voted 13-7 against a federal report declaring that the dental fillings are completely safe, citing the need for further study. After a second 13-7 vote by the advisers, the FDA consultants said the report's conclusions were unreasonable due to the large amounts of quality information available.

Tom Barth, a local dentist, said he thinks the amalgam fillings are proven to be safe. He said most negative criticism of the silver fillings has been from people who give their opinions instead of citing actual research or proof.

"I don't think it's better or worse anyway," Barth said. "Amalgam is proven to be a very safe restoration. We have a lot of people who are not in mainstream dentistry giving opinions that aren't researched.

"We don't treat our patients by opinions - we treat them by research. Amalgam has a long track record of being a good restorative."

Barth said he has amalgams in his own mouth and is not worried about mercury poisoning. He said amalgams have a good track record, better than composites, in fact, because they have been around longer.

"There are people that don't like amalgam because of mercury, but when you condense it, a lot of the mercury comes to the surface," he said. "As you're carving it down, you get most of the mercury rich material in it. What mercury that is left in the metal, when it hardens, it remains in the metal. Nobody is being poisoned with the mercury in the amalgams."

Randy Regier, a K-State graduate and practicing dentist in Overland Park, Kan., agrees that amalgam is safe. However, he also said amalgam causes decay in teeth due to metal contraction that causes separation between the filling and tooth.

"I don't like them. They do so much damage to teeth over time," Regier said. "I've got amalgams in my mouth. I wouldn't have them in there if I thought they were unsafe, but the composite bonding is such superior material over amalgams, so anyone putting in amalgams still is practicing malpractice, I feel."

Ryan Gallagher, freshman in biology, plans to attend dental school. He said he agrees with the FDA advisers' decision.

"I think it's probably something that we should have looked into before we decided to put it into people's mouths," Gallagher said. "A lot of things we consider to be harmless usually aren't."

However, the American Dental Association disagrees. Dean Cloutier, president of the Connecticut State Dental Association, wrote a response to negative media coverage on the ADA's Web site, www.ada.org. In his response, Cloutier said special-interest groups are using amalgam to set public policy and are not listening to the experts.

"Major organizations entrusted with protecting the public's health have reviewed a veritable mountain of scientific evidence and concluded that amalgam is a safe, effective material to treat cavities," Cloutier said. "These include the National Institutes of Health, the Centers for Disease Control and Prevention, the World Health Organization and the American Dental Association.

"Who do we want advising us about health care? These trusted scientific and public health organizations or a group that believes these agencies and the nation's dentists are involved in a vast conspiracy?"