Should a United Nations global treaty on mercury pollution become reality, America's dentists could find the U.S. government's proverbial hands inside their patients' mouths.

That is the goal of "mercury-free" activists, who are pinning their hopes on an international consensus to get a ban on dentists filling routine cavities with "silver amalgam" containing mercury, already present in the mouths of some 122 million Americans.

At a meeting earlier this week to discuss the next round of "mercury talks" at a U.N. Environmental Program (UNEP) summit in Nairobi, Kenya -- scheduled for Monday -- State Department officials reportedly said they hope to garner support for a legally-binding treaty to reduce worldwide mercury emissions.

"We're working towards dentists eventually being mandated to stop using 'silver fillings' to plug cavities," Dr. David Simone, a dental surgeon from Northbrook, Ill., who attended the State Department meeting, told FoxNews.com. Simone is chairman of the Environmental Committee of the International Academy of Oral Medicine & Toxicology (IAOMT), a worldwide professional network that advocates the practice of mercury-free dentistry. 

"That is why this treaty is so important: it addresses the fact the mercury is unhealthy for the body and the environment and validates the need for it to be replaced with safer alternatives," he said.

Now in its infancy, the treaty could include creation of a standard method to measure mercury emissions and a gradual "phase down" of certain products containing mercury. But how and when that will take shape remains unclear, according to a spokesman from the department's Bureau of Oceans, International and Scientific Affairs.

During the meeting, Simone said State Department officials reiterated that amalgam fillings, which are composed of several metals, including mercury, will likely remain on the U.N.'s designated list of products to eventually be phased down with passage of the so-called global mercury treaty.

But even as the U.N. conference proceeds, a contentious debate persists about the potential health risks associated with mercury exposure from amalgam fillings, and competing studies conflict over whether the amount of mercury in fillings translates into significant health risks associated with mercury exposure.

Advocates for getting rid of the dental profession's 150-year-old practice of using amalgam to fill cavities say the fillings can leach mercury into the mouth

But in 2009, the U.S. Food and Drug Administration reaffirmed its position that dental amalgam is safe and effective, a position lauded by the American Dental Association, the nation's largest association of dentists.

"FDA has left the decision about dental treatment right where it needs to be ― between the dentist and the patient," then-ADA President John S. Findley said after the policy statement.

In many countries, amalgam remains the most popular material for cavity repair. Notable exceptions are Norway, Denmark and Sweden, which banned the use of amalgam fillings in 2009, the same year the FDA declared it safe. 

Freya Koss, president of Pennsylvania's Coalition for Mercury-Free Dentistry, says the FDA's position is not only wrong, but dangerous. Koss attributes being stricken with Myasthenia Gravis, an auto-immune disease of the nerves and muscles, less than one week after having an old mercury amalgam filling removed.

She fought for the passage of a Philadelphia law that now requires dentists in the city to provide a brochure informing patients that amalgam fillings contain 50 percent mercury and may be harmful to their health. 

"Unless there's a global mandate telling them to do so, who is going to make dentists tell their patients the truth?" Koss asked. "If the government knows mercury is dangerous, they have an obligation to educate people."

Dr. Marc Rosenblum, director of general dentistry and biomaterials research for the University Medical & Dental School of New Jersey, disagrees. 

"There are really two driving forces in this debate over amalgam going on here -- political and scientific," he said. "Based on the science, I don't think there's a place for either the State Department or the U.N. to be involved."

Robert Ferguson, founder and president of the Science and Public Policy Institute (SPPI), sees the controversy surrounding dental amalgam as little more than the latest scare to drive more regulation.

"The public should be cautious about the alarm over dental amalgams," Ferguson said, pointing to similar concerns of a now disputed link between mercury-based preservatives in vaccines and autism. 

"Unless a connection can be reliably determined with a wealth of scientific study, regulations end up having a cumulative effect of limiting choices," he said.