Dentists in US battle gag over warning about fillings

Kathryn Kranhold

Dentists are suing state regulators in the US over what they contend is a gag order preventing them from discussing with patients the potential health hazards of the most common form of dental fillings. At issue are those silver-coloured fillings that dot most people’s teeth. Referred to by the dental profession as silver amalgam, the fillings are actually about half mercury, with some silver, copper, tin and zinc mixed in.

Mercury opponents argue that mercury vapour from the fillings seep into the body, contributing to a range of health problems from fatigue to immunity suppression to neurological diseases. The dental establishment, including the American Dental Association, argues that low level of vapour causes no harm and that raising such safety issues with patients would unduly alarm them. The science on the issue is inconclusive.

The suit was filed last Wednesday in federal court in Greenbelt, Maryland, by five dentists and seven patients claiming injury from mercury in their fillings. The plaintiffs argue that dental regulators use “control of dental licences to punish, or to threaten punishment of dentists who criticise mercury amalgam,” violating the dentists’ constitutional right to free speech.

The dentists’ attorney, Charles Brown of Washington, D.C., says the plaintiffs want the court to order licensing boards to stop enforcing any policy that “prevents, limits or intimidates dentists” from discussing the controversy or advocating “mercury-free” dentistry. The suit also seeks certification as a defendants’ class action naming 50 of the country’s 52 licensing agencies.

In a statement, Maryland’s licensing board administrator, Art Williams, said the board “acted lawfully and has done so in order to protect consumers”.

The dental establishment maintains that some dentists have used the controversy to encourage patients to remove amalgam fillings with mercury and replace them with more expensive material such as gold, porcelain and a tooth-coloured resin composite. Resin, the least expensive alternative, costs as much as 25 per cent more than fillings containing mercury.

The Amalgam Wars began in the mid-1800s, when dentists first started using mercury-based material to treat tooth decay. Originally, it was the dentists who used mercury who came under fire from colleagues who didn’t believe it was as safe as gold or tooth extractions. But soon mercury became the material of choice, mostly because it was cheaper and easier to use — it was less painful than having hot gold poured into a tooth. In 1976, when the US Food and Drug Administration began regulating medical devices, it grandfathered in mercury-based fillings as an approved dental material.