Photo: David Joyce via Flickr
At more than 100,000 offices and clinics across America, dentists stay busy placing and removing amalgam fillings as they care for their patients.
Dental amalgam – a mixture of metals such as silver, tin, copper and zinc bound together by mercury – is valued by clinicians for its workability, low cost and strength. Regulated as a medical device, dental amalgam is considered safe for most patients over the age of 6. Continue reading
Preventing tooth decay not only helps people; it helps the environment, according to a newly announced United Nations-backed convention.
Less tooth decay means fewer amalgam fillings and, from an environmental standpoint, that means less mercury waste entering the world’s air, water and soil.
Photo by tallasiandude, via Flickr.com.
The Minamata Convention on Mercury – approved on Jan. 19 in Geneva and named after a Japanese city where the industrial release of mercury led to devastating health consequences – aims to reduce the amount of mercury released into the environment by mining operations, power plants and other industries and businesses, including dental practices.
The hazardous use of mercury in gold mining was a major focus of the convention, which requires governments to develop national action plans to ban the most harmful forms of mercury use.
While the accord did not ban the use of dental amalgams, it called for nations to set objectives aimed at dental disease prevention and health promotion that would minimize the need for dental restorations. The treaty also called for research and development of mercury-free materials for restorations and for the promotion of sound environmental practices that would reduce the release of mercury waste by dental clinics.
The convention was applauded by dental groups, including the International Association for Dental Research and the American Dental Association which oppose the banning of mercury for dental uses.
“Caries, the disease that causes tooth decay, afflicts 90 percent of the world’s population, making this a global public health issue,” ADA president Dr. Robert A. Faiella told ADA News.
“The ADA is gratified that the treaty conditions pertaining to dental amalgam protect this important treatment option without restrictions for our patients while balancing the need to protect the environment. It is vital for people throughout the world to continue to have access to a safe, durable, affordable treatment for tooth decay.”
Dental amalgam, which contains mercury predominantly bound to metals including silver, zinc, copper and tin, has been used for dental restorations for over 150 years. And while questions about its safety remain a subject of intense debate for some consumer groups, amalgam’s continued use has long been defended by mainstream dental organizations.
The U.S. Environmental Protection Agency defines mercury as a neurotoxicant and observes that “outbreaks of methylmercury poisonings have made it clear that adults, children, and developing fetuses are at risk from ingestion exposure to mercury.”
Exposure can occur when people eat fish containing methylmercury, break products containing elemental mercury, or use compounds that contain mercury, according to the EPA.
In 2009, the US Food and Drug Administration acknowledged that dental amalgam “releases low levels of mercury vapor, a chemical that at high exposure levels is well-documented to cause neurological and renal adverse health effects.” The rule went on to state that “clinical studies had not established a causal link between dental amalgam and adverse health effects in adults and children age 6 or over.”
The FDA issued a regulation classifying dental amalgam and its component parts – elemental mercury and a powder alloy as a Class II (moderate risk) medical device, recommending that the product labeling include:
The agency revisited the question of amalgam safety in 2010. At a two-day meeting, the question of how much mercury people with amalgam fillings were exposed to was put to an expert panel.
The panel was asked to weigh questions about the validity and usefulness of the many clinical studies that focused upon the possible risks of dental amalgam and also heard testimony from practitioners who vouched for the safety of amalgam and patients who blamed a range of illnesses on their amalgam fillings.
Based upon the feedback of the panel, and its own review of testimony about risk assessment and the value of various clinical studies, the FDA was expected to decide whether to make changes in how it regulates the use of the material. When asked for an update on such a decision, FDA spokeswoman Michelle Bolek said, “The FDA is continuing to review and evaluate the safety of amalgam and will let the public know if there are any changes to our current recommendations.”
As The New York Times‘ Toxic Waters captures attention across the country, the Associated Press has released its own story about government oversight failing to stop massive contamination, this time from abandoned mercury mines in California.
The AP’s Jason Dearen found that the government has only tried to clean up a handful of the hundreds of abandoned mercury mines in California’s coastal mountains.
According to Dearen, “mercury mines are the biggest sources of the pollution in San Francisco Bay and the Sacramento-San Joaquin River Delta, the largest estuary on the Pacific Coast.” At least 100,000 impoverished people are eating fish tainted with levels of toxins beyond EPA guidelines, Dearen found.
“Records and interviews show that federal regulators have conducted about 10 cleanups at major mercury mines with mixed results, while dozens of sites still foul the air, soil and water.”
In the Columbia Daily Tribune, dietitian and columnist Melinda Hemmelgarn discusses a 2005 study recently published in Environmental Health in which researchers found detectable levels of mercury in nine out of 20 samples of high fructose corn syrup.
Hemmelgarn says the neurotoxin get into high fructose corn syrup when “processors use mercury-grade caustic soda to separate corn starch from the corn kernel.” Most processing plants now use mercury-free technologies, she said, but consumers have no way to distinguish between syrup made with mercury and syrup made without it.
Renee Dufault, who directed the 2005 study, said her findings were ignored by the FDA and, until this January, unpublished by scientific journals. According to Dufault, the Corn Refiners Association called the study outdated, saying that they haven’t used mercury in syrup production for years.
Dufault responds by pointing to a 2008 small-scale regional study conducted by the Institute of Agriculture and Trade Policy that tested 55 consumer products containing significant amounts of high fructose corn syrup and found mercury in almost a third of them.
