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.
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:
- A warning against the use of dental amalgam in patients with mercury allergy;
- A warning that dental professionals use adequate ventilation when handling dental amalgam;
- A statement discussing the scientific evidence on the benefits and risk of dental amalgam, including the risks of inhaled mercury vapor. The statement will help dentists and patients make informed decisions about the use of dental amalgam.
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.”