FDA updates amalgam guidance for at-risk groups

The US Food and Drug Administration recently updated its recommendations concerning dental amalgam and potential risks that may be associated with mercury-containing fillings used to restore the missing structure and surfaces of a decayed tooth, according to a press release from the agency.

The FDA has found that certain groups may be at greater risk for potential harmful health effects of mercury vapor released from the device. The agency is recommending that certain high-risk groups avoid receiving dental amalgam restorations when possible and appropriate.

The groups that may be at a greater risk for these harmful effects include:

• Pregnant women and their developing fetuses
• Women who are planning to become pregnant
• Nursing women and their newborns and infants
• Children, especially those under the age of 6
• Individuals with pre-existing neurological diseases such as multiple sclerosis, Alzheimer’s disease, or Parkinson’s disease
• Individuals with impaired kidney function
• Individuals with known allergies or heightened sensitivity to mercury or other components of dental amalgam

The FDA has reviewed scientific literature, monitored reports, and held public discussions regarding the health effects of dental amalgam and amalgam-related mercury vapor for over 20 years. Dental amalgam is a mixture of mercury and a powdered alloy made up of silver, tin, and copper. The amalgam releases small amounts of mercury vapor over time, the FDA’s statement read. How much vapor is released can depend on the age of the filling, as well as the person’s habits, such as teeth grinding. Low-levels of inhaled mercury vapor are generally not harmful to most people, but these high-risk individuals may be at increased risk of adverse health outcomes.

These uncertainties in the most vulnerable patients are why the agency is recommending people who may be at high risk for adverse health effects of mercury exposure use non-mercury alternatives to dental amalgam, the FDA’s statement read. Such alternatives could include composite resins and glass ionomer cement fillings. Dental amalgam-related mercury vapor release may be highest during placement or removal of the filling. Therefore the FDA does not recommend the removal or replacement of existing amalgam fillings in good condition unless it’s deemed medically necessary because removing intact amalgam fillings in good condition can cause a temporary increase in exposure to mercury vapor and the potential loss of healthy tooth structure.

While the FDA’s reviews have generally arrived at the same conclusion—that the majority of evidence suggests exposure to mercury vapor from amalgam does not lead to harmful health effects for most people—uncertainties remain about the effects of long-term exposure to amalgam may have on the high-risk groups listed above, the potential for mercury in amalgam to convert to other mercury compounds in the body, and whether the accumulation of mercury in some body fluids and tissues results in other unintended health outcomes.

It’s the FDA’s stance that the benefits of materials in agency-approved or cleared implantable and insertable medical devices outweigh their risks for most patients. However, it’s crucial to closely monitor and evaluate new benefit-risk related data, according to the press release.

For more information, read the FDA’s information for patients about amalgam fillings here, or read about the FDA’s recommendations regarding the risk of amalgam use in certain populations here. The agency’s meeting of the Immunology Devices Panel of the Medical Devices Advisory Committee was held in November 2019, and the meeting materials can be accessed here.