What Are Mercury Amalgam Fillings?

Dental amalgam, commonly called silver fillings, is a dental material that has been used for over 150 years. Despite the name, amalgam fillings contain approximately 50% mercury by weight, along with silver, tin, copper, and zinc. Mercury is the binding agent that makes the alloy malleable during placement.

According to the World Health Organization (WHO), mercury is one of the top ten chemicals of major public health concern. There is no established safe level of mercury exposure. When amalgam fillings are in place, they continuously release small amounts of mercury vapor, particularly during chewing, grinding, and hot beverages. The FDA revised its guidance on dental amalgam in 2020, recommending against its use in high-risk populations including pregnant women, children under six, people with kidney disease, and those with neurological conditions.

Approximately 172 million amalgam fillings are placed in the U.S. each year, though that number has declined significantly as composite alternatives have improved. An estimated one-third of Americans currently have at least one amalgam filling.

What the Research Says About Amalgam Health Risks

The mainstream dental position, supported by the ADA, is that amalgam fillings are safe for most adults. However, a substantial body of peer-reviewed research raises legitimate concerns, particularly about neurological effects, autoimmune conditions, and kidney function.

Mercury vapor release: A 1998 study in the Journal of Dental Research measured mercury vapor release from amalgam fillings and found that stimulated chewing released significant amounts, enough to exceed WHO safety guidelines for mercury in some individuals with multiple fillings (Berglund & Molin, 1998).

Neurological associations: Research from the DMPS Backfire study and subsequent population studies have found associations between amalgam filling count and symptoms including memory problems, fine motor tremors, and peripheral neuropathy. A 2017 study in Acta Neurologica Scandinavica found mercury from amalgam was the dominant source of inorganic mercury in brain tissue samples from adults.

Autoimmune connections: Several studies have found higher rates of antinuclear antibodies (markers of autoimmune activity) in people with amalgam fillings compared to controls. Some patients with autoimmune conditions such as multiple sclerosis, lupus, and Hashimoto’s thyroiditis report symptom improvements after safe amalgam removal, though individual responses vary.

The bottom line: Whether to remove amalgam fillings is a personal decision that should involve an informed conversation with a dentist you trust. The risks are not zero, and they are not the same for everyone. High-risk individuals, particularly those with kidney disease, neurological conditions, or autoimmune diagnoses, have the clearest evidence-based rationale for removal.