Mercury Fillings and Children: What Parents Should Know

What is a "silver" filling?

Dental amalgam is the silver-colored material dentists have used to fill cavities for more than a century. It is a mix of metals, and about half of it by weight is elemental mercury. Amalgam is strong and inexpensive, which is why it is still placed in some offices and covered by some public programs. It releases small amounts of mercury vapor, especially when the tooth is chewing or grinding.

The alternatives are tooth-colored materials: composite resin (the white fillings most adults now get) and glass ionomer, a material often used in baby teeth that also releases fluoride.

What the new study found

Researchers led by Kelli Williams, PhD, MPH, of the University of Pennsylvania analyzed national health survey data (NHANES, 2015–2018) on about 6,700 U.S. children and teens ages 1 to 19. The survey included dental exams plus blood and urine mercury tests. The study was published in the Journal of the National Medical Association on September 29, 2026.

• Fillings and mercury go together. Among children ages 1 to 5, those with amalgam fillings were about 25 times more likely to have detectable inorganic mercury in their blood than those without.
• Mexican American toddlers and preschoolers (ages 1 to 5) were about four times as likely as white children the same age to have amalgam fillings, and about six times as likely to have detectable blood mercury (11.9% vs. 1.6%).
• Asian children and teens (ages 3 to 19) had the highest rate of detectable urine mercury: 42% vs. 18% of white children.
• Black children were about 1.65 times as likely as white children to have detectable mercury.

The authors' concern is timing. The years before age 6 are when the brain and nervous system develop fastest, and that is the age group the FDA singles out as most sensitive to mercury.

What the study does not show

This is an important distinction for parents. The study measured whether mercury was detectable, not whether children were harmed. It was a snapshot in time, so it shows a strong link between amalgam fillings and mercury levels, but it did not follow children to see whether their health or development was affected. Diet (certain fish) and other sources also contribute to mercury exposure. What the study does show clearly is a gap: children of color are more likely to receive the older filling material during the years they are most sensitive to it.

What the FDA recommends

In 2020 the U.S. Food and Drug Administration recommended that certain higher-risk groups avoid getting new amalgam fillings "when possible and appropriate," and receive alternatives such as composite resin or glass ionomer instead. The groups it named include:

• Children, especially those under 6
• Pregnant women, women planning a pregnancy, and nursing mothers
• People with certain neurological diseases or impaired kidney function
• People with a known mercury allergy or sensitivity

Public programs are moving away from amalgam

In July 2026 the federal Centers for Medicare & Medicaid Services urged every state Medicaid program to phase out coverage of mercury fillings and pay for tooth-colored ones instead. It is a recommendation, not a requirement, so coverage will vary by state. The Indian Health Service plans to stop using amalgam in its clinics by 2027, and the countries that signed the international Minamata Convention on mercury have committed to phasing out dental amalgam by 2034.

What to ask your child's dentist

At Comfort Family Dental, the fillings we place are tooth-colored. Most importantly, we would rather your child never need one: see our page on children's dentistry for first visits, sealants and fluoride, or call us with questions about fillings your child already has.

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