The short answer: Mercury fillings, the silver-colored fillings dentists call amalgam, are about half mercury and release small amounts of mercury vapor. Large trials and expert reviews have not found that this harms most people, so health agencies advise against removing fillings in good condition, which costs healthy tooth and can briefly raise exposure. The FDA suggests that pregnant women, children and some other groups avoid new amalgam when possible. Controlled studies do not support claims that removal cures chronic illness. A global treaty will phase out amalgam by 2034, with exceptions, to reduce mercury pollution.
Some dentists who describe themselves as “biological,” “holistic” or “integrative” oppose amalgam fillings and promote removing them, and one of the field’s main academies includes heavy-metal “detoxification” in its definition of the approach (Jucá et al., 2024). Worry about the mercury in fillings goes back a long way: a dispute over amalgam in the 1840s, the so-called amalgam war, eventually forced the first national dental society in the United States to disband (Hyson, 2006).
This article looks at what amalgam is, how much mercury it releases, what the strongest studies show about health effects, whether removing fillings helps, and whether amalgam is being banned.
What is a silver (amalgam) filling?
Dental amalgam, often called a silver filling because of its color, is a mixture of mercury, silver, copper, tin and zinc. It is about half mercury by weight (U.S. Food and Drug Administration, 2020b).
Amalgam is effective and relatively inexpensive, and it is still the material of choice for back teeth in some low- and middle-income countries (Worthington et al., 2021). Its drawbacks include its metallic color, the need to cut away more of the tooth than bonded fillings usually require, and concerns about its mercury content (Yikici Çöl et al., 2025).
Once in place, amalgam fillings release small amounts of mercury as a vapor. How much depends on the number and age of the fillings and on habits such as tooth grinding and gum chewing (U.S. Food and Drug Administration, 2020b).
How much mercury do fillings release?
Mercury comes in different forms. Fillings release elemental mercury vapor, which can be breathed in (DeRouen et al., 2006; U.S. Food and Drug Administration, 2020b). Fish and shellfish are the main source of another form, methylmercury (World Health Organization, 2024).
One study measured mercury in the blood and urine of adults before and after their fillings were removed. It estimated the daily dose absorbed from amalgam at up to about 3 micrograms (µg) for an average number of fillings and 7.4 µg for people with many. Both were within limits proposed by the World Health Organization (WHO) and US agencies, and below the WHO’s tolerable dose of 30 µg a day (Halbach et al., 2008).
In the children’s trials described below, children with amalgam fillings had more mercury in their urine than children with tooth-colored fillings, but the levels were lower than those known to be toxic (Worthington et al., 2021).
Are mercury fillings safe? What the strongest studies found
Two randomized trials in children
In 2006, two randomized controlled trials published their results side by side. Each assigned children who needed fillings to either amalgam or tooth-colored composite resin and then followed them for years.
The New England Children’s Amalgam Trial enrolled 534 children aged 6 to 10 in Boston and Maine. Over five years, they had an average of 15 tooth surfaces filled. There were no statistically significant differences between the groups in IQ, memory, visual-motor skills or kidney function. The groups’ IQ changes differed by 1.0 point (95% confidence interval −0.6 to 2.5), and the authors noted that very small effects on IQ could not be ruled out (Bellinger et al., 2006).
The Casa Pia trial in Lisbon, Portugal, enrolled 507 children aged 8 to 10 and followed them for seven years. Memory, attention, visual-motor function and nerve conduction showed no statistically significant differences between the groups at any point. From five years on, children in the composite group needed about 50% more additional restorative treatment, such as new or repaired fillings (DeRouen et al., 2006).
A question about genetic susceptibility
Later analyses of the Casa Pia children tested whether common gene variants change how children respond to mercury. Among boys with certain variants, higher mercury exposure was linked with poorer results on a broad range of neurobehavioral tests; among girls, the effects were much more limited (Woods et al., 2014).
These analyses were carried out after the trial ended, and they measured mercury from all sources, not only from fillings (Woods et al., 2014). They raise a question for future research rather than settling it.
Pregnancy
The Norwegian Mother and Child Cohort Study looked at 69,474 pregnancies. The number of teeth with amalgam fillings was not linked with preterm birth, low birth weight, birth defects or stillbirth (Lygre et al., 2016).
What expert reviews conclude
A 2021 Cochrane review found very low-certainty evidence suggesting there may be no clinically important difference in safety between amalgam and composite fillings (Worthington et al., 2021). A 2015 opinion for the European Commission concluded that amalgam carries a low risk of adverse health effects for the general population, but that alternatives should be the first choice for baby teeth and for pregnant patients (Scientific Committee on Emerging and Newly Identified Health Risks [SCENIHR], 2015).
The US Food and Drug Administration (FDA) says studies do not show conclusive evidence that amalgam harms the general population (U.S. Food and Drug Administration, 2020b). It also says that while low levels of inhaled mercury vapor are generally not harmful to most people, some groups may be at increased risk, and uncertainties remain about long-term effects in those groups (U.S. Food and Drug Administration, 2020a).
Who should avoid new amalgam fillings?
In 2020, the FDA recommended that people in these groups use alternatives to amalgam whenever possible and appropriate (U.S. Food and Drug Administration, 2020a):
- Pregnant women and their developing babies
- Women who are planning to become pregnant
- Nursing women and their newborns and infants
- Children, especially those younger than 6
- People with pre-existing neurological disease
- People with impaired kidney function
- People with a known heightened sensitivity (allergy) to mercury or other components of amalgam
The FDA does not recommend removing or replacing amalgam fillings that are in good condition unless it is medically necessary. Removal can cause a temporary increase in mercury vapor exposure and the loss of healthy tooth structure, potentially doing more harm than good (U.S. Food and Drug Administration, 2020a). For more on children’s teeth, see the parent’s guide to kids’ teeth.
What is biological (holistic) dentistry?
Biological dentistry is also called holistic or integrative dentistry. The International Academy of Biological Dentistry and Medicine defines it as an approach that includes “mercury-safe” dentistry, testing dental materials for compatibility with each patient, and methods drawing on energy, electromagnetics, sound, light, acupuncture, homeopathy, nutrition and detoxification of heavy metals (Jucá et al., 2024).
The authors of a 2024 study of Instagram posts on the topic note that biological dentists advocate against amalgam and fluoride and oppose root canal treatment, despite scientific evidence to the contrary. Of the 500 most engaged-with posts they analyzed, 68% contained misinformation and 52% were financially motivated, and misinformation was more likely in posts by health professionals (Jucá et al., 2024).
Some of the field’s starting points are sound: the mouth and the rest of the body really are connected, as our guide to how oral health affects your body explains. The problem is claims that go beyond the evidence.
What is SMART amalgam removal?
For removing fillings, groups such as the International Academy of Oral Medicine and Toxicology promote protocols like the Safe Mercury Amalgam Removal Technique (SMART). These combine a rubber dam (a thin sheet that isolates the tooth), high-volume suction and cold-water spray with steps such as oxygen through a nasal cannula, full protective coverings and cutting fillings out in sections. Some dentists also use “detox” agents such as chlorella or activated charcoal (Yikici Çöl et al., 2025).
Does removing mercury fillings improve your health?
What a hospital clinic found
In 1993, Huddinge University Hospital in the Stockholm area of Sweden opened a clinic for people who believed their fillings were making them ill. Dentists, physicians and psychologists examined several hundred patients. Common complaints included widespread pain, weakness, extreme tiredness and dizziness (Langworth et al., 2002).
The patients’ median mercury levels in blood and urine were in the normal range, and the amount of amalgam in their mouths was not linked with their symptoms. Seven percent had a medical condition that had not been diagnosed before, such as thyroid disease, anemia, heart disease, kidney disease or cancer. Twenty-six had a skin-test allergy to mercury, gold or palladium. The researchers concluded that their results did not support mercury from fillings as the cause and that the complaints may have various explanations (Langworth et al., 2002).
The randomized trial
In a trial in Germany, 90 people with complaints they attributed to amalgam, which could not be explained by a medical or psychological disorder, were randomly assigned to one of three groups: amalgam removal, removal plus a “biological detoxification” program of high-dose vitamins and trace elements, or a health promotion program without removal (Melchart et al., 2008).
After 12 months, complaint scores fell by an average of 3.5 points in both removal groups and by 2.5 points in the group that kept their fillings, a difference that was not statistically significant. All three approaches were followed by meaningful improvement, and the detox program added no benefit to removal alone (Melchart et al., 2008).
The Norwegian study
In a project initiated by Norway’s Ministry of Health and Care Services, 32 people with unexplained symptoms they blamed on amalgam had all their fillings replaced. A year later, their score on a general health complaints index had fallen from 43.3 to 30.5. That was a larger drop than the 1.2 points seen in 28 people with similar unexplained symptoms who did not attribute them to amalgam and had no fillings removed (adjusted difference −8.0 points; 95% confidence interval −15.4 to −0.5) (Björkman et al., 2020).
Levels of inorganic mercury in the blood fell after removal, but the researchers found no statistically significant link between people’s mercury levels and their symptoms (Björkman et al., 2023). Because the groups were not randomly assigned, the patients knew their fillings had been replaced and there was no placebo treatment, the study cannot separate the effect of removing mercury from the effects of expectation and extra care.
Is it safe to remove mercury fillings?
Removing an intact filling means losing healthy tooth structure and may briefly raise mercury vapor exposure (U.S. Food and Drug Administration, 2020b).
In a Swedish study, 28 people had all their amalgam fillings removed in a single session, with water spray and high-volume suction. In the 10 treated without a rubber dam, mercury in blood plasma and urine rose significantly afterward; in the 18 treated with one, it did not. A year later, mercury levels in both groups were well below where they started (Berglund & Molin, 1997).
Removal also exposes the dental team. In a dental school training lab, drilling amalgam out of artificial teeth with both water spray and high-volume suction kept mercury vapor between 4 and 19 µg per cubic meter of air, below the local (Alberta, Canada) 8-hour workplace limit of 25 µg. Without either, readings averaged 214 µg, and more than a third exceeded the 125 µg ceiling that should never be crossed (Warwick et al., 2013).
These standard precautions reduce exposure (Berglund & Molin, 1997; Warwick et al., 2013). We could not find controlled studies testing whether extra steps, such as full-body coverings, nasal oxygen or charcoal and chlorella “detox” agents, make any difference to patients’ health.
Do mercury tests and detox programs work?
Some practitioners test for “mercury toxicity” with a provoked or challenge urine test, giving a chelating drug such as DMSA, DMPS or EDTA before collecting urine. A review in the Journal of Medical Toxicology found that these tests are not standardized or validated, that chelators raise urinary mercury regardless of a person’s exposure, and that there are no reference ranges for the results. Because chelating agents can also cause adverse reactions, the review concluded the tests should not be used (Ruha, 2013).
As for detox programs, the German trial described above found that adding a high-dose vitamin and trace-element program to amalgam removal brought no extra benefit (Melchart et al., 2008).
When should amalgam fillings be replaced?
A filling that is cracked, broken or has new decay around it needs repair, whatever it is made of. European experts found no general reason to remove amalgam fillings that are in good condition, except in patients diagnosed with an allergic reaction to one of its components (SCENIHR, 2015).
A related case is a lichenoid contact reaction: a patch inside the mouth that develops where the tissue touches a filling material such as amalgam. In a follow-up study of 44 patients, these contact reactions were significantly more likely to fade after the suspected fillings were replaced than oral lichen planus, a similar-looking immune condition, which did not fade in any case. That makes a proper diagnosis important before replacing intact fillings (Mårell et al., 2014).
Are mercury fillings being banned?
Much of the case against amalgam is environmental. In the United States, dental offices are the main source of mercury reaching sewage treatment plants, about 5.1 tons a year, and most of it is later released to the environment. Under a 2017 rule, the Environmental Protection Agency (EPA) requires dental offices that place or remove amalgam to use amalgam separators (U.S. Environmental Protection Agency, n.d.).
In November 2025, the parties to the Minamata Convention on Mercury, a global treaty, agreed to phase out dental amalgam by 2034, with an exception when a dentist considers it necessary for a patient (International Institute for Sustainable Development, 2025). The European Union moved sooner, banning amalgam from January 1, 2025, except when a dentist judges it strictly necessary for a patient’s specific medical needs (Council of the European Union, 2024).
In the United States, federal health programs have started moving away from amalgam. In February 2026, the Department of Health and Human Services (HHS) announced that the Indian Health Service will stop using it in its facilities by 2027 (U.S. Department of Health and Human Services, 2026a). In July 2026, the Centers for Medicare & Medicaid Services urged every state Medicaid program to restrict or end coverage of amalgam fillings or to encourage tooth-colored fillings instead, citing possible higher risks for groups such as pregnant women and young children (U.S. Department of Health and Human Services, 2026b). The American Dental Association responded to the first decision by saying that no properly designed scientific study has shown that amalgam causes long-term health effects or disease (American Dental Association, 2026).
Amalgam vs. composite (tooth-colored) fillings
The most common alternative is composite resin, a tooth-colored material bonded to the tooth. In the 2021 Cochrane review, composite fillings in back teeth failed almost twice as often as amalgam (risk ratio 1.89; 95% confidence interval 1.52 to 2.35) and were about twice as likely to develop new decay around them (risk ratio 2.14; 95% confidence interval 1.67 to 2.74), based on low-certainty evidence from two trials in children (Worthington et al., 2021).
Composites have improved considerably since those trials were carried out, and they may also carry their own risks to health and the environment (Worthington et al., 2021). European experts concluded that the alternatives to amalgam have clinical limitations and need more research (SCENIHR, 2015).
What it means for you
If you already have amalgam fillings
If your fillings are intact and not causing problems, the FDA and European experts advise leaving them alone (U.S. Food and Drug Administration, 2020a; SCENIHR, 2015), and the American Dental Association calls removing amalgam fillings that are still serviceable, just to replace them with a mercury-free material, unwarranted (American Dental Association, 2026). Your dentist will check them at regular visits and repair any that fail.
If you need a new filling
Ask about the options for that tooth, including how long each material is likely to last. If you are pregnant, planning a pregnancy or breastfeeding, if the filling is for a child (especially one under 6), or if you have a neurological disease, reduced kidney function or a known allergy to mercury or other amalgam ingredients, the FDA suggests an alternative to amalgam whenever possible and appropriate (U.S. Food and Drug Administration, 2020a). To avoid needing fillings in the first place, see how to prevent cavities, and for early decay, whether a cavity can heal on its own.
If you think your fillings are making you ill
See your doctor for a full checkup before any dental work, since other conditions can cause the same symptoms (Langworth et al., 2002). Avoid provoked urine tests, which a medical toxicology review says should not be used (Ruha, 2013), and be cautious about detox programs (Melchart et al., 2008).
Questions to ask your dentist
- Is this filling failing, or would it be replaced for health reasons?
- What material would you use instead, and how long does it usually last?
- Will you use a rubber dam, water spray and high-volume suction?
- What evidence supports any test, supplement or detox product you’re recommending?
When to see a dentist
Book a dental visit if:
- A filling is cracked, chipped or loose, or has fallen out.
- You have pain when biting, or new sensitivity to hot, cold or sweets.
- You have a sore, white or red patch inside your mouth that doesn’t go away.
- You’re pregnant or planning a pregnancy and need dental work.
If a broken filling causes severe pain or swelling, see what to do in a dental emergency.
The bottom line
Amalgam fillings release small amounts of mercury, but the best studies, including two randomized trials in children, have not found that this harms most people. Removing intact fillings costs healthy tooth and can briefly raise exposure, and controlled studies have not shown that removal cures chronic symptoms. Amalgam is being phased out, largely to reduce mercury pollution, so new fillings will increasingly be tooth-colored, while existing fillings in good condition can stay.
References
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References checked October 2026 · Editorial policy · Report a correction
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