Mercury Dental Amalgam Fillings and FDA Guidance: What the Guidance Actually Says

Short answer

• In September 2020, the US Food and Drug Administration (FDA) updated its recommendations on dental amalgam, the silver colored filling material that is about half mercury by weight. The FDA recommended that certain higher risk groups avoid new amalgam fillings whenever possible and appropriate, and use a non mercury material instead. It did not ban amalgam, and it did not recommend that anyone remove an amalgam filling that is in good condition. For people outside the higher risk groups, the FDA states that studies do not show conclusive evidence that dental amalgam causes harmful health effects in the general population, and amalgam remains one of the filling options a patient and dentist can choose between. This article reports that guidance as the FDA states it, group by group, including what the agency says it does not know. It is general information only. It is not a diagnosis and it does not replace advice from your own dentist or doctor. If you need a filling, or you are worried about a filling you already have, the decision belongs in a conversation with your dental provider, who knows your teeth and your health history.

What Dental Amalgam Is

Dental amalgam is a mixture of mercury and a powdered alloy made of silver, tin, and copper. The FDA patient page also lists zinc among the component metals. The FDA states that dental amalgam is approximately half, 50 percent, mercury by weight. Because of its silver color, it is often called a silver filling, even though mercury is its largest single ingredient.

Amalgam has been used to fill cavities for more than 100 years. It is hard and durable, it withstands strong chewing forces, and the FDA notes that it has advantages in certain clinical situations: for patients at higher risk of tooth decay, for large fillings in back teeth where biting forces are high, and where moisture near the gumline makes some other materials harder to place. Its use has declined over recent years as tooth colored materials have become more widely used and their durability has improved.

The health question about amalgam is a question about mercury vapor. The FDA states that amalgam fillings may release small amounts of mercury in the form of a vapor, depending on the number and age of existing fillings and on habits such as tooth grinding and gum chewing. When a new amalgam filling is placed or an old one is removed, there may be a temporary increase in exposure to mercury vapor. The FDA also states that while there are no known health risks associated with swallowing small particles of dental amalgam, inhaling mercury vapor may be harmful in certain patients. People with multiple amalgam fillings may have slightly higher mercury levels in blood or urine, but the FDA states those levels usually remain at a level considered safe. The guidance that follows is built on that distinction: low level vapor exposure that most people appear to tolerate, and a set of groups for whom the FDA judges the uncertainty differently.

What the FDA Recommended in September 2020

On September 24, 2020, the FDA issued updated recommendations concerning dental amalgam and potential risks to certain high risk individuals. The agency said it had reviewed scientific literature, monitored reports, and held public discussions on dental amalgam for over 20 years, and that it was acting because certain groups may be at greater risk for potential harmful health effects of mercury vapor released from the material.

The core recommendation has two halves, and both halves matter:

• For the higher risk groups listed in the next section, the FDA recommends avoiding dental amalgam whenever possible and appropriate, and using non mercury alternatives such as composite resins and glass ionomer cement fillings instead.
• For everyone, including people in the higher risk groups, the FDA is not recommending that existing amalgam fillings in good condition be removed or replaced, unless removal is considered medically necessary.

The wording whenever possible and appropriate is part of the guidance, not a loophole added later. The FDA leaves the final material decision with the patient and the dental provider, because a specific tooth, a large cavity, or a hard to keep dry placement site can change what is clinically workable. The recommendation is also not a finding that amalgam has been proven to harm the groups named. The FDA is explicit that uncertainties remain: about the effects of long term exposure on the specific higher risk groups, about the potential for mercury from amalgam to convert to other mercury compounds in the body, and about whether accumulation of mercury in some body fluids and tissues results in other unintended health outcomes. The 2020 recommendations are a precaution taken in the face of that limited information, and reading them as either a ban or a clean bill of health misstates them in opposite directions.

The Higher Risk Groups, One by One

The FDA statement lists the groups that may be at greater risk for potential harmful health effects from mercury vapor in amalgam. If you are in one of these groups and you need a new filling, the FDA recommends that you avoid dental amalgam if possible and appropriate, and talk to your dental provider about your health history and the other treatment options. The groups are:

Pregnant women and their developing fetuses

The FDA patient page explains that placement of new amalgam fillings in a pregnant woman may result in high, transient spikes of mercury exposure to the mother and fetus. Some studies have shown a relationship between the number of amalgam fillings a mother has and mercury levels in umbilical cord blood. The FDA adds that results from these studies did not identify any certain associations with harmful health effects, and that the data is very limited. The recommendation to avoid new amalgam in pregnancy rests on that combination of a plausible exposure route and limited outcome data, not on proven harm.

Women who are planning to become pregnant

This group is named separately in the FDA statement. The logic follows from the pregnancy group: a filling placed shortly before a pregnancy is still a recent filling during it. If you are planning a pregnancy and you need dental work, raise the material question at the appointment rather than after the filling is placed.

Nursing women and their newborns and infants

The FDA states that the amount of mercury in breast milk is typically very low. Some studies have reported a relationship between the number of amalgam fillings a mother has and the amount of mercury in breast milk. The FDA also states that the very few, limited studies conducted to evaluate possible harm to infants and children exposed to dental amalgam mercury through breastfeeding did not identify any definite associations with harmful health effects. Even so, nursing women and their newborns and infants remain on the higher risk list for new fillings.

Children, especially those younger than six years of age

Clinical studies in children ages six and older have not found a definite connection between the use of dental amalgam and harmful health effects, according to the FDA. Studies on children under the age of six are very limited, and the FDA notes that the developing neurological systems of children may be especially sensitive to exposure to mercury vapor. That gap in the evidence for the youngest children is the stated basis for the recommendation. Parents weighing filling materials for a young child can find broader context in our guide to children’s dentistry and gentle care for young children, and our article on what a cavity feels like covers the symptoms that usually bring a child to the dentist in the first place.

People with pre-existing neurological disease

The FDA statement names multiple sclerosis, Alzheimer’s disease, and Parkinson’s disease as examples. The FDA patient page notes that studies show mercury is localized in certain tissues of the body, including the brain and the kidneys, and that very limited clinical information is available about possible health effects of mercury vapor exposure on individuals who already have neurological impairments. A person with one of these conditions who needs a filling should discuss material choice with both the dentist and, where relevant, the clinician managing the condition.

People with impaired kidney function

The kidney is one of the tissues where mercury is localized, and the same limited information problem applies: the FDA states that very limited clinical information is available about possible health effects of mercury vapor exposure on people who already have kidney dysfunction. Impaired kidney function is therefore its own listed group, separate from neurological disease.

People with known heightened sensitivity or allergy to mercury or other amalgam components

Some people have an allergy or sensitivity to mercury or to another component of dental amalgam, such as silver, copper, tin, or zinc. The FDA states that such people may report or experience health effects after placement of an amalgam filling, including allergic reactions and oral ulcers, as well as more generalized symptoms. For this group the issue is not long term uncertainty but a known individual reaction, and an alternative material avoids the offending component directly.

What the FDA Says for Everyone Else

If you are not in one of the groups above, the FDA guidance does not ask you to avoid amalgam, and it does not ask you to welcome it either. It presents a material with stated benefits and stated limits, to be chosen with your dentist.

On the evidence, the FDA patient page states plainly that studies on people with dental amalgam do not show conclusive evidence that dental amalgam causes harmful health effects in the general population. On benefits, the FDA notes that amalgam can be the workable choice for large fillings in back teeth, for placements where moisture is a problem, and for patients at higher risk of tooth decay, and that alternative materials, while improved, may not reach the durability of amalgam in areas with higher biting forces. The American Dental Association (ADA) takes a firmer position in the same direction: its patient site, MouthHealthy, states that according to the best available scientific evidence, dental amalgam remains a safe and effective option for filling cavities, that the mercury in amalgam combines with the other metals to form a safe, stable material, and that the ADA, the US Centers for Disease Control and Prevention, and the World Health Organization all agree dental amalgam is a safe and effective cavity filling material. The ADA also acknowledges the FDA position on the same page, noting that the FDA recommends certain high risk groups avoid the material if possible and appropriate. The two positions are compatible when read carefully: a general population judgment from the ADA, and a precaution for named groups from the FDA. Neither body recommends removing sound fillings, as the next section explains.

Should Intact Amalgam Fillings Be Removed?

No, not routinely. This is the second half of the FDA guidance, and it applies to everyone, including people in the higher risk groups.

The FDA patient page states that if your filling is in good condition and your dentist or health care professional says there is no decay beneath the filling, removal of the amalgam filling is not recommended. The reasons are practical. Removing intact amalgam fillings may result in unnecessary loss of healthy tooth structure, and removal potentially exposes you to a temporary increase in mercury vapor released during the removal process itself. In other words, the procedure done to reduce mercury exposure briefly raises it, while also costing healthy tooth. The FDA states that intact amalgam fillings in anyone, including those at greater risk such as pregnant or nursing mothers and children, should not be removed for the purpose of preventing any disease or health condition, unless removal is considered medically necessary by a health care professional.

Removal does have legitimate triggers, and they are clinical rather than material based:

• A filling that is cracked, worn, leaking, or otherwise failing.
• New decay beneath or around the filling.
• A tooth that needs a crown or other restoration that requires the old filling to come out.
• A diagnosed sensitivity or allergy to a component of the filling, where your dentist or physician advises removal and replacement.

If you have a health condition, especially sensitivity or allergy to mercury, or neurological or kidney disease, the FDA advises discussing the need for removal and replacement with your dentist or physician rather than deciding alone. If a clinician proposes removing sound fillings, it is reasonable to ask what clinical finding makes removal necessary and what the risks of removal itself are. Our guide to how cavities are treated and what a dentist does explains when a filling is placed, repaired, or replaced as part of ordinary cavity care.

The Alternatives, in Neutral Terms

The FDA names composite resins and glass ionomer cements as the non mercury alternatives to consider for higher risk patients. Both are tooth colored, which is one reason use of amalgam has declined as these materials have become more widely used.

Resin based composites are the most common alternative. The FDA notes that they typically require removal of less healthy tooth structure for placement than amalgam, they are color matched to the tooth, and they contain no heavy metals. Against that, the FDA notes the durability of alternative materials may not reach that of amalgam, especially in back teeth where biting forces and wear are highest, that resin based materials may require more time for placement, and that they carry their own risks, with primary concerns being potential exposure and hypersensitivity to certain chemicals such as methacrylate, and how long they will last.

Glass ionomer cements are the other FDA named option, also tooth colored, and used where their handling and fluoride releasing properties suit the tooth. The ADA lists glass ionomers alongside tooth colored composites as standard filling options, and also notes ceramic, zirconia, and gold inlays and onlays among the wider set of restorative choices for suitable cases.

No alternative is risk free and no alternative is right for every tooth. A large cavity in a back molar that is hard to keep dry is a different problem from a small cavity in a front tooth. The FDA closes its patient guidance with the framing this article follows: if you need a filling, discuss all treatment options with your dental provider, including the benefits and risks of dental amalgam and other restorative materials, to help you make an informed decision, and if you are concerned about mercury exposure from dental amalgam, resin based materials should be strongly considered.

Fillings During Pregnancy and While Nursing

Because pregnancy and nursing appear on the higher risk list, the material question deserves direct handling. The FDA recommendation concerns new amalgam fillings: avoid them if possible and appropriate, and use a non mercury material when one can meet the clinical needs of the tooth. It is not a recommendation to avoid dental care. Untreated decay is itself a problem, and a needed filling should not simply be postponed without a plan. What changes is the conversation. Tell your dentist that you are pregnant, planning a pregnancy, or nursing, even if you think it is obvious, and ask which material is proposed and why it suits that tooth.

For fillings already in place, the guidance runs the other way. The FDA states that intact amalgam fillings should not be removed during pregnancy or nursing for the purpose of preventing a disease or health condition, unless a health care professional considers removal medically necessary. Removal is the moment of highest temporary vapor exposure, which is exactly what the guidance for these groups is trying to avoid adding. If a filling fails during pregnancy, that is a clinical problem to treat on its merits with your dentist, and where relevant your obstetric clinician, not a reason to extend the work to sound fillings nearby.

Amalgam Fillings and MRI Scans

Questions about MRI scans and metal fillings are common, and they sit outside the FDA amalgam recommendations themselves, so they should not be dressed up as FDA guidance. The practical position is straightforward. The metals in dental amalgam are not ferromagnetic, so a filling is not pulled or dislodged by the scanner magnet, and standard NHS patient guidance for functional MRI states that normal dental amalgam fillings do not prohibit a person from being scanned. Metal in or near the area being imaged can still distort the images in some head and neck scans, which is an image quality issue for the imaging team to manage, not a reason a filling must be removed.

The safe habit is disclosure. Always tell the imaging team about dental fillings, implants, braces, and any other metal in or on your body before a scan, because MRI safety screening depends on the full list of materials and devices, not on fillings alone. The imaging team, not this article and not your dentist, decides what a specific scanner and a specific scan require.

The Environmental Side, Briefly

Mercury in dentistry is also an environmental question, separate from the patient guidance above. The ADA, citing the US Environmental Protection Agency (EPA), states that less than 1 percent of mercury released to the environment from human made sources comes from dentistry. Since 2020, the ADA notes, dentists in the United States have used devices called amalgam separators, which capture amalgam particles from dental office wastewater so the material can be collected and recycled rather than discharged. That system is the main environmental control on amalgam in current US practice: it governs waste from placements and removals in the dental office, and it is one more reason routine removal of sound fillings has a cost beyond the individual tooth, because every removal generates amalgam waste that must be captured and handled.

How to Talk to Your Dentist About a New Filling

The FDA guidance is written as a conversation, and a short set of questions makes it usable at an appointment:

1. Which material are you proposing for this tooth, and why does it suit this cavity?
2. I am in one of the FDA higher risk groups. Can a composite resin or glass ionomer filling meet the needs of this tooth instead?
3. If amalgam is proposed because of the size or position of the cavity, what is the trade off if we use a tooth colored material here?
4. For my existing amalgam fillings, are any of them failing or decayed, or are they all in good condition?
5. If replacement of a sound filling is suggested, what is the clinical reason, and what are the risks of removal itself?

Asking these questions is not second guessing your dentist. The FDA states that the decision about what material to use to fill cavities is one that should be made between you and your dental provider, and a physician if needed, and the ADA likewise encourages patients to talk with their dentist about cavity treatment options and what is right for them. Prevention closes the loop: the ADA notes that the best dental filling is no dental filling, and that brushing twice a day with fluoride toothpaste, cleaning between teeth daily, eating a balanced diet low in added sugar, and visiting the dentist regularly sharply reduce the chance of needing any filling at all. The FDA adds that a healthy diet, proper oral hygiene, and regular dental checkups help teeth and existing fillings last as long as possible.

Frequently Asked Questions

Did the FDA ban amalgam fillings?

No. The FDA issued recommendations in September 2020 that certain higher risk groups avoid new dental amalgam fillings whenever possible and appropriate. It did not ban the material, and it continues to present amalgam as an option for other patients, with stated advantages in large back tooth fillings and hard to keep dry placements.

What are the FDA higher risk groups for amalgam?

Pregnant women and their developing fetuses; women planning to become pregnant; nursing women and their newborns and infants; children, especially those younger than six years of age; people with pre existing neurological disease such as multiple sclerosis, Alzheimer’s disease, or Parkinson’s disease; people with impaired kidney function; and people with known heightened sensitivity or allergy to mercury or other components of dental amalgam.

Should I have my amalgam fillings removed?

Not if they are in good condition and there is no decay beneath them. The FDA does not recommend removing intact amalgam fillings, including for people in the higher risk groups, unless a health care professional considers removal medically necessary. Removal can cost healthy tooth structure and temporarily increases mercury vapor exposure during the procedure.

Are amalgam fillings still used?

Yes, though use has generally declined as alternative materials have become more widely used. The FDA notes amalgam retains advantages in certain situations, including large fillings in back teeth and placements where moisture is a problem. Practice varies by clinic, tooth, and patient, and patients in the FDA higher risk groups should expect a non mercury material to be considered first.

Can I get a filling while pregnant?

Dental care, including a needed filling, should be discussed with your dentist rather than simply avoided. Under FDA guidance, a pregnant patient is in a higher risk group for amalgam, so a non mercury material such as composite resin or glass ionomer should be used when possible and appropriate for the tooth. Tell your dentist you are pregnant and ask which material is proposed. Existing intact amalgam fillings should not be removed during pregnancy unless removal is medically necessary.

What is amalgam made of, and how much of it is mercury?

Dental amalgam is a mixture of mercury with a powdered alloy of silver, tin, and copper, and the FDA patient page also lists zinc among its component metals. The FDA states that dental amalgam is approximately half, 50 percent, mercury by weight. It releases small amounts of mercury vapor over time, which is the exposure the FDA guidance addresses.

What does the FDA say about amalgam for everyone else?

For the general population, the FDA states that studies do not show conclusive evidence that dental amalgam causes harmful health effects. People with multiple amalgam fillings may have slightly higher mercury levels in blood or urine, but the FDA states those levels usually remain at a level considered safe. Amalgam remains a material a patient and dentist can choose, weighing its durability against the benefits and risks of the alternatives.

Can I have an MRI if I have amalgam fillings?

An amalgam filling is not, on its own, a reason you cannot be scanned, because the metals in amalgam are not ferromagnetic and standard patient guidance treats normal amalgam fillings as no bar to scanning. Always tell the imaging team about fillings, implants, and any other metal before a scan, because they manage safety screening and any image distortion for the specific examination.

Sources & references

• US Food and Drug Administration, Information for Patients About Dental Amalgam Fillings. https://www.fda.gov/medical-devices/dental-amalgam-fillings/information-patients-about-dental-amalgam-fillings
• US Food and Drug Administration, FDA Issues Recommendations for Certain High-Risk Groups Regarding Mercury-Containing Dental Amalgam, September 24, 2020. https://www.fda.gov/news-events/press-announcements/fda-issues-recommendations-certain-high-risk-groups-regarding-mercury-containing-dental-amalgam
• American Dental Association, MouthHealthy, Dental Amalgam. https://www.mouthhealthy.org/all-topics-a-z/dental-amalgam
• American Dental Association, Amalgam Fillings: Patient Education Conversation Points. https://www.ada.org/-/media/Project/ADA%20Organization/ADA/ADA-org/Files/Resources/Practice/ADA_Amalgam_Patient_Conversation.pdf
• Birmingham Women's and Children's NHS Foundation Trust, Functional MRI patient notes (dental amalgam and scanning). https://bwc.nhs.uk/functional-mri-fmri/