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U.S. Department of Health and Human Services

Medical Devices

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About Dental Amalgam Fillings

What is dental amalgam?

Picture of a dental amagam embedded in a tooth

Dental amalgam is a dental filling material used to fill cavities caused by tooth decay. It has been used for more than 150 years in hundreds of millions of patients.

Dental amalgam is a mixture of metals, consisting of liquid mercury and a powdered alloy composed of silver, tin, and copper. Approximately 50% of dental amalgam is elemental mercury by weight.

Dental amalgam fillings are also known as “silver fillings” because of their silver-like appearance.

When placing dental amalgam, the dentist first drills the tooth to remove the decay and then shapes the tooth cavity for placement of the amalgam filling. Next, under appropriate safety conditions, the dentist mixes the powdered alloy with the liquid mercury to form an amalgam putty. (These components are provided to the dentist in a capsule as shown in the graphic.) This softened amalgam putty is placed in the prepared cavity, where it hardens into a solid filling.

Image of a capsule containing liquid mercury and amalgam putty.

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What should I know before getting a dental amalgam filling?

Deciding what filling material to use to treat dental decay is a choice that must be made by you and your dentist.

As you consider your options, you should keep in mind the following information.

Potential Benefits:

Dental amalgam fillings are strong and long-lasting, so they are less likely to break than some other types of fillings.

Dental amalgam is the least expensive type of filling material.

Potential Risks:

Dental amalgam contains elemental mercury. It releases low levels of mercury vapor that can be inhaled. High levels of mercury vapor exposure are associated with adverse effects in the brain and the kidneys.

FDA has reviewed the best available scientific evidence to determine whether the low levels of mercury vapor associated with dental amalgam fillings are a cause for concern. Based on this evidence, FDA considers dental amalgam fillings safe for adults and children ages 6 and above. The amount of mercury measured in the bodies of people with dental amalgam fillings is well below levels associated with adverse health effects. Even in adults and children ages 6 and above who have fifteen or more amalgam surfaces, mercury exposure due to dental amalgam fillings has been found to be far below the lowest levels associated with harm. Clinical studies in adults and children ages 6 and above have also found no link between dental amalgam fillings and health problems.

There is limited clinical information about the potential effects of dental amalgam fillings on pregnant women and their developing fetuses, and on children under the age of 6, including breastfed infants. However, the estimated amount of mercury in breast milk attributable to dental amalgam is low and falls well below general levels for oral intake that the Environmental Protection Agency (EPA) considers safe. FDA concludes that the existing data support a finding that infants are not at risk for adverse health effects from the breast milk of women exposed to mercury vapor from dental amalgam. The estimated daily dose of mercury vapor in children under age 6 with dental amalgams is also expected to be at or below levels that the EPA and the Centers for Disease Control and Prevention (CDC) consider safe. Pregnant or nursing mothers and parents with young children should talk with their dentists if they have concerns about dental amalgam.

Some individuals have an allergy or sensitivity to mercury or the other components of dental amalgam (such as silver, copper, or tin). Dental amalgam might cause these individuals to develop oral lesions or other contact reactions. If you are allergic to any of the metals in dental amalgam, you should not get amalgam fillings. You can discuss other treatment options with your dentist.

For more information on FDA's scientific review and findings, see the new "Information for Use" statement required in dental amalgam labeling, and other documents in the Related Resources section.

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Why is mercury used in dental amalgam?

Approximately half of a dental amalgam filling is liquid mercury and the other half is a powdered alloy of silver, tin, and copper. Mercury is used to bind the alloy particles together into a strong, durable, and solid filling. Mercury’s unique properties (it is the only metal that is a liquid at room temperature and that bonds well with the powdered alloy) make it an important component of dental amalgam that contributes to its durability.

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Is the mercury in dental amalgam the same as the mercury in some types of fish?

No. There are several different chemical forms of mercury: elemental mercury, inorganic mercury, and methylmercury. The form of mercury associated with dental amalgam is elemental mercury, which releases mercury vapor. The form of mercury found in fish is methylmercury, a type of organic mercury. Mercury vapor is mainly absorbed by the lungs. Methylmercury is mainly absorbed through the digestive tract. The body processes these forms of mercury differently and has different levels of tolerance for mercury vapor and methylmercury. Methylmercury is more toxic than mercury vapor.

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If I am concerned about the mercury in dental amalgam, should I have my fillings removed?

If your fillings are in good condition and there is no decay beneath the filling, FDA does not recommend that you have your amalgam fillings removed or replaced. Removing sound amalgam fillings results in unnecessary loss of healthy tooth structure, and exposes you to additional mercury vapor released during the removal process.

However, if you believe you have an allergy or sensitivity to mercury or any of the other metals in dental amalgam (such as silver, tin, or copper), you should discuss treatment options with your dentist.

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