Dental amalgam is a dental filling material used to fill cavities caused by tooth decay.

Dental amalgam is a mixture of metals, consisting of liquid (elemental) mercury and a powdered alloy composed of silver, tin, and copper. Approximately half (50%) of dental amalgam is elemental mercury by weight. The chemical properties of elemental mercury allow it to react with and bind together the silver/copper/tin alloy particles to form an amalgam.

Dental amalgam fillings are often referred to as “silver fillings” because of their silver-like appearance, although the use of this term in not recommended because the term does not correctly explain the materials in amalgam.

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 encapsulated powdered alloy with the liquid mercury to form an amalgam putty. This softened amalgam putty is placed and shaped in the prepared cavity, where it rapidly hardens into a solid filling.

The FDA plans to update the public if significant new information becomes available.


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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 should be made by you and your dentist. As you consider your options, you should keep in mind the following information about dental amalgam fillings:

Benefits of Dental Amalgam:

  • Strong and long-lasting, so they are less likely to break than some other types of fillings.
  • Useful in patients that have a high risk of tooth decay, for large tooth preparations, and where moisture makes it difficult for other materials such as resins to establish a bond to tooth.
  • Least expensive type of filling material.
  • Used for more than 150 years in hundreds of millions of patients around the world.

Potential Risks of Dental Amalgam:

  • Contains elemental mercury.
    • Releases low levels of mercury in the form of a vapor that can be inhaled and absorbed by the lungs. Exposure to high levels of mercury vapor, which may occur in some occupational settings, has been associated with adverse effects in the brain and the kidney.
  • Developing neurological systems in fetuses and young children may be more sensitive to the neurotoxic effects of mercury vapor.
    • Very limited to no clinical data is available regarding long-term health outcomes in pregnant women and their developing fetuses, and children under the age of six, including infants who are breastfed. Pregnant women and parents with children under six who are concerned about the absence of clinical data as to long-term health outcomes should talk to their dentist.
  • Although the available evidence does not show that exposure to mercury from dental amalgam will lead to adverse health effects in the general population, exposure to mercury may pose a greater health risk in the groups of people listed below, who may be more susceptible to potential adverse effects generally associated with mercury.
    • Pregnant women and their developing fetuses;
    • Women who are 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;
    • People with impaired kidney function;
    • People with known heightened sensitivity (allergy) to mercury or other components (silver, copper, tin) of dental amalgam.
  • Some individuals have an allergy or other 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 sensitivity reactions.
    • If you are allergic or otherwise sensitive to any of the metals in dental amalgam, you should not get amalgam fillings. You can discuss other treatment options with your dentist.

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 a liquid at room temperature that bonds well with the alloy powder) make it an important component of dental amalgam that contributes to its durability.


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. However, some recent studies show that inorganic mercury from dental amalgam and organic (methylated) mercury from seafood can transform into each other in the body, making it difficult to distinguish between their potential health effects.


What is bioaccumulation?

Bioaccumulation refers to the build-up or steadily increasing concentration of a chemical in organs or tissues in the body. Mercury from dental amalgam and other sources (e.g., fish) is bioaccumulative. Although much of the mercury (either from dental amalgam or food) is eliminated, part of it can accumulate in the bodily fluids and tissues  including the kidneys and brain. However, studies have not shown that increased mercury levels and bioaccumulation due to dental amalgam result in detectable damage to target organs. For more information about bioaccumulation, please see Mercury Overview.


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, the FDA does not recommend that you have your amalgam fillings removed or replaced. Removing intact amalgam fillings results in unnecessary loss of healthy tooth structure and exposes you to a temporary increase in mercury vapor released during the removal process. Intact amalgam fillings in any individual, including the sensitive groups such as pregnant/nursing mothers and children, should not be removed for the purpose of preventing any disease or health condition, unless considered medically necessary by a health care professional. If you have a health condition (especially sensitivity/allergy to mercury, or neurological/kidney disease), you may discuss the need for removal and replacement with your dentist and/or physician.


Are there any concerns regarding the use of dental amalgam in certain high-risk populations?

Information reviewed by the FDA over the past two decades points to uncertainties about the effects of mercury exposure from dental amalgam, the acceptable exposure levels for mercury vapor (gas), the potential for mercury to collect in the body, and whether the degree of accumulation of mercury from dental amalgam results in adverse health outcomes. The majority of evidence shows exposure to mercury from dental amalgam does not lead to negative health effects in the general population. Exposure to mercury may pose a greater health risk in certain groups of people, who may be more susceptible to potential adverse effects generally associated with mercury. These high-risk populations include:

  • Pregnant women and their developing fetuses;
  • Women who are 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;
  • People with impaired kidney function;
  • People with known heightened sensitivity (allergy) to mercury or other components (silver, copper, tin) of dental amalgam.

If you fall into any of the greater risk groups listed above, the FDA strongly encourages the use of non-amalgam restorations (fillings) such as composite resins and glass ionomer cements if your dentist thinks these materials are appropriate for your affected tooth’s structure and location, and if you have no history of allergic reaction or hypersensitivity to these materials.

The FDA does not recommend anyone remove or replace existing amalgam fillings in good condition unless it is considered medically necessary by a health care professional (for example, documented hypersensitivity to the amalgam material). Removing intact amalgam fillings results in unnecessary loss of healthy tooth structure and a temporary increase in exposure due to additional mercury vapor released during the removal process.

The durability of any tooth restoration depends on many factors besides dental filling material. To help your teeth and fillings last as long as possible, you should maintain a healthy diet, proper oral hygiene, and regular dental checkups.

Everyone should discuss treatment options, including their associated benefits and risks, with your dentist. View the FDA’s informational brochure for patients and ask your dentist if you have additional questions.


Dental Amalgam: Additional Resources

Dental Amalgam Regulation Documents

FDA Literature Reviews

FDA Safety Communications

Advisory Committee Meetings

Other Resources

The following links to the Agency for Toxic Substances and Disease Registry (ATSDR) website and the Environmental Protection Agency (EPA) website provide additional information about sources of mercury exposure, environmental aspects, and bioaccumulation.

The FDA does not regulate the environmental safe handling or disposal of dental amalgam.  Handling and disposal of dental amalgam is regulated by the EPA and state and local authorities.