Dental amalgam is a mixture of metals, consisting of liquid (elemental) mercury and a powdered alloy composed of silver, tin, and copper. Approximately 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 also known as “silver fillings” because of their silver-like appearance. Despite the name, “silver fillings” do contain elemental mercury.
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 and shaped in the prepared cavity, where it rapidly hardens into a solid filling.
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.
FDA continues to evaluate the available information on dental amalgam, and will update the information on this web page as necessary. As you consider your options, you should keep in mind the following information.
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.
Dental amalgam contains elemental mercury. It releases low levels of mercury in the form of a vapor that can be inhaled and absorbed by the lungs. 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 weight of credible scientific evidence reviewed by FDA does not establish an association between dental amalgam use and adverse health effects in the general population. Clinical studies in adults and children ages 6 and above have found no link between dental amalgam fillings and health problems.