Amalgam

Fillings made with amalgam also are known as silver fillings. Over the years concerns have been raised about the use of amalgam because it contains mercury.

What is amalgam?

Amalgam is a combination of metals that has been used in dentistry for more than 200 years and is still commonly used today. Although it sometimes is called "silver amalgam," amalgam actually consists of a combination of silver, mercury, tin and copper, and small amounts of zinc, indium or palladium.

With the development of tooth-colored materials to restore teeth, amalgam is used less often than in the past, but the newer materials cannot be used for all situations. Amalgam has been popular as a material for dental fillings and restorations because it is less expensive than other materials and holds up better over time, especially in teeth that undergo pressure and wear from chewing.

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Is amalgam safe?

The U.S. Food and Drug Administration (FDA) have evaluated research on the safety of dental amalgam and have not found any reason to limit its use.

Millions of people have amalgam fillings. Although concern has been raised over the mercury in amalgam, and the issue has been studied extensively, researchers have not found evidence of significant health problems related to the use of amalgam in fillings.

Mercury is a metal that occurs naturally in the environment. Mercury can exist as a liquid —as is seen in many thermometers— or when heated, as a gas. It also can be combined with many other materials.

Everyone is exposed to mercury through air, drinking water, soil and food. Concerns have been raised, for instance, about the amount of mercury accumulating in fish as a result of pollution. Mercury enters the air from industries that burn mercury-containing fuels. Mercury from all sources can accumulate in body organs.

As with most substances, the degree of harm caused by mercury in the body is related to the amount. Very low levels do not cause any ill effects. At higher levels— for instance, when workers are exposed to mercury through their jobs —mercury can cause a number of symptoms including anxiety, irritability, memory loss, headaches and fatigue.

The controversy over mercury in amalgam centers on how much mercury is released from fillings and absorbed into the body. In the past, it was thought that amalgam fillings were inert, meaning that no mercury was released once the filling was complete. In recent years, sophisticated tests have shown that very small amounts of mercury in the form of vapor can be released as the amalgam wears.

Research on this issue is complex and has arrived at various estimates of the actual amount of mercury released. However, several reviews of the research have concluded that any amount released from amalgam in the mouth is very low.

Studies have shown that the amount of mercury you are exposed to from your fillings is less than the amount that most people are exposed to in their daily environment or in the food they eat.

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Pregnancy and amalgam fillings?

Research over the years has not demonstrated any health effects from amalgam fillings in pregnant women. However, mercury can cross the placenta. In general, dentists recommend that pregnant women avoid unnecessary dental care. During pregnancy, the placement of amalgam restorations should be avoided. Pregnant women who need a cavity filled can talk with their dentists about alternatives to amalgam restorations.

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Alternatives to amalgam

Dentists use other materials to restore teeth, such as composite resin, porcelain and gold. Amalgam is stronger and with much better properties than composite resin (a tooth-colored plastic material) and requires less time in the dentists' chair. Because it wears faster than amalgam, composite resin can not be used in every situation.

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Should I visit an amalgam-free practice?

It is not necessary to seek treatment at a practice that does not use mercury. However, if you have a mercury allergy, you may want to consider it. Generally, if you have any concerns about amalgam fillings, talk to your dentist about them and whether there are alternatives to amalgam that would work for you.

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Should I have my amalgam fillings removed?

Replace amalgam fillings only when necessary, such as when fillings are worn or broken or for cosmetic reasons. Since there is no evidence that amalgam fillings can cause a problem, Dr. Alvarez thinks it is best not to remove existing restorations that function well. If you are concerned about amalgam as a restorative material, choose a different material for your new restorations."

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