Dental amalgam is a common material used to fill cavities. 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. Here are answers to some common questions about dental amalgam.
What is amalgam?
Amalgam is a combination of metals that has been the most popular and effective filling material used in dentistry for the last 150 years. Although it sometimes is called “silver amalgam,” amalgam actually consists of a combination of metals. These include silver, mercury, tin and copper. Small amounts of zinc, indium or palladium also may be used.
Tooth-colored materials now can be used to restore teeth. Therefore, amalgam is used less often than in the past. However, the newer materials can’t be used for all situations. Amalgam is less costly than other materials. It also holds up better over time, especially in teeth that undergo a lot of pressure and wear from chewing.
Why the concern about mercury in amalgam?
Mercury is a metal that occurs naturally in the environment. Mercury can exist as a liquid, as in many thermometers. When heated, it becomes 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 building up in fish as a result of pollution. Mercury enters the air from industries that burn mercury-containing fuels. Mercury from all sources can build up 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 don’t cause any ill effects. At higher levels — for instance, when workers are exposed to mercury through their jobs — mercury can cause several symptoms. These include anxiety, irritability, memory loss, headaches and fatigue.
The controversy over amalgam centers on how much mercury fillings released and how much the body absorbs. In the past, amalgam fillings were thought to be inert. This would mean that no mercury was released once the filling was placed in the tooth. In recent years, sophisticated tests have changed this view. Very small amounts of mercury in the form of vapor can be released as the amalgam filling 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.