Dental amalgam is made from a combination of metals that include mercury, silver, tin, and copper. Sometimes described as “silver-colored” fillings, dental amalgam has been used by dentists for more than 100 years because it lasts a long time and is less expensive than other cavity-filling materials such as tooth-colored composites or gold fillings.
Because of their durability, these silver-colored fillings are often the best choice for large cavities or those that occur in the back teeth where a lot of force is needed to chew. Amalgam hardens quickly so it is useful in areas that are difficult to keep dry during placement, such as below the gum line. Because it takes less time to place than tooth-colored fillings, amalgam is also an effective material for children and special needs people who may have a difficult time staying still during treatment.
One disadvantage of amalgam is that these types of fillings are not natural looking, especially when the filling is near the front of the mouth, where it may show when you laugh or speak. Also, to prepare the tooth, the dentist may need to remove more tooth structure to place an amalgam filling than for other types of fillings.