Silver amalgam and composite resin are the two most common materials used to restore teeth damaged by decay. There are situations where one material is preferable over the other, and similarly, there are disadvantages to both of these filling materials.

The American Dental Association's official position regarding silver amalgam is that it is a "safe, durable and cost-effective material that dentists have used in tooth restorations for more than 150 years." But some practitioners have expressed concern over the safety of amalgams, and the controversy over its use continues. The concern is due to the fact that amalgam is composed of 35 percent silver, 15 percent tin or tin mixed with copper, a trace of zinc, and 50 percent mercury - a highly toxic heavy metal when in it liquid state.

Anti-amalgam dentists have tried unsuccessfully to prove that the amalgam releases large amounts of mercury vapor when there is friction on the surface of the filling, such as when you chew. And no level of mercury vapor is considered safe. Their "proof" has been refuted by every controlled scientific study run by the A.D.A. and other independent sources. The A.D.A. points out that, once bound to the other metals, the mercury in dental amalgam is completely harmless. Those with a weakened immune system or a mercury allergy are cautioned not to have amalgam fillings placed.

Silver amalgam is a more durable tooth filling material than composite resin in teeth that are subjected to a lot of biting pressure. And an amalgam filling costs less than a comparable composite filling. But silver fillings are less attractive than tooth-colored fillings, so they're typically not placed in front teeth. Also, the amalgam fillings expand and contract more with heat and cold, which can eventually cause the filling to fracture your tooth. Silver amalgam fillings can also corrode and leak, which can allow decay to develop underneath the filling. This can also give a gray appearance to the entire tooth.

Resin fillings result in a natural-looking smile. The color can be closely matched to your natural teeth, so the restorations are nearly undetectable. And because the resin compound actually bonds to your tooth, the seal is tighter and the restored tooth can be even stronger than it was before.

Composite resin fillings can also be made much smaller than an amalgam filling used to restore the same amount of decayed tooth, so less natural tooth structure is lost. However, a resin filling costs more than an amalgam filling in the short term. But overall, resin fillings are a more conservative treatment. Less of your natural tooth structure needs to be removed in preparation for their placement, and they do a better job of protecting your tooth in the long run, as there's less chance that your tooth will fracture and require a crown in the future.

As with any health care choice, it is best to discuss your concerns and the available treatment options for your specific situation with your own dentist!