Amalgam Restorations

Silver amalgam restorations are the traditional silver filling materials. They have been used with success by all dentists for more than 150 years. Silver amalgam fillings were originally meant to be a low-cost substitute filling material for those patients who could not afford the standard-of-care gold restorations. They can be used to replace small or large amounts of tooth structure lost through decay or fracture. They are not as technique sensitive as some other restorations. They are composed of silver, tin, mercury, copper, and other metals. Some of the newer silver amalgam materials are mercury-free. We have no long-term studies on how well these mercury-free amalgams will serve, so in this practice they are not used. An alternative is a composite resin tooth colored material, or "resin" restoration, which has its own set of advantages and disadvantages.

The silver amalgams available have a life expectancy of 14 years with a plus/minus deviation of 14 years. However, properly placed and maintained they have performed over 50 years.

They can last a long time or may need to be replaced within a year of when they were originally completed. As with resin restorations, the smaller the filling, the longer it can last. This is still the restorative material of choice for many dentists but that number is declining due to esthetic demands from patients. Most chairside restorations for back teeth, regardless of size, are silver amalgam. With the advent of the newer bonded resin materials, many posterior (back) teeth that previously would have been restored with amalgam are now being restored with the more conservative and more naturally appearing tooth colored resin and porcelain materials. This is dependent on the size of the anticipated restoration. Silver amalgam fillings can now also be bonded when there is little remaining tooth. This, of course, adds to the total fee charged for the restoration, but none in this practice are placed without bonding.

Disadvantages: The primary disadvantage of the silver fillings are esthetics. It is impossible to have them look like a natural tooth when they are silver, and the appearance can deteriorate as time goes by. If the surrounding enamel is thin, the gray/black color of the metal will show through. So they can make the tooth look darker. They add no strength to the tooth, unless bonded, but if the size is large, then like any restoration it needs to be covered with a crown. Depending on the shape of the filling, they can weaken the tooth because they have a higher expansion/contraction ratio than the surrounding tooth. These forces can, after time, cause the tooth to fracture. They are not considered a conservative restoration because they require more tooth prepared (drilled) than is actually necessary to be removed due to the decay. This extra drilling is strictly to allow the retention of the restoration, which is primarily by mechanical means even though bonding agents are used to seal and bond the restoration. In some instances, it might be more cost-effective and better for the gingival (gum) health to place a cast restoration (crown or onlay). This would be the case when the silver filling would be very large. When there are extensive amounts of tooth structure to be rebuilt/replaced, it is often quite difficult to establish the proper physiologic contour to the tooth. In addition, the remaining tooth structure, especially the root(s) may be more prone to fracture.

Advantages of the silver amalgam fillings are that they are quick and easy to place, relatively inexpensive, and have a long proven record of success.

If finances are a major concern and cosmetics are not important, then this material is well suited for all types of restorations. If the cavity is small or on a previously undamaged portion of a tooth, a more conservative resin restoration would be a better choice.

If you have any questions about silver amalgam restorations, please feel free to ask us.

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