Dental Amalgam was a commonly used dental filling that has been around for more than 150 years. It is a mixture of tin, mercury, silver, and other trace metals. Amalgam has many advantages over other restorative materials, such as low cost, strength, durability, and bacteriostatic effects. Amalgam can be placed in a wet oral environment and still last for many years, but composite resin or any bonded restoration must be placed in a dry field with no contamination from water, saliva or blood.
Amalgam is used in dentistry for a number of reasons. It is relatively easy to use and manipulate during placement; it remains soft for a short time so it can be packed to fill any irregular volume, and then forms a hard compound. This hard amalgam compound is practically void of mercury, making it a safe restoration. Amalgam possesses greater longevity, up to 50 years, when compared to other direct restorative materials like composite. On average, most amalgam restorations serve for 10 to 12 years, whereas resin-based composites serve for about half that time. However, with recent improvements in composite material science and a better understanding of the technique-sensitivity of placement, it should be noted that this difference is decreasing.
There are circumstances in which composite (white fillings) serves better than amalgam; when amalgam is not indicated, or when a more conservative preparation would be beneficial, composite is the recommended restorative material. These situations would include small occlusal restorations, in which amalgam would require the removal of more sound tooth structure, as well as in “enamel sites beyond the height of contour.”
The American Dental Association Council on Scientific Affairs has concluded that both amalgam and composite materials are considered safe and effective for tooth restoration.