Amalgam Use and Benefits

Dental amalgam, in widespread use for over 150 years, is one of the oldest materials used in oral health care. Its use extends beyond that of most drugs, and is predated in dentistry only by the use of gold. Dental amalgam is the end result of mixing approximately equal parts of elemental liquid mercury (43 to 54 percent) and an alloy powder (57 to 46 percent) composed of silver, tin, copper, and sometimes smaller amounts of zinc, palladium, or indium.

Because of a general decline of dental caries among school children and young adults, the use of dental amalgam began to decrease in the 1970s. There are also changes in patterns of dental caries, largely the result of topical and systematic fluoride, sealant use, improved oral hygiene practices and products and possibly dietary modifications. In 1990, over 200 million restorative procedures were provided in the United States; of these, dental amalgam accounted for roughly 96 million, a 38 percent reduction since 1979. This trend is expected to continue.

There are also reports that carious lesions today are generally smaller, easier to treat, and managed by more conservative treatment that retains tooth structure. Because of this decrease in the frequency and size of dental caries, there has been a relative increase in the use of alternative dental restorative materials. The most commonly used and less expensive of the alternate materials, however, cannot be used for large lesions and need more frequent replacement. Also, there are currently many serviceable dental amalgam restorations that will need replacing in the future. Approximately 70 percent of the resotrations placed annually are replacements. Most of these replacements will require amalgam or other metallic materials, because compositie materials often lack sufficient strength or durability to be considered adequate substitutes.

 

 

Today, dental amalgam is used in the following situations:

• in individuals of all ages,
• in stress-bearing areas and in small-to moderate-sized cavities in the posterior teeth,
• when there is severe destruction of tooth structure and cost is an overriding consideration,
• as a foundation for cast-metal, metal-ceramic, and ceramic restorations,
• when patient commitment to personal oral hygiene is poor,
• when moisture control is problematic with patients,
• when cost is an overriding patient concern.

It is not used when:

• esthetics are important, such as in the anterior teeth and in lingual endodontic-access (root canal) restorations of the anterior teeth,
• patients have a hisotry of allergy to mercury or other amalgam components,
• a large restoration is needed and the cost of other restorative materials is not a significant factor in the treatment decision.