Casting alloys: the materials and "The Clinical Effects".

This manuscript is published as part of the proceedings of the NIH Technology Assessment Conference on Effects and Sideeffects of Dental Restorative Materials, August 26-28,1991, National Institutes of Health, Bethesda, Maryland, and did not undergo the customary journal peer-review process. I t is estimated that 96% of adults in the United States between the ages of 18 and 65 have one or more carious or filled teeth, with an average of almost 10 decayed or filled teeth for each adult (Miller etal, 1987). The best treatment for carious teeth, to prevent loss and restore masticatory function, often involves the use of cast dental restorations. This paper will discuss the chemical compositions of noble and base metal dental alloys and, based on 72-month data from a 10-year clinical study (Morris etal., 1986), will summarize the clinical behavior of alloys with "representative formulations". "Noble" refers to metals with marked resistance to oxidation and chemical reaction. Silver is not considered noble in the context of dental casting alloys. "Precious" refers to an economic value. The American Dental Association has stated that "semi-precious" has no meaning in dentistry because no definition has been agreed on (ADA, 1984). "Base metal" refers to metal elements that are chemically reactive to their environment (Phillips, 1991).