Dental amalgam
AssigneeSpecial Metals Corporation
InventorsKamal Asgar, Steven H. Reichman
Life of this patent
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Abstract
An improved metal powder blend and improved dental amalgams produced therefrom comprising a mechanical mixture containing controlled proportions of an amalgamatable silver-base alloy powder and a substantially non-amalgamatable eutectic alloy powder containing a controlled quantity of tin which upon trituration with mercury forms a substantially continuous matrix having dispersed therethrough discrete phases of the non-amalgamatable powder particles which impart improved mechanical properties to the resultant dental restoration.
Claims7
A metal powder for use in the preparation of dental restorations and the like by trituration with mercury comprising a mechanical mixture containing about 55% to about 90% of a first powder comprised of a silver-base amalgamatable alloy and about 10% to about 45% of a second powder composed of a substantially non-amalgamatable silver-containing alloy, said first powder consisting essentially of at least about 65% silver, up to about 6% copper, up to about 2% zinc and at least about 25% tin, said second powder consisting essentially of about 1% to about 20% tin, silver as the major alloying agent, and a third alloying constituent individually selected from the group consisting of 5% to 50% cadmium, 5% to 50% zinc, 5% to 50% aluminum, copper in an amount to provide a silver-to-copper ratio of about 2.6:1, up to 30% indium in combination with copper wherein the latter is present in an amount to provide a silver-to-copper ratio of about 2.6:1;
- said first and said second powder being of an average particle size of less than about 100 microns.
A dental amalgam consisting essentially of a continuous matrix composed of an amalgam having dispersed therethrough a plurality of discrete phases chemically bonded by said continuous matrix, said amalgam containing from about 40% to about 60% mercury, from about 22% to about 54% of an amalgamatable alloy powder containing at least about 65% silver, up to about 6% copper, up to about 2% zinc, and greater than about 25% tin;
- said discrete phases comprising about 4% to about 27% of said amalgam consisting essentially of an alloy containing silver, from about 1% to about 20% tin, and the balance an alloying constituent individually selected from the group consisting of 5% to 50% cadmium, 5% to 50% zinc, 5% to 50% aluminum, copper in an amount to provide a silver-to-copper ratio of about 2.6:1, up to 30% indium in combination with copper wherein the latter is present in an amount to provide a silver-to-copper ratio of about 2.6:1;
- said discrete phases being of a size less than about 100 microns.
Dependencies are inferred from the claim text.