Published online by Cambridge University Press: 03 March 2011
This paper describes a novel technology for a mercury-free metallic direct filling material, a substitute to dental amalgams. The consolidation relies both on cold-welding that takes place under moderate pressure between suitably surface-treated silver particles and on silver-tin intermetallic compound formation at ambient temperature. A dilute acid is used for removing the silver surface oxide layers, thereby promoting the cold-welding process. The condensability, namely the ability of a loose powder to undergo consolidation within a short time duration, at body temperature and under moderate pressure has been investigated for a variety of mixtures of silver, tin, and prealloyed silver-coated intermetallic powders. The resulting metallic composite material displays transverse rupture strength values higher than those of amalgams and somewhat lower values of compressive strength and Knoop hardness.