Abstract: An apparatus for the grinding or polishing of cylindrical (telescopic) or conical primary crown castings, which as tooth replacements are to be mounted in appropriate anchoring members and which have pins extending from their top sides in axial alignment with the centerlines of the castings, includes a base having a support column extending upwardly therefrom and supporting an electric motor having a shaft with a grinding or polishing disc mounted thereon and a crown casting receptacle is rotatably so supported on the base that its angle relative to the base is adjustably lockable and, locked at a given angle, it is movable toward the grinding disc for engagement of the casting with the grinding disc so as to be abraded at a desired angle the motor and grinding disc being surrounded by a shroud forming an air flow space in communication with the interior of the support column which also has a suction nozzle adapted to be connected to a suction line for the removal of grinding and polishing dust through the ai

Abstract: Gold alloys for firing on porcelain for dental purposes are prepared from 80 to 90% gold, 5 to 15% platinum, 0.5 to 10% palladium, 0.5 to 3% rhodium, 0.1 to 3% indium, 0 to 3% tin and optionally 0.1 to 2% tantalum and/or tungsten in place of or in addition to the rhodium.

Abstract: A silver free, low gold, noble metal alloy for firing on dental porcelain is prepared consisting of 30 to 55% gold, 30 to 60% palladium, 1 to 12% tin, 0 to 10% indium, 0.1 to 3% germanium, and 0.05 to 1% rhenium and/or 0.05 to 1% ruthenium.

Abstract: Gold alloys for firing on porcelain for dental purposes are prepared from 60 to 90 weight % gold, 5 to 35 weight % platinum, 0.1 to 3 weight % indium, 0 to 10 weight % palladium, 0.5 to 3 weight % rhodium, 0 to 3 weight % tin, 0.1 to 2 weight % tantalum and/or tungsten and 0.3 to 2 weight % zinc, the weight ratio of the platinum group metals to zinc to tantalum and/or tungsten are 15-30:1:0.5-1.3.