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AssigneeThe Board of Regents, State of Florida, University of Florida
InventorsJoy M. Barrett, David E. Clark, Larry L. Hench
Estimating the term…
A glass-ceramic containing Li.sub.2 O, CaO, Al.sub.2 O.sub.3, SiO.sub.2, platinum and Nb.sub.2 O.sub.5 is disclosed. It is highly suitable for use in dental restorations because of its combination of castability, chemical durability and mechanical strength. The aesthetic qualities of natural teeth may be reproduced by proper control of processing parameters, e.g. addition of coloring additives and devitrification heat treatment schedule. Dental restorations may be made by casting a melt in a conventional dental laboratory investment mold, followed by devitrification. Fracture of cast margins is avoided because of the mechanical strength and toughness of the glass-ceramic. Partial restorations can be bonded with dental cement directly to the tooth of a recipient without the need for building the restoration upon an undercoat of metal alloy.
A glass consisting essentially of about 25 to about 33 mole percent Li.sub.2 O, about 73.5 to about 52 mole percent SiO.sub.2, about 0.5 to about 5 mole percent Al.sub.2 O.sub.3 and about 1 to about 10 mole percent CaO.
A glass capable of being heat treated in situ to yield a glass-ceramic, said glass comprising Li.sub.2 O;
A glass-ceramic substantially free of cracks arising from the local volume change of crystallization, said glass-ceramic comprising Li.sub.2 O;
Dependencies are inferred from the claim text.