Lithium silicate materials
DCFirst Claim
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1. A process for manufacturing a lithium silicate restoration comprising preparing a lithium silicate blank which comprises:
- (a) producing a melt of a starting glass containing the initial components SiO2, Li2O, and P2O5 or other nucleation agent as the main components;
(b) pouring the melt of the starting glass into a mould to form a starting glass blank and cooling the glass blank to room temperature;
(c) subjecting the starting glass blank to a first heat treatment at a first temperature to give a glass product which contains nuclei suitable for forming lithium metasilicate crystals;
or(b′
) pouring the melt of the starting glass into a mould to form a starting glass blank and cooling the glass blank to a first temperature;
(c′
) holding the starting glass blank at the first temperature to give a glass product which contains nuclei suitable for forming lithium metasilicate crystals;
(d) subjecting the glass product of step (c) or (c′
) to a second heat treatment at a second temperature which is higher than the first temperature to obtain the lithium silicate blank with lithium metasilicate crystals as the main crystalline phase;
(e) cooling the lithium silicate blank having the lithium metasilicate crystals as the main crystalline phase; and
(f) shaping the cooled lithium silicate blank with lithium metasilicate crystals as the main crystalline phase into the shape of a dental restoration.
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Abstract
Lithium silicate materials are described which can be easily processed by machining to dental products without undue wear of the tools and which subsequently can be converted into lithium silicate products showing high strength.
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Citations
63 Claims
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1. A process for manufacturing a lithium silicate restoration comprising preparing a lithium silicate blank which comprises:
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(a) producing a melt of a starting glass containing the initial components SiO2, Li2O, and P2O5 or other nucleation agent as the main components; (b) pouring the melt of the starting glass into a mould to form a starting glass blank and cooling the glass blank to room temperature; (c) subjecting the starting glass blank to a first heat treatment at a first temperature to give a glass product which contains nuclei suitable for forming lithium metasilicate crystals;
or(b′
) pouring the melt of the starting glass into a mould to form a starting glass blank and cooling the glass blank to a first temperature;(c′
) holding the starting glass blank at the first temperature to give a glass product which contains nuclei suitable for forming lithium metasilicate crystals;(d) subjecting the glass product of step (c) or (c′
) to a second heat treatment at a second temperature which is higher than the first temperature to obtain the lithium silicate blank with lithium metasilicate crystals as the main crystalline phase;(e) cooling the lithium silicate blank having the lithium metasilicate crystals as the main crystalline phase; and (f) shaping the cooled lithium silicate blank with lithium metasilicate crystals as the main crystalline phase into the shape of a dental restoration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A process for fabricating a lithium silicate dental article making use of a machinable lithium metasilicate glass ceramic blank comprising:
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(a) melting a starting glass composition comprising SiO2, Li2O, and P2O5 or other nucleation agent as the main components; (b) forming the molten glass into shaped blanks; (c) heat treating the glass blanks to convert the glass blanks into machinable glass-ceramic blanks comprising a lithium metasilicate phase as the main crystalline phase; (d) cooling the lithium silicate blank having the lithium metasilicate crystals as the main crystalline phase; (e) machining the cooled blanks into the shape of a dental article; and (f) heat treating the shaped dental article comprising the lithium metasilicate phase to fully or partially convert the lithium metasilicate into lithium disilicate. - View Dependent Claims (26, 27, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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28. The process of 25 wherein the heat treating to fully or partially convert the lithium metasilicate into lithium disilicate is in the temperature range of from about 700°
- C. to about 950°
C.
- C. to about 950°
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50. A process for fabricating a lithium silicate glass-ceramic dental article making use of a machinable glass ceramic blank comprising:
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(a) melting a starting glass composition comprising SiO2, Li2O, P2O5 or other nucleation agent; (b) forming the molten glass into shaped blanks; (c) heat treating the glass blanks to convert the glass blanks into machinable glass-ceramic blanks comprising a metastable lithium metasilicate phase as the main crystalline phase and having a strength of 80 to 180 MPa and a fracture toughness of at least about 0.8 MPam0.5; (d) cooling the lithium silicate blank having the lithium metasilicate phase as the main crystalline phase; (e) machining the cooled blanks into the shape of a dental article; and (f) heat treating the shaped dental article comprising the metastable lithium silicate phase to fully or partially convert the metastable phase into a final phase to provide a glass-ceramic dental article with a strength of at least about 250 MPa and a fracture toughness of at least about 1.5 MPam0.5. - View Dependent Claims (51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63)
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Specification