Methods of manufacturing dental restorations using nanocrystalline materials
First Claim
1. A method of manufacturing a dental article comprising:
- forming particulate ceramic material consisting essentially of ceramic crystallites with average size of less than about 20 nm into a dental article;
sintering the particulate ceramic material without the application of external pressure at a temperature less than about 1300°
C. to provide a final ceramic material having grains of average grain size exceeding 100 nanometers and not exceeding about 400 nanometers and a final density exceeding 95% of the theoretical density of the ceramic material;
wherein the final ceramic material exhibits at least 30% relative transmission of visible light when measured through a thickness in the range of about 0.3 to about 0.5 mm.
5 Assignments
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Accused Products
Abstract
Dental articles are produced using relatively low sintering temperatures to achieve high density dental articles exhibiting strengths equal to and greater than about 700 MPa. Ceramic powders comprised of nanoparticulate crystallites are used to manufacture dental articles. The ceramic powders may include sintering agents, binders and other similar additives to aid in the processing of the ceramic powder into a dental article. The ceramic powders may be processed into dental articles using various methods including, but not limited to, injection molding, gel-casting, slip casting, or electroforming, hand, cad/camming and other various rapid prototyping methods. The ceramic powder may be formed into a suspension, pellet, feedstock material or a pre-sintered blank prior to forming into the dental article.
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Citations
33 Claims
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1. A method of manufacturing a dental article comprising:
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forming particulate ceramic material consisting essentially of ceramic crystallites with average size of less than about 20 nm into a dental article; sintering the particulate ceramic material without the application of external pressure at a temperature less than about 1300°
C. to provide a final ceramic material having grains of average grain size exceeding 100 nanometers and not exceeding about 400 nanometers and a final density exceeding 95% of the theoretical density of the ceramic material;wherein the final ceramic material exhibits at least 30% relative transmission of visible light when measured through a thickness in the range of about 0.3 to about 0.5 mm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of manufacturing a dental article comprising:
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forming particulate ceramic material consisting essentially of ceramic crystallites with average size of less than about 20 nm into a dental article; sintering the particulate ceramic material without the application of external pressure at a temperature less than about 1300°
C. to provide a final ceramic material having grains of average grain size exceeding 100 nanometers and not exceeding about 400 nanometers and a final density exceeding 95% of the theoretical density of the ceramic material;wherein the particulate ceramic material exhibits linear shrinkage after fully sintering, in the range from about 15% to about 25% and wherein the shrinkage is substantially isotropic. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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18. A method of manufacturing a dental article comprising:
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forming particulate ceramic material consisting essentially of ceramic crystallites with average size of less than about 20 nm into a dental article; sintering the particulate ceramic material without the application of external pressure at a temperature less than about 1300°
C. to provide a final ceramic material having grains of average grain size exceeding 100 nanometers and not exceeding about 400 nanometers and a final density exceeding 95% of the theoretical density of the ceramic material;wherein the final grain size of the ceramic material is about 10-20 times larger than the starting crystallite size and the final pore size does not exceed the size of the starting crystallite size; and wherein the final ceramic material exhibits at least 30% relative transmission of visible light when measured through a thickness of about 0.5 mm.
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Specification