US 12,115,032 B2
Dental zirconia blank having high relative density
Toshio Kitamura, Kyoto (JP); and Rieko Aiba, Kyoto (JP)
Assigned to SHOFU INC., Kyoto (JP)
Filed by SHOFU INC., Kyoto (JP)
Filed on Apr. 19, 2023, as Appl. No. 18/136,575.
Application 18/136,575 is a division of application No. 15/805,396, filed on Nov. 7, 2017, granted, now 11,660,172.
Claims priority of application No. 2016-217662 (JP), filed on Nov. 7, 2016; and application No. 2017-209868 (JP), filed on Oct. 31, 2017.
Prior Publication US 2023/0255734 A1, Aug. 17, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. A61C 13/00 (2006.01); A61C 13/08 (2006.01)
CPC A61C 13/0022 (2013.01) [A61C 13/0004 (2013.01); A61C 13/082 (2013.01)] 7 Claims
 
1. A dental cutting zirconia blank produced with a pre-sintered body of a dental cutting zirconia blank comprising at least three layers having different color tones,
wherein, at least one layer consists of zirconia powder containing 4 to 15 mol % of yttria and/or erbium oxide as a stabilizer,
wherein the pre-sintered body of the dental cutting zirconia blank becomes usable in an oral cavity by a process comprising:
a step of cutting and machining the pre-sintered body of the dental cutting zirconia blank, and
a step of perfect-sintering the cut and machined pre-sintered body of the dental cutting zirconia blank to a state usable in the oral cavity,
wherein the pre-sintered body of the dental cutting zirconia blank satisfies the following relationship:
54≤Relative density (%)={(Pre-sintering density)/(Perfect-sintering density)}×100≤70
wherein the Pre-sintering density indicates a density of the pre-sintered body of the dental cutting zirconia blank, and the Perfect-sintering density indicates a density of the dental cutting zirconia blank in use in the oral cavity, and
wherein the at least three layers include:
an E layer which has the lowest saturation after perfect-sintering and is positioned on one of an uppermost layer or a lowermost layer of the pre-sintered body of the dental cutting zirconia blank,
a C layer which has the highest saturation after perfect-sintering and is positioned on the other of the uppermost layer or the lowermost layer of the pre-sintered body of the dental cutting zirconia blank, and
an M layer which is positioned between the E layer and the C layer, and
a content of yttria in mol % in the at least three layers is constant.