Patents by Inventor Yasutaka KUDO
Yasutaka KUDO has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20240067570Abstract: The present invention provides a pre-sintered body for obtaining a zirconia sintered body that can satisfy both high strength and high translucency, and a method of production of such a pre-sintered body. The present invention relates to a zirconia pre-sintered body comprising a secondary aggregate having an average particle diameter of 275 nm or less, the secondary aggregate comprising zirconia, and a stabilizer capable of preventing a phase transformation of zirconia, the secondary aggregate comprising a larger particle having an average primary particle diameter of 100 nm or more and 200 nm or less, and a smaller particle having an average primary particle diameter of 10 nm or more and less than 60 nm.Type: ApplicationFiled: December 23, 2021Publication date: February 29, 2024Applicant: Kuraray Noritake Dental Inc.Inventors: Kirihiro NAKANO, Nobusuke KASHIKI, Yasutaka KUDO, Yoshihisa ITO
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Publication number: 20240059579Abstract: The present invention provides a granule and green compact suited for obtaining a high-translucency and high-strength zirconia sintered body, and a high-density and uniform pre-sintered body. The invention also provides methods of production of such a granule and green compact. The present invention relates to a granule comprising zirconia, a stabilizing agent capable of preventing a phase transformation of zirconia, and a binder, the granule having a compression ratio R of 0.46 to 0.53 as calculated by the formula (1) below when tapped and filled into a columnar die in compliance with JIS R 1628:1997, and compressed by uniaxial pressing at a rate of 1 mm/s to 33 MPa, R=(H?D)/H??(1) wherein H represents a height of the granule tapped and filled into the columnar die before applying pressure, and D represents an amount of strain up to 33 MPa.Type: ApplicationFiled: December 22, 2021Publication date: February 22, 2024Applicant: Kuraray Noritake Dental Inc.Inventors: Kirihiro NAKANO, Nobusuke KASHIKI, Yasutaka KUDO, Yoshihisa ITO
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Patent number: 11802237Abstract: The present invention provides a method for producing a powder containing zirconia particles and a fluorescent agent that enables easy production of a zirconia sintered body having both high translucency and high strength despite containing a fluorescent agent. The present invention relates to a method for producing a zirconia particle- and fluorescent agent-containing powder, comprising: a mixing step of mixing a zirconia particle-containing slurry and a liquid-state fluorescent agent; and a drying step of drying the slurry containing the zirconia particles and the fluorescent agent. Preferably, the fluorescent agent comprises a metallic element, and the powder comprises the fluorescent agent in an amount of 0.001 to 1 mass % in terms of an oxide of the metallic element relative to a mass of zirconia. Preferably, the zirconia particles have an average primary particle diameter of 30 nm or less. Preferably, the zirconia particles comprises 2.0 to 9.0 mol % yttria.Type: GrantFiled: July 27, 2018Date of Patent: October 31, 2023Assignee: KURARAY NORITAKE DENTAL INC.Inventor: Yasutaka Kudo
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Patent number: 11479510Abstract: The present invention provides a method for producing a zirconia particle-containing powder that enables easy production of a zirconia sintered body having both high translucency and high strength. The present invention relates to a method for producing a zirconia particle-containing powder, comprising a drying step of spray drying a slurry containing zirconia particles, wherein the zirconia particles have an average primary particle diameter of 30 nm or less, and the slurry comprises a dispersion medium containing a liquid having a surface tension at 25° C. of 50 mN/m or less. Preferably, the zirconia particles comprise 2.0 to 9.0 mol % yttria. Preferably, wherein the content of the liquid in the dispersion medium is 50 mass % or more.Type: GrantFiled: July 27, 2018Date of Patent: October 25, 2022Assignee: KURARAY NORITAKE DENTAL INC.Inventor: Yasutaka Kudo
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Patent number: 11401461Abstract: The present invention provides a zirconia sintered body containing a fluorescent agent and having excellent translucency and excellent strength. The present invention also provides a zirconia shaped body and a zirconia calcined body from which the zirconia sintered body can be obtained. The present invention relates to a zirconia sintered body comprising a fluorescent agent, wherein the zirconia sintered body comprises 4.5 to 9.0 mol % yttria, and has a crystal grain size of 180 nm or less, and a three-point flexural strength of 500 MPa or more. The present invention relates to a zirconia shaped body comprising a fluorescent agent, wherein the zirconia shaped body comprises 4.5 to 9.0 mol % yttria, and has a three-point flexural strength of 500 MPa or more after being sintered at 1,100° C. for 2 hours under ordinary pressure, and a crystal grain size of 180 nm or less after being sintered at 1,100° C. for 2 hours under ordinary pressure.Type: GrantFiled: July 27, 2018Date of Patent: August 2, 2022Assignee: KURARAY NORITAKE DENTAL INC.Inventors: Yasutaka Kudo, Makiko Kato, Koichi Okada
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Publication number: 20220153649Abstract: A zirconia sintered body may excel in translucency, strength, and linear light transmittance with no use of an HIP device, and a zirconia molded body and a zirconia pre-sintered body from which such a zirconia sintered body can be obtained. A zirconia molded body may include zirconia particles with 2.0 to 9.0 mol % yttria, an average primary particle diameter of 60 nm or less, and 0.5 mass % or less zirconia particles having a particle diameter >100 nm, wherein the zirconia molded body has ?L*(W?B) of 5+ through a thickness of 1.5 mm. A zirconia pre-sintered body may include 2.0 to 9.0 mol % yttria, and have a ?L*(W?B) of 5+ through a thickness of 1.5 mm. A zirconia sintered body may include: a fluorescent agent; 2.0 to 9.0 mol % yttria, and have a linear light transmittance of 1% or more through a thickness of 1.0 mm.Type: ApplicationFiled: March 5, 2020Publication date: May 19, 2022Applicant: KURARAY NORITAKE DENTAL INC.Inventor: Yasutaka KUDO
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Publication number: 20220135486Abstract: A zirconia sintered body may excel in translucency, strength, in linear light transmittance, and can be produced by short-time sintering without an HIP device, and be used in zirconia molded bodies and pre-sintered bodies from which such a zirconia sintered body can be obtained. A zirconia molded body with zirconia particles and 2.0 to 9.0 mol % yttria, having an average primary particle diameter less than 60 nm, and a monoclinic crystal system in a fraction of ?55%. The zirconia molded body may have ?1% undissolved yttria. A zirconia pre-sintered body may have such zirconia particles, wherein the zirconia pre-sintered body has ?L*(W?B) of ?5 through a thickness of 1.5 mm. A zirconia sintered body may have a fluorescent agent and 2.0 to 9.0 mol % yttria, and a crystal grain size of ?180 nm.Type: ApplicationFiled: March 5, 2020Publication date: May 5, 2022Applicant: KURARAY NORITAKE DENTAL INC.Inventors: Yasutaka KUDO, Yoshihisa ITO
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Patent number: 11077646Abstract: A zirconia composition, a zirconia semi-sintered body, a zirconia sintered body, and a dental product are provided. The zirconia sintered body contains 4 mol % to 7 mol % of yttria as stabilizer, and a shielding material. The zirconia sintered body comprises first region and second region having a higher content ratio of the shielding material than the first region. Difference between content ratio of yttria in the first region and that of yttria in the second region is 1 mol % or less.Type: GrantFiled: June 4, 2020Date of Patent: August 3, 2021Assignee: KURARAY NORITAKE DENTAL INC.Inventors: Yoshihisa Ito, Yasutaka Kudo
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Publication number: 20210102116Abstract: The present invention provides a zirconia sintered body containing a fluorescent agent and having excellent translucency and excellent strength. The present invention also provides a zirconia shaped body and a zirconia calcined body from which the zirconia sintered body can be obtained. The present invention relates to a zirconia sintered body comprising a fluorescent agent, wherein the zirconia sintered body comprises 4.5 to 9.0 mol % yttria, and has a crystal grain size of 180 nm or less, and a three-point flexural strength of 500 MPa or more. The present invention relates to a zirconia shaped body comprising a fluorescent agent, wherein the zirconia shaped body comprises 4.5 to 9.0 mol % yttria, and has a three-point flexural strength of 500 MPa or more after being sintered at 1,100° C. for 2 hours under ordinary pressure, and a crystal grain size of 180 nm or less after being sintered at 1,100° C. for 2 hours under ordinary pressure.Type: ApplicationFiled: July 27, 2018Publication date: April 8, 2021Applicant: KURARAY NORITAKE DENTAL INC.Inventors: Yasutaka KUDO, Makiko KATO, Koichi OKADA
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Publication number: 20210102115Abstract: The present invention provides a method for producing a powder containing zirconia particles and a fluorescent agent that enables easy production of a zirconia sintered body having both high translucency and high strength despite containing a fluorescent agent. The present invention relates to a method for producing a zirconia particle- and fluorescent agent-containing powder, comprising: a mixing step of mixing a zirconia particle-containing slurry and a liquid-state fluorescent agent; and a drying step of drying the slurry containing the zirconia particles and the fluorescent agent. Preferably, the fluorescent agent comprises a metallic element, and the powder comprises the fluorescent agent in an amount of 0.001 to 1 mass % in terms of an oxide of the metallic element relative to a mass of zirconia. Preferably, the zirconia particles have an average primary particle diameter of 30 nm or less. Preferably, the zirconia particles comprises 2.0 to 9.0 mol % yttria.Type: ApplicationFiled: July 27, 2018Publication date: April 8, 2021Applicant: KURARAY NORITAKE DENTAL INC.Inventor: Yasutaka KUDO
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Publication number: 20200369573Abstract: The present invention provides a method for producing a zirconia particle-containing powder that enables easy production of a zirconia sintered body having both high translucency and high strength. The present invention relates to a method for producing a zirconia particle-containing powder, comprising a drying step of spray drying a slurry containing zirconia particles, wherein the zirconia particles have an average primary particle diameter of 30 nm or less, and the slurry comprises a dispersion medium containing a liquid having a surface tension at 25° C. of 50 mN/m or less. Preferably, the zirconia particles comprise 2.0 to 9.0 mol % yttria. Preferably, wherein the content of the liquid in the dispersion medium is 50 mass % or more.Type: ApplicationFiled: July 27, 2018Publication date: November 26, 2020Applicant: KURARAY NORITAKE DENTAL INC.Inventor: Yasutaka KUDO
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Publication number: 20200298536Abstract: A zirconia composition, a zirconia semi-sintered body, a zirconia sintered body, and a dental product are provided. The zirconia sintered body contains 4 mol % to 7 mol % of yttria as stabilizer, and a shielding material. The zirconia sintered body comprises first region and second region having a higher content ratio of the shielding material than the first region. Difference between content ratio of yttria in the first region and that of yttria in the second region is 1 mol % or less.Type: ApplicationFiled: June 4, 2020Publication date: September 24, 2020Applicant: Kuraray Noritake Dental Inc.Inventors: Yoshihisa Ito, Yasutaka Kudo
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Patent number: 10703076Abstract: A zirconia composition, a zirconia semi-sintered body, a zirconia sintered body, and a dental product are provided. The zirconia sintered body contains 4 mol % to 7 mol % of yttria as stabilizer, and a shielding material. The zirconia sintered body comprises first region and second region having a higher content ratio of the shielding material than the first region. Difference between content ratio of yttria in the first region and that of yttria in the second region is 1 mol % or less.Type: GrantFiled: December 25, 2015Date of Patent: July 7, 2020Assignee: KURARAY NORITAKE DENTAL INC.Inventors: Yoshihisa Ito, Yasutaka Kudo
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Publication number: 20180002235Abstract: There are provided zirconia composition, zirconia semi-sintered body and zirconia sintered body, and dental product in which defect-generation is suppressed and transparency varies. The zirconia sintered body contains 4 mol % to 7 mol % of yttria as stabilizer. The zirconia sintered body contains shielding material. The zirconia sintered body comprises first region and second region having a higher content ratio of the shielding material than the first region. Difference between content ratio of yttria in the first region and that of yttria in the second region is 1 mol % or less.Type: ApplicationFiled: December 25, 2015Publication date: January 4, 2018Applicant: KURARAY NORITAKE DENTAL INC.Inventors: Yoshihisa ITO, Yasutaka KUDO
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Patent number: 9844495Abstract: The present invention provides a self-adhesive composite resin having excellent adhesiveness to tooth structures and excellent mechanical strength. The present invention relates to a self-adhesive dental composite resin containing: an asymmetric acrylamide-methacrylic acid ester compound (a); an acid group-containing (meth)acrylic polymerizable monomer (b); a hydrophobic crosslinkable polymerizable monomer (c); a photopolymerization initiator (d); and a filler (e).Type: GrantFiled: June 10, 2015Date of Patent: December 19, 2017Assignee: KURARAY NORITAKE DENTAL INC.Inventors: Yasutaka Kudo, Yamato Nojiri, Mitsuru Takei
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Publication number: 20170135910Abstract: The present invention provides a self-adhesive composite resin having excellent adhesiveness to tooth structures and excellent mechanical strength. The present invention relates to a self-adhesive dental composite resin containing: an asymmetric acrylamide-methacrylic acid ester compound (a); an acid group-containing (meth)acrylic polymerizable monomer (b); a hydrophobic crosslinkable polymerizable monomer (c); a photopolymerization initiator (d); and a filler (e).Type: ApplicationFiled: June 10, 2015Publication date: May 18, 2017Applicant: KURARAY NORITAKE DENTAL INC.Inventors: Yasutaka KUDO, Yamato NOJIRI, Mitsuru TAKEI