Kuraray Noritake Dental Inc.

Yasutaka Kudo

Yoshihisa Ito

Koichi Okada

Yamato Nojiri

Mitsuru Takei

Makiko Kato

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 ΔL*(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.

Zirconia molded body and pre-sintered body capable of being sintered in short time

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 ΔL*(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 ΔL*(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.

Zirconia sintered body having high linear light transmittance

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.

Method for producing powder containing zirconia particles and fluorescent agent

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&#xb0; 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.

Method for producing zirconia particle-containing powder

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&#xb0; C. for 2 hours under ordinary pressure, and a crystal grain size of 180 nm or less after being sintered at 1,100&#xb0; C. for 2 hours under ordinary pressure. The present invention relates to a zirconia calcined body comprising a fluorescent agent, wherein the zirconia calcined 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&#xb0; C. for 2 hours under ordinary pressure, and a crystal grain size of 180 nm or less after being sintered at 1,100&#xb0; C. for 2 hours under ordinary pressure.

Zirconia sintered body containing fluorescent agent

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.

Zirconia composition, zirconia semi-sintered body and zirconia sintered body, as well as dental product

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). The asymmetric acrylamide-methacrylic acid ester compound (a) is represented by the following general formula (1): where X is an optionally substituted, linear or branched Cto Caliphatic group or an optionally substituted aromatic group, the aliphatic group is optionally interrupted by at least one linking group selected from the group consisting of &#x2014;O&#x2014;, &#x2014;S&#x2014;, &#x2014;CO&#x2014;, &#x2014;CO&#x2014;O&#x2014;, &#x2014;O&#x2014;CO&#x2014;, &#x2014;NR&#x2014;, &#x2014;CO&#x2014;NR&#x2014;, &#x2014;NR&#x2014;CO&#x2014;, &#x2014;CO&#x2014;O&#x2014;NR&#x2014;, &#x2014;O&#x2014;CO&#x2014;NR&#x2014;, and &#x2014;NR&#x2014;CO&#x2014;NR&#x2014;, and Ris a hydrogen atom or an optionally substituted, linear or branched Cto Caliphatic group.

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Aichi, Japan

Yasutaka Kudo