Tosoh Corporation

Sho Azechi

Hiroyuki Fujisaki

Akiko Ito

Yuki Ushio

Hitoshi Nagayama

Kiyotaka Kawamura

Ayako Watanabe

Yuuki Ito

A layered body, which has a change in texture derived from zirconia, particularly a change in translucency and is suitable as a dental prosthetic member, a precursor thereof, or a method for producing these. The layered body has a structure in which two or more layers containing zirconia containing a stabilizer are layered, the layered body including at least: a first layer containing zirconia having a stabilizer content of higher than or equal to 4 mol %; and a second layer containing zirconia having a stabilizer content different from that of the zirconia contained in the first layer. At least one layer contains one or more elements capable of coloring zirconia.

Zirconia layered body

A method for manufacturing a zirconia sintered body includes molding a powder composition that has a yttria content of more than 3% by mole and 5.2% by mole or less and that contains a first zirconia powder having a yttria content of 2% by mole or more and 4% by mole or less and a second zirconia powder having a yttria content of more than 4% by mole and 6% by mole or less to obtain a green body, and sintering the green body to obtain a sintered body.

Zirconia sintered body and method for manufacturing the same

A zirconia powder is provided comprising a yttria source and zirconia, wherein a content of the yttria source is 4.5 mol % or more and 6.5 mol % or less and the remainder is zirconia, a ratio of a total of tetragonal and cubic crystals to an entire crystal phase of zirconia is 90% or less, a BET specific surface area is 7.5 m/g or more and 15 m/g or less, and an average crystallite size is 325 &#x212b; or greater. The powders are useful in producing sintered bodies having the mechanical strength and the translucency desired for use in dental prosthetic materials, and precursors thereof.

Zirconia sintered body and production method thereof

Provided is at least any of a layered body, which has a change in texture derived from zirconia, particularly a change in translucency and is suitable as a dental prosthetic member, a precursor thereof, or a method for producing these. There is provided a layered body having a structure in which two or more layers containing zirconia containing a stabilizer are layered, the layered body including at least: a first layer containing zirconia having a stabilizer content of higher than or equal to 4 mol %; and a second layer containing zirconia having a stabilizer content different from that of the zirconia contained in the first layer.

There is provided at least any of a layered body which has a change in color tone and in which it is unnecessary to select a colorant and the content of the colorant in consideration of a difference in the sintering behavior between layers, a precursor thereof, or a method for producing these. Provided is a layered body which has a structure, in which two or more layers containing stabilizer-containing zirconia and a colorant are layered, and in which types and contents of the colorants contained in the layers are equal to each other, the layered body including at least: a first layer containing a colorant and zirconia which has a stabilizer content of higher than or equal to 3.3 mol %; and a second layer containing a colorant and zirconia which has a stabilizer content different from that of the zirconia contained in the first layer.

A zirconia sintered body is provided and includes yttria and zirconia, containing yttria by a content ranging from 4.5 mol % or more to 6.5 mol % or less and zirconia as the remainder, the total light transmittance of a 1-mm thick sample measured in compliance with JIS K 7361-1 being 46.5% or higher, the three-point bending strength being 700 MPa or higher, and a ratio of an integrated value for the total light transmittance to an integrated value for the parallel light transmittance of a 1-mm thick sample measured at the measurement wavelength ranging from 400 to 700 nm being 1.3% or less.

Provided are a zirconia sintered body capable of being widely used as a dental material, in particular, a zirconia sintered body capable of being applied to both a dental material for a back tooth and a dental material for a front tooth and a simple and easy method for manufacturing the zirconia sintered body. The method for manufacturing a zirconia sintered body includes a molding step of molding a powder composition that has an yttria content of more than 3% by mole and 5.2% by mole or less and that contains a first zirconia powder having an yttria content of 2% by mole or more and 4% by mole or less and a second zirconia powder having an yttria content of more than 4% by mole and 6% by mole or less to obtain a green body, and a sintering step of sintering the green body to obtain a sintered body.

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Yamaguchi, Japan

Sho Azechi