JP2016117618A - Zirconia composition, zirconia calcinated body, zirconia sintered body and manufacturing zirconia sintered body and dental product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zirconia sintered body having fluorescence and light transmissivity and a manufacturing method therefor, a composition for manufacturing the zirconia sintered body, a calcinated body and a dental product containing the zirconia sintered body.SOLUTION: A partially stabilized zirconia sintered body contains a fluorescence agent. Average crystal particle diameter of a zirconia crystal measured on a cross section of the zirconia sintered body is 120 nm or less. The fluorescence agent with a mass of 0.01% to 1.5% inclusive based on the mass of the partially stabilized zirconia is added and sintered. Transmissivity of light with wave length of 700 nm transmitting the zirconia with thickness of 0.5 mm is 15% or more.SELECTED DRAWING: None

Description

  The present invention relates to a zirconia composition, a zirconia calcined body, a zirconia sintered body, and a method for producing the same. Moreover, this invention relates to the dental product containing a zirconia sintered compact.

  A sintered body of zirconium oxide (hereinafter referred to as “zirconia”) having tetragonal crystal as a main crystal phase (hereinafter referred to as “zirconia sintered body”) has excellent characteristics such as high strength and high toughness. For this reason, the zirconia sintered compact is used for various uses, such as a prosthesis and a tool used for tooth treatment.

The translucency of a general zirconia sintered body is not high. However, the zirconia sintered body is required to have high translucency depending on applications. Thus, for example, Patent Document 1 and Patent Document 2 disclose zirconia sintered bodies with improved translucency. The translucent zirconia sintered body described in Patent Document 1 is composed of zirconia containing 2 mol% to 4 mol% of yttria, and has a relative density of 99% or more, a crystal grain size of 0.15 μm or less, and 600 nm absorption scattering. The coefficient is 5.0 mm ⁻¹ or less. The translucent zirconia sintered body described in Patent Document 2 is a translucent zirconia sintered body composed of primary particles and having a density of at least 99 percent of the full density, wherein the primary particles are tetragonal oxides. The diameter of any pores present in the zirconia sintered body having a main phase that is zirconium and a dimension of 100 nm or less is about 25 nm or less.

  In Non-Patent Document 1 and Non-Patent Document 2, zirconia sintering is performed using a high solid concentration slurry in which zirconia nanoparticles are dispersed for the purpose of producing a nanocrystalline zirconia sintered body of a large-sized member or a member having a complicated shape. The body is being made.

  Patent Document 3 discloses a fluorescent zirconia material that contains a fluorescent component that can emit fluorescence after baking at a temperature in the range of 1300 to 1600 ° C. in an oxidizing atmosphere, and that emits fluorescence when excited by light of a predetermined wavelength. ing.

JP 2008-214168 A Special table 2010-514665 gazette JP 2010-222466 A

Shinya Takeno and two others, “Preparation of Nanocrystalline Zirconia Sintered Body by Casting of Nanoparticle Suspension”, 2012 Annual Meeting of the Ceramic Society of Japan, The Ceramic Society of Japan, March 19, 2012, p . 57 Shinya Takeno and two others, “Preparation of tetragonal zirconia nanoceramics by casting of nanoslurry”, Tokai Branch 44th Tokai Young Ceramist Social Meeting of the Ceramic Society of Japan 2012 Summer Seminar of Tokai Branch of the Ceramic Society of Japan Tokai Branch Meeting, June 28, 2012, p. 51

  The following analysis is given from the perspective of the present invention.

  Natural teeth have a certain translucency. When a zirconia sintered body is used as a dental prosthesis, if the translucency of the prosthesis is too low, teeth treated with the prosthesis will stand out from the surrounding natural teeth. On the other hand, when the translucent property of the prosthesis is too high, the abutment tooth is seen through the prosthesis in a state where the prosthesis is covered with the abutment tooth. Therefore, the zirconia sintered body used for the dental prosthesis is required to have translucency such that the abutment teeth are not transparent.

  Natural teeth are also fluorescent. When the dental prosthesis has no fluorescence, natural teeth emit light in an ultraviolet irradiation environment (for example, in an amusement facility environment produced using black light), but the prosthesis emits light. do not do. That is, only the teeth treated with the prosthesis become black and the teeth appear to be missing.

  Therefore, when using a zirconia sintered compact for a dental prosthesis, for example, it is desirable for the zirconia sintered compact to have both translucency and fluorescence.

  The zirconia sintered bodies described in Patent Documents 1 and 2 and Non-Patent Documents 1 and 2 do not have fluorescence. Therefore, even if a dental prosthesis is produced with a single zirconia sintered body of each document, a prosthesis having both translucency and fluorescence like a natural tooth cannot be produced. Therefore, in the dental industry, in order to impart fluorescence to a prosthesis, baking is performed after applying a porcelain made of glass or glass ceramic containing a fluorescent agent on the surface of a zirconia sintered body. . However, such a porcelain treatment is a great effort in the prosthesis manufacturing process. Therefore, it is desirable that the porcelain processing steps be as few as possible.

  The fluorescent zirconia material described in Patent Document 3 needs to be fired at 1300 ° C. or higher in order to be sintered. Since the fluorescent agent is decomposed at such a firing temperature, it is necessary to add a large amount of the fluorescent agent in order to exhibit high fluorescence in the zirconia sintered body. However, when a large amount of fluorescent agent is added, the translucency is lowered in the zirconia sintered body.

  According to the first aspect of the present invention, a partially stabilized zirconia sintered body containing a fluorescent agent is provided. The average crystal grain size of zirconia crystals observed in the cross section of the zirconia sintered body is 120 nm or less. A fluorescent agent having a mass of 0.01% to 1.5% with respect to the mass of the partially stabilized zirconia is added and sintered. The transmittance of light having a wavelength of 700 nm that passes through a zirconia sintered body having a thickness of 0.5 mm is 15% or more.

  According to the 2nd viewpoint of this invention, the dental product containing the zirconia sintered compact which concerns on a 1st viewpoint is provided.

  According to the third aspect of the present invention, partially stabilized zirconia particles having an average particle diameter of 20 nm or less, a fluorescent agent having a mass of 0.01% to 1.5% with respect to the mass of the partially stabilized zirconia, A composition is provided comprising:

  According to the 4th viewpoint of this invention, the calcined body obtained by baking the composition which concerns on a 3rd viewpoint at the temperature of 650 degreeC-850 degreeC is provided.

  According to the fifth aspect of the present invention, partially stabilized zirconia particles having an average particle diameter of 20 nm or less and a fluorescent agent having a mass of 0.01% to 1.5% with respect to the mass of the partially stabilized zirconia are mixed. Thus, a method for producing a zirconia sintered body is provided, which includes a step of producing a composition and a step of firing the composition at a temperature of 900 ° C. to 1200 ° C. to sinter zirconia particles.

  ADVANTAGE OF THE INVENTION According to this invention, the zirconia sintered compact and dental product which have both fluorescence and translucency can be provided. In particular, it is possible to provide a zirconia sintered body capable of producing a dental product having fluorescence without using a porcelain for imparting fluorescence. Moreover, the manufacturing method of the composition for obtaining such a zirconia sintered compact and a dental product, a calcined body, and a zirconia sintered compact can be provided.

  The preferable form of each said viewpoint is described below.

  According to the preferable form of the first viewpoint, the fluorescent light is emitted when light having a predetermined wavelength is irradiated.

  According to a preferred embodiment of the first aspect, the transmittance of light having a wavelength of 365 nm that passes through the zirconia sintered body having a thickness of 0.5 mm is 3% or more.

According to a preferred form of the first aspect, the fluorescent agent is Y ₂ SiO ₅ : Ce.

  According to a preferred form of the first aspect, the fluorescent light is emitted when the zirconia sintered body having a thickness of 0.5 mm is irradiated with light containing light having a wavelength of 365 nm.

  According to a preferred embodiment of the first aspect, the transmittance of light having a wavelength of 700 nm is 30% or more.

  According to a preferred embodiment of the third aspect, the fluorescent agent is contained in a mass of 0.01% to 1% with respect to the mass of the partially stabilized zirconia.

According to a preferred embodiment of the third aspect, the fluorescent agent is Y ₂ SiO ₅ : Ce.

  According to the preferred form of the fifth aspect, in the step of producing the composition, a fluorescent agent having a mass of 0.01% or more and 1% or less is mixed with respect to the mass of the partially stabilized zirconia.

According to a preferred form of the fifth aspect, the fluorescent agent is Y ₂ SiO ₅ : Ce.

  According to the preferable form of the fifth aspect, in the step of sintering the zirconia particles, the composition is fired at a temperature of 900 ° C. to 1150 ° C.

  According to a preferred form of the fifth aspect, the method for producing a zirconia sintered body includes a step of forming a composition by forming a composition, and firing the formed body at a temperature in the range of 650 ° C to 850 ° C. And a step of producing a calcined body.

  In the following description, reference numerals of the drawings are added for understanding of the invention and are not intended to be limited to the illustrated embodiments. In each embodiment, the same elements are denoted by the same reference numerals.

  The zirconia sintered body of the present invention will be described. The zirconia sintered body of the present invention is a sintered body in which partially stabilized zirconia (PSZ) particles are mainly sintered, and has partially stabilized zirconia as a matrix phase. In the following description, what is simply referred to as “zirconia” shall mean partially stabilized zirconia. In the zirconia sintered body of the present invention, the main crystal phase of zirconia is preferably tetragonal or tetragonal and cubic. It is preferable that the zirconia sintered body does not substantially contain a monoclinic system (in a stage immediately after sintering, for example, in an untreated hydrothermal treatment test stage).

  For example, in the X-ray diffraction line of a zirconia sintered body (untreated hydrothermal degradation test), 2θ relative to the height of the peak existing near the position where the [111] peak derived from tetragonal crystals with 2θ of around 30 ° occurs. The ratio of the heights of the peaks existing near the position where the [11-1] peak derived from the monoclinic crystal near 28 ° (ie, “[11-1] peak derived from the monoclinic crystal whose 2θ is near 28 ° The height of the peak existing near the position where it occurs ”/“ the height of the peak near the position where the [111] peak derived from tetragonal crystals with 2θ of about 30 ° occurs ”; ”) Is preferably 0.10 or less, more preferably 0.05, and no monoclinic peak is substantially detected (ie, the monoclinic peak ratio is 0). Further preferred.

  The zirconia sintered body of the present invention includes not only a sintered body obtained by sintering molded zirconia particles under normal pressure or non-pressurization, but also HIP (Hot Isostatic Pressing) treatment, etc. A sintered body densified by high-temperature pressure treatment is also included.

The zirconia sintered body of the present invention contains zirconium oxide and its stabilizer. The stabilizer generally suppresses the phase transition of tetragonal zirconia to monoclinic crystals. By suppressing the phase transition, strength, durability and dimensional accuracy can be increased. Examples of the stabilizer include oxides such as calcium oxide (CaO), magnesium oxide (MgO), yttrium oxide (Y ₂ O ₃ ) (hereinafter referred to as “yttria”), and cerium oxide (CeO ₂ ). It is done. The stabilizer is preferably added in such an amount that the tetragonal zirconia particles can be partially stabilized. For example, when using yttria as a stabilizer, the content of yttria is preferably 2 mol% or more, and more preferably 2.5 mol% or more with respect to the total number of moles of zirconia and yttria. When the content of the stabilizer is too low, the progress of the phase transition is not sufficiently suppressed even if the decrease in bending strength and fracture toughness can be suppressed. The yttria content is preferably 4 mol% or less, more preferably 3.5 mol% or less, based on the total number of moles of zirconia and yttria. When the content of the stabilizer is increased too much, the bending strength and fracture toughness are lowered even if the phase transition can be suppressed. Note that zirconia partially stabilized by adding a stabilizer is called partially stabilized zirconia. The content of the stabilizer in the zirconia sintered body can be measured by, for example, inductively coupled plasma (ICP) emission spectroscopy, fluorescent X-ray analysis, or the like.

  The zirconia sintered body of the present invention has translucency and fluorescence.

  Regarding the translucency, the transmittance of light having a wavelength of 700 nm passing through a 0.5 mm-thick zirconia sintered body is preferably 15% or more, more preferably 20% or more, and 25% or more. More preferably, it is more preferably 30% or more, more preferably 35% or more, and further preferably 40% or more. If the transmittance is too low, when the zirconia sintered body is used as a dental prosthesis, the teeth treated with the prosthesis have a great difference from the appearance of the surrounding natural teeth. Further, the transmittance is preferably 70% or less, more preferably 65% or less, and further preferably 60% or less. If the transmittance is too high, when the zirconia sintered body is used as a dental prosthesis, the abutment teeth are seen through the prosthesis.

  Regarding the translucency, the transmittance at which light having a wavelength of 356 nm passes through a zirconia sintered body having a thickness of 0.5 mm is preferably 3% or more, more preferably 5% or more, and 7% or more. More preferably, it is 8% or more, more preferably 9% or more. By increasing the translucency of light having a wavelength equivalent to the excitation wavelength of the fluorescent agent, it is possible to improve the fluorescence described later.

  Regarding the fluorescence, the relative luminescence intensity of the zirconia sintered body when irradiated with light having an excitation wavelength on the 0.5 mm thick zirconia sintered body is “Celabian (registered trademark) ZR” manufactured by Kuraray Noritake Dental Co., Ltd. Compared to the emission intensity of the sintered body of “Internal Stain Fluoro” under the same conditions, it is preferably 10% or more, more preferably 14% or more, and further preferably 40% or more. The relative light emission intensity of the zirconia sintered body is preferably 100% or less. For example, the light source emits light including light having a wavelength of 365 nm. When the excitation wavelength is 365 nm, the emission intensity is, for example, the emission intensity obtained by integrating measurement values in the wavelength range of 390 nm to 650 nm.

  The zirconia sintered body contains a fluorescent agent. It is preferable that the fluorescent agent is added in an amount capable of obtaining desired fluorescence and translucency for the zirconia sintered body. For example, it is preferable to add a fluorescent agent to the raw material at an addition rate as described later.

The fluorescent agent only needs to emit fluorescence with light of any wavelength. Examples of usable fluorescent agents include Y ₂ SiO ₅ : Ce, Y ₂ SiO ₅ : Tb, (Y, Gd, Eu) BO ₃ , Y ₂ O ₃ : Eu, YAG: Ce, and ZnGa ₂ O ₄ : Zn, BaMgAl ₁₀ O ₁₇ : Eu, and the like can be given. The fluorescent agent is preferably based on yttria, more preferably Y ₂ SiO ₅ : Ce.

When the zirconia sintered body is used as a dental prosthesis, one that emits light by ultraviolet rays, for example, ultraviolet rays having a wavelength of 280 nm to 400 nm, is preferable, and examples of the fluorescent agent include Y ₂ SiO ₅ : Ce.

  The average crystal grain size of the crystal grains in the zirconia sintered body is preferably 120 nm or less, more preferably 100 nm or less, and further preferably 90 nm or less. The average particle diameter can be measured based on, for example, a field emission scanning electron microscope (FE-SEM) photograph of a cross section of the zirconia sintered body and the equivalent circle diameter of the particles in the photographed image.

  Next, the composition and calcined body for producing the zirconia sintered body of the present invention will be described. The composition and the calcined body serve as a precursor (intermediate product) of the above-described zirconia sintered body of the present invention. The calcined body is obtained by firing (that is, calcining) the composition at a temperature that does not lead to sintering. In addition, the calcined body includes a molded body (for example, a cutting process). For example, a dental prosthesis (for example, a crown shape) obtained by processing a calcined zirconia disk with a CAD / CAM (Computer-Aided Design / Computer-Aided Manufacturing) system is also included in the calcined body.

  The composition and calcined body contain partially stabilized zirconia crystal particles containing a stabilizer. The composition and the calcined body further contain a fluorescent agent.

  The average particle diameter of the zirconia particles in the composition is preferably 30 nm or less, and more preferably 20 nm or less. The average particle diameter can be measured from a photographed image obtained by photographing zirconia particles with a transmission electron microscope (TEM).

Examples of the stabilizer in the composition and calcined body include oxides such as calcium oxide (CaO), magnesium oxide (MgO), yttria, and cerium oxide (CeO ₂ ). The stabilizer is preferably added in such an amount that the zirconia particles in the sintered body can be partially stabilized. For example, when using yttria as a stabilizer, the content of yttria is preferably 2 mol% or more, and more preferably 2.5 mol% or more with respect to the total number of moles of zirconia and yttria. The yttria content is preferably 4 mol% or less, more preferably 3.5 mol% or less, based on the total number of moles of zirconia and yttria.

  The addition ratio of the fluorescent agent in the composition and the calcined body is relatively preferably 0.01% or more, more preferably 0.05% or more, based on the mass of the partially stabilized zirconia, 0 0.1% or more is more preferable, and 0.5% or more is preferable. If the content is too low, it will not emit fluorescence. If the addition rate is too low, the sintered body will not emit fluorescence. The addition rate of the fluorescent agent is relatively preferably 1.5% or less, and more preferably 1% or less, based on the partially stabilized zirconia mass. When the addition rate is too high, the translucency and strength of the zirconia sintered body are reduced. The addition rate of the above fluorescent agent is, for example, 0.05%, when 5 g of the fluorescent agent is added when the partially stabilized zirconia is 100 g.

  The content of the fluorescent agent can be theoretically calculated from the addition amount with respect to the mass of zirconia and the production method.

  In the composition of the present invention, a powder, a fluid in which the powder is added to a solvent, a fluid in which the powder is dispersed in the solvent, a fluid in which zirconia particles are dispersed in the solvent, and the powder are formed into a predetermined shape. Also included are molded bodies. That is, the composition may be in the form of powder, paste, slurry, gel, sol, or wet composition (that is, it may be in a solvent or contain a solvent). Also good). The composition may contain additives such as a binder and a pigment. In addition, in the calculation of the content rate, the mass of additives such as a solvent and a binder is not considered.

  When the composition of the present invention is a molded body, it may be molded by any molding method, for example, can be molded by press molding, injection molding, stereolithography, gel casting, or the like. Alternatively, multi-stage molding may be performed. For example, the composition of the present invention may be subjected to press molding and further subjected to CIP (Cold Isostatic Pressing) treatment.

  The calcined body of the present invention can be obtained by firing the composition of the present invention at 650 ° C. to 850 ° C. under normal pressure.

  The calcined body of the present invention becomes the zirconia sintered body of the present invention by firing at 900 ° C. to 1200 ° C. under normal pressure.

  Next, an example of the manufacturing method of the composition of this invention, a calcined body, and a sintered compact is demonstrated.

  First, a zirconia sol is prepared. As a method for producing a zirconia sol containing 2 mol% to 4 mol% yttria as a stabilizer and partially stabilized zirconia fine particles having an average particle diameter of 20 nm or less, any known method can be used without any limitation. For example, a manufacturing method as disclosed in JP-A-5-170442 can be used. Specifically, a zirconium oxychloride aqueous solution and a yttrium chloride aqueous solution were previously mixed, the mixed solution was added to a solution containing water, aqueous ammonia, and ammonium hydrogen carbonate, and the resulting slurry was added at 80 ° C to A method of heat treatment at a temperature of 200 ° C., separation and washing after addition of hydrochloric acid can be used. The particle diameter of the zirconia fine particles in the zirconia sol is preferably 30 nm or less, more preferably 20 nm or less, and further preferably 15 nm or less.

  As a sol containing yttria-stabilized zirconia nanoparticles, 22 mass% to 25 mass% of partially stabilized zirconia fine particles having an yttria content of 3 mol% and an average particle diameter of 11 to 12 nm are obtained from Nikkei Mel. Sol-containing sols are commercially available and can be suitably used in this embodiment.

  Next, a fluorescent agent is added to the zirconia sol to produce the composition of the present invention. As the fluorescent agent, the compounds listed above can be used. The addition amount of the fluorescent agent can be determined so as to be the content of the fluorescent agent in the composition as described above. At least one of a pH adjusting agent, a dispersing agent and a gelling agent can be added to the zirconia sol. As the pH adjuster, for example, tetramethylammonium hydroxide can be used. As the dispersant, for example, triammonium citrate can be used. As the gelling agent, for example, gelatin, agarose and the like can be used. The composition may be concentrated, for example, to a solids concentration of 70%.

  Next, the composition is poured into a mold and dried to prepare a molding composition. Drying can be performed at room temperature, for example.

  Next, the zirconia particles are sintered by firing the molding composition to produce a zirconia sintered body. The sintering temperature for obtaining a sintered body is preferably 900 ° C. or higher, and more preferably 1050 ° C. or higher. The sintering temperature is preferably 1200 ° C. or lower, and more preferably 1150 ° C. or lower.

  When producing a calcined body, the molding composition is fired at a temperature lower than the sintering temperature to produce a calcined body. The calcining temperature for obtaining the calcined body is preferably 650 ° C. or higher, and more preferably 700 ° C. or higher. The calcining temperature is preferably 850 ° C. or lower. Next, the calcined body is fired at the sintering temperature to sinter the zirconia powder to produce a zirconia sintered body.

  By sintering at the sintering temperature, fluorescence can be expressed in the sintered body even if the addition amount of the fluorescent agent is small. Moreover, the energy cost in sintering can be reduced. Furthermore, deterioration of the firing furnace can be delayed. Furthermore, the firing time can be shortened.

  The forming process may be performed by cutting or the like at the stage of the calcined body, or may be performed after sintering. The molding process can be performed using, for example, a CAD / CAM system.

  Thereby, the zirconia sintered compact which has translucency and fluorescence as described above can be manufactured.

  Next, the dental product of the present invention will be described. The dental product includes a zirconia sintered body as described above. Examples of the dental product include a dental prosthesis, an orthodontic product, and a dental implant product. Dental prostheses can be used as full counts, inlays, onlays and the like. In addition, the dental prosthesis may include porcelain for color adjustment and external shape adjustment on the surface of the zirconia sintered body.

  The method for producing a dental product is the same as the method for producing a sintered body, except that the calcined body or the sintered body is formed into a desired shape (for example, a crown shape).

  A zirconia sintered body was prepared, and its translucency and fluorescence were measured.

[Production of composition]
First, an aqueous sol containing partially stabilized zirconia particles in which 3 mol% of yttria (Y ₂ O ₃ ) is solid-solved (MELOx Nanosize 3Y manufactured by Nikkei Mel) (23% zirconia concentration, average particle diameter of zirconia particles (crystallite diameter) ) 11-12 nm (catalog value))). Next, Y ₂ SiO ₅ : Ce was added as a fluorescent agent to this sol, a predetermined amount of tetramethylammonium hydroxide was added as a pH adjuster, and a predetermined amount of triammonium citrate was added as a dispersant. The amount of the fluorescent agent added is shown in Table 1 below. The addition amount of the fluorescent agent is a relative mass with respect to the mass of the partially stabilized zirconia. Next, a predetermined amount of agarose as a gelling agent was added to the mixture while heating and stirring the mixture to prepare a slurry composition.

  Next, the slurry-like composition was poured into a mold and dried at room temperature for 16 days. This produced the molding composition. Next, the molding composition was fired at about 700 ° C. for 1 hour to prepare a zirconia calcined body. Next, the calcined body was fired at about 1100 ° C. for 2 hours to produce a zirconia sintered body.

As a comparative example, translucency and fluorescence were also measured for a sample obtained by adding a fluorescent agent to commercially available zirconia powder (containing 3 mol% yttria, TZ-3YSB-E manufactured by Tosoh Corporation) having an average particle size of 90 nm (reference value). 1% by mass of the fluorescent agent Y ₂ SiO ₅ : Ce was added to the zirconia powder, and the mixture was molded by uniaxial pressing (20 MPa). Next, the molded body was further CIP molded, and as Comparative Example 1, the molded body was fired at 1350 ° C. for 2 hours to produce a zirconia sintered body. Further, as Comparative Example 2, a molded body was fired at 1100 ° C. for 2 hours.

Further, as a reference example, the translucency and fluorescence were measured for a commercially available porcelain material having fluorescence. The term porcelain used here means that when a non-fluorescent zirconia sintered body is used as a dental prosthesis, it is baked on the surface of the zirconia sintered body in order to impart fluorescence to the prosthesis (eg, framework). Glass or glass ceramic. The porcelain used in Reference Example 1 is Celabian (registered trademark) ZR (Opacious Body OBA ₄ ) manufactured by Kuraray Noritake Dental Co., Ltd., and the porcelain used in Reference Example 2 is Kuraray Noritake Dental Co., Ltd. Celabian (registered trademark) ZR (internal stain Fluoro). The porcelain used in Reference Example 2 has very high fluorescence among the same series of products. First, porcelain was mixed with water, and the resulting slurry was poured into a mold and then concentrated to obtain a molded body. Next, the compact was fired at a temperature shown in Table 1 for 1 minute in a dental firing furnace to produce a fired body.

  A sample for measuring translucency and fluorescence was prepared by processing the obtained sintered body to a thickness of 0.5 mm and mirror polishing both surfaces.

  For translucency, an integrating sphere was inserted into a spectrophotometer (U-3900H type) manufactured by Hitachi High-Technologies Corporation, and the transmittance of light with wavelengths of 700 nm and 365 nm was measured.

  The fluorescence is measured by irradiating the sample with a 450 W xenon lamp as the light source, measuring the emission of the sample in the wavelength range of 370 nm to 700 nm with a detector (R928P manufactured by Hamamatsu Photonics), and in the range of 390 nm to 650 nm (excitation). A value obtained by integrating the measured values at a wavelength of 365 nm) was defined as emission intensity. Table 1 also shows the relative intensity when the emission intensity of Reference Example 2 is 100. A double monochromator was installed behind the xenon lamp so as to irradiate the sample with light having a wavelength of 365 nm and a hand width of 0.4 nm. In addition, a bypass filter was installed after the sample so that excitation light did not enter the detector.

  In Comparative Example 1, since a large amount of fluorescent agent was added, sufficient translucency could not be obtained. On the other hand, in Examples 1 to 4, a light transmittance of 25% or more was obtained for 700 nm light, and a light transmittance of 8% or more was obtained for 365 nm light. In Examples, since the addition rate of the fluorescent agent is low, it is considered that the decrease in translucency could be suppressed. In addition, it is considered that the fluorescence can be enhanced by increasing the light transmittance at a wavelength equivalent to the excitation wavelength.

  In Comparative Example 2, the zirconia powder was not sintered, and a zirconia sintered body was not obtained. This is presumably because the firing temperature was too low relative to the particle size of the zirconia particles. On the other hand, in Examples 1 to 4, zirconia sintered bodies could be obtained even when the firing temperature was 1100 ° C. This is considered because the particle diameter of zirconia particles is small.

  In Comparative Example 1, although the addition rate of the fluorescent agent was high, the fluorescence was low. On the other hand, in Examples 1 to 4, higher fluorescence than Comparative Example 1 was obtained even when the addition rate of the fluorescent agent was low. This is because in Comparative Example 1, the sintering temperature is high, and thus the fluorescence is lost due to decomposition of the fluorescent agent, etc., whereas in Examples 1 to 4, the sintering temperature is low, so the sintered body This is probably because a larger amount of the fluorescent agent was allowed to remain therein. Further, as described above, in Examples 1 to 4, it is considered that the fluorescence can be enhanced because the translucency of light having an excitation wavelength is higher than those in Comparative Examples 1 and 2.

  Thereby, in Examples 1-4, it was confirmed that it has both the fluorescence which can be used as a dental prosthesis, and translucency.

  About the zirconia sintered compact obtained in Example 4 and the comparative example 1, the crystal grain diameter of the zirconia was measured by the SEM image. Image analysis software Image-Pro Plus Ver. 5.0 was used for the measurement of the crystal grain size. The crystal grain size was calculated as the equivalent circle diameter. The crystal grain size in Example 4 was 88 nm. On the other hand, the crystal grain size in Comparative Example 1 was 228 nm. In the sintered body according to the example, it is considered that the translucency could be improved by reducing the crystal grain size. Further, it is considered that hydrothermal deterioration is less likely to occur by reducing the crystal grain size.

  Further, in Examples 1 to 4, fluorescence and translucency equivalent to those of Reference Example 1 are obtained. Therefore, when the zirconia sintered body of the present invention is used for a dental product, the baking operation of porcelain for imparting fluorescence becomes unnecessary. In addition, since the necessity of considering the thickness of the porcelain to be baked on the base material is reduced, it becomes easy to form a prosthesis for the patient's oral environment. Therefore, according to the present invention, dental treatment work can be simplified.

  The disclosures of the above-mentioned patent documents and non-patent documents are incorporated herein by reference. The zirconia composition, the zirconia sintered body, the method for producing the zirconia sintered body, and the dental product of the present invention have been described based on the above embodiment, but the present invention is not limited to the above embodiment. In the framework of the entire disclosure, and based on the basic technical concept of the present invention, various disclosed elements (including each element of each claim, each element of each embodiment or example, each element of each drawing, etc.) It goes without saying that various modifications, changes and improvements can be included. Various combinations and replacements of various disclosed elements (including each element of each claim, each element of each embodiment or example, each element of each drawing, etc.) within the scope of the entire disclosure of the present invention. Selection is possible.

  Further problems, objects, and developments of the present invention will become apparent from the entire disclosure of the present invention including the claims.

  Regarding numerical ranges described in this document, any numerical value or small range included in the range should be construed as being specifically described even if there is no specific description.

Claims (16)

A partially stabilized zirconia sintered body containing a fluorescent agent,
The average grain size of zirconia crystals observed in the cross section of the zirconia sintered body is 120 nm or less,
The fluorescent agent having a mass of 0.01% or more and 1.5% or less with respect to the mass of the partially stabilized zirconia is added and sintered,
A zirconia sintered body, wherein the transmittance of light having a wavelength of 700 nm that passes through the zirconia sintered body having a thickness of 0.5 mm is 15% or more.   The zirconia sintered body according to claim 1, which emits fluorescence when irradiated with light having a predetermined wavelength.   The zirconia sintered body according to claim 1 or 2, wherein a transmittance of light having a wavelength of 365 nm that transmits through the zirconia sintered body having a thickness of 0.5 mm is 3% or more. The fluorescent _agent, Y 2 _SiO 5: is Ce, zirconia sintered body according to any one of claims 1 to 3.   The zirconia sintered body according to claim 4, which emits fluorescence when the zirconia sintered body having a thickness of 0.5 mm is irradiated with light including light having a wavelength of 365 nm.   The zirconia sintered body according to any one of claims 1 to 5, wherein the transmittance of light having a wavelength of 700 nm is 30% or more.   A dental product comprising the zirconia sintered body according to any one of claims 1 to 6. Partially stabilized zirconia particles having an average particle size of 20 nm or less;
A fluorescent agent having a mass of 0.01% to 1.5% with respect to the mass of the partially stabilized zirconia;
A composition comprising:   The composition of Claim 8 containing the said fluorescent agent of the mass of 0.01% or more and 1% or less with respect to the mass of partially stabilized zirconia. The composition according to claim 8 or 9, wherein the fluorescent agent is Y ₂ SiO ₅ : Ce.   A calcined body obtained by firing the composition according to any one of claims 8 to 10 at a temperature of 650C to 850C. A step of preparing a composition by mixing partially stabilized zirconia particles having an average particle diameter of 20 nm or less and a fluorescent agent having a mass of 0.01% or more and 1.5% or less with respect to the mass of the partially stabilized zirconia;
Baking the composition at a temperature of 900 ° C. to 1200 ° C. to sinter the zirconia particles;
The manufacturing method of the zirconia sintered compact containing this.   The manufacturing method of the zirconia sintered compact of Claim 12 which mixes the said fluorescent agent of the mass of 0.01% or more and 1% or less with respect to the mass of partially stabilized zirconia in the process of producing the said composition. The fluorescent _agent, Y 2 _SiO 5: is Ce, the manufacturing method of the zirconia sintered body according to claim 12 or 13.   The method for producing a zirconia sintered body according to any one of claims 12 to 14, wherein in the step of sintering the zirconia particles, the composition is fired at a temperature of 900C to 1150C. Molding the composition to produce a molded body;
The manufacturing method of the zirconia sintered body as described in any one of Claims 12-15 further including the process of baking the said molded object at the temperature of the range of 650 to 850 degreeC, and producing a calcined body. .