Dental porcelain paste, dental porcelain kit, and method for producing dental porcelain prosthesis

Abstract

The present invention relates to: a dental porcelain paste that contains a glass powder (A), an organic solvent (B), and a colorant (C), the color of which disappears during firing, and that satisfies at least one condition selected from condition (1) and condition (2); a dental porcelain kit; and a method for producing a dental porcelain prothesis. Condition (1): the color difference ΔE* calculated from a color tone obtained by measuring, in the L*a*b* color space, the color of the dental porcelain paste at a thickness of 0.5 mm before firing and a color tone obtained by measuring, in the L*a*b* color space, the color of a fired body having a thickness of 0.5 mm, the fired body being obtained by vacuum firing the dental porcelain paste at 740°C, is 8.5 or higher. Condition (2): the lightness difference ΔL* calculated from a lightness obtained by measuring, in the L*a*b* color space, the color of the dental porcelain paste at a thickness of 0.5 mm before firing and a lightness obtained by measuring, in the L*a*b* color space, the color of the fired body having a thickness of 0.5 mm that is obtained by vacuum firing the dental porcelain paste at 740°C is 6.5 or higher.

Description

Dental porcelain paste, dental porcelain kit, and method for manufacturing dental porcelain prosthesis

[0001] The present invention relates to a dental porcelain paste, a dental porcelain kit containing the dental porcelain paste, and a method for producing a dental porcelain prosthesis using the dental porcelain paste.

[0002] Ceramics have a transparency and color similar to that of natural teeth, making them an essential material for the fabrication of dental crowns, which require aesthetic appeal. Generally, dental crowns are fabricated by repeatedly building up and firing a frame (e.g., a metal frame or a ceramic frame) that covers an abutment tooth using a dental mixing solution consisting of porcelain, water, and one or more organic solvents, or a paste-like porcelain prepared by mixing ceramics with water and one or more organic solvents. Powdered porcelain is complicated because it requires the addition of a solvent each time, and skilled labor is required to adjust the mixing ratio and viscosity according to the desired color. However, paste-like porcelain shortens the time required for dental technician work because the porcelain and solvent are premixed to a viscosity that is easy for dental technicians to work with. For example, Patent Document 1 discloses a paste-like dental porcelain containing a colorant (A) that decolorizes during firing, an organic solvent (B), and a porcelain powder (C), the porcelain powder (C) containing an inorganic pigment.

[0003] In addition, zirconium oxide (zirconia), aluminum oxide (alumina), feldspar glass, disilicate glass, etc. are used as base materials for dental prostheses made of ceramic materials. Recently, these materials have been increasingly processed using dental CAD / CAM systems and used as dental prostheses. Typical examples of dental prostheses made of ceramic materials include porcelain fused to metal (PFM) type, porcelain fused to zirconia (PFZ) type, full contour zirconia (FCZ) type, and lithium disilicate (LDS) type dental prostheses. Dental porcelains such as stain porcelains and glaze porcelains are used to finish these dental prostheses. For example, Patent Document 2 discloses a color-adjusting composition for ceramic dental crown porcelains, which contains two or more aluminosilicate glasses and a colorant, and is characterized in that each of the two or more aluminosilicate glasses satisfies specific requirements.

[0004] JP 2017-193492 A JP 2009-207743 A

[0005] Generally, glaze porcelain is used primarily for the purpose of polishing dental prostheses, and is required to have a small color difference from the base material (hereinafter also referred to as "base") after firing. Therefore, the porcelain paste used as the glaze porcelain is transparent to translucent and has almost no saturation even before firing. However, when using such a porcelain paste, it is difficult to distinguish between coated and uncoated areas and to confirm the coating thickness during the application process, which results in porcelain overspray and uneven application. This porcelain overspray and uneven application can have adverse effects such as poor aesthetics, increased time required for adjusting opposing and proximal contacts, and increased application and firing cycles required to compensate for uncoated and insufficient areas. Therefore, to enable dental porcelain pastes to be used as glaze porcelains, it is necessary to further improve the visual identifiability (hereinafter simply referred to as "identifiability") of the dental porcelain pastes applied to a substrate before firing. Patent Document 1 mentions the color difference between the paste before and after firing. However, this mainly addresses the problem that, when staining is performed, the color tone of the porcelain differs before and after firing, requiring skilled techniques to predict the color tone after firing and adjust the color tone during porcelain build-up. Patent Document 1 therefore focuses on suppressing the color difference between the dental porcelain paste before and after firing. Therefore, the examples of the dental porcelain pastes disclosed in Patent Document 1 are primarily examples of stain porcelains, and do not disclose glaze porcelains. When the dental porcelain pastes disclosed in Patent Document 1 are used as glaze porcelains, further improvement in the aforementioned identifiability is required. As mentioned above, the main purpose of glaze porcelain is to achieve a glossy finish, so it is desirable that the color difference between the fired body obtained by firing the dental porcelain paste and the base be small. Patent Document 2 also does not mention the above-mentioned problems associated with the use of glaze porcelain. Therefore, when dental porcelain pastes are to be used as glaze porcelain, there is a demand for even greater improvement in their distinguishability.

[0006] Therefore, an object of the present invention is to provide a dental porcelain paste that is excellent in distinguishability during application before firing.

[0007] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by using a dental porcelain paste that contains a glass powder (A), an organic solvent (B), and a colorant (C) that loses its color upon firing and that satisfies certain conditions, and have thus completed the present invention.

[0008] That is, the present invention includes the following inventions: [1] A dental porcelain paste containing a glass powder (A), an organic solvent (B), and a colorant (C) that is decolorized upon firing, and satisfying at least one condition selected from the following conditions (1) and (2): Condition (1): A dental porcelain paste having a thickness of 0.5 mm before firing is formed into a L ＊ a ＊ b ＊ The color tone obtained by measuring the color in the color space and the L ＊ a ＊ b ＊ The color difference ΔE calculated from the color tone obtained by measuring the color in the color space ＊ Condition (2): Dental porcelain paste with a thickness of 0.5 mm before firing is applied to the L ＊ a ＊ b ＊ The brightness obtained by measuring the color in the color space and the L value of a 0.5 mm thick fired body obtained by vacuum firing the dental porcelain paste at 740°C were measured. ＊ a ＊ b ＊ The lightness difference ΔL calculated from the lightness obtained by measuring the color in the color space ＊ is 6.5 or more [2] The substrate is L ＊ a ＊ b ＊ The color tone obtained by measuring the color in the color space and the dental porcelain paste applied to the substrate in a thickness of 0.5 mm were measured using the L ＊ a ＊ b ＊ The color difference ΔE1 calculated from the color tone obtained by measuring the color in the color space ＊[3] The dental porcelain paste according to the above [1], wherein the base material is L ＊ a ＊ b ＊ The color tone obtained by measuring the color in the color space and the sintered body obtained by applying the dental porcelain paste to the substrate so that the thickness after firing becomes 65 μm and firing it in a vacuum at 740° C. are measured. ＊ a ＊ b ＊ The color difference ΔE2 calculated from the color tone obtained by measuring the color in the color space ＊The dental porcelain paste according to [1] or [2] above, wherein the value of the chromaticity of component (C) is 3.0 or less. [4] The dental porcelain paste according to any one of [1] to [3] above, wherein the content of component (C) is 0.001 parts by mass or more and less than 0.60 parts by mass per 100 parts by mass of the total of components (A) and (B). [5] The dental porcelain paste according to any one of [1] to [4] above, wherein component (C) contains an organic dye that dissolves in component (B). [6] The dental porcelain paste according to [5] above, wherein the organic dye is an aromatic organic dye. [7] The dental porcelain paste according to [5] or [6] above, wherein the organic dye is at least one selected from the group consisting of anthraquinone compounds, azo compounds, xanthene compounds, porphyrin compounds, phthalocyanine compounds, and triarylmethane compounds. [8] The dental porcelain paste according to any one of [1] to [7] above, wherein the chromaticity of component (C) is 0.001 parts by mass or more and less than 0.60 parts by mass per 100 parts by mass of components (A) and (B). [9] The dental porcelain paste according to [8], wherein the content of the fluorescent agent is 0.001 to 0.50 parts by mass per 100 parts by mass of the total of components (A) and (B).

[10] The dental porcelain paste according to any one of [1] to [9], which contains an inorganic pigment.

[11] A dental porcelain kit comprising the dental porcelain paste according to any one of [1] to

[10] , and a color sample for adjusting the application thickness of the dental porcelain paste.

[12] A method for producing a dental prosthesis, comprising: a step (I) of applying the dental porcelain paste according to any one of [1] to

[10] to a substrate; and a step (II) of firing the dental porcelain paste applied to the substrate.

[13] The dental prosthesis according to

[12] , wherein the firing temperature in step (II) is 700°C or higher.

[14] The method for producing a dental prosthesis according to

[12] or

[13] , wherein in the step (I), a color sample for adjusting the thickness of the dental porcelain paste to be applied is used.

[0009] According to the present invention, a dental porcelain paste that is excellent in distinguishability during application before firing can be provided.

[0010] The present invention will be described in detail below using embodiments. In this specification, the upper and lower limits of numerical ranges (such as the content of each component, values ​​calculated from each component, and physical properties) can be combined as appropriate. That is, in this specification, the lower and upper limits described in stages for numerical ranges can be independently combined. For example, a description of the same item, "preferably 10 to 90, more preferably 30 to 60," can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60." Furthermore, for a numerical range, for example, based on a description of "preferably 10 to 90, more preferably 30 to 60," the upper limit can be specified as "10 or more" or "30 or more" without specifying a specific upper limit. Similarly, the upper limit can be specified as "90 or less" or "60 or less" without specifying a specific lower limit. Unless otherwise specified, a numerical range simply described as "10 to 90" represents a range of 10 to 90. As described above, for example, from the description of "preferably 10 or more, more preferably 30 or more" and the description of "preferably 90 or less, more preferably 60 or less" for the same item, the "preferable lower limit (10)" and the "more preferable upper limit (60)" can be combined to form "10 or more and 60 or less." Similarly, as described above, the lower limit alone can be specified as "10 or more" or "30 or more," and similarly, the upper limit alone can be specified as "90 or less" or "60 or less." The same applies when the upper limit of the numerical range is "less than" or when the lower limit is "greater than." Furthermore, in this specification, unless otherwise specified, as described above, the term "distinguishing ability" refers to the property of being able to visually distinguish between areas where the dental porcelain paste has been applied and areas where it has not been applied on a base, when the dental porcelain paste has been applied before firing. Specifically, it refers to the property evaluated by the method described in the Examples. In addition, in this specification, unless otherwise specified, when simply referring to a "fired body", the "fired body" refers to a fired body obtained by firing a dental porcelain paste.

[0011] [Dental porcelain paste] A dental porcelain paste (hereinafter also simply referred to as "porcelain paste") according to one embodiment of the present invention contains a glass powder (A) (hereinafter also simply referred to as "component (A)"), an organic solvent (B) (hereinafter also simply referred to as "component (B)"), and a colorant (C) (hereinafter also simply referred to as "component (C)") that loses its color upon firing, and satisfies at least one condition selected from the following conditions (1) and (2). Condition (1): A 0.5 mm thick dental porcelain paste before firing is applied to a porcelain paste having a thickness of L. ＊ a ＊ b ＊ The color tone obtained by measuring the color in the color space and the L ＊ a ＊ b ＊ The color difference ΔE calculated from the color tone obtained by measuring the color in the color space ＊ Condition (2): Dental porcelain paste with a thickness of 0.5 mm before firing is applied to the L ＊ a ＊ b ＊ The brightness obtained by measuring the color in the color space and the L value of a 0.5 mm thick fired body obtained by vacuum firing the dental porcelain paste at 740°C were measured. ＊ a ＊ b ＊ The lightness difference ΔL calculated from the lightness obtained by measuring the color in the color space ＊ is 6.5 or more. Furthermore, the dental porcelain paste contains a colorant (C) that is decolorized during firing, thereby making it possible to satisfy at least one of the conditions (1) and (2).

[0012] <Condition (1)> Color difference ΔE according to the condition (1) ＊ If ΔE is 8.5 or more, the difference between the color tone of the ceramic paste before firing and the color tone of the fired body obtained by firing the ceramic paste becomes large. ＊ When the value of the color difference ΔE is 8.5 or more, when the ceramic paste before firing is applied to a base, it becomes easy to clearly distinguish the area where the ceramic paste is applied, and the distinguishability of the ceramic paste is improved. ＊is preferably 11.0 or more, more preferably 15.0 or more, even more preferably 20.0 or more, still more preferably 30.0 or more, and still more preferably 40.0 or more. ＊ There is no particular upper limit to the color difference ΔE ＊ is preferably 95.0 or less, more preferably 90.0 or less, even more preferably 85.0 or less, and even more preferably 80.0 or less. As described above, these stepwise lower limit values ​​and upper limit values ​​can be independently combined. For example, in one embodiment of the present invention, the color difference ΔE ＊ is 8.5 to 95.0, preferably 11.0 to 95.0, more preferably 15.0 to 90.0, even more preferably 20.0 to 85.0, still more preferably 30.0 to 80.0, and even more preferably 40.0 to 80.0. ＊ Specifically, is calculated by the method described in the Examples.

[0013] <Condition (2)> Furthermore, the lightness difference ΔL according to the condition (2) ＊ When the lightness difference ΔL is 6.5 or more, when the ceramic paste before firing is applied to a base, it becomes easy to clearly distinguish the area where the ceramic paste is applied, and the distinguishability of the ceramic paste is improved, for the same reason as in the explanation of the condition (1). ＊ is preferably 11.0 or more, more preferably 15.0 or more, even more preferably 18.0 or more, still more preferably 20.0 or more, and still more preferably 25.0 or more. ＊ There is no particular upper limit to the color difference ΔL ＊ is preferably 100.0 or less, more preferably 80.0 or less, and even more preferably 60.0 or less. As described above, these stepwise lower limit values ​​and upper limit values ​​can be independently combined. For example, in one embodiment of the present invention, the lightness difference ΔL ＊is 6.5 to 100.0, preferably 11.0 to 100.0, more preferably 15.0 to 80.0, even more preferably 18.0 to 80.0, still more preferably 20.0 to 60.0, and even more preferably 25.0 to 60.0. ＊ Specifically, is calculated by the method described in the Examples.

[0014] In addition, from the viewpoint of further improving the distinguishability of the dental porcelain paste, the dental porcelain paste has a base material of L ＊ a ＊ b ＊ The color tone obtained by measuring the color in the color space and the dental porcelain paste applied to the substrate in a thickness of 0.5 mm were measured using the L ＊ a ＊ b ＊ The color difference ΔE1 calculated from the color tone obtained by measuring the color in the color space ＊ is preferably 11.0 or more, more preferably 15.0 or more, even more preferably 20.0 or more, even more preferably 30.0 or more, and even more preferably 40.0 or more. ＊ There is no particular limitation on the upper limit of the color difference ΔE1 ＊ is preferably 95.0 or less, more preferably 90.0 or less, even more preferably 85.0 or less, and even more preferably 80.0 or less. As described above, these stepwise lower limit values ​​and upper limit values ​​can be independently combined. For example, in one embodiment of the present invention, ＊ is preferably 11.0 to 95.0, more preferably 15.0 to 90.0, even more preferably 20.0 to 85.0, still more preferably 30.0 to 80.0, and even more preferably 40.0 to 80.0. ＊ Specifically, the color difference ΔE1 is calculated by the method described in the Examples. ＊ The "substrate" used in the calculation of the color difference ΔE1 ＊Specifically, it refers to a specific substrate to be described in the Examples below. Therefore, it does not limit the type of "substrate" to which the ceramic paste is applied, nor does it limit the type of "substrate" to which the ceramic paste is applied in step (I) below.

[0015] In addition, for example, from the viewpoint of minimizing the influence of the fired body on the color tone of the base, the dental porcelain paste is preferably made of a base material such as L. ＊ a ＊ b ＊ The color tone obtained by measuring the color in the color space and the sintered body obtained by applying the dental porcelain paste to the substrate so that the thickness after firing becomes 65 μm and firing it in a vacuum at 740° C. are measured. ＊ a ＊ b ＊ The color difference ΔE2 calculated from the color tone obtained by measuring the color in the color space ＊ is preferably 3.0 or less, more preferably 2.5 or less, even more preferably 2.0 or less, still more preferably 1.5 or less, and even more preferably 1.2 or less. ＊ There is no particular restriction on the lower limit of the color difference ΔE2 ＊ is preferably 0.0 or more. As described above, the lower limit value and the upper limit value described in stages can be independently combined. For example, in one embodiment of the present invention, ＊ is preferably 0.0 to 3.0, more preferably 0.0 to 2.5, even more preferably 0.0 to 2.0, still more preferably 0.0 to 1.5, and even more preferably 0.0 to 1.2. ＊ Specifically, the color difference ΔE2 is calculated by the method described in the Examples. ＊ The "substrate" used in the calculation of refers to the substrate described in the examples below.

[0016] Hereinafter, each component contained in the dental porcelain paste according to one embodiment of the present invention will be described in order.

[0017] <Glass Powder (A)> The glass powder (A) is not particularly limited, but is preferably one that can be used for dental purposes and may contain crystals. Examples of materials for component (A) include SiO ２ Examples of such glasses include glass containing SiO as the main component (the component with the highest content in the glass), and glass-ceramics. ２ Besides, Al ２ O ３ , B ２ O ３ , ZnO, K ２ O, Na ２ O, Li ２ O, ZrO ２ , CaO, MgO, Sb ２ O ３ , CeO ２ , BaO, SnO ２ For example, amorphous potassium aluminosilicate glass (4SiO ２ ・Al ２ O ３ ・K ２ At least one glass selected from the group consisting of amorphous potassium aluminosilicate glass, leucite crystal type glass, fluoroapatite glass, and lithium silicate glass can be suitably used. Among these, amorphous potassium aluminosilicate glass is more preferable. Examples of the crystals include leucite, potassium feldspar, fluorphlogopite, diopside, mica, β-spodumene (LiAlSi ２ O ６ ), β-calcium metaphosphate, apatite, magnesium titanate, β-eucryptite, alumina, etc. Depending on the application of the ceramic paste, component (A) can be used alone or in appropriate combination of two or more.

[0018] Furthermore, the raw material of the glass that is the material for component (A) can be a ceramic raw material that is widely used, and SiO ２ , Al ２ O ３ , B ２ O ３ , ZnO, K ２ O, Na ２O, Li ２ O, ZrO ２ , CaO, MgO, Sb ２ O ３ , CeO ２ , BaO, SnO ２ and the like; when heated in air, SiO ２ , Al ２ O ３ , B ２ O ３ , ZnO, K ２ O, Na ２ O, Li ２ O, ZrO ２ , CaO, MgO, Sb ２ O ３ , CeO ２ , BaO, SnO ２ or a mixture of the oxides and the materials that can be converted to the oxides when heated in the atmosphere. In this case, the glass composition to be obtained is calculated in advance, and the raw material blend is determined and mixed. The method for mixing the raw materials is not particularly limited, and it is preferable that the raw materials are uniformly dispersed.

[0019] These mixed raw materials are heated to about 700°C or higher. The heating method is not particularly limited as long as all of the raw materials are melted and a uniform melt is produced. The method for cooling the melt is also not particularly limited, and air cooling or the like can be used.

[0020] The glass lump thus obtained is crushed and classified to obtain component (A) with an adjusted particle size. The method for crushing and classifying the glass lump is not particularly limited, and examples of crushing devices include compression crushers such as jaw crushers and cone crushers; ball mills such as vibration ball mills and planetary mills; media-agitation crushers such as tower crushers, stirred tank crushers, and annular crushers; high-speed rotary impact crushers such as pin mills and disk mills; other roll mills; jet crushers; and autogenous crushers. Examples of classifying devices include sieve classifiers such as vibrating sieves and sifters; centrifugal classifiers such as cyclones; and wet classifiers such as sedimentation classifiers. In these crushing devices or classifying devices, it is preferable to use devices coated with resin, glass, or the like to prevent the inclusion of metal impurities.

[0021] The average particle size of component (A) is preferably 1 to 30 μm, more preferably 2 to 20 μm, and even more preferably 3 to 9 μm. An average particle size of 1 μm or more is preferred because it makes it easier to prevent a decrease in the transparency of the prosthesis. Furthermore, an average particle size of 30 μm or less is preferred because it makes it easier to apply the porcelain paste. The average particle size of component (A) refers to the volume-based average particle size (D50) that can be determined by measurement using a laser diffraction scattering method, and can be measured, for example, by the method described in the Examples.

[0022] The glass transition temperature of component (A) is preferably 400 to 600°C, more preferably 420 to 580°C, and even more preferably 450 to 550°C, from the viewpoint of enabling firing at lower temperatures and shortening firing times. From the same viewpoint, the softening point of component (A) is preferably 500 to 680°C, more preferably 520 to 650°C, and even more preferably 550 to 630°C. A glass transition temperature of 400°C or higher or a softening point of 500°C or higher is preferred because it prevents sagging of component (A) during firing. Furthermore, a glass transition temperature of 600°C or lower or a softening point of 680°C or lower is preferred because it enables firing at low temperatures and prevents deformation of ceramic frames made of lithium disilicate-based glass ceramics or the like due to high-temperature firing.

[0023] The linear thermal expansion coefficient (50 to 500°C) of component (A) can be appropriately selected depending on the material of the base to which the ceramic paste is applied, and is not particularly limited, but is preferably 4.0 x 10 －６ ~6.0 x 10 －６ / °C, for example, 6.1 × 10 －６ ~13.5 x 10 －６ / °C, and may be 6.3 x 10 －６ ~12.5 x 10 －６ For example, when a ceramic paste is used on a base containing zirconia as the main component, the linear thermal expansion coefficient of the component (A) may be 9.0 × 10 －６ ~11.0 x 10 －６ For example, when a ceramic paste is used on a base mainly composed of alumina, the linear thermal expansion coefficient of the component (A) is preferably 6.1 × 10 －６ ~8.8 x 10 －６ The linear thermal expansion coefficient can be measured by, for example, heating a sample from room temperature (25°C) to 500°C using a thermal analyzer TMA120 (manufactured by Seiko Instruments Inc., temperature rise rate 5°C / min). The linear thermal expansion coefficient can be adjusted by a known method, for example, ２ It can be adjusted by the O content.

[0024] The content of component (A) in the dental porcelain paste is preferably 40 to 80 parts by mass, more preferably 45 to 75 parts by mass, and even more preferably 50 to 70 parts by mass, per 100 parts by mass of the total of components (A) and (B).

[0025] <Organic Solvent (B)> Examples of the organic solvent (B) include esters such as dimethyl phthalate, diethyl phthalate, and dibutyl phthalate; monohydric alcohols such as methanol, ethanol, 1-propanol, 2-propanol, isopropanol, 1-butanol, 2-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-hexanol, 2-hexanol, 3-hexanol, 2-methyl-1-pentanol, 3-methyl-1-pentanol, 4-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 2,2-dimethyl-1-butanol, and 2-ethyl-1-butanol; 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, 2,4-pentanediol, 1,2-hexanediol, 2,5-hexanediol, 1-methyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2-methyl-1,4-butanediol, 3-methyl-1,3-butanediol (also known as isoprene glycol), 2-methyl-2,4-pentanediol polyhydric alcohols such as 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 3-benzyloxy-1,2-propanediol, 4-benzyloxy-1,2-butanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (molecular weight: 200 to 600), propylene glycol, dipropylene glycol, polypropylene glycol, glycerin, 1,2,3-butanetriol, and 1,2,6-hexanetriol; aromatic alcohols such as 2-phenoxyethanol and benzyl alcohol;Examples of the component (B) include polyhydric alcohol monoethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, and triethylene glycol monomethyl ether; and (meth)acrylic polymerizable monomers such as 2-hydroxyethyl (meth)acrylate. Component (B) can be used singly or in appropriate combination of two or more.

[0026] Component (B) is preferably at least one selected from the group consisting of polyhydric alcohols, aromatic alcohols, and polyhydric alcohol monoethers, and more preferably at least one selected from polyhydric alcohols and aromatic alcohols. Furthermore, of the aforementioned compounds, component (B) is more preferably at least one selected from the group consisting of 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol (also known as isoprene glycol), 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, and 2-phenoxyethanol. Component (B) is preferably an alcohol that is liquid at 20°C. The boiling point of component (B) is preferably 100 to 300°C, more preferably 100 to 280°C, and even more preferably 100 to 250°C.

[0027] The content of component (B) in the dental porcelain paste is not particularly limited, but is preferably 20 to 60 parts by mass, more preferably 25 to 55 parts by mass, and even more preferably 30 to 50 parts by mass, relative to 100 parts by mass of the total of components (A) and (B). A content of component (B) of 20 parts by mass or more is preferred because it improves the kneadability of components (A) and (B) and facilitates the formation of a paste. Furthermore, a content of component (B) of 60 parts by mass or less is preferred because it is easy to ensure the amount of glass component in the porcelain paste and facilitates the application of the porcelain paste.

[0028] <Colorant (C) that Discolors Upon Firing> Because the colorant (C) that discolors upon firing discolors upon firing, when the pre-fired porcelain paste is applied to a base, the area where the porcelain paste is applied becomes clearly discernible. Meanwhile, the coloring derived from component (C) in the fired body obtained by firing the porcelain paste is discolored, thereby minimizing the impact of the fired body on the color tone of the base. Here, in this specification, the phrase "discolors upon firing" in reference to component (C) refers not only to the disappearance of the color of the colorant itself upon firing, but also to the disappearance of the color derived from component (C) in the porcelain paste upon firing. In other words, it is believed that the reason for the discoloration of the coloring due to component (C) is due to component (C) burning out during firing. As described above, the use of component (C) enables the dental porcelain paste to satisfy at least one of the conditions (1) and (2). In this specification, the term "discoloration" in component (C) refers to the color difference ΔE between the fired body of the ceramic paste (I) and the fired body of the ceramic paste (II) when the ceramic paste (I) contains the glass powder (A) and the organic solvent (B) but does not contain the colorant (C) that is discolored during firing, and the ceramic paste (II) is prepared by adding the colorant (C) that is discolored during firing to the ceramic paste (I) at 700°C or higher. * The calcination conditions other than the calcination temperature and the color difference ΔE *The method for measuring ab is as described in the Examples below.

[0029] Component (C) preferably contains an organic dye that dissolves in component (B). Here, "dissolves in component (B)" means that no white turbidity is visually observed when 1 g of component (C) is added to 10 mL of component (B) at 25°C. The content of the organic dye is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 98% by mass or more, and 100% by mass or less, based on 100% by mass of component (C). As described above, these stepwise lower and upper limits can be independently combined. For example, in one embodiment of the present invention, the content of the organic dye is preferably 60 to 100% by mass, more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, and even more preferably 98 to 100% by mass, based on 100% by mass of component (C).

[0030] Furthermore, the organic dye is preferably an aromatic organic dye. The aromatic organic dye is an organic dye containing one or more optionally substituted aromatic groups, and is preferably an aromatic organic dye having an auxochrome in addition to a chromophore. The chromophore is not particularly limited as long as it is an atomic group that is bonded to an aromatic ring and causes color development. Examples of the atomic group include a nitro group, an azo group, a ketimide group (>C=N-), a carbonyl group, a carbon-carbon double bond, a carbon-carbon triple bond, a carbon-nitrogen multiple bond, a thiocarbonyl group, a nitroso group, and an azoxy group. The aromatic organic dye may contain one of these atomic groups alone or two or more of them in appropriate combination. Examples of the auxochrome include a hydroxyl group, an amino group, a carboxyl group, a sulfone group, and a halogen atom. The aromatic organic dye may contain one of these auxochromes alone or two or more of them in appropriate combination.

[0031] The organic dye is preferably at least one selected from the group consisting of anthraquinone compounds, azo compounds, xanthene compounds, porphyrin compounds, phthalocyanine compounds, and triarylmethane compounds, more preferably at least one selected from the group consisting of anthraquinone compounds, azo compounds, xanthene compounds, and phthalocyanine compounds, and even more preferably at least one selected from azo compounds and phthalocyanine compounds. These compounds have good color development properties, making it possible to reduce the content of component (C) in the ceramic paste, and are also preferred from the viewpoints of reducing the amount of unburned component (C) remaining during firing, as described above, and further suppressing the occurrence of bubbles and carbonization in the resulting fired body.

[0032] Specific examples of these organic dyes are not limited as long as the effects of the present invention are achieved, and include, for example, the organic dyes shown below. In the following description, for example, the expression "C.I. Direct Blue (25, 86, 90, 108)" means "C.I. Direct Blue 25, C.I. Direct Blue 86, C.I. Direct Blue 90, C.I. Direct Blue 108."C.I. Direct Blue (25, 86, 90, 108) C.I. Solvent Blue (11, 14, 18, 25, 37, 44, 45, 49, 58, 59, 68, 78, 94) C.I. Acid Blue (1, 3, 7, 9, 15, 83, 90, 103, 104, 158, 161, 249) C.I. Basic Blue (1, 3, 7, 9, 25, 105) C.I. Disperse Blue (198) C.I. Mordant Blue (1) C.I. Solvent Red (25, 27, 30, 35, 49, 83, 89, 100, 122, 138, 149, 150, 160, 179, 218, 230) C.I. Acid Red (6, 8, 9, 13, 14, 18, 26, 27, 51, 52, 87, 88, 89, 92, 94, 97, 111, 114, 115, 134, 145, 151, 154, 180, 183, 184, 186, 198) C.I. Direct Red (20, 37, 39, 44) C.I. Basic Red (12, 13) C.I. Disperse Red (5, 7, 13, 17, 58) C.I. Solvent Black (3, 5, 7, 27, 28, 29, 35, 45, 46) C.I. Solvent Yellow (2, 5, 14, 15, 16, 19, 21, 33, 56, 62, 77, 83, 93, 162) C.I. Disperse Yellow (3, 4, 7, 31, 54, 61, 201) C.I. Direct Yellow (1, 11, 12, 28) C.I. Acid Yellow (1, 3, 11, 17, 23, 38, 40, 42, 76, 98) C.I. Basic Yellow (1) C.I. Solvent Violet (13, 33, 45, 46) C.I. Disperse Violet (22, 24, 26, 28, 31) C.I. Acid Violet (49) C.I. Basic Violet (2, 7, 10) C.I. Solvent Orange (1, 2, 5, 6, 37, 45, 62, 99) C.I. Acid Orange (1, 7, 8, 10, 20, 24, 28, 33, 56, 74) C.I. Direct Orange (1) C.I. Disperse Orange (5) C.I. Direct Brown (6, 58, 95, 101, 173) C.I. Acid Brown (14) Component (C) can be used alone or in appropriate combination of two or more.

[0033] The content of the component (C) in the dental porcelain paste is not particularly limited, but for example, ＊ , ΔL ＊ , ΔE1 ＊ From the viewpoint of facilitating a larger value, the amount is preferably 0.001 parts by mass or more, more preferably 0.002 parts by mass or more, even more preferably 0.004 parts by mass or more, and even more preferably 0.010 parts by mass or more, relative to 100 parts by mass of the total of component (A) and component (B). Also, from the viewpoint of suppressing the occurrence of bubbles and carbonization in the fired body, for example, the amount is preferably less than 0.60 parts by mass, more preferably 0.50 parts by mass or less, even more preferably 0.40 parts by mass or less, and even more preferably 0.30 parts by mass or less, relative to 100 parts by mass of the total of component (A) and component (B). As mentioned above, these stepwise lower limit and upper limit values ​​can be independently combined. For example, in one embodiment of the present invention, the content of the component (C) in the dental porcelain paste is preferably 0.001 parts by mass or more and less than 0.60 parts by mass, more preferably 0.002 to 0.50 parts by mass, even more preferably 0.004 to 0.40 parts by mass, and still more preferably 0.010 to 0.30 parts by mass, relative to 100 parts by mass of the total of the components (A) and (B).

[0034] To further enhance the effects of the present invention, the total content of components (A), (B), and (C) in the dental porcelain paste is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, even more preferably 99% by mass or more, and even more preferably 99.5% by mass or more, and is 100% by mass or less, based on 100% by mass of the dental porcelain paste. As described above, these lower and upper limits can be independently combined. For example, in one embodiment of the present invention, the total content of components (A), (B), and (C) in the dental porcelain paste is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, even more preferably 98 to 100% by mass, and even more preferably 99.5 to 100% by mass, based on 100% by mass of the dental porcelain paste.

[0035] (Fluorescent Agent) From the viewpoint of reproducing the fluorescence of natural teeth, the porcelain paste preferably further contains a fluorescent agent. The fluorescent agent is not limited to a specific type as long as the effects of the present invention are achieved. For example, Y ２ SiO ５ : Ce, Y ２ SiO ５ :Tb, (Y, Gd, Eu)BO ３ , Y ２ O ３ :Eu, YAG:Ce, ZnGa ２ O ４ :Zn, BaMgAl １０ O １７ These fluorescent agents may be used singly or in appropriate combination of two or more.

[0036] When the porcelain paste contains a fluorescent agent, the content of the fluorescent agent is not particularly limited as long as the effects of the present invention are achieved, but from the viewpoint of easily expressing the fluorescence of natural teeth, for example, the content is preferably 0.001 part by mass or more, more preferably 0.010 part by mass or more, even more preferably 0.050 part by mass or more, still more preferably 0.10 part by mass or more, and preferably 0.50 part by mass or less, more preferably 0.45 part by mass or less, even more preferably 0.40 part by mass or less, and still more preferably 0.35 part by mass or less, relative to 100 parts by mass of the total of components (A) and (B). As mentioned above, these lower limit values ​​and upper limit values ​​described in stages can be independently combined. For example, in one embodiment of the present invention, the content of the fluorescent agent in the dental porcelain paste is preferably 0.001 to 0.50 parts by mass, more preferably 0.010 to 0.45 parts by mass, even more preferably 0.050 to 0.40 parts by mass, and still more preferably 0.10 to 0.35 parts by mass, relative to 100 parts by mass of the total of component (A) and component (B).

[0037] (Inorganic Pigment) The ceramic paste may further contain an inorganic pigment. The type of the inorganic pigment is not limited as long as the effects of the present invention are achieved, and examples thereof include praseodymium oxide, vanadium oxide, iron oxide, nickel oxide, chromium oxide, manganese oxide, cerium oxide, tin oxide compounds (e.g., composite oxides containing tin (II) oxide and tin (IV) oxide (e.g., vanadium tin yellow, chrome tin pink, etc.)), bismuth vanadium yellow, vanadium zirconium yellow, praseodymium yellow, cobalt blue, manganese pink, chrome alumina pink, chrome iron zinc, titanium oxide (TiO ２ ), zirconium oxide (ZrO ２ ), zirconium silicate (ZrSiO ４ These inorganic pigments can be used alone or in appropriate combination of two or more.

[0038] When the ceramic paste contains an inorganic pigment, the content of the inorganic pigment is not particularly limited as long as the effects of the present invention are achieved, but for example, it is preferably 0.001 part by mass or more, more preferably 0.010 part by mass or more, even more preferably 0.050 part by mass or more, still more preferably 0.10 part by mass or more, and preferably 0.50 part by mass or less, more preferably 0.45 part by mass or less, even more preferably 0.40 part by mass or less, and still more preferably 0.30 part by mass or less, relative to 100 parts by mass of the total of component (A) and component (B). As mentioned above, these lower limit values ​​and upper limit values ​​described in stages can be independently combined. For example, in one embodiment of the present invention, the content of the inorganic pigment in the dental porcelain paste is preferably 0.001 to 0.50 parts by mass, more preferably 0.010 to 0.45 parts by mass, even more preferably 0.050 to 0.40 parts by mass, and still more preferably 0.10 to 0.30 parts by mass, relative to 100 parts by mass of the total of component (A) and component (B).

[0039] <Other Components> In addition to the components (A) to (C) and the optional fluorescent agent and inorganic pigment, the porcelain paste may contain other components as needed, as long as they do not impair the effects of the present invention. Examples of such other components include water, colorants other than component (C), opacifiers, pH adjusters, polymerization accelerators, and polymerization initiators. For example, water may be routinely mixed into a dental porcelain paste according to one embodiment of the present invention during use. However, as long as the dental porcelain paste satisfies the composition requirements and achieves the effects of the present invention, water routinely mixed into the dental porcelain during use is not considered a component of the dental porcelain paste according to one embodiment of the present invention. In other words, water that is unintentionally mixed into a porcelain paste during use is different from the water in the other components.

[0040] One embodiment of the method for producing a dental porcelain paste of the present invention includes, for example, a production method including a step of mixing at least the components (A), (B), and (C), as well as one or more components selected from the fluorescent agent, inorganic pigment, and other components that may be added as needed. The mixing conditions are not particularly limited, and the components to be contained may be added all at once or in portions. A conventional kneading machine can be used for mixing. Examples include a mortar, a twin-screw kneading machine (twin mix), a triple-screw kneading machine (trimix), a kneader, and a planetary mixer. Of these, a mortar or a planetary mixer is preferred.

[0041] [Uses of Dental Porcelain Paste] The porcelain paste can be used, for example, to prepare dental prostheses such as ceramic inlays, onlays, laminate veneers, and crowns. The uses of the porcelain paste are not particularly limited, and it can be used, for example, as body porcelain (dentin-colored porcelain), cervical porcelain, incisal porcelain (enamel-colored porcelain), translucent porcelain, opaque porcelain, stain porcelain, glaze porcelain, and the like. Furthermore, the dental porcelain paste of one embodiment of the present invention has a significant color difference from the material used in the dental porcelain base before firing, making it easy to visually distinguish between the coated and uncoated areas of the porcelain paste applied to the base. Furthermore, the dental porcelain paste of one embodiment of the present invention has a color that is largely different from the color difference between the base and the porcelain paste after firing, and therefore has almost no effect on the color of the base. Furthermore, the dental porcelain paste of one embodiment of the present invention has the effect of suppressing the occurrence of bubbles and black spots. Therefore, the dental porcelain paste according to one embodiment of the present invention is suitable for applications requiring greater discernibility in the application process before firing. As described above, the porcelain paste is preferably used as a stain porcelain or a glaze porcelain used primarily for finishing ceramic prostheses, and more preferably as a glaze porcelain.

[0042] For example, when the porcelain paste is used as a glaze porcelain, it is preferably used for finishing dental prostheses formed from the aforementioned ceramic materials. As mentioned above, typical examples of dental prostheses formed from the aforementioned ceramic materials include PFM-type, PFZ-type, FCZ-type, and LDS-type dental prostheses. Among these, the FCZ-type has a zirconia surface, which prevents the self-glazing effect from being achieved. Therefore, to achieve a high level of polishing, the porcelain paste must be applied to a certain thickness (e.g., 20 μm or more). As mentioned above, the porcelain paste has excellent discriminability and the application thickness can be easily adjusted. Therefore, the porcelain paste is suitable for use with FCZ-type dental prostheses, among the aforementioned types of dental prostheses.

[0043] Another embodiment of the present invention is the use of a dental porcelain paste for treating teeth (for example, cosmetic dental treatment, treatment of missing teeth, prosthetic restorative treatment such as artificial teeth, caries treatment, etc.). The above-mentioned porcelain pastes may be used alone or in appropriate combination of two or more types, as long as the effects of the present invention are achieved.

[0044] [Dental Porcelain Kit] A dental porcelain kit according to one embodiment of the present invention includes the dental porcelain paste according to the embodiment of the present invention described above and a color sample for adjusting the application thickness of the dental porcelain paste. The dental porcelain paste included in the dental porcelain kit is the same as that described in the section on the dental porcelain paste, and preferred embodiments thereof are also the same. The color sample for adjusting the application thickness of the dental porcelain paste is used to determine the application thickness of the porcelain paste based on the color tone of the coating film obtained when the dental porcelain paste is applied to a specific base before firing. The color sample may be any color sample that allows a user to visually confirm the color tone of the porcelain paste when applied to a specific base, such as a zirconia substrate, at a specific thickness. For example, the color sample may be a reproduction of the color tone of the ceramic paste applied to a specific substrate at a specific thickness, and may be painted on paper, a plastic plate, a metal plate, a ceramic plate, or the like, so that the user of the ceramic paste can visually confirm the color tone. Alternatively, the color sample may be a photograph or actual sample of the ceramic paste at each application thickness. For example, when the ceramic paste is applied to a substrate in a range of 20 to 40 μm, the color sample may be one that allows the user to visually confirm the color tone of the ceramic paste applied at certain thickness intervals (e.g., color tone at a thickness of 20 μm, color tone at a thickness of 25 μm) or at certain thickness ranges (e.g., color tone at a thickness of 20 to 25 μm, color tone at a thickness of 25 to 30 μm) within that range. The substrate used to prepare the color sample is not particularly limited. For example, when a substrate made of zirconia is used as the base, the color sample can be prepared as a color sample that can confirm the color tone of the coating surface formed by applying the ceramic paste to the zirconia substrate in a specific thickness.

[0045] [Method for manufacturing a dental prosthesis] A method for manufacturing a dental prosthesis according to one embodiment of the present invention includes a step (I) of applying the dental porcelain paste according to one embodiment of the present invention to a substrate, and a step (II) of firing the dental porcelain paste applied to the substrate.

[0046] <Step (I)> In step (I), the dental porcelain paste is applied to a substrate. The dental porcelain paste used in step (I) is the same as that described above in the section on dental porcelain paste, and preferred embodiments thereof are also the same. The "substrate" (undercoat) to which the porcelain paste is applied in step (I) is not particularly limited and can be appropriately selected depending on the intended use of the porcelain paste. For example, when the porcelain paste is used as a glaze porcelain, it is preferably used to finish dental prostheses made of the aforementioned ceramic materials. Examples of substrates for dental prostheses made of these ceramic materials include zirconium oxide (zirconia), aluminum oxide (alumina), feldspar glass, and lithium disilicate glass. As mentioned above, zirconia does not provide a polishing effect due to the self-glazing effect, and therefore, to achieve a polishing effect, the porcelain paste must be applied to a certain thickness (e.g., 20 μm or more). As mentioned above, the porcelain paste has excellent discriminability and the application thickness is easily adjustable. Therefore, the porcelain paste can be suitably used for a substrate made of zirconia. The shape of the substrate is not particularly limited. For example, when the porcelain paste is used as a glaze porcelain, it is preferably used for finishing a dental prosthesis made of a ceramic material, as described above, and therefore the shape of the substrate is preferably processed into the shape of the dental prosthesis.

[0047] In step (I), the ceramic paste can be applied (adhered) to the substrate using, for example, a brush or paintbrush. Alternatively, depending on the type of ceramic paste, a spray can be used. Furthermore, the substrate can be immersed in a container filled with the ceramic paste. In this case, it is preferable to seal the container beforehand to prevent the coating agent from flowing onto the inner surface of the substrate.

[0048] The thickness of the coating film formed by applying the porcelain paste can be appropriately set depending on the application, but for example, when the porcelain paste is used as a glaze porcelain, a certain thickness in the resulting fired body makes it easier to impart a gloss, so the thickness is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more. Furthermore, from the viewpoint of preventing the entrapment of air bubbles due to an excessively thick porcelain paste and from the viewpoint of reducing the influence of the thickness of the resulting fired body on the occlusal surfaces, occlusal diameter, and contact between prostheses, the thickness is preferably 50 μm or less, more preferably 45 μm or less, and even more preferably 40 μm or less.

[0049] In step (I), it is preferable to use the dental porcelain paste application thickness adjustment sample described in the section on the dental porcelain kit. That is, it is preferable to use the dental porcelain kit, which is one embodiment of the present invention, in step (I). As described above, by using the application thickness adjustment sample, it becomes easier to adjust the application thickness to a predetermined thickness even when applying by visual inspection or manual work. The dental porcelain paste application thickness adjustment sample preferably used in step (I) is the same as that described in the section on the dental porcelain kit, and its preferred embodiments are also the same.

[0050] <Step (II)> In step (II), the dental porcelain paste applied to the substrate is fired. The firing temperature (maximum firing temperature) for firing the porcelain paste can be set appropriately depending on the type of porcelain, the form of use, the type of base, etc., and is not particularly limited as long as it is a temperature at which component (C) is discolored by firing. However, it is preferably 700°C or higher, more preferably 720°C or higher, even more preferably 730°C or higher, and preferably 1050°C or lower, more preferably 1000°C or lower, and even more preferably 980°C or lower. As described above, these stepwise lower and upper limits can be independently combined. For example, in one embodiment of the present invention, the firing temperature in step (II) is preferably 700 to 1050°C, more preferably 720 to 1000°C, and even more preferably 730 to 980°C. The temperature rise rate during firing up to the maximum firing temperature can be appropriately changed depending on the type of porcelain, and is not particularly limited, but is preferably 10 to 70°C / min, more preferably 15 to 60°C / min, and even more preferably 20 to 50°C / min.

[0051] The porcelain paste may be dried before firing, and the drying conditions are not particularly limited. Furthermore, the firing may be vacuum firing, which is performed under vacuum conditions, since the amount of bubbles present inside the glass powder (A) is significantly reduced, resulting in a dental prosthesis with improved transparency and aesthetics. The degree of vacuum in vacuum firing is not particularly limited, and may be, for example, 750 mmHg or less, or 730 mmHg or less. The temperature at which evacuation begins is not particularly limited, and may be, for example, 550 to 700°C. When vacuum firing is performed, the porcelain paste may be heated under vacuum conditions during temperature rise, and then released to atmospheric pressure when the maximum firing temperature is reached, and then maintained under atmospheric pressure.

[0052] The present invention includes embodiments in which the above-described configurations are combined in various ways within the scope of the technical concept of the present invention, as long as the effects of the present invention are achieved.

[0053] Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples in any way.

[0054] <Preparation of Glass Powder> SiO２ , Al ２ O ３ , ZnO, K ２ O, Na ２ O, Li ２ O, CaO, MgO, Sb ２ O ３ , CeO ２ Amorphous potassium aluminosilicate glass frits composed of BaO and BaO were pulverized in a planetary mill to produce powders having the average particle sizes shown in Tables 1 and 2 below. The average particle size was measured as a volume-based average particle size (D50) by a laser diffraction / scattering method. The measurement was performed using a "Microtrac (registered trademark) MT3300II" (manufactured by Microtrac Corporation) as the measuring device, and water was used as the dispersion medium.

[0055] [Examples 1 to 14 and Comparative Example 1] Each component shown in Tables 1 and 2 below was mixed in the amount (parts by mass) shown in Tables 1 and 2 in a mortar at room temperature (25°C) for about 10 minutes to prepare dental porcelain pastes.

[0056] [Evaluation of Dental Porcelain Paste] The properties of each of the porcelain pastes prepared in the Examples and Comparative Examples were measured by the following methods. The evaluation results are shown in Tables 1 and 2 below.

[0057] <Color Tone Evaluation of Dental Porcelain Paste Before Firing> Each porcelain paste was placed in a stainless steel ring (inner diameter 15 mm, thickness 0.5 mm), and pressed against two glass slides ("ASLAB (registered trademark) glass slides" manufactured by AS ONE Corporation, width 25 mm, length 75 mm, thickness 1 mm) from above and below. The L value against a white background was measured using a spectrophotometer ("CM-3610A" manufactured by Konica Minolta, Inc., D65 light source, geometric conditions c (di: 8°, de: 8°), diffuse illumination: 8° light reception, measurement mode SCI, measurement diameter / illumination diameter = φ8 mm / φ11 mm). ＊ a ＊ b ＊ Value (JIS Z 8781-4:2013 Colorimetry - Part 4: CIE 1976 L ＊ a ＊ b ＊ The results were used to measure the color tone L1 of the dental porcelain paste before firing. ＊ , a1 ＊, b1 ＊ (n=3).

[0058] <Evaluation of Color Tone of Fired Body After Firing Porcelain Paste> Each porcelain paste was vacuum-fired at a maximum firing temperature of 740°C and polished with #1500 abrasive paper to obtain a fired body with an inner diameter of 15 mm and a thickness of 0.5 mm. The firing conditions other than the maximum firing temperature were as follows: drying time before firing: 6 minutes; firing start temperature: 400°C; heating rate: 45°C / min; vacuum start temperature: 650°C; vacuum degree: 720 mmHg; release to atmospheric pressure (vacuum release) upon reaching 740°C and retention for 1 minute; and rapid cooling to room temperature (25°C) after retention. Each of the obtained fired bodies was pressed against two glass slides ("Azlab (registered trademark) glass slides" manufactured by AS ONE Corporation, width 25 mm, length 75 mm, thickness 1 mm) from above and below, and the L value against a white background was measured using a spectrophotometer ("CM-3610A" manufactured by Konica Minolta, Inc., D65 light source, geometric conditions c (di: 8°, de: 8°), diffuse illumination: 8° light reception, measurement mode SCI, measurement diameter / illumination diameter = φ8 mm / φ11 mm). ＊ a ＊ b ＊ Value (JIS Z 8781-4:2013 Colorimetry - Part 4: CIE 1976 L ＊ a ＊ b ＊ The results were used to measure the color tone L2 of the fired body. ＊ , a2 ＊ , b2 ＊ (n=3).

[0059] <Calculation of Color Tone Difference Before and After Firing> The change in color tone (color tone difference) of the ceramic paste before and after firing was calculated using the following formula from the color tone of the ceramic paste before firing and the color tone of the fired body obtained by firing the ceramic paste. ΔE ＊ = {(L2 ＊ -L1 ＊ ) ２ + (a2 ＊ -a1 ＊ ) ２ + (b2 ＊ -b1 ＊ ) ２} １／２ ΔL ＊ = | L2 ＊ -L1 ＊ | Above ΔE＊ However, the color difference ΔE according to the above-mentioned condition (1) ＊ In addition, the above ΔL ＊ However, the lightness ΔL according to the above-mentioned condition (2) ＊ is.

[0060] <Preparation of Substrate> The substrates to be evaluated, as described below, were prepared. First, a dental zirconia sample (trade name "KATANA (registered trademark) Ziroconia STML A3", thickness 14 mm, manufactured by Kuraray Noritake Dental Co., Ltd.) was cut into a disk-like shape with a diameter of 19 mm and a thickness of 1.6 mm using a dental cutting machine DWX-51D (manufactured by Roland DG Corporation) to prepare a molded product. Next, using a firing furnace (trade name "Noritake Katana (registered trademark) F-1N") manufactured by SK Medical Electronics Co., Ltd., the molded product was fired from room temperature (25°C) in air, heated to 1550°C at a heating rate of 10°C / min, and fired at 1550°C for 2 hours (air firing), and polished with #1500 abrasive paper to prepare a substrate composed of a zirconia sintered body in a disk-like shape with a diameter of 14 mm and a thickness of 1.2 mm.

[0061] <Evaluation of distinguishability of ceramic paste> Each of the prepared ceramic pastes was applied to the substrate prepared above, and the distinguishability of the applied area was evaluated according to the following criteria (n=3). "A": The area where the paste was applied could be clearly distinguished visually. "F": The difference in color tone between the substrate and the ceramic paste was unclear, making it difficult to distinguish the applied area visually.

[0062] <Color difference ΔE1 between ceramic paste and base material before firing ＊ First, the prepared substrate was measured for L against a white background using a spectrophotometer ("CM-3610A" manufactured by Konica Minolta, Inc., D65 light source, geometric condition c (di: 8°, de: 8°), diffused illumination: 8° light reception, measurement mode SCI, measurement diameter / illumination diameter = φ8 mm / φ11 mm). ＊ a ＊ b ＊ Value (JIS Z 8781-4:2013 Colorimetry - Part 4: CIE 1976 L ＊ a ＊ b ＊ The results were used to measure the color tone L3 of the substrate. ＊ , a3＊ , b3 ＊ (n=3). The color tone of the substrate was L3 ＊ = 73.4, a3 ＊ = 4.0, b3 ＊ = 27.4. Next, a stainless steel ring (inner diameter 15 mm, thickness 0.5 mm) was placed on the substrate, and each of the prepared porcelain pastes was placed inside the ring. Thereafter, a slide glass ("Azlab (registered trademark) slide glass" manufactured by AS ONE Corporation, width 25 mm, length 75 mm, thickness 1 mm) was pressed against the ring from above, and color measurement (L ＊ a ＊ b ＊ The results obtained were used to calculate the color tone L4 after applying the paste. ＊ , a4 ＊ , b4 ＊ (n=3) Color difference ΔE1 between the dental porcelain paste before firing and the base material ＊ was calculated using the following formula: ＊ = {(L4 ＊ -L3 ＊ ) ２ + (a4 ＊ -a3 ＊ ) ２ + (b4 ＊ -b3 ＊ ) ２} １／２

[0063] <Evaluation of bubbles and carbonization after firing> Each of the prepared porcelain pastes was applied to the substrate and then vacuum-fired at 740°C to obtain a fired body. Each of the fired bodies was observed at 100x magnification using an optical microscope ("DIGITAL MICROSCOPE KH-7700" manufactured by Hirox Corporation) to evaluate the presence or absence of bubbles and carbonized materials. The evaluation criteria were as follows (n=3): a fired body obtained by vacuum-firing at 750°C using a conventional dental porcelain ("CERABIAN (registered trademark) ZR FC Paste Stain Clear Glaze" manufactured by Kuraray Noritake Dental Co., Ltd.) was compared with the results of observation using the same optical microscope and procedures as above. "A": Compared to the conventional dental porcelain, the same level of bubbles was observed, and no black spots were observed. "B": Compared to conventional dental porcelain, there are more bubbles, but they are not a problem for practical use, and no black spots are visible. "F": Compared to conventional dental porcelain, there are clearly more bubbles, black spots, or both.

[0064] <Color difference ΔE2 between fired body and base material ＊ First, the prepared substrate was measured for L against a white background using a spectrophotometer ("CM-3610A" manufactured by Konica Minolta, Inc., D65 light source, geometric condition c (di: 8°, de: 8°), diffused illumination: 8° light reception, measurement mode SCI, measurement diameter / illumination diameter = φ8 mm / φ11 mm). ＊ a ＊ b ＊ Value (JIS Z 8781-4:2013 Colorimetry - Part 4: CIE 1976 L ＊ a ＊ b ＊ The results were used to measure the color tone L3 of the substrate. ＊ , a3 ＊ , b3 ＊ (n=3). The color tone of the substrate was L3 ＊ = 73.4, a3 ＊ = 4.0, b3 ＊= 27.4. Next, each ceramic paste prepared so that the thickness of the fired body after firing would be 65 μm was applied to the prepared substrate, and then fired in a vacuum at a maximum firing temperature of 740°C to obtain a fired body. The firing conditions other than the maximum firing temperature were as follows: drying time before firing: 6 minutes; firing start temperature: 400°C; temperature rise rate: 45°C / min; vacuum start temperature: 650°C; vacuum degree: 720 mmHg; release to atmospheric pressure (vacuum release) upon reaching 740°C and retention for 1 minute; and rapid cooling to room temperature (25°C) after retention. Each of the obtained fired bodies was measured for color (L ＊ a ＊ b ＊ The results were used to calculate the color tone of the fired body (L5). ＊ , a5 ＊ , b5 ＊ The color difference ΔE2 between the fired body obtained after firing the ceramic paste and the substrate ＊ was calculated using the following formula (n=3): ＊ = {(L5 ＊ -L3 ＊ ) ２ + (a5 ＊ -a3 ＊ ) ２ + (b5 ＊ -b3 ＊ ) ２} １／２

[0065]

[0066]

[0067] From the results of Tables 1 and 2, the porcelain pastes of Examples 1 to 14, which contain components (A) to (C) and satisfy at least one condition selected from conditions (1) and (2), have a color difference ΔE1 between the porcelain paste in a state before firing and the substrate to which the paste is applied. ＊ Furthermore, after firing, the ceramic pastes of Examples 1 to 14 had a color difference ΔE2 between the fired body obtained by firing the ceramic paste and the substrate. ＊It can be seen that the difference in the density of the porcelain pastes of Examples 1 to 13 was small, and there was almost no effect on the color tone of the underlying substrate. Furthermore, the porcelain pastes of Examples 1 to 13 generated similar amounts of bubbles in the fired body compared to conventional dental porcelains, and no black spots were observed. Furthermore, the porcelain paste of Example 14 generated more bubbles in the fired body compared to conventional dental porcelains, but to an extent that did not pose a problem in practical use, and no black spots were observed. Therefore, it can be seen that the dental porcelain paste of one embodiment of the present invention is suitable for applications requiring greater distinctiveness in the application process before firing.

[0068] As described above, the dental porcelain paste of one embodiment of the present invention exhibits a large color difference from the base material before firing, making it easy to visually distinguish between coated and uncoated areas. Therefore, the dental porcelain paste of one embodiment of the present invention can prevent porcelain paste overspray and easily adjust the coating thickness, resulting in excellent distinguishability during application before firing. Furthermore, the dental porcelain paste of one embodiment of the present invention changes color after firing, virtually eliminating the color difference from the base material. This has the effect of substantially eliminating any effect on the base color and suppressing the occurrence of bubbles and black spots. Therefore, the dental porcelain paste of one embodiment of the present invention can be suitably used, for example, as a glaze porcelain. Furthermore, with the recent increase in demand for ceramic prostheses, and with the increasing demand for aesthetics, the frequency of dental porcelain use is expected to increase. From this perspective, the dental porcelain paste of one embodiment of the present invention is also useful.

Claims

1. A dental porcelain paste comprising a glass powder (A), an organic solvent (B), and a colorant (C) that is decolorized upon firing, and which satisfies at least one of the following conditions (1) and (2): Condition (1): A dental porcelain paste having a thickness of 0.5 mm before firing is placed in a ＊ a ＊ b ＊ The color tone obtained by measuring the color in the color space and the sintered body having a thickness of 0.5 mm obtained by sintering the dental porcelain paste in a vacuum at 740° C. are measured. ＊ a ＊ b ＊ The color difference ΔE calculated from the color tone obtained by measuring the color in the color space ＊ is 8.5 or higher Condition (2): A dental porcelain paste having a thickness of 0.5 mm before firing is placed in a ＊ a ＊ b ＊ The brightness obtained by measuring the color in the color space and the L value of a 0.5 mm thick sintered body obtained by vacuum sintering the dental porcelain paste at 740° C. ＊ a ＊ b ＊ The lightness difference ΔL calculated from the lightness obtained by measuring the color in the color space ＊ is 6.5 or higher

2. The base material is L ＊ a ＊ b ＊ The color tone obtained by measuring the color in a color space and the dental porcelain paste applied to the substrate in a thickness of 0.5 mm were measured using a L ＊ a ＊ b ＊ The color difference ΔE1 calculated from the color tone obtained by measuring the color in the color space ＊ 2. The dental porcelain paste according to claim 1, wherein the viscosity is 11.0 or more.

3. The base material is L ＊ a ＊ b ＊ The dental porcelain paste was applied to the substrate so that the thickness after firing was 65 μm, and the fired body was fired at 740° C. in a vacuum. ＊ a ＊ b ＊ The color difference ΔE2 calculated from the color tone obtained by measuring the color in the color space ＊ 2. The dental porcelain paste according to claim 1, wherein the viscosity is 3.0 or less.

4. 2. The dental porcelain paste according to claim 1, wherein the content of component (C) is 0.001 parts by mass or more and less than 0.60 parts by mass per 100 parts by mass of the total of components (A) and (B).

5. 2. The dental porcelain paste of claim 1, wherein component (C) comprises an organic pigment that dissolves in component (B).

6. The dental porcelain paste according to claim 5 , wherein the organic pigment is an aromatic organic pigment.

7. 6. The dental porcelain paste according to claim 5, wherein the organic dye is at least one selected from the group consisting of anthraquinone-based compounds, azo-based compounds, xanthene-based compounds, porphyrin-based compounds, phthalocyanine-based compounds, and triarylmethane-based compounds.

8. The dental porcelain paste of claim 1 further comprising a fluorescent agent.

9. 9. The dental porcelain paste according to claim 8, wherein the content of the fluorescent agent is 0.001 to 0.50 parts by mass per 100 parts by mass of the total of the components (A) and (B).

10. 10. The dental porcelain paste of claim 1, further comprising an inorganic pigment.

11. A dental porcelain kit comprising the dental porcelain paste according to any one of claims 1 to 10 and a color sample for adjusting the application thickness of the dental porcelain paste.

12. A method for producing a dental prosthesis, comprising: a step (I) of applying the dental porcelain paste according to any one of claims 1 to 10 to a substrate; and a step (II) of firing the dental porcelain paste applied to the substrate.

13. The method for producing a dental prosthesis according to claim 12, wherein the firing temperature in the step (II) is 700°C or higher.

14. The method for producing a dental prosthesis according to claim 12, further comprising using a color sample for adjusting the thickness of the dental porcelain paste to be applied in the step (I).