Paste-like dental glass composition

Abstract

The present invention provides a paste-type dental glass composition that exhibits a good usability and a suppression of paste sagging, and that enables a precise adjustment of the color post-firing free of discoloration, e.g., to black or grey. The present invention relates to a paste-type dental glass composition comprising a glass powder (A) and an organic solvent (B) that has a viscosity at 20°C of not more than 2,500 mPa · s and has no more than two hydroxyl groups in the molecule, wherein the composition substantially does not contain an organic compound having three or more hydroxyl groups in the molecule.

Description

Technical Field

[0001] The present invention relates to a paste-like dental glass composition that is used for prosthetic restoration such as artificial teeth having aesthetics similar to natural teeth, has good operability during manual building by dental technicians, and does not change color to black or gray after firing.

Background Art

[0002] Since ceramics have a transparency and color tone similar to natural teeth, they are an essential material for fabricating dental crowns that require aesthetics.

[0003] In this dental crown fabrication process, generally, a dental kneading liquid composed of ceramic materials, water, organic solvents, etc., or a ceramic material that has been previously mixed with water, organic solvents, etc. and made into a paste form is used, and the operation of building up and firing on a frame (for example, a metal frame, a ceramics frame) that covers the abutment teeth is repeated to fabricate the dental crown. In particular, as the demand for ceramic materials is increasing more and more and individual aesthetic requirements are rising, it is expected that the frequency of use of dental ceramic materials will increase.

[0004] In this paste-like ceramic material, a solvent with low volatility is used so that water, organic solvents, etc. do not evaporate and the ceramic material does not dry out during the work by dental technicians. Also, since generally fine powder glass powder is used in the ceramic material, the solvent is required to have good compatibility with the powder and to adjust the paste properties so that dental technicians can work with good operability. Further, since it is a factor in discoloration after firing (mainly discoloration from gray to black), it is required that no organic matter remains after firing.

[0005] For example, Patent Document 1 discloses a paste-like dental ceramic material containing a component in which a synthetic and / or natural hydrophilic group-containing polymer material is dissolved in one or more organic solvents and / or water selected from divalent and trivalent alcohols, ethers having remaining hydroxyl groups, and hydroxy (meth) acrylates, and it is proposed that the polymer material decomposes and burns efficiently after building up the ceramic material.

[0006] In addition, Patent Document 2 discloses a paste-like dental ceramic material containing a colorant that decolors during firing, an organic solvent, and ceramic powder, and it is proposed that no organic matter remains after firing and there is no discoloration.

[0007] However, in Patent Documents 1 and 2, it has been found that depending on the firing temperature after the ceramic material is built up, there is a problem that organic matter remains after firing and discolors to black or gray. Also, depending on the organic solvent selected (for example, glycerin (boiling point: 290°C)) or the polymer material (for example, methyl cellulose), during firing after the ceramic material is built up, a condensation reaction or polymerization reaction occurs with the boron component contained in the ceramic powder, and it has been found that there is a problem that organic matter remains after firing and discolors to black, gray, or the like.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] Therefore, an object of the present invention is to provide a paste-like dental glass composition that can accurately adjust the color tone without discoloring to black, gray, or the like after firing, and in which sagging of the paste is suppressed and the operability is good.

Means for Solving the Problems

[0010] As a result of intensive studies to solve the above problems, the present inventors have found that the above problems are solved by a paste-like dental glass composition containing glass powder (A) and a specific organic solvent (B) having two or less hydroxyl groups in the molecule, and have further completed the present invention through repeated studies.

[0011] That is, the present invention includes the following inventions. [1] A paste-like dental glass composition containing glass powder (A) and an organic solvent (B) having two or less hydroxyl groups in the molecule and a viscosity at 20 ° C of 2500 mPa·s or less, and substantially free of an organic compound having three or more hydroxyl groups in the molecule. [2] The paste-like dental glass composition according to [1], further containing a thickening agent (C), wherein the thickening agent (C) comprises at least one selected from the group consisting of an organic compound (C-1) having a viscosity at 20 ° C greater than 2500 mPa·s, an organic compound (C-2) that is solid at normal temperature, and an inorganic compound (C-3). [3] The paste-like dental glass composition according to [1] or [2], wherein the organic solvent (B) is a dihydric alcohol compound. [4] The paste-like dental glass composition according to any one of [1] to [3], wherein the organic solvent (B) is a dihydric alcohol compound having a branched chain with 3 to 20 carbon atoms. [5] The paste-like dental glass composition according to [4], wherein the dihydric alcohol compound having a branched chain with 3 to 20 carbon atoms comprises at least one selected from the group consisting of 1-methyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2-methyl-1,4-butanediol, 3-methyl-1,3-butanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and 2-ethyl-1,3-hexanediol. [6] The paste-like dental glass composition according to any one of [1] to [5], wherein the boiling point of the organic solvent (B) is 100 to 350 ° C. [7] The paste-like dental glass composition according to any one of [1] to [6], wherein the viscosity of the organic solvent (B) at 20 ° C is 20 mPa·s or more. [8] The paste-like dental glass composition according to any one of [1] to [7], wherein the glass transition temperature of the glass powder (A) is 400 to 600 ° C. [9] The paste-like dental glass composition according to any one of [1] to [8], wherein the softening point of the glass powder (A) is 500 to 680°C.

[10] A method for manufacturing a dental prosthesis, comprising a step of firing the paste-like dental glass composition according to any one of [1] to [9] at 700 to 1050°C.

[11] A method for manufacturing the paste-like dental glass composition according to any one of [1] to [9], comprising a step of mixing the glass powder (A) and an organic solvent (B) having 2 or less hydroxyl groups in the molecule and having a viscosity of 2500 mPa·s or less at 20°C.

Advantages of the Invention

[0012] The paste-like dental glass composition of the present invention has no residual organic matter after firing, does not discolor, can accurately adjust the color tone, suppresses the sagging of the paste, and has good operability, so that it can easily adjust the color tone of the ceramic material. In addition, the paste-like dental glass composition of the present invention does not dry out during troweling and also has excellent operability.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, preferred embodiments of the present invention will be described.

[0014] The paste-like dental glass composition of the present invention contains a glass powder (A) and an organic solvent (B) (hereinafter sometimes simply referred to as "organic solvent (B)") having 2 or less hydroxyl groups in the molecule and having a viscosity of 2500 mPa·s or less at 20°C, and substantially does not contain an organic compound having 3 or more hydroxyl groups in the molecule.

[0015] The paste-like dental glass composition of the present invention has good aesthetics after firing and is in a state of complete combustion after firing. Complete combustion means (1) the color tone after firing is not darkened by residual organic matter, (2) it does not contain large bubbles after firing, etc.

[0016] <Glass powder (A)> First, the glass powder (A) contained in the paste-like dental glass composition of the present invention will be described.

[0017] The glass powder (A) used in the paste-like dental glass composition of the present invention is not particularly limited as long as it can be used as a dental glass composition and may contain crystals. Examples of the material of the glass powder include glass having SiO2 as the main component (the material with the highest content (for example, 45% by mass or more, 50% by mass or more, 55% by mass or more)), or devitrified glass. Such glass may contain Al2O3, B2O3, ZnO, K2O, Na2O, Li2O, ZrO2, CaO, MgO, Sb2O3, etc. in addition to SiO2. In the glass, for example, the content of SiO2 may be 55 to 75% by mass, may be 57 to 72% by mass, or may be 58 to 70% by mass. The content of Al2O3 may be 3 to 18% by mass, may be 3.5 to 16% by mass, or may be 4 to 15% by mass. The content of B2O3 may be 0 to 25% by mass, may be 0 to 20% by mass, or may be 0 to 18% by mass. The content of ZnO may be 0 to 5% by mass, may be 0 to 3% by mass, or may be 0 to 1% by mass. The content of K2O may be 0 to 10% by mass, may be 0 to 9% by mass, or may be 0 to 8% by mass. The content of Na2O may be 0 to 10% by mass, may be 1 to 9% by mass, or may be 1 to 8% by mass. The content of Li2O may be 0 to 1.5% by mass, may be 0 to 1.0% by mass, or may be 0 to 0.9% by mass. The content of CaO may be 0 to 10% by mass, may be 0 to 9% by mass, or may be 0 to 8% by mass. The content of ZrO2 may be 0 to 5% by mass, may be 0 to 4% by mass, or may be 0 to 3% by mass. The content of MgO may be 0 to 10% by mass, may be 0 to 9% by mass, or may be 0 to 8% by mass. The content of Sb2O3 may be 0 to 3% by mass, may be 0 to 2% by mass, or may be 0 to 1% by mass. Specifically, at least one of amorphous type potassium aluminosilicate glass (4SiO2·Al2O3·K2O), leucite crystal type potassium aluminosilicate glass, fluoroapatite glass, and lithium silicate glass can be used.Among these, in particular, a potassium aluminosilicate glass of the leucite crystal type is preferred. Further, examples of the crystal include leucite, potassium feldspar, fluorophlogopite, diopside, mica, β-spodumene (LiAlSi2O6), β-calcium metaphosphate, apatite, magnesium titanate, β-eucryptite, alumina, and the like. Further, depending on the applications such as ceramic materials for metal firing, all-ceramics, and laminated veneer, the glass powder (A) can be used by appropriately combining one or more kinds thereof.

[0018] In addition, as the raw material substance of the glass powder (A), generally used ceramic raw materials can be widely used, and each component itself such as SiO2, Al2O3, B2O3, ZnO, K2O, Na2O, Li2O, ZrO2, CaO, MgO, Sb2O3, CeO2, BaO, SnO2, and / or a substance that can become the above components when heated in the air can be used. In that case, the glass composition to be obtained in advance is determined by calculation, and each raw material formulation is determined and mixed. The method of mixing the raw material substances is not particularly limited, and it is preferably uniformly dispersed.

[0019] These mixed raw material substances are heat-treated at about 700 ° C or higher to produce glass. The heat treatment method is not particularly limited as long as all of the mixed raw material substances are dissolved and uniformly form an amorphous state, and sublimation of components does not occur. Subsequently, the method of cooling the melt is also not particularly limited, and it can be air-cooled or the like.

[0020] The glass mass thus obtained is pulverized, classified, and made into powder with adjusted particle size. The method of pulverizing and classifying the glass mass is not particularly limited. Examples of the pulverizing apparatus include compression pulverizers such as jaw crushers and cone crushers; ball mills such as vibration ball mills and planetary mills; medium stirring type pulverizers such as tower pulverizers, stirring tank type pulverizers, and annular type pulverizers; high-speed rotary impact pulverizers such as pin mills and disk mills; and other roll mills, jet pulverizers, self-grinding mills, etc. Examples of the classifying apparatus include sieve classifiers such as vibrating sieves and shifters, centrifugal classifiers such as cyclones, and wet classifiers such as sedimentation classifiers. In these pulverizing apparatuses or classifying apparatuses, in order to avoid contamination with metal impurities, it is preferable to use apparatuses coated with resin, glass, or the like.

[0021] In the present invention, the components and contents contained in the glass powder (A) are not particularly limited. However, since firing at a lower temperature is possible due to a decrease in the glass transition temperature or softening point, and the firing time can be shortened, etc., it is preferable to contain a boron component. In the present invention, since the condensation reaction and polymerization reaction with the boron component can be suppressed, even when the content of the boron component in the glass powder (A) is high, no organic matter remains after firing and it does not change color to black, gray, etc. For example, even when the content of the boron component is 2.0% by mass or more, further 5.0% by mass or more, further 10% by mass or more, and further 15% by mass or more with respect to the entire glass powder (A), no organic matter remains after firing and it does not change color to black, gray, etc.

[0022] The glass transition temperature of the glass powder (A) is preferably 400 to 600 °C, more preferably 420 to 580 °C, and even more preferably 450 to 550 °C, from the viewpoint that firing at a lower temperature is possible and the firing time can be shortened. Also, from the same viewpoint, the softening point of the glass powder (A) is preferably 500 to 680 °C, more preferably 520 to 650 °C, and even more preferably 550 to 630 °C. If the glass transition temperature is less than 400 °C or the softening point is less than 500 °C, there is a risk of sagging during firing. Also, if the glass transition temperature is greater than 600 °C or the softening point is greater than 680 °C, firing at a low temperature is not possible and firing at a high temperature is required, and there is a risk of deformation of the ceramic frame made of lithium disilicate-based glass ceramics or the like. The method for measuring the glass transition temperature and the softening point is as described in the examples below.

[0023] The linear thermal expansion coefficient (50 to 500 °C) of the glass powder (A) can be appropriately selected according to the material of the abutment tooth or the frame, etc., and is not particularly limited, but it may be about 4.0×10 -6 ~6.0×10 -6 / °C. In another embodiment, the linear thermal expansion coefficient (50 to 500 °C) of the glass powder (A) may be about 6.1×10 -6 ~13.5×10 -6 / °C, and may be about 6.3×10 -6 ~12.5×10 -6 / °C. For example, when using a paste dental glass composition as a dental ceramic material for a frame mainly composed of zirconia (for example, 50% by mass or more, 70% by mass or more), those of about 9.0×10 -6 ~11.0×10 -6 / °C are preferred. When using a paste dental glass composition as a dental ceramic material for a frame mainly composed of alumina (for example, 50% by mass or more, 70% by mass or more), those of about 6.1×10 -6 ~8.8×10 -6Those of about / ℃ are preferred. The linear thermal expansion coefficient can be measured by heating the sample from room temperature to 500 °C at a heating rate of 5 °C / min using a thermomechanical analyzer TMA8311 (manufactured by Rigaku Corporation). The adjustment of the linear thermal expansion coefficient can be carried out by a known method, for example, it can be adjusted by the content of K2O.

[0024] The glass powder (A) may contain pigments such as inorganic pigments and opacifying agents. Examples of the inorganic pigments contained in the glass powder (A) include praseodymium oxide, vanadium oxide, iron oxide, nickel oxide, chromium oxide, manganese oxide, cerium oxide, tin oxide compounds (for example, tin(II) oxide, tin(IV) oxide, composite oxides containing tin(IV) oxide as a component (for example, vanadium tin yellow, chromium tin pink, etc.)), bismuth vanadium yellow, vanadium zirconium yellow, praseodymium yellow, cobalt blue, manganese pink, chromium alumina pink, chromium iron zinc, titanium oxide (TiO2), zirconium oxide (ZrO2), etc. Examples of the opacifying agents include zirconium silicate, tin(IV) oxide, zirconium oxide (ZrO2), zinc oxide, titanium oxide (TiO2), aluminum oxide, etc. These are appropriately contained according to the desired color tone. The pigments may be used alone or in combination of two or more.

[0025] The glass powder (A) may be surface-treated with a surface treatment agent. Examples of the surface treatment agent include silane coupling agents. The silane coupling agent is not particularly limited, and examples thereof include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, trimethylsilanol, methyltrichlorosilane, methyldichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, vinyltrichlorosilane, trimethylbromosilane, diethylsilane, vinyltriacetoxysilane, ω-(meth)acryloxyalkyltrimethoxysilane (the number of carbon atoms between the (meth)acryloxy group and the silicon atom: 3 to 12, such as γ-methacryloxypropyltrimethoxysilane, etc.), ω-(meth)acryloxyalkyltriethoxysilane (the number of carbon atoms between the (meth)acryloxy group and the silicon atom: 3 to 12, such as γ-methacryloxypropyltriethoxysilane, etc.). The surface treatment agent may be used alone or in combination of two or more.

[0026] As the glass powder (A), commercially available products can also be used. The commercially available products may contain inorganic pigments. When a commercially available product that does not contain an inorganic pigment is used as the glass powder (A), an inorganic pigment can be added to the commercially available product for use. Examples of commercially available products that can be used as the glass powder (A) containing an inorganic pigment include Celayabian (registered trademark) ZR (product name, manufactured by Kuraray Noritake Dental Co., Ltd.), Celayabian (registered trademark) ZR Press (product name, manufactured by Kuraray Noritake Dental Co., Ltd.), and the like. Other commercially available products include "Vintage AL" and "Vintage ZR" (product names, manufactured by Matsuura Co., Ltd.), "Nobel Round" (product name, manufactured by Nobel Biocare Japan Co., Ltd.), "Cellcon Ceram S" (product name, manufactured by Dentsply Sankin Co., Ltd.), and the like.

[0027] The content of the glass powder (A) is not particularly limited, but is preferably 50 to 90% by mass, more preferably 52 to 88% by mass, and even more preferably 54 to 84% by mass with respect to the entire paste-like dental glass composition of the present invention. If the content exceeds 90% by mass, the kneadability of the glass powder (A) and the organic solvent (B) may decrease, and there is a risk that it may be difficult to form a paste. On the other hand, if the content of the glass powder is less than 50% by mass, the viscosity of the kneaded product of the glass powder and the organic solvent may decrease, and the operability during tamping may deteriorate. In the present specification, the upper limit value and the lower limit value of the numerical range (the content of each component, the value calculated from each component, and each physical property, etc.) are not particularly limited as long as the effects of the present invention are not impaired, and can be appropriately combined.

[0028] The particle size of the glass powder (A) can be set according to the use site and is not particularly limited, but is preferably 1.0 to 10 μm. For example, when used as an opaque ceramic material, the average particle size of the powder of the glass powder (A) contained in the paste-like dental glass composition is preferably 3.0 to 10 μm. The average particle size of the powder ceramic material for stain is preferably 1.0 to 7.0 μm.

[0029] The average particle diameter of the glass powder (A) can be determined by measurement using the laser diffraction scattering method. Specifically, for example, the laser diffraction scattering method can be used to measure on a volume basis using a 0.2% aqueous sodium hexametaphosphate solution as a dispersion medium with a laser diffraction particle size distribution measuring device (SALD-2300: manufactured by Shimadzu Corporation).

[0030] <Organic solvent (B)> Next, the organic solvent (B) will be described.

[0031] The organic solvent (B) needs to be an organic solvent having 2 or less hydroxyl groups in the molecule in order to suppress the condensation reaction and polymerization reaction with the boron component contained in the glass powder. When an organic solvent having 3 or more hydroxyl groups in the molecule is used, during the firing after building up, the condensation reaction and polymerization reaction with the boron component contained in the glass powder proceed, the burnout deteriorates, and organic substances remain after firing, changing color to black, gray, or the like. Therefore, the organic solvent (B) does not substantially contain an organic solvent having 3 or more hydroxyl groups in the molecule. The content of the organic solvent having 3 or more hydroxyl groups in the molecule can be, for example, 1000 mass ppm or less, preferably 100 mass ppm or less, more preferably 10 mass ppm or less, still more preferably 1 mass ppm or less, particularly preferably 0.1 mass ppm or less, and most preferably 0 mass ppm, based on the mass of the paste-like dental glass composition. Examples of the organic solvent having 3 or more hydroxyl groups in the molecule include trihydric alcohol compounds such as glycerin, 1,2,4-butanetriol, 1,2,3-butanetriol, and 1,2,6-hexanetriol.

[0032] On the other hand, when an organic solvent (B) with too high a viscosity is used alone, the viscosity is too high, which may make it difficult to prepare the paste. Therefore, the viscosity at 20°C is 2500 mPa·s or less. From the viewpoints of kneadability and paste viscosity, 2100 mPa·s or less is preferable, 1700 mPa·s or less is more preferable, and 1300 mPa·s or less is even more preferable. On the other hand, in order to adjust the paste properties to have good operability without dripping, an organic solvent with a viscosity at 20°C of 20 mPa·s or more is preferable, 50 mPa·s or more is more preferable, 100 mPa·s or more is even more preferable, and 150 mPa·s or more is particularly preferable.

[0033] Since the organic solvent (B) of the present invention needs to burn out more sufficiently so as not to affect the color tone after firing, the boiling point is preferably 350°C or less, more preferably 320°C or less, even more preferably 300°C or less, and particularly preferably 280°C or less. Furthermore, when an organic solvent with a boiling point of less than 100°C is used, the organic solvent volatilizes even at room temperature, causing the paste to dry and making it difficult to stably maintain the paste properties, and there is a risk that the operability required during building cannot be obtained. Therefore, an organic solvent with a boiling point of 100°C or more is preferable. As the organic solvent (B), those with a boiling point of 100 to 350°C are preferable, those with a boiling point of 100 to 320°C are more preferable, those with a boiling point of 100 to 300°C are even more preferable, and those with a boiling point of 100 to 280°C are particularly preferable.

[0034] Examples of the organic solvent (B) of the present invention include dihydric alcohol compounds and monohydric alcohol compounds. Examples of the dihydric alcohol compounds include straight-chain dihydric alcohol compounds having 2 to 15 carbon atoms (preferably 3 to 12 carbon atoms, more preferably 4 to 10 carbon atoms), such as 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, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (molecular weight: 200 to 600), propylene glycol, dipropylene glycol, polypropylene glycol, etc.; branched-chain dihydric alcohol compounds having 3 to 20 carbon atoms (preferably 4 to 15 carbon atoms, more preferably 5 to 12 carbon atoms), such as 1-methyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2-methyl-1,4-butanediol, 3-methyl-1,3-butanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, etc.; dihydric alcohol compounds having an aryl group having 6 to 14 carbon atoms, such as 3-benzyloxy-1,2-propanediol, 4-benzyloxy-1,2-butanediol, 4-benzyloxy-1,3-butanediol, etc.Examples of the monohydric alcohol compounds include monohydric alcohol compounds having an aliphatic group with 1 to 15 carbon atoms, 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, 2-ethyl-1-butanol, 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, triethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, etc.; and monohydric alcohol compounds having an aryl group with 6 to 14 carbon atoms, such as ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, benzyl alcohol, 3-(benzyloxy)-1-propanol, 2-(benzyloxy)-1-butanol, 5-(benzyloxy)-1-pentanol, etc.Among these, from the viewpoints of compatibility with the glass powder (A) and viscosity, a dihydric alcohol compound is preferred, a dihydric alcohol compound having a branched chain is more preferred, 1-methyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2-methyl-1,4-butanediol, 3-methyl-1,3-butanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol are even more preferred, 3-methyl-1,3-butanediol (boiling point: about 203 °C, viscosity at 20 °C: about 250 mPa·s), 3-methyl-1,5-pentanediol (boiling point: about 250 °C, viscosity at 20 °C: about 173 mPa·s), 2,4-diethyl-1,5-pentanediol (boiling point: about 264 °C, viscosity at 20 °C: about 1650 mPa·s), 2-ethyl-1,3-hexanediol (boiling point: about 244 °C, viscosity at 20 °C: about 271 mPa·s) are particularly preferred. These organic solvents (B) can be used alone or in appropriate combinations of two or more.

[0035] In the paste-like dental glass composition of the present invention, in particular, by containing a dihydric alcohol compound having a branched carbon structure, sagging of the paste can be suppressed and workability can be improved. The reason is not clear, but the present inventors presume as follows. That is, since a dihydric alcohol compound having a branched chain with a predetermined number of carbon atoms generates an appropriate polarity, the compatibility with the glass powder is improved. Also, even if the number of carbon atoms is increased, it does not solidify at room temperature and can maintain a liquid state with an appropriate viscosity and boiling point. Therefore, when mixed with the glass powder, it is presumed that the paste does not dry and sagging of the paste can be suppressed.

[0036] <Thickener (C)> The paste-like dental glass composition of the present invention may further contain a thickening agent (C). However, the thickening agent (C) excludes organic compounds having three or more hydroxyl groups in the molecule. In the paste-like dental glass composition of the present invention, by containing an organic solvent (B), the thickening agent (C) can be minimized. The thickening agent (C) may be used alone or in combination of two or more. The thickening agent (C) used in the present invention includes at least one selected from the group consisting of an organic compound (C-1) having a viscosity at 20°C greater than 2500 mPa·s, an organic compound (C-2) that is solid at room temperature, and an inorganic compound (C-3).

[0037] For the same reason as described above, the thickening agent (C) substantially does not contain organic compounds having three or more hydroxyl groups in the molecule. The content of the organic compound having three or more hydroxyl groups in the molecule can be, for example, 1000 mass ppm or less, preferably 100 mass ppm or less, more preferably 10 mass ppm or less, still more preferably 1 mass ppm or less, particularly preferably 0.1 mass ppm or less, and most preferably 0 mass ppm, based on the mass of the paste-like dental glass composition. Examples of the organic compound having three or more hydroxyl groups in the molecule include polysaccharide compounds such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, xanthan gum, guar gum, carrageenan, tamarind seed gum, and pectin; sugar alcohol compounds such as sorbitol, erythritol, xylitol, and trehalose; and synthetic polyol compounds such as diglycerin, triglycerin, polyglycerin, and polyvinyl alcohol. The paste-like dental glass composition of the present invention substantially does not contain an organic compound having three or more hydroxyl groups, whether it is an organic solvent or a thickening agent.

[0038] The organic compound (C-1) used in the present invention and having a viscosity at 20°C greater than 2500 mPa·s (hereinafter sometimes simply referred to as "organic compound (C-1)") is not particularly limited as long as good thickening properties can be obtained. Examples include radical polymerizable polyfunctional (meth)acrylates such as 2,2-bis[4-(3-acryloyloxy-2-hydroxypropoxy)phenyl]propane, 2,2-bis[4-(3-(methacryloyloxy-2-hydroxypropoxy)phenyl]propane (commonly known as "Bis-GMA"), 2,2,4-trimethylhexamethylene bis(2-carbamoyloxyethyl) dimethacrylate (UDMA); silicone oils such as dimethyl silicone oil and methylphenyl silicone oil. The upper limit of the viscosity of the organic compound (C-1) is not particularly limited, but if it is too high, there is a risk of inhibiting the burnout of the organic solvent (B), or a risk of poor burnout of the thickener (C) itself, which may deteriorate the burnout. Also, considering the influence on the color tone after firing and the possibility of generating bubbles, the viscosity at 20°C may be 1,500,000 mPa·s or less. The viscosity of the organic compound (C-1) at 20°C is preferably 2700 mPa·s or more, more preferably 2900 mPa·s or more, and even more preferably 3000 mPa·s or more.

[0039] Examples of the organic compound (C-2) which is solid at normal temperature and used in the present invention (hereinafter sometimes simply referred to as "organic compound (C-2)") include water-soluble polymer compounds such as sodium polyacrylate, ammonium polyacrylate, polyethylene oxide, polyethylene glycol (molecular weight: 1000 or more), polyvinylpyrrolidone, and low molecular weight fatty acid compounds. Examples of the fatty acid compound include fatty acid metal salts having a fatty acid group with 10 to 30 carbon atoms such as calcium stearate, magnesium stearate, zinc stearate, and aluminum stearate; fatty acid esters such as polyethylene glycol fatty acid esters such as polyethylene glycol monostearate; fatty acids such as 12-hydroxystearic acid; and fatty acid amides such as stearic acid amide, oleic acid amide, and ethylene bisoleic acid amide, and compounds having a fatty acid group with 8 to 30 carbon atoms are exemplified, and compounds having a fatty acid group with 10 to 28 carbon atoms are preferred. The organic compound (C-2) includes organic compounds having no fluidity at normal temperature, and further includes paste-like organic compounds and slurry-like organic compounds having fluidity, but organic compounds having fluidity and a viscosity at 20 ° C of 1,500,000 mPa·s or less are included in the organic compound (C-1).

[0040] The content of the organic compound (C-1) or (C-2) can be minimized by the content of the organic solvent (B). When the paste-like dental glass composition contains the organic compound (C-1) or (C-2), the content of the organic compound (C-1) or the organic compound (C-2) is preferably 0.01 to 10% by mass, more preferably 0.05 to 8.0% by mass, and even more preferably 0.1 to 6.0% by mass based on the whole paste-like dental glass composition. When the content is 0.01% by mass or more, a thickening effect can be obtained, the paste is less likely to drip, and the operability is better. When the content is 10% by mass or less, the viscosity of the composition does not become too high, the paste properties are moderately soft, it becomes easier to apply and it becomes easier to build up evenly. When the paste-like dental glass composition contains both the organic compound (C-1) and the organic compound (C-2), it is preferable that the total content of the organic compound (C-1) and the organic compound (C-2) is within the above range. Further, when the paste-like dental glass composition contains the organic compound (C-1) or (C-2), if a large amount of a high-viscosity component is blended, there is a risk of inhibiting the burnout of the organic solvent (B), and there is a risk of deteriorating the burnout such as poor burnout of the thickener (C) itself, and from the points of the influence on the color tone and the possibility of generating bubbles, the content of the organic compound (C-1) or the organic compound (C-2) (when containing both the organic compound (C-1) and the organic compound (C-2), the total content of the organic compound (C-1) and the organic compound (C-2)) is preferably less than the content of the organic solvent (B) in the whole paste-like dental glass composition.

[0041] Examples of the inorganic compound (C-3) used in the present invention include inorganic oxide particles such as silica, alumina, titania, and zirconia, or composite oxide particles composed of these, calcium phosphate, hydroxyapatite, ytterbium fluoride, yttrium fluoride, smectite (aluminum magnesium silicate), bentonite, water glass (aqueous sodium silicate solution), and the like. Among these, particles of silica, alumina, and titania produced by the flame pyrolysis method are preferred. For example, "Aerosil (registered trademark) OX50", "Aerosil (registered trademark) 50", "Aerosil (registered trademark) 130", "Aerosil (registered trademark) 200", "Aerosil (registered trademark) 380", "Aerosil (registered trademark) MOX80", "Aerosil (registered trademark) R972", "Aerosil (registered trademark) RY50", "Aeroxide (registered trademark) AluC", "Aeroxide (registered trademark) TiO2P 25", "VP Zirconium Oxide 3-YSZ", and "VP Zirconium Oxide 3-YSZ PH" manufactured by Nippon Aerosil Co., Ltd. are used. More preferably, silica particles produced by the flame pyrolysis method are used. For example, the "Aerosil (registered trademark)" series of products manufactured by Nippon Aerosil Co., Ltd. are used.

[0042] When the inorganic compound (C-3) is a particle, it may be surface-treated with a surface treatment agent. Examples of the surface treatment agent include silane coupling agents. The silane coupling agent is not particularly limited, and examples thereof include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, trimethylsilanol, methyltrichlorosilane, methyldichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, vinyltrichlorosilane, trimethylbromosilane, diethylsilane, vinyltriacetoxysilane, ω-(meth)acryloxyalkyltrimethoxysilane (the number of carbon atoms between the (meth)acryloxy group and the silicon atom: 3 to 12, for example, γ-methacryloxypropyltrimethoxysilane, etc.), ω-(meth)acryloxyalkyltriethoxysilane (the number of carbon atoms between the (meth)acryloxy group and the silicon atom: 3 to 12, for example, γ-methacryloxypropyltriethoxysilane, etc.). The surface treatment agent may be used alone or in combination of two or more.

[0043] The average particle diameter of the particles is preferably 1 to 50 nm, more preferably 5 to 40 nm, from the viewpoint of uniform dispersibility in the composition. The average particle diameter can be measured as the average value of the particle diameters of 100 randomly selected particles by taking an electron micrograph of the particles. When the particles are non-spherical, the particle diameter is taken as the arithmetic mean of the longest and shortest lengths of the filler particles, and when the particles are agglomerated particles, the particle diameter of the primary particles is taken.

[0044] The shape of the particles is not particularly limited, and they can be used as powders of amorphous or spherical particles.

[0045] The content of the inorganic compound (C-3) can be minimized by the inclusion of the organic solvent (B). When the paste-like dental glass composition contains the inorganic compound (C-3), the content of the inorganic compound (C-3) is preferably 0.001 to 10% by mass, more preferably 0.005 to 5.0% by mass, still more preferably 0.01 to 1.0% by mass, and particularly preferably 0.05 to 0.4% by mass, based on the total amount of the paste-like dental glass composition. When the content is 0.001% by mass or more, a thickening effect is obtained, the paste is less likely to drip, and the operability is better. When the content is 10% by mass or less, the viscosity of the composition does not become too high, the paste properties are moderately soft, it is easier to apply and build up uniformly, and there is no risk of significant clouding after firing. Also, when the paste-like dental glass composition contains the inorganic compound (C-3), if it is blended in a large amount, there is a possibility that specific components (such as Si, Al, Ti, etc.) may affect the color tone, and the desired color tone may not be obtained. Therefore, the content of the inorganic compound (C-3) is preferably less than the content of the organic solvent (B) in the total amount of the paste-like dental glass composition.

[0046] The paste-like dental glass composition of the present invention may further contain other components (optional components) as long as the effects of the present invention are not impaired, in addition to the glass powder (A), the organic solvent (B), and the thickener (C). Examples of such other components include water, colorants, pH adjusters, polymerization accelerators, polymerization initiators, and the like. The colorant may be amorphous or crystalline. Further, the glass powder (A) may contain a crystalline powder as the colorant. Examples of the colorant include colorants that decolorize during firing. Examples of the colorant that decolorizes during firing include food dyes that dissolve in organic solvents. Examples of food dyes include organic dyes containing two or more aromatic groups such as Yellow No. 4 (tartrazine), Yellow No. 5 (sunset yellow FCF), Red No. 2 (amaranth), Red No. 102 (new coccine), Blue No. 1 (brilliant blue FCF), Blue No. 2 (indigocarmine), Green No. 3 (fast green FCF), and Red No. 102 (new coccine); organic dyes containing a condensed aromatic group having xanthene as a nucleus such as Acid Red 289, bromopyrogallol red, rhodamine B, rhodamine 6G, rhodamine 6GP, rhodamine 3GO, rhodamine 123, eosin, eosin B, eosin Y, fluorescein, and fluorescein isothiocyanate (xanthene-based dyes); cochineal dyes (carminic acid dyes); and betalain-based dyes such as beet red (main components: isobetanin and betanin), betanin, isobetanin, probetanin, and neobetanin. In one embodiment, there is provided a paste-like dental glass composition that contains the glass powder (A) and an organic solvent (B) having two or fewer hydroxyl groups in the molecule and a viscosity of 2500 mPa·s or less at 20°C, and substantially does not contain an organic compound having three or more hydroxyl groups in the molecule and a colorant that decolorizes during firing. Substantially not containing a colorant that decolorizes during firing means the same as described for the content of the organic solvent having three or more hydroxyl groups in the molecule. The content of the other components is not particularly limited, but is preferably 15.0% by mass or less, and more preferably 12.0% by mass or less.

[0047] The paste-like dental glass composition of the present invention can be used for producing dental prostheses such as inlays, onlays, laminated veneers, and crowns made of ceramics.

[0048] The frame for building up the paste-like dental glass composition of the present invention is not particularly limited, and examples include metal frames and ceramic frames (e.g., zirconia frames).

[0049] The use of the paste-like dental glass composition of the present invention is not particularly limited, and it can be used as body ceramics (dentine-colored ceramics), cervical ceramics, incisal ceramics (enamel-colored ceramics), translucent ceramics, opaque ceramics, stain ceramics, etc.

[0050] To produce a dental prosthesis, after building up the paste-like dental glass composition of the present invention, it is fired. The firing temperature (maximum firing temperature) can be appropriately changed according to the type of ceramics, usage form, etc., and is not particularly limited as long as the inorganic pigment can develop color, but 700°C or higher is preferable, 730°C or higher is more preferable, and 760°C or higher is even more preferable. The upper limit of the firing temperature is not particularly limited, but 1050°C or lower is preferable, 1000°C or lower is more preferable, and 980°C or lower is even more preferable. The heating rate during firing up to the maximum firing temperature can be appropriately changed according to the type of ceramics and is not particularly limited, but about 10 - 70°C / min is preferable, and about 20 - 60°C / min is more preferable. Also, before firing after building up the paste-like dental glass composition of the present invention, it may be dried, and the drying conditions are not particularly limited. Furthermore, the firing after building up the paste-like dental glass composition of the present invention may be vacuum firing performed under vacuum because the dental prosthesis obtained by significantly reducing the bubbles present inside the glass composition is more excellent in transparency and more excellent aesthetic properties can be obtained. The degree of vacuum in vacuum firing is not particularly limited and may be 750 mmHg or lower. The vacuum start temperature is not particularly limited and may be about 550 - 700°C.

[0051] As a suitable production method for the paste-like dental glass composition of the present invention, there can be mentioned a production method having a step of mixing glass powder (A) and an organic solvent (B). The mixing conditions are not particularly limited, and the components to be included may be charged all at once or dividedly. As the kneader for mixing, an ordinary kneader can be used. For example, a mortar, a twin-screw kneader (twin mix), a triple-screw kneader (tri mix), a kneader, a planetary mixer, etc. can be mentioned. Among these, it is preferable to use a mortar or a planetary mixer.

[0052] Since the paste-like dental glass composition of the present invention only needs to be in a paste form that can be tamped during use, for example, it can be provided as a dental ceramic material kit composed of a liquid component (first agent) containing an organic solvent (B) and a powder component (second agent) containing glass powder (A), and the user mixes the first agent and the second agent immediately before use to obtain a paste-like dental glass composition. In such a kit form, based on the above description, the types, contents, boiling points, etc. of each component (A) and (B) can be appropriately changed, and for any component, changes such as addition and deletion can be made.

[0053] As another embodiment of the present invention, there can be mentioned the use of a paste-like dental glass composition containing glass powder (A) and an organic solvent (B) for treating teeth (for example, aesthetic dental treatment, treatment of missing teeth, prosthetic restoration treatment such as artificial teeth, treatment of dental caries, etc.).

[0054] In any of the above-described embodiments, based on the above description, the types, contents, boiling points, etc. of each component can be appropriately changed, and for any component, changes such as addition and deletion can be made. Also, in any of the above-described embodiments, the composition and characteristic values of each paste-like dental glass composition can be appropriately changed and combined.

[0055] The present invention includes embodiments in which the above-described configurations are variously combined within the scope of the technical idea of the present invention as long as the effects of the present invention are achieved.

Examples

[0056] Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples, and many modifications are possible by those with ordinary knowledge in the art within the scope of the technical idea of the present invention.

[0057] Examples 1 to 27 and Comparative Examples 1 to 7 The paste-like dental glass compositions of each example and comparative example were prepared as follows, and their properties were evaluated. The results are shown in Tables 2 and 3.

[0058] [Preparation of Paste-Like Dental Glass Composition] For the glass powder (A), each raw material was mixed so as to have the components (unit: mass%) shown in Table 1, and the glass produced by heat treatment and cooling was pulverized to obtain glass powders (A-1), (A-2), (A-3), or Cerabian (registered trademark) ZR External Stain Red (manufactured by Kuraray Noritake Dental Co., Ltd.), a commercially available product, was used.

[0059] [Table 1]

[0060] Subsequently, the glass powder (A) and each component shown in Table 2 or Table 3 were mixed in a mortar at room temperature for about 10 minutes in the mass% shown in Table 2 or Table 3 to prepare a paste-like dental glass composition. The components used are as follows.

[0061] [Organic Solvent (B)] 3-Methyl-1,3-butanediol: manufactured by Kuraray Co., Ltd., boiling point: about 203°C, viscosity at 20°C: about 250 mPa·s 3-Methyl-1,5-pentanediol: manufactured by Kuraray Co., Ltd., boiling point: about 250°C, viscosity at 20°C: about 173 mPa·s 2,4-Diethyl-1,5-pentanediol: manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 264°C, viscosity at 20°C: about 1650 mPa·s 2-Ethyl-1,3-hexanediol: Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 244 °C, viscosity at 20 °C: about 271 mPa·s 1,3-Butanediol: Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 207 °C, viscosity at 20 °C: about 96 mPa·s 1,4-Butanediol: Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 235 °C, viscosity at 20 °C: about 85 mPa·s 1,5-Pentanediol: Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 239 °C, viscosity at 20 °C: about 128 mPa·s 1,2-Hexanediol: Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 222 °C, viscosity at 20 °C: about 87 mPa·s Polyethylene glycol (molecular weight 200): Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 250 °C (decomposes at 220 °C), viscosity at 20 °C: about 65 mPa·s Ethylene glycol monobenzyl ether: Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 244 °C, viscosity at 20 °C: about 41 mPa·s Ethylene glycol monophenyl ether: Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 244 °C, viscosity at 20 °C: about 29 mPa·s Triethylene glycol monomethyl ether: Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 248 °C, viscosity at 20 °C: about 8 mPa·s

[0062] [Thickener (C)] Bis-GMA: Sigma-Aldrich Japan, viscosity at 20 °C: about 100000 mPa·s 12-Hydroxystearic acid: Manufactured by Tokyo Chemical Industry Co., Ltd., white solid Aerosil (registered trademark) R976S: Manufactured by Nippon Aerosil Co., Ltd., hydrophobic fine particle silica, white powder Aerosil (registered trademark) 300: Manufactured by Nippon Aerosil Co., Ltd., hydrophilic fine particle silica, white powder

[0063] [Organic solvents other than organic solvent (B)] Glycerin: Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 290 °C, viscosity at 20 °C: about 1412 mPa·s 1,2,4 - Butanetriol: Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 312 °C 1,2,3 - Butanetriol: Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 305 °C 1,2,6 - Hexanetriol: Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point: about 345 °C, viscosity at 20 °C: 2460 mPa·s

[0064] [Thickener other than thickener (C)] Xanthan gum: Manufactured by Tokyo Chemical Industry Co., Ltd., light yellow solid Methyl cellulose: Manufactured by Tokyo Chemical Industry Co., Ltd., white solid

[0065] [Others] Purified water: Manufactured by Ken-ei Pharmaceutical Co., Ltd., boiling point: about 100 °C, viscosity at 20 °C: about 1 mPa·s

[0066] (1) Method for measuring glass transition temperature and softening point of glass powder (A) In accordance with JIS T 6526:2018, using a thermomechanical analyzer TMA8311 (manufactured by Rigaku Corporation, heating rate 10 °C / min, measured by the compression load method), the values were obtained from the measured thermo - expansion curve (n = 3). The average values were taken as the glass transition temperature and the softening point.

[0067] (2) Method for measuring viscosity of paste The viscosity of the prepared paste - like dental glass composition was measured at room temperature under the condition of 20 rpm using a B - type viscometer (Brookfield viscometer), and the average value was calculated (n = 3). The viscosity of the paste is preferably 2000 - 80000 mPa·s, more preferably 3500 - 65000 mPa·s, still more preferably 5000 - 55000 mPa·s, and particularly preferably 7000 - 45000 mPa·s.

[0068] (3) Method for measuring sagging property of paste After placing 500 ± 10 mg of the prepared paste-like dental glass composition on a glass plate, it was tilted vertically, and the distance (mm) that the paste moved after 90 seconds was measured, and the average value was calculated (n = 3). As for the sagging property of the paste, 80 mm or less is preferable, 40 mm or less is more preferable, 10 mm or less is further preferable, and 5 mm or less is particularly preferable.

[0069] (4) Method for evaluating discoloration after firing and evaluating appearance after firing The prepared paste-like dental glass composition was placed on a zirconia plate measuring 10 mm in length and 35 mm in width, and then fired under the firing conditions described in Tables 2 and 3 to obtain a sintered body. Regarding the discoloration of the obtained sintered body, the color was visually confirmed (n = 3). When none of the sintered body samples were discolored (such as black discoloration or gray discoloration), it was evaluated as "〇", and when even one was discolored, it was evaluated as "△". In addition, the appearance of the obtained sintered body was evaluated according to the following evaluation criteria (n = 3). For example, when all the sintered body samples met the "〇" criteria, it was evaluated as "〇", and when there was even one "△" sample, it was evaluated as "△". <Evaluation criteria> ○: There is a sense of transparency and it has been fired sufficiently, or in the case of pigment blending, the color has developed sufficiently. △: A slight decrease in the sense of transparency can be seen, or in the case of pigment blending, the color development is slightly small. ×: There is no sense of transparency and it has not been fired, or in the case of pigment blending, the color has not developed.

[0070] As a result, in Comparative Examples 1 to 5 containing an organic solvent having 3 or more hydroxyl groups in the molecule, and Comparative Examples 6 and 7 containing a thickener having 3 or more hydroxyl groups in the molecule, black or gray discoloration due to organic matter was visually observed after firing, whereas in Examples 1 to 27, no discoloration was observed. In addition, in Examples 1 to 27, the sagging of the paste was suppressed, and since it was a paste with a preferable viscosity, it was confirmed that the operability in the placing operation was good.

[0071]

Table 2

[0072]

Table 3

Industrial Applicability

[0073] The paste-like dental glass composition of the present invention suppresses the sagging of the paste and has good workability, so that the building-up operation becomes easy. In particular, as the demand for ceramic crowns is increasing more and more and individual aesthetic requirements are rising, the use frequency of dental ceramic materials is expected to increase. Therefore, the paste-like dental glass composition of the present invention is useful.

Claims

1. A paste-like dental glass composition for firing, comprising glass powder (A) and an organic solvent (B) having two or less hydroxyl groups in the molecule and a viscosity at 20°C of 2500 mPa·s or less, wherein the organic solvent (B) is a divalent alcohol compound having a branched chain with 5 to 12 carbon atoms and / or a monovalent alcohol compound having a phenyl group with 8 to 14 carbon atoms, and substantially free of an organic compound having three or more hydroxyl groups in the molecule.

2. Further comprising a thickening agent (C), wherein the thickening agent (C) comprises at least one selected from the group consisting of an organic compound (C-1) having a viscosity at 20°C greater than 2500 mPa·s, an organic compound (C-2) that is solid at normal temperature, and an inorganic compound (C-3), the paste-like dental glass composition for firing according to Claim 1.

3. The paste-like dental glass composition for firing according to Claim 1 or 2, wherein the organic solvent (B) is a divalent alcohol compound.

4. The paste-like dental glass composition for firing according to Claim 1 or 2, wherein the monovalent alcohol compound having a phenyl group with 8 to 14 carbon atoms comprises at least one selected from the group consisting of ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, 3-(benzyloxy)-1-propanol, 2-(benzyloxy)-1-butanol, and 5-(benzyloxy)-1-pentanol.

5. The paste-like dental glass composition for firing according to Claim 1 or 2, wherein the divalent alcohol compound having a branched chain with 5 to 12 carbon atoms comprises at least one selected from the group consisting of 2-methyl-1,4-butanediol, 3-methyl-1,3-butanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and 2-ethyl-1,3-hexanediol.

6. The paste-like dental glass composition for firing according to Claim 1 or 2, wherein the boiling point of the organic solvent (B) is 100 to 350°C.

7. The paste-like dental glass composition for firing according to Claim 1 or 2, wherein the viscosity of the organic solvent (B) at 20°C is 20 mPa·s or more.

8. The paste-like dental glass composition for firing according to claim 1 or 2, wherein the glass transition temperature of the glass powder (A) is 400 to 600°C.

9. The paste-like dental glass composition for firing according to claim 1 or 2, wherein the softening point of the glass powder (A) is 500 to 680°C.

10. A method for manufacturing a dental prosthesis, comprising a step of firing the paste-like dental glass composition for firing according to claim 1 or 2 at 700 to 1050°C.

11. A step of mixing a glass powder (A) and an organic solvent (B) having two or less hydroxyl groups in the molecule and having a viscosity of 2500 mPa·s or less at 20°C is included. The organic solvent (B) is a divalent alcohol compound having a branched chain with 5 to 12 carbon atoms and / or a monovalent alcohol compound having a phenyl group with 8 to 14 carbon atoms. A method for manufacturing a paste-like dental glass composition for firing according to claim 1 or 2, which substantially does not contain an organic compound having three or more hydroxyl groups in the molecule.

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