Dental ceramic coloring solution

Abstract

The present invention provides a dental ceramic coloring solution which makes it possible to suppress a decline in the strength of a dental ceramic, and to impart a pink color thereto which is required for a dental application. The present invention pertains to a coloring solution for coloring a dental ceramic, said coloring solution containing a coloring component and a solvent, wherein the coloring component contains an Er component and a Co component.

Description

[Technical Field]

[0001] The present invention relates to a dental ceramic coloring solution, and more particularly to a dental ceramic coloring solution suitable for use in producing dental prostheses such as inlays, onlays, veneers, crowns, bridges, abutments, dental posts, dentures, denture bases, and implant components (fixtures and abutments) machined using a dental CAD / CAM system. [Background technology]

[0002] Traditionally, metals have been commonly used for dental products (e.g., dental prostheses such as typical veneers, dental crowns, crowns, and dental implants, as well as orthodontic products and dental implant products). However, metals have the drawback of being clearly different in color from natural teeth, lacking aesthetic appeal, and can also cause allergies due to metal elution. Therefore, to solve the problems associated with the use of metals, ceramic materials such as aluminum oxide (alumina) and zirconium oxide (zirconia) have been used in dental products as alternatives to metals. Zirconia, in particular, is strong and relatively aesthetically pleasing, and demand for it has been increasing, especially as prices have fallen in recent years.

[0003] In recent years, CAD / CAM systems have become widespread, in which the final shape of a dental prosthesis or a large implant prosthesis is designed by computer and then cut using a milling machine. Zirconia is commonly used as the material for the mill blanks, the cutting material used in CAD / CAM systems, due to the emphasis on aesthetics. In particular, zirconia, which has different colors arranged vertically in the thickness direction to reproduce natural tooth color and meet aesthetic requirements, has recently become popular. For colors that are difficult to reproduce, high aesthetic requirements have been met by further coating and coloring dental porcelain on the ceramic surface machined to the shape of the dental prosthesis.

[0004] However, the technique of coating and coloring dental porcelain requires specialized knowledge and excellent skills. Specifically, coloring with dental porcelain requires the reproduction of the precise shape and structure of natural teeth by building up the dental porcelain, as well as the development of highly aesthetic colors, which requires a high level of skill.

[0005] Therefore, in order to avoid the problems that arise from the use of dental porcelain, a commonly used method for coloring dental prostheses is to apply a coloring solution to dental ceramics to color them, thereby giving them a more aesthetic appearance, instead of using dental porcelain, which requires skill.

[0006] For example, Patent Document 1 discloses a coloring solution for coloring dental ceramic articles, which contains a rare earth element metal or ion and a transition metal or ion as coloring agents, and lists erbium as one of the rare earth elements. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2010-534245 Summary of the Invention [Problem to be solved by the invention]

[0008] On the other hand, dental ceramics may be required to be colored pink. Examples of dental materials that require a pink color include prostheses that include the gingival area. Examples of prostheses that include the gingival area include those used in subgingival areas of implant superstructures and large dental prostheses called ALL-ON-4 (a procedure in which four implants are implanted into the bone in a balanced manner), which reproduce the gingival area with a prosthesis. When the coloring solution of Patent Document 1 is used as a zirconia coloring solution for such applications, a large amount of erbium, such as approximately 15% by mass, is required to achieve the required pink color. However, because erbium also functions as a stabilizer for zirconia, the large amount of erbium contained in the coloring solution can lead to a decrease in the physical properties of zirconia, such as strength. Therefore, in dental applications requiring a pink color, dental ceramics have not been able to achieve both pink coloring and strength.

[0009] Therefore, an object of the present invention is to provide a dental ceramics coloring solution that can prevent a decrease in the strength of dental ceramics and can impart the pink color required for dental use. [Means for solving the problem]

[0010] As a result of extensive research to solve the above problems, the present inventors discovered that by incorporating a Co component in addition to an Er component, a colored solution can be obtained that can exhibit the pink color tone required for dental applications even with a reduced Er component content, and after further investigation, they have completed the present invention.

[0011] That is, the present invention includes the following inventions. [1] A coloring component and a solvent are included, A coloring solution for coloring dental ceramics, wherein the coloring component comprises an Er component and a Co component. [2] Regarding the L*a*b* color system (L*, a*, b*) of dental ceramics after coloring and sintering, a* is 4.5 to 15.0, The coloring solution according to [1], wherein b* is −5.0 to 10. [3] The coloring solution according to [1] or [2], wherein L* is 65 to 95 in (L*, a*, b*) according to the L*a*b* color system. [4] The coloring solution according to any one of [1] to [3], wherein the coloring component further contains an Al component. [5] The coloring solution according to any one of [1] to [4], wherein the Er component is an ion or a complex. [6] The coloring solution according to any one of [1] to [5], wherein the Er component is a component derived from at least one selected from the group consisting of erbium chloride hydrate, erbium perchlorate hydrate, erbium nitrate hydrate, erbium oxalate hydrate, and erbium acetate hydrate. [7] The coloring solution according to any one of [1] to [6], wherein the Co component is an ion or a complex. [8] The coloring solution according to any one of [1] to [6], wherein the Co component is a component derived from at least one selected from the group consisting of cobalt(II) chloride hydrate, cobalt(II) perchlorate hydrate, cobalt(II) fluoride hydrate, cobalt(II) nitrate hydrate, cobalt(II) oxalate hydrate, and cobalt(II) acetate hydrate. [9] The coloring solution according to any one of [1] to [8], wherein the content of the Er component is 110 to 310 mmol / L in terms of Er ions.

[10] The coloring solution according to any one of [1] to [9], wherein the content of the Co component is 0.0340 to 1.70 mmol / L in terms of Co ions.

[11] The coloring solution according to any one of [1] to

[10] , wherein the solvent contains water and / or an organic solvent.

[12] The coloring solution according to

[11] , wherein the organic solvent contains at least one selected from the group consisting of alcohols, glycols, triols, and ketones.

[13] The coloring solution according to any one of [1] to

[12] , wherein the dental ceramic contains zirconia as a main component.

[14] The coloring solution according to

[13] , wherein the dental ceramics further contains yttria.

[15] The coloring solution according to

[14] , wherein the content of yttria is 1.5 to 10 mol% based on the total mol of zirconia and yttria.

[16] Dental ceramics having an Er component and a Co component supported on the surface.

[17] The dental ceramics according to

[16] , wherein an Al component is further supported on the surface.

[18] The dental ceramics according to

[16] or

[17] , wherein the Er component is an ion or a complex.

[19] The dental ceramics according to any one of

[16] to

[18] , wherein the Co component is an ion or a complex.

[20] The dental ceramics according to any one of

[16] to

[19] , wherein the dental ceramics contains zirconia as a main component.

[21] The dental ceramics according to

[20] , wherein the dental ceramics further contains yttria.

[22] The dental ceramics according to

[21] , wherein the content of yttria is 1.5 to 10 mol% based on the total mol of zirconia and yttria. [Effect of the Invention]

[0012] According to the present invention, it is possible to provide a coloring solution for dental ceramics that can suppress a decrease in the strength of dental ceramics and can impart a pink color tone required for dental applications. [Embodiments for Carrying Out the Invention] [[ID=CO]]

[0013] The present invention is a coloring solution for coloring dental ceramics, which includes a coloring component and a solvent, and the coloring component includes an Er component and a Co component.

[0014] <Er component> First, the Er component included in the coloring component of the present invention will be described. The Er component includes an ion or a complex of Er and is contained to color zirconia pink.

[0015] The Er ion or complex may be added to the coloring solution as a salt containing Er cations and anions, or as a complex containing Er and its ligands. Examples of the anions or ligands include OAc. - , NO3 - , NO2 - , CO3 2- , HCO3 - , ONC - , SCN - , SO4 2- , SO3 2- , glutarate, lactate, gluconate, propionate, butyrate, glucuronate, benzoate, phenolate, halogen anions (fluoride, chloride, bromide), acetate, etc. Ac means an acetyl group.

[0016] Specific examples of compounds that can be added to the coloring solution of the present invention to incorporate the above ions or complexes include trivalent erbium compounds such as tris(acetylacetonato)erbium hydrate, erbium chloride hydrate (erbium chloride hexahydrate), erbium perchlorate hydrate, erbium acetate hydrate (erbium acetate tetrahydrate), erbium oxide, erbium oxalate hydrate, erbium nitrate hydrate, erbium stearate, erbium fluoride, erbium tetraborate, erbium iodide hydrate, erbium sulfide, and erbium sulfate hydrate. Among these, erbium chloride hydrate, erbium perchlorate hydrate, erbium nitrate hydrate, erbium oxalate hydrate, and erbium acetate hydrate are preferred from the viewpoints of solubility and color development. The Er component can be used alone or in combination of two or more.

[0017] As the content of the Er component in the coloring solution, it is preferably 110 to 310 mmol / L as Er ions in the whole solution, more preferably 120 to 300 mmol / L, and even more preferably 130 to 290 mmol / L. When the content is less than 110 mmol / L, the pink color development may be insufficient, and there is a risk that the high aesthetic requirements cannot be met. When the content exceeds 310 mmol / L, the Er component functions as a stabilizer for zirconia, and there is a risk that the physical properties such as the strength of zirconia may decrease. The content of the Er component can be measured, for example, by inductively coupled plasma (ICP) emission spectroscopic analysis, fluorescent X-ray analysis, etc. In addition, the content of the metal component in this specification can be measured by this method.

[0018] <Co component> Next, the Co component contained in the coloring solution of the present invention will be described. The Co component contains Co ions or complexes and is contained for coloring in a pink color without deteriorating the physical properties such as the strength of zirconia.

[0019] By applying a dental ceramic coloring solution containing the Co component, the reason why the desired pink color tone can be imparted without reducing the strength of the dental ceramics is not clear, but the present inventors presume as follows. That is, when the dental ceramics are zirconia, by adding Co ions with a valence smaller than that of Zr ions, oxygen ion vacancies are introduced into the zirconia crystal structure, and the substantial ionic radius of O ions decreases, which increases the radius ratio between O ions and Zr ions and brings about the stabilization of the fluorite structure. Therefore, it is presumed that the decrease in the strength of zirconia is suppressed. 4+ ions, oxygen ion vacancies are introduced into the zirconia crystal structure, and the substantial ionic radius of O 2+ ions decreases, which increases the radius ratio between O 2- ions and Zr 2- ions, resulting in the stabilization of the fluorite structure, and it is presumed that the decrease in the strength of zirconia is suppressed. 4+ ions and brings about the stabilization of the fluorite structure, so it is presumed that the decrease in the strength of zirconia is suppressed.

[0020] Co ions or complexes may be added to the coloring solution as salts containing Co cations and anions, or as complexes containing Co and its ligands. Examples of the anions or ligands include OAc. - , NO3 - , NO2 - , CO3 2- , HCO3 - , ONC - , SCN - , SO4 2- , SO3 2- , glutarate, lactate, gluconate, propionate, butyrate, glucuronate, benzoate, phenolate, halogen anions (fluoride, chloride, bromide), acetate, etc.

[0021] Specific examples of compounds that can be added to the coloring solution of the present invention to incorporate the above ions or complexes include bis(acetylacetonato)diaquacobalt(II), tris(acetylacetonato)cobalt(III), cobalt(II) amidosulfate hydrate, cobalt(II) benzoate, cis-tetraamminedichlorocobalt(III) chloride, pentaamminechlorocobalt(III) chloride, hexaamminecobalt(III) chloride, hexaamminecobalt(III) nitrate, ammonium diamminetetranitrocobaltate(III), triamminedichlorocobalt(III), bis(acetylacetonato)diaquacobalt(II), tris(acetylacetonato)diaquacobalt(III ... Amminetrinitrocobalt(III), tetraamminedinitrocobalt(III) chloride, potassium diamminetetranitrocobaltate(III), cobalt(II) chloride hydrate (e.g., cobalt(II) chloride hexahydrate), cobalt(II) chloride, cobalt(III) chloride, cobalt(II) octanoate, cobalt(II) oleate, cobalt(II) perchlorate hydrate (cobalt(II) perchlorate hexahydrate), cobalt(II) fluoride hydrate (cobalt(II) fluoride dihydrate, cobalt(II) fluoride trihydrate, cobalt(II) fluoride tetrahydrate), octacarbonyl nicobalt (Co2(CO)8), cobalt(II) formate hydrate, cobalt(II) citrate hydrate, cobalt disilicide, cobalt(II) acetate, cobalt(II) acetate hydrate (cobalt(II) acetate tetrahydrate), cobalt(II) oxide, cobalt(III) oxide, tricobalt tetroxide (Co3(CO)4), potassium hexacyanocobaltate(III), cobalt(II) bromide, cobalt(II) bromide hydrate, cobalt(II) oxalate hydrate (e.g., cobalt(II) oxalate dihydrate, cobalt(I I) tetrahydrate, etc.), cobalt resinate, cobalt(II) nitrate hydrate (cobalt(II) nitrate trihydrate, cobalt(II) nitrate hexahydrate), cobalt(II) metazirconate, cobalt(II) hydroxide, cobalt(III) hydroxide, cobalt(II) stearate, cobalt(II) selenate, cobalt(II) selenate hexahydrate, cobalt(II) tungstate tetrahydrate, cobalt(II) hydroxide carbonate, ammonium tetrakis(thiocyanato)cobaltate(II) hydrate, cobalt(II) thiocyanate, cobalt(II) metatitanate,Examples of suitable Cobalt compounds include potassium hexanitrocobaltate(III), sodium hexanitrocobaltate(III), hexaamminecobalt(III) sulfate, cobalt boride, cobalt(II) molybdate hydrate, cobalt(II) iodide hydrate, cobalt(II) laurate, cobalt(II) sulfide, cobalt(II) sulfate hydrate, cobalt(II) phosphide, and cobalt(II) phosphate hydrate. Among these, cobalt(II) chloride hydrate, cobalt(II) perchlorate hydrate, cobalt(II) fluoride hydrate, cobalt(II) nitrate hydrate, cobalt(II) oxalate hydrate, and cobalt(II) acetate hydrate are preferred from the viewpoints of solubility and color development. These Co components can be used alone or in combination of two or more.

[0022] The content of the Co component in the coloring solution is preferably 0.0340 to 1.70 mmol / L, more preferably 0.0380 to 1.50 mmol / L, and even more preferably 0.0420 to 1.30 mmol / L, as Co ions in the entire solution. If the content is less than 0.0340 mmol / L, the Er component must be contained in excess of 310 mmol / L to achieve pink coloring, which may reduce the physical properties of zirconia, such as its strength. If the content exceeds 1.70 mmol / L, the blue tinge increases, making it impossible to achieve pink coloring.

[0023] The coloring solution of the present invention preferably further contains an Al component. The Al component contains Al ions or complexes, which can increase the reddish color and may also improve the strength of zirconia.

[0024] Although the reason why the application of a dental ceramic coloring solution containing an Al component increases the reddish color and improves the strength of zirconia is unclear, the inventors speculate as follows: The increase in reddish color is believed to be due to the presence of the Al corundum crystal structure and the Co component, which produces a reddish purple color and increases the overall reddish color. Furthermore, the improvement in zirconia strength is believed to be due to the dispersion of the Al component between zirconia crystals, which increases the specific surface area of ​​the intercrystalline bonds and improves the intercrystalline bonding strength, and this bonding strength is responsible for the high toughness inherent to the Al component.

[0025] The Al ions or complexes may be added to the coloring solution as salts containing Al cations and anions, or as complexes containing Al and its ligands, such as OAc - , NO3 - , NO2 - , CO3 2- , HCO3 - , ONC - , SCN - , SO4 2- , SO3 2- , glutarate, lactate, gluconate, propionate, butyrate, glucuronate, benzoate, phenolate, halogen anions (fluoride, chloride, bromide), acetate, etc.

[0026] Specific examples of compounds that can be added to the coloring solution of the present invention to incorporate the above ions or complexes include aluminum ethoxide, aluminum butoxide, aluminum propoxide, barium aluminate, magnesium aluminate, lithium aluminate, aluminum benzoate, aluminum chloride hydrate (aluminum chloride hexahydrate), aluminum oleate, aluminum perchlorate hydrate (aluminum perchlorate trihydrate, aluminum perchlorate hexahydrate, etc.), aluminum citrate hydrate (aluminum citrate monohydrate), aluminum gluconate, and lithium tetrachloroaluminate. Examples of aluminum components include aluminum, lithium aluminum tetrachloride, aluminum oxide, aluminum selenate hydrate, aluminum oxalate hydrate, aluminum tartrate hydrate, aluminum metazirconate, aluminum hydroxide octanoate, aluminum stearate, aluminum titanate, aluminum lactate, aluminum palmitate, lithium aluminum tetrahydride, lithium aluminum tetrahydride, aluminum iodide, aluminum laurate, aluminum butyrate, aluminum nitrate hydrate (aluminum nitrate nonahydrate, etc.), aluminum sulfide, and cesium aluminum sulfate hydrate. Among these, aluminum chloride hydrate, aluminum perchlorate hydrate, aluminum oxalate hydrate, and aluminum nitrate hydrate are preferred from the viewpoint of solubility. These aluminum components can be used alone or in appropriate combinations of two or more.

[0027] The content of the Al component in the coloring solution is preferably 0.100 to 40.0 mmol / L of the entire solution, more preferably 0.200 to 30.0 mmol / L, and even more preferably 0.400 to 25.0 mmol / L. If the blending amount is less than 0.100 mmol / L, there is a risk that a sufficient reddish hue cannot be obtained or that the effect of improving the strength of zirconia cannot be obtained, while if the blending amount exceeds 40.0 mmol / L, there is a risk that the aesthetics will be reduced.

[0028] The coloring solution of the present invention may contain other metal components as long as the effects of the present invention are not impaired. For example, if the coloring solution contains a Zr component, the strength of the zirconia to which the coloring solution is applied may be improved.

[0029] The Zr component includes Zr ions or complexes. The Zr ions or complexes may be added to the coloring solution as a salt containing Zr cations and anions, or as a complex containing Zr and its ligands. The anions or ligands include, for example, OAc. - , NO3 - , NO2 - , CO3 2- , HCO3 - , ONC - , SCN - , SO4 2- , SO3 2- , glutarate, lactate, gluconate, propionate, butyrate, glucuronate, benzoate, phenolate, halogen anions (fluoride, chloride, bromide), acetate, etc.

[0030] Specific examples of compounds that can be added to the coloring solution of the present invention to incorporate the above ions or complexes include zirconium chloride hydrate (IV), zirconium sulfide (IV), tetrakis(acetylacetonato)zirconium (IV), zirconium chloride (IV), zirconium octanoate (IV), zirconium oxide oleate (IV), dichlorobis(η5-cyclopentadienyl)zirconium (IV), zirconium oxide acetate (IV), zirconium oxide (IV) hydrate, zirconium oxide stearate (IV), zirconium oxide nitrate (IV) hydrate, zirconium (IV) n-butoxide, zirconium carbide, dizirconium trioxide carbonate (IV) hydrate (ZrOCO3·ZrO2·nH2O), ammonium hexafluorozirconate (IV), zirconium iodide (IV), zirconium oxide laurate (IV) (Zr(C 11 H 23COO)2O), zirconium(IV) sulfate hydrate, zirconium(IV) dihydrogen phosphate oxide, etc. Among these, zirconium chloride oxide hydrate(IV), zirconium chloride(IV), zirconium acetate oxide(IV), zirconium oxide(IV) hydrate, zirconium nitrate oxide hydrate are preferred, with zirconium chloride oxide hydrate(IV) being more preferred, from the viewpoint of further improving the strength of dental ceramics. The Zr component can be used alone or in appropriate combination of two or more.

[0031] The content of the Zr component in the coloring solution is preferably 0.0650 to 0.900 mol / L in the entire solution, more preferably 0.0800 to 0.850 mol / L, and even more preferably 0.0900 to 0.800 mol / L, from the viewpoint of improving the strength of dental ceramics. When the content is 0.0650 mol / L or more, the effect of improving the strength of dental ceramics can be obtained, and when it is 0.900 mol / L or less, the strength can be improved without deteriorating the aesthetics of the dental ceramics.

[0032] The coloring solution of the present invention preferably contains water and / or an organic solvent as a solvent. The water and / or organic solvent dissolves the coloring component and Zr component, improving the permeability of the coloring solution into dental ceramics. The content of the solvent in the coloring solution is preferably 45 to 99 mass%, more preferably 60 to 98.5 mass%, and even more preferably 75 to 98 mass%.

[0033] The water used must be substantially free of impurities that adversely affect the effects of the present invention, and purified water, distilled water, ion-exchanged water, or pure water is preferred. The water content in the coloring solution is preferably 45 to 99% by mass, more preferably 60 to 98.5% by mass, and even more preferably 75 to 98% by mass.

[0034] The organic solvent may be any solvent capable of dissolving the cation, and is preferably a mixture selected from alcohols, glycols, triols, ketones, and combinations thereof. Specific examples include 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, ethylene glycol monobenzyl ether, and propylene glycol. alcohols such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobenzyl ether, propylene glycol monopropyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, benzyl alcohol, 2-(benzyloxy)ethanol, 3-(benzyloxy)-1-propanol, 2-(benzyloxy)-1-butanol, and 5-(benzyloxy)-1-pentanol;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 200-600), propylene glycol, dipropylene glycol, polypropylene glycol, 1-methyl-1,3-propanediol Examples of suitable organic solvents include diols such as 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; triols such as glycerin, 1,2,4-butanetriol, 1,2,3-butanetriol, and 1,2,6-hexanetriol; and ketones such as acetone, 2-butanone, 2-pentanone, isobutyl ketone, diisobutyl ketone, and cyclohexanone. These organic solvents can be used alone or in combination of two or more. The organic solvent may also be used as a thickener, as described below, to adjust the viscosity.

[0035] The content of the organic solvent in the coloring solution is preferably 45 to 99 mass %, more preferably 60 to 98.5 mass %, and even more preferably 75 to 98 mass %.

[0036] The coloring solution may contain a complexing agent to the extent that the effect of the present invention is not impaired. Adding a complexing agent may be beneficial for improving the storage stability of the coloring solution, accelerating the dissolution process of salts added to the coloring solution, and / or increasing the amount of salts that can be dissolved in the coloring solution.

[0037] The complexing agent is generally capable of forming a complex with the metal ions present in the coloring solution. The formed complex must be soluble in the solvent. For example, the complexing agent can be used in at least a stoichiometric ratio with respect to the molar amount of the ions contained in the coloring solution, and good results can be obtained if the molar ratio of the complexing agent to the cations in the coloring solution is about 1, or about 2, or about 3 or more.

[0038] Examples of the complexing agent include N,N-di(2-hydroxyethyl)glycine, acetylacetonate, crown ether, cryptand, ethylenediamine triacetate and its salts, ethylenediaminetetraacetate and its salts, nitrilotriacetate and its salts, citric acid and its salts, triethylenetetraamine, porphine, polyacrylate, polyasparagine, acidic peptide, phthalocyanine, salicylate, glycinate, lactate, propylenediamine, ascorbate, oxalic acid and its salts, and mixtures thereof. The complexing agent can be used alone or in appropriate combination of two or more.

[0039] The content of the complexing agent in the coloring solution is not particularly limited as long as the effects of the present invention are achieved. For example, it is preferable to contain an amount sufficient to dissolve the cations in the solution or prevent precipitation of these cations. Specifically, the content in the coloring solution is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.10% by mass or more. There is no specific upper limit to the content, but it is preferably 50% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less. If the amount of complexing agent used is too small, it may not dissolve completely, and if the amount of complexing agent used is too large, excess complexing agent itself may remain undissolved.

[0040] The pH of the coloring solution of the present invention is preferably 0 to 9, more preferably 1 to 7, and even more preferably 2 to 6. If the pH is outside the above range, cations may begin to precipitate from the solution. For example, when the coloring solution is an aqueous solution, the pH is preferably 0 to 9. Furthermore, when the coloring solution does not contain a complexing agent, the pH is preferably 0 to 6, and when it contains a complexing agent, the pH is preferably 3 to 9. The pH can be measured using a commercially available pH meter (for example, the compact pH meter LAQUA twin manufactured by Horiba, Ltd.).

[0041] The coloring solution of the present invention preferably has an appropriate viscosity so that the required amount of solution can be applied to the ceramic surface and can also migrate into the pores of an unsintered ceramic body (also referred to herein as a "molded body") or a calcined ceramic body. The appropriate viscosity at 20°C is, for example, preferably 0.1 to 10,000 mPa, more preferably 0.5 to 6,000 mPa, and even more preferably 1 to 3,000 mPa. If the viscosity is too high, the coloring solution may not be able to be absorbed into the pores of the unsintered ceramic body or the calcined ceramic body. The method for measuring viscosity is not particularly limited, but it can be measured at 25°C using a Brookfield viscometer.

[0042] The colored solution of the present invention may contain a thickener to give it an appropriate viscosity, provided that the effect of the present invention is not impaired.

[0043] The thickener may be selected from the organic solvents described above to adjust the viscosity, or may be selected from the thickeners described below. Examples of thickeners other than the organic solvents described above include polysaccharide compounds such as methylcellulose, carboxycellulose, hydroxyethylcellulose, xanthan gum, guar gum, carrageenan, tamarind seed gum, and pectin; sugar alcohol compounds such as sorbitol, erythritol, xylitol, and trehalose; synthetic polyol compounds such as diglycerin, triglycerin, polyglycerin, and polyvinyl alcohol; and solid organic compounds such as sodium polyacrylate, ammonium polyacrylate, polyethylene oxide, polyethylene glycol (molecular weight 1000 or more), polyvinylpyrrolidone, calcium stearate, magnesium stearate, zinc stearate, aluminum stearate, polyethylene glycol monostearate, 12-hydroxystearic acid, stearamide, oleamide, and ethylenebisoleamide. These thickeners can be used alone or in appropriate combinations of two or more.

[0044] The content of the thickener in the colored solution of the present invention is preferably 0.01 to 10% by mass, more preferably 0.02 to 8% by mass, and even more preferably 0.05 to 5% by mass.

[0045] The coloring solution of the present invention may contain other additives as long as they do not impair the effects of the present invention.

[0046] Examples of the additives include stabilizers (e.g., methoxyphenol, hydroquinone, topanol A (2,4-dimethyl-6-tert-butylphenol), and mixtures thereof (excluding stabilizers capable of suppressing the phase transition of zirconia)), buffers (e.g., acetates, amino buffers, and mixtures thereof), preservatives (e.g., sorbic acid, benzoic acid, and mixtures thereof), and mixtures thereof. One type of additive may be used alone, or two or more types may be used in combination.

[0047] The content of the additive in the colored solution of the present invention can be, for example, 0.01 to 10% by mass, or may be 0.05 to 5% by mass, or may be 0.1 to 3% by mass.

[0048] The coloring solution of the present invention may contain, as its coloring component, a colorant that is decolorized after calcination of zirconia. The colorant that is decolorized after calcination of zirconia is not limited as long as it is decolorized after calcination of zirconia and satisfies the color difference before and after calcination, and examples thereof include organic dyes.

[0049] The organic dye is not particularly limited as long as it has a chromophore and is soluble in the coloring solution. However, aromatic organic dyes, i.e., organic dyes containing one or more optionally substituted aromatic groups, are preferred, and aromatic organic dyes having an auxochrome in addition to a chromophore are more preferred. 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, and examples of the chromophore 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 organic dye may contain one of these atomic groups alone or in combination with two or more of them. Examples of the auxochrome include a hydroxyl group, an amino group, a carboxyl group, a sulfone group, and a halogen atom. The organic dye may contain one of these auxochromes alone or in combination with two or more of them.

[0050] Furthermore, since colorants that are harmful or toxic to humans cannot be used as colorants to be decolorized after firing of zirconia, food colorants are preferred as the organic colorants, and food colorants that dissolve in the coloring solution are more preferred. Examples of such food colorants include organic colorants 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 (indigo carmine), Green No. 3 (Fast Green FCF), and Red No. 102 (New Coccine); Acid Red 289, Bromopyrogallol Red, Rhodamine B, Rhodamine 6G, Rhodamine 6GP, Rhodamine 3GO, Rhodamine 123, Eosin (Eosin B, Eosin Y), Fluorescein, and Fluorescein Isothiocyanate. Examples of suitable organic dyes include organic dyes containing a condensed aromatic group with a xanthene nucleus (xanthene dyes); cochineal dyes (carminic acid dyes); beet red (main components: isobetanin and betanin), betanin, isobetanin, probetanin, neobetanin, and other betalain dyes. Preferred are organic dyes containing two or more aromatic groups and having a ketimide group or an azo group as a chromophore, 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), Green No. 3 (Fast Green FCF), and isobetanin. Furthermore, the colorant (A) can be changed depending on the content of the stabilizer for the zirconia calcined body to which the coloring solution of the present invention is applied. In a preferred embodiment, the colorant (A) is an organic dye containing two or more aromatic groups, a ketimide group or an azo group as a chromophore, and a sulfone group as an auxochrome. In this specification, the term "aromatic group" includes aromatic groups whose ring structure is composed only of carbon atoms and heteroaromatic groups whose ring structure contains an element other than carbon (oxygen, nitrogen, etc.). Colorants that decolorize after firing of zirconia can be used alone or in appropriate combinations of two or more.Furthermore, the coloring intensity of the colorant that is decolorized after calcining zirconia varies depending on the pH of the coloring solution, and the compound structure may differ depending on the pH. However, as long as the effects of the present invention are achieved, the pH of the coloring solution for zirconia is not particularly limited, and a pH that shows an appropriate coloring intensity can be adopted and used depending on the type of colorant that is decolorized after calcining zirconia.

[0051] The content of the colorant that is decolorized after firing the zirconia is not particularly limited as long as the liquid components can develop color, but is preferably 0.009 to 3.0 mass% relative to the total mass of the coloring solution, more preferably 0.09 to 1.6 mass%, even more preferably 0.2 to 1.4 mass%, and particularly preferably 0.25 to 1.2 mass%.

[0052] In one embodiment, the coloring solution is one in which the coloring components are substantially free of colorants that decolorize after calcination of zirconia. The term "substantially free of colorants that decolorize after calcination of zirconia" means that the content of colorants that decolorize after calcination of zirconia is preferably less than 0.009% by mass, more preferably less than 0.001% by mass, and even more preferably less than 0.0001% by mass, relative to the total mass of the coloring solution, and may even be 0% by mass.

[0053] The coloring solution of the present invention can impart the pink hue required for dental applications to dental ceramics. Regarding the chromaticity (L*, a*, b*) of the dental ceramics after coloring and sintering according to the L*a*b* color system, a* is preferably 4.5 to 15.0, more preferably 4.8 to 14.5, and even more preferably 5.0 to 14.0. b* is preferably -5.0 to 10, more preferably -4.4 to 9, and even more preferably -4.0 to 8. L* is preferably 65 to 95, more preferably 68 to 92, and even more preferably 70 to 90. The chromaticity (L*, a*, b*) can be measured as described in the Examples.

[0054] The dental ceramics to be colored with the coloring solution of the present invention are not particularly limited as long as they contain ceramics, and examples thereof include those containing zirconia (also called "zirconium oxide" or "ZrO"), alumina (also called "aluminum oxide" or "AlO"), feldspar glass, disilicate glass, porcelain, etc. Dental ceramics preferably contain zirconia and / or alumina, and more preferably contain zirconia as the main component. When dental ceramics contain zirconia as the main component, the zirconia content is more preferably 65% ​​by mass or more, particularly preferably 75% by mass or more, and most preferably 85% by mass or more.

[0055] The dental ceramics to be colored with the coloring solution of the present invention may be unsintered or calcined, as long as they are not yet sintered. However, from the viewpoint of penetration of the coloring solution, when the dental ceramics contain zirconia as a main component, it is preferable that the dental ceramics be calcined zirconia.

[0056] Another embodiment of the present invention is a dental ceramic (colored ceramic calcined or unsintered body) having Er and Co components supported on its surface. The content of the Er and Co components is not particularly limited as long as the effects of the present invention are achieved, and can be appropriately adjusted by, for example, the amount of the coloring solution of the present invention applied, depending on the desired intensity of color development after sintering. Furthermore, the range of support of the Er and Co components can be adjusted by applying the coloring solution of the present invention, etc., to allow them to penetrate into spaces communicating with the outside of the ceramic calcined or unsintered body by utilizing capillary action, thereby appropriately adjusting support not only on the outermost surface but also within the surface. Note that "supported" generally refers to a state in which the components are attached to a carrier; in the present invention, it refers to a state in which the components are attached to the ceramic by adsorption or other means.

[0057] The dental ceramics of the present invention can be imparted with the pink color tone required for dental applications after firing without reducing strength.

[0058] As described above, the ceramic calcined body or green body preferably contains zirconia as a main component. Hereinafter, zirconia will be described. In the present invention, the calcined body before being colored with the coloring solution is simply referred to as a "zirconia calcined body," and the calcined body after coloring is simply referred to as a "colored zirconia calcined body." The coloring solution of the present invention can also be used to color a green zirconia body. In this case, a zirconia sintered body is produced without going through the calcination step. When such a sintered body is assumed, the conditions in the following description of the zirconia calcined body can be similarly applied to a preferred embodiment of the green zirconia body.

[0059] The zirconia calcined body of the present invention will now be described. The zirconia calcined body is composed primarily of zirconia (ZrO2: zirconium oxide), and refers to a body that is formed according to the desired dental product and then calcined. The zirconia calcined body refers, for example, to a body in which zirconia particles (powder) are formed into a block in a state where they are not completely sintered. The main component may be 50% by mass or more. The zirconia content in the zirconia calcined body of the present invention is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. For example, when used in dental prostheses or dental implant products, the zirconia calcined body can be produced by press-molding zirconia powder using a known technique into a disk or block, which is then subjected to a process such as calcination. The density of the zirconia calcined body is 2.7 g / cm 3 The density of the zirconia calcined body is preferably 4.0 g / cm or more. 3 Less than 3.8 g / cm is preferred 3 Less than 3.6 g / cm is more preferable. 3The following is more preferable. A density within this range facilitates molding. The density of the calcined body can be calculated, for example, by dividing the mass of the calcined body by the volume of the calcined body. The three-point bending strength of the zirconia calcined body is preferably 15 to 70 MPa, more preferably 18 to 60 MPa, and even more preferably 20 to 50 MPa. The bending strength can be measured using a test piece measuring 5 mm thick, 10 mm wide, and 50 mm long, in accordance with ISO 6872:2015, except for the size of the test piece. The test piece's face and C-face (the surface where the corners of the test piece are chamfered at a 45° angle) are sanded in the longitudinal direction with 600-grit sandpaper. The test piece is positioned so that the widest surface faces vertically (the load direction). The bending test measurement is performed with a span of 30 mm and a crosshead speed of 0.5 mm / min.

[0060] The predominant crystal system of zirconia in the calcined zirconia, zirconia powder, and zirconia powder compact is preferably monoclinic. In the present invention, the phrase "the predominant crystal system is monoclinic" refers to the ratio f of the monoclinic system in zirconia calculated by the following formula (1) to the total amount of all crystal systems (monoclinic, tetragonal, and cubic systems) in zirconia. m In calcined zirconia, zirconia powder, and zirconia powder compacts, the monoclinic fraction f in zirconia calculated by the following formula (1) is m is preferably 55% or more, more preferably 60% or more, even more preferably 70% or more, even more preferably 75% or more, particularly preferably 80% or more, even more particularly preferably 85% or more, and most preferably 90% or more, based on the total amount of monoclinic, tetragonal, and cubic crystals. m can be calculated from the following formula (1) based on the peaks in the X-ray diffraction (XRD) pattern using CuKα radiation. The main crystal system may contribute to increasing the shrinkage temperature and shortening the firing time during firing of the zirconia calcined body.

[0061] In the calcined zirconia body, the peaks of the tetragonal and cubic crystals may not be substantially detected. That is, the monoclinic fraction f m can be set to 100%.

[0062]

number

[0063] In equation (1), I m (111) and I m (11-1) indicates the peak intensity of the (111) and (11-1) planes of the monoclinic system of zirconia, respectively. t (111) indicates the peak intensity of the (111) plane of the tetragonal crystal system of zirconia. c (111) indicates the peak intensity of the (111) plane of the cubic crystal system of zirconia.

[0064] The zirconia calcined body in the present invention preferably contains a stabilizer capable of suppressing the phase transition of zirconia. For example, it is preferable that a stabilizer capable of suppressing the phase transition of zirconia is contained in zirconia before calcination.

[0065] Examples of stabilizers capable of suppressing the phase transition of zirconia include yttrium oxide (Y2O3) (hereinafter referred to as "yttria"), calcium oxide (CaO), magnesium oxide (MgO), yttria, cerium oxide (CeO2), scandium oxide (Sc2O3), niobium oxide (Nb2O5), lanthanum oxide (La2O3), erbium oxide (Er2O3), and praseodymium oxide (Pr6O 11Examples of suitable stabilizers include oxides such as zirconia, samarium oxide (SmO), europium oxide (EuO), and thulium oxide (TmO), with yttria being preferred. These may be used singly or in combination. In a preferred embodiment, the coloring solution is one in which the dental ceramic to be colored contains zirconia as a primary component and further contains yttria as a stabilizer, with the stabilizer being substantially yttria alone. In the preferred embodiment, the stabilizer being substantially yttria alone means that the content of stabilizers other than yttria is less than 0.1 mol%, preferably 0.05 mol% or less, more preferably 0.01 mol% or less, and even more preferably 0.001 mol% or less, based on a total of 100 mol% of zirconia and stabilizers. In particular, since the coloring solution contains an Er component, in the preferred embodiment, the coloring solution according to the present invention contains an Er component, resulting in a pink color deeper than would be expected if the dental ceramic also contained an Er component. Therefore, it is preferable that the dental ceramic does not contain erbium oxide as a stabilizer. However, in the above embodiment, dental ceramics that do not contain erbium oxide as a stabilizer may contain a trace amount of erbium oxide as a pigment.

[0066] When the zirconia calcined body contains a stabilizer, the content of the stabilizer is preferably 0.1 to 18 mol%, more preferably 1 to 15 mol%, and even more preferably 1.5 to 10 mol%, based on 100 mol% of the total of zirconia and stabilizer. In a preferred embodiment, the dental ceramics and coloring solution for coloring the dental ceramics contain zirconia as a main component and the content of yttria is 1.5 to 10 mol%, based on the total moles of zirconia and yttria. In the preferred embodiment, the content of yttria is preferably 2.0 to 9.0 mol%, more preferably 2.5 to 8.5 mol%, and even more preferably 2.8 to 8.0 mol%.

[0067] The zirconia calcined body of the present invention may optionally contain colorants (including pigments, composite pigments, and fluorescent agents), alumina (Al2O3), titanium oxide (TiO2), silica (SiO2), etc. These components may be used alone or in combination of two or more. Examples of the pigment include oxides of at least one element selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Sn, Sb, Bi, Ce, Pr, Sm, Eu, Gd, Tb, and Er. Examples of the composite pigment include (Zr,V)O2, Fe(Fe,Cr)2O4, (Ni,Co,Fe)(Fe,Cr)2O4·ZrSiO4, and (Co,Zn)Al2O4. Examples of the fluorescent agent include Y2SiO5:Ce, Y2SiO5:Tb, (Y, Gd, Eu)BO3, Y2O3:Eu, YAG:Ce, ZnGa2O4:Zn, and BaMgAl 10 O 17 :Eu, etc.

[0068] A typical method for producing the zirconia calcined body of the present invention will be described below. First, granules composed of a zirconia raw material containing a stabilizer (preferably zirconia particles whose main crystal system is monoclinic) are prepared and press-molded into a shape such as a block or disk. Next, the molded body is subjected to cold isostatic pressing (CIP) as needed. The pressure during this process is, for example, 50 to 500 MPa. Next, the molded body is subjected to a calcination process. The calcination is performed by gradually increasing the temperature from room temperature to 800 to 1200°C and maintaining the temperature for approximately 1 to 6 hours to obtain a zirconia calcined body. The obtained zirconia calcined body is machined using conventionally known equipment depending on the final dental product. For example, if the dental product is a dental prosthesis, it is machined into a crown shape using CAD / CAM or the like.

[0069] The zirconia calcined body may be a commercially available product, such as "Noritake Katana (registered trademark) Zirconia" (model numbers: Disc UTML, Disc STML, Disc ML, Disc HT, and Disc LT) (all manufactured by Kuraray Noritake Dental Co., Ltd.).

[0070] The method for producing a colored zirconia calcined body according to the present invention includes a step of incorporating the coloring solution into the cut zirconia calcined body. Examples of methods for incorporating the coloring solution include applying the coloring solution to the zirconia calcined body using a brush, immersing the zirconia calcined body in a container containing the coloring solution, or spraying the coloring solution onto the zirconia calcined body using a sprayer. Conventional known tools and devices can be used. When a zirconia sintered body is produced directly from a green body without the calcination step, the coloring solution may be incorporated into the cut zirconia green body.

[0071] The present invention further encompasses a zirconia sintered body made from the colored zirconia calcined body. A method for producing the zirconia sintered body includes a step of firing the colored zirconia calcined body. The firing temperature (maximum firing temperature) can be appropriately changed depending on the type of zirconia. It is not particularly limited as long as the Er and Co components contained in the coloring solution develop color. However, it is preferably 1350°C or higher, more preferably 1450°C or higher, and even more preferably 1500°C or higher. The upper limit of the firing temperature is not particularly limited, but is preferably 1700°C or lower. The zirconia sintered body includes not only sintered bodies obtained by sintering molded zirconia particles under normal pressure or without pressure, but also sintered bodies obtained by densifying the zirconia particles by high-temperature pressure treatment such as HIP (hot isostatic pressing).

[0072] The content of the stabilizer in the zirconia sintered body can be measured by, for example, inductively coupled plasma (ICP) emission spectroscopy, fluorescent X-ray analysis, or the like.

[0073] The zirconia sintered body of the present invention preferably has at least one of partially stabilized zirconia and fully stabilized zirconia as a matrix phase. In the zirconia sintered body, the main crystalline phase of zirconia is at least one of a tetragonal system and a cubic system. The zirconia sintered body may contain both a tetragonal system and a cubic system. It is preferable that the zirconia sintered body is substantially free of a monoclinic system. Note that zirconia that is partially stabilized by adding a stabilizer is called partially stabilized zirconia (PSZ), and zirconia that is fully stabilized is called fully stabilized zirconia.

[0074] The present invention includes dental products made of the zirconia sintered body. Examples of the dental products include dental prostheses, orthodontic products, and dental implant products. Examples of the dental prostheses that can be used include zirconia inlays, onlays, laminate veneers, and crowns.

[0075] In any of the above embodiments, the type, content, etc. of each component can be changed as appropriate, and any component can be added, deleted, etc. Furthermore, in any of the above embodiments, the composition and property values ​​of the coloring solution can be changed and combined as appropriate.

[0076] The present invention includes embodiments in which the above-described configurations are combined in various ways within the technical scope of the present invention, as long as the effects of the present invention are achieved. [Example]

[0077] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0078] [Examples 1 to 17 and Comparative Examples 1 to 3] The coloring solutions of the Examples and Comparative Examples were prepared as follows, and their properties were evaluated. The results are shown in Tables 1 and 2.

[0079] [Preparation of coloring solution] A colored solution was prepared by mixing the components shown in Tables 1 and 2 at room temperature in the amounts shown in the tables. The molar concentration of each metal component in the colored solution was measured by inductively coupled plasma (ICP) emission spectroscopy (SPS3500, manufactured by Hitachi High-Tech Science Corporation).

[0080] [Preparation of zirconia calcined body] Next, the preparation of the zirconia calcined body to which the coloring solution is applied will be described.

[0081] First, a zirconia powder containing a stabilizer was prepared. 9.9 mass% (5.5 mol%) of yttria as a stabilizer was added to 90.1 mass% of zirconia powder whose primary crystal system was monoclinic to prepare a mixture. Next, this mixture was added to water to prepare a slurry, which was then wet-pulverized and mixed in a ball mill until the average particle size reached 0.13 μm or less. The pulverized slurry was dried using a spray dryer, and the resulting powder was fired at 950°C for 2 hours to prepare a powder (primary powder). The average particle size can be determined by a laser diffraction scattering method. Specifically, the laser diffraction scattering method can be performed using a laser diffraction particle size distribution analyzer (SALD-2300, manufactured by Shimadzu Corporation) on a volume basis, using a 0.2% aqueous solution of sodium hexametaphosphate as a dispersion medium.

[0082] Water was added to the obtained primary powder to prepare a slurry, which was then wet-pulverized and mixed in a ball mill until the average particle size was 0.13 μm or less. A binder was added to the pulverized slurry, which was then dried in a spray dryer to produce a powder (secondary powder). The produced secondary powder was used as a raw material powder to produce the zirconia calcined body described below.

[0083] Next, a method for producing a zirconia calcined body will be described. 1.32 g of the raw material powder was filled into a mold with a diameter of 19 mm and subjected to primary press molding using a uniaxial press molding machine at a surface pressure of 57.5 kN for 20 seconds. The obtained primary press molded body was fired at 1000°C for 2 hours to produce a zirconia calcined body.

[0084] [Measurement of chromaticity of sintered body and color evaluation] The prepared coloring solution was applied to the produced zirconia calcined body, and then fired under the firing conditions shown in Tables 1 and 2 to obtain a sintered body. The obtained sintered body was polished into a disk with a diameter of 15 mm and a thickness of 1.2 mm, and measured against a white background using a spectrophotometer manufactured by Olympus Corporation (product name "Crystal Eye CE100-DC / JP", light source: 7-band LED light source). * a * b * Color system (JIS Z 8781-4:2013 Colorimetry-Part 4: CIE 1976 L * a * b * The chromaticity was measured (n=3) according to a color space. The average values ​​of the measured values ​​are shown in Tables 1 and 2. The color of the obtained sintered body was also evaluated visually.

[0085] [Measurement of biaxial bending strength of sintered body] The prepared coloring solution was applied to the produced zirconia calcined body, and then fired under the firing conditions shown in Tables 1 and 2 to obtain sintered bodies with a diameter of 15 mm and a thickness of 1.2 mm. The biaxial bending strength of the obtained sintered bodies was measured (n=5) at a crosshead speed of 0.5 mm / min using a desktop universal precision testing machine Autograph (product name "AGS-X") manufactured by Shimadzu Corporation in accordance with JIS T 6526:2012. The average values ​​of the measured values ​​are shown in Tables 1 and 2. In addition, the rate of change in biaxial bending strength was calculated using the following formula, with the zirconia sintered body that was not colored with the coloring solution (Comparative Example 1) as the standard. Rate of change in biaxial bending strength (%) = {(biaxial bending strength of sintered body coated with coloring solution and fired - biaxial bending strength of uncolored zirconia sintered body) / biaxial bending strength of uncolored zirconia sintered body} × 100

[0086] [Table 1]

[0087] [Table 2]

[0088] As shown in Table 2, in Comparative Example 1, in which no coloring solution was applied, the specimen was white and did not develop a pink color. In Comparative Example 2, in which the specimen was colored with a coloring solution containing only the Er component, the biaxial bending strength was reduced by 35.9% compared to Comparative Example 1, in which no coloring solution was applied. In Comparative Example 3, in which the specimen was colored with a coloring solution containing only the Co component, the specimen developed a bluish-purple color and was unable to achieve a pink color. In contrast, as shown in Tables 1 and 2, in Examples 1 to 17, the decrease in strength of the zirconia was suppressed and the specimen was able to be colored pink. [Industrial Applicability]

[0089] The coloring solution of the present invention can suppress a decrease in the strength of dental ceramics and can impart the pink color required for dental applications, making it suitable for use as a dental ceramic coloring solution. In particular, the frequency of use of dental ceramic coloring solutions is expected to increase as demand for ceramic dental crowns continues to grow and individual aesthetic needs become more stringent, making the dental ceramic coloring solution of the present invention useful. The coloring solution of the present invention can be suitably used for prosthetics that include the gingival area. Examples of prosthetics that include the gingival area include use in subgingival areas of implant superstructures and large dental prosthetics known as ALL-ON-4 (a surgical procedure in which four implants are implanted into the bone in a balanced manner) that reproduce the gingival area with a prosthetic.

Claims

1. A coloring component and a solvent are included, the coloring component includes an Er component and a Co component, A coloring solution for coloring dental ceramics, wherein the content of the Er component is 110 to 310 mmol / L in terms of Er ions.

2. Regarding the L*, a*, b* of dental ceramics after coloring and sintering according to the L*a*b* color system, a* is 4.5 to 15.0, 2. The coloring solution according to claim 1, wherein b* is from −5.0 to 10.

3. 3. The coloring solution according to claim 1, wherein L* is 65 to 95 in (L*, a*, b*) according to the L*a*b* color system.

4. The coloring solution according to any one of claims 1 to 3, wherein the coloring component further comprises an Al component.

5. 5. The coloring solution according to claim 1, wherein the Er component is an ion or a complex.

6. 6. The coloring solution according to claim 1, wherein the Er component is a component derived from at least one selected from the group consisting of erbium chloride hydrate, erbium perchlorate hydrate, erbium nitrate hydrate, erbium oxalate hydrate, and erbium acetate hydrate.

7. The coloring solution according to any one of claims 1 to 6, wherein the Co component is an ion or a complex.

8. 7. The coloring solution according to claim 1, wherein the Co component is at least one selected from the group consisting of cobalt(II) chloride hydrate, cobalt(II) perchlorate hydrate, cobalt(II) fluoride hydrate, cobalt(II) nitrate hydrate, cobalt(II) oxalate hydrate, and cobalt(II) acetate hydrate.

9. 9. The coloring solution according to claim 1, wherein the content of the Co component is 0.0340 to 1.70 mmol / L in terms of Co ions.

10. The coloring solution according to any one of claims 1 to 9, wherein the solvent comprises water or / and an organic solvent.

11. The coloring solution according to claim 10, wherein the organic solvent comprises at least one selected from the group consisting of alcohols, glycols, triols, and ketones.

12. The coloring solution according to any one of claims 1 to 11, wherein the dental ceramic contains zirconia as a main component.

13. 13. The coloring solution of claim 12, wherein the dental ceramic further comprises yttria.

14. 14. The coloring solution according to claim 13, wherein the content of yttria is 1.5 to 10 mol % based on the total moles of zirconia and yttria.

15. A dental ceramic having an Er component and a Co component carried on the surface thereof and colored with the coloring solution according to any one of claims 1 to 14.

16. The dental ceramic according to claim 15, further comprising an Al component supported on the surface thereof.

17. 17. The dental ceramic according to claim 15, wherein the Er component is an ion or a complex.

18. The dental ceramic according to any one of claims 15 to 17, wherein the Co component is an ion or a complex.

19. The dental ceramic according to any one of claims 15 to 18, wherein the dental ceramic contains zirconia as a main component.

20. 20. The dental ceramic of claim 19, further comprising yttria.

21. 21. The dental ceramic according to claim 20, wherein the content of yttria is 1.5 to 10 mol % based on the total moles of zirconia and yttria.

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