Dental glass composition

Abstract

This invention provides a dental glass composition that offers excellent fixation for dental restorations, requires no fixing firing, can be repeatedly colored, and allows for the stacking of dental porcelain materials. The dental glass composition comprises glass powder (A) and a wax component (B). The average particle size of the glass powder (A) is preferably 0.05 μm to 50 μm. The boiling point of the aforementioned wax component (B) is preferably below 400°C.

Description

Technical Field

[0001] This invention relates to dental glass compositions for coloring and tinting of dental restorations, and methods for manufacturing dental restorations using the same. More specifically, it relates to dental glass compositions suitable for use in, for example, crowns, inlays, bridges, implant superstructures, and prosthetic teeth made of ceramic materials, and particularly to dental glass compositions suitable for tinting compositions (hereinafter sometimes referred to as "ceramic colorants") for ceramic crowns and methods for manufacturing dental restorations using the same. Background Technology

[0002] As dental restorations that restore the aesthetics of natural teeth (such as overlays, crowns, and dentures), there are ceramic dental restorations, such as metal-ceramic dental restorations and all-ceramic dental restorations, which use dental porcelain materials to represent ivory and enamel tones in various materials such as metals, zirconium oxide, alumina, feldspar glass, and disilicate glass.

[0003] In the manufacturing methods of ceramic dental restorations, techniques exist to mimic the color tones of natural teeth, imitating features such as the white band, dentin, neck of the tooth, staining of the proximal surfaces, capillary cracks, and enamel cracks. In such cases, for example, by using a porcelain coloring agent on the dental restoration, the ceramic restoration easily blends into the color tone of the natural teeth surrounding the tooth to which the restoration is applied.

[0004] When using ceramic colorants, an appropriate shade of ceramic colorant is applied to a glass mixing plate or colorant tray. Ceramic colorants are typically provided in powder or paste form. When the ceramic colorant is in powder form, an appropriate amount of powder is applied to the glass mixing plate or colorant tray. Then, water and a special liquid to impart coating properties are added to the powder, and the powder-to-liquid ratio is adjusted to the desired paste properties, followed by refining and paste formation. Furthermore, when the ceramic colorant is in paste form, its viscosity may increase over time during storage or after an appropriate amount is applied to the glass mixing plate or colorant tray, causing changes in the paste properties and making it difficult to apply. This can lead to problems with coating properties such as seepage. Therefore, there is a need for ceramic colorants that are easy to handle and have excellent coating properties.

[0005] In addition, in order to simulate natural teeth, as a general technique for coloring ceramic dental restorations, there are "internal coloring method" which uses a ceramic colorant sandwiched between enamel-representing ceramic and ivory-representing ceramic, and "surface coloring method" which uses a ceramic colorant on the outermost surface of enamel-representing ceramic.

[0006] In these methods, in order to bond the inorganic pigment components contained in the porcelain colorant to the dental restoration, and in the case of the internal colorant method, in order not to affect the subsequent stacking of other porcelain materials, it is necessary to calcine each porcelain colorant to the optimal degree of calcination using a dental ceramic calcination furnace after applying the porcelain colorant to the dental restoration (hereinafter sometimes referred to as "fixed calcination"). Multiple calcinations are required in the manufacture of dental restorations. Therefore, there is a need for porcelain colorants that can shorten the manufacturing process.

[0007] As a color-adjusting composition for ceramic crown ceramic materials, for example, Patent Document 1 discloses a ceramic colorant in powder or paste form containing a specific aluminosilicate glass.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2009-207743 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] However, it is known that in Patent Document 1, the ceramic colorant needs to be applied in a paste state. Each time it is used, the powder and liquid must be mixed to prepare the paste. Furthermore, if the viscosity is too high, it is difficult to apply; if the paste viscosity is too low, seepage occurs during application, making it difficult to adjust. In addition, when using the paste-like ceramic colorant described in Patent Document 1, the following problems also exist: the viscosity increases over time, the paste properties change, and it becomes difficult to apply.

[0013] Furthermore, in Patent Document 1, both the internal colorant method and the surface colorant method require repeated coating and calcination each time. Additionally, in the internal colorant method, the colorant must be fixed and calcined before the surface layer of ceramic material is stacked, resulting in multiple steps. It is known that if the colorant is not fixed and calcined, the subsequently stacked ceramic material may unintentionally contain colorant, or the colorant may not be fixed. Therefore, problems such as the color of the colorant flowing out before or during the calcination of the stacked ceramic material may occur.

[0014] Therefore, the object of the present invention is to provide a dental glass composition that has excellent fixation for dental restorations, does not require fixed firing, can be repeatedly colored, and allows dental porcelain to be stacked thereon.

[0015] means for solving problems

[0016] In order to solve the above-mentioned problems, the inventors conducted repeated and in-depth research and found that by using a dental glass composition containing glass and wax components, a dental patch that can be directly applied to dental restorations without the need to prepare a paste and that has the desired color even without the fixing and calcination necessary for the internal coloring agent method can be obtained. Through further repeated research, the present invention was completed.

[0017] That is, the present invention includes the following technical solutions.

[0018] [1] A dental glass composition comprising glass powder (A) and a wax component (B).

[0019] [2] The dental glass composition according to [1], wherein the average particle size of the aforementioned glass powder (A) is 0.05 μm to 50 μm.

[0020] [3] The dental glass composition according to [1] or [2], wherein the boiling point of the aforementioned wax component (B) is below 400°C.

[0021] [4] The dental glass composition according to any one of [1] to [3], wherein the melting point of the aforementioned wax component (B) is 35 to 120°C.

[0022] [5] The dental glass composition according to [4], wherein the aforementioned wax component (B) comprises a high melting point wax (B-1) having a melting point of 75°C or higher and 120°C or lower.

[0023] [6] The dental glass composition according to any one of [1] to [5], wherein the content of the aforementioned wax component (B) is 3 to 65% by mass.

[0024] [7] The dental glass composition according to any one of [1] to [6] further comprises an oil component (C).

[0025] [8] The dental glass composition according to [7], wherein the boiling point of the aforementioned oil component (C) is 100 to 400 °C.

[0026] [9] The dental glass composition according to [7] or [8], wherein the content of the aforementioned oil component (C) is 0.3 to 30% by mass.

[0027]

[10] The dental glass composition according to any one of [1] to [9] is a porcelain coloring agent.

[0028]

[11] A method for manufacturing dental fittings includes: a step of coating a dental glass composition as described in any one of [1] to

[10] onto a dental fitting substrate having a ceramic surface; and a step of not calcining the aforementioned substrate coated with the aforementioned dental glass composition, but calcining it after stacking dental porcelain.

[0029]

[12] In the method for manufacturing dental fittings according to

[11] , the calcination temperature in the calcination process after stacking the aforementioned dental porcelain material is 700 to 1100°C.

[0030] Invention Effects

[0031] According to the present invention, a dental glass composition is provided that offers excellent fixation for dental restorations, requires no fixed firing, can be repeatedly colored, and allows for the stacking of dental porcelain. Furthermore, the dental glass composition according to the present invention exhibits suppressed changes over time, excellent operability, allows for thin-film coating of dental restorations, and lacks flowability, thus enabling coating without exudation. Moreover, in addition to using the dental glass composition of the present invention alone on dental restorations, a color gradient can be applied from the neck of the tooth towards the incisal edge using a brush, eyeshadow brush, or other sponge, or by blending with the fingers, allowing for easy fabrication of dental restorations with desired colors with good operability. Furthermore, since subsequent porcelain stacking can be performed without fixed firing, the manufacturing process for dental restorations can be shortened. Detailed Implementation

[0032] The dental glass composition of the present invention is characterized in that it comprises glass powder (A) and a wax component (B).

[0033] <Glass Powder (A)>

[0034] First, the glass powder (A) included in the glass composition of the present invention will be described. The glass powder (A) used in the present invention is not particularly limited as long as it achieves the effects of the present invention; any dental glass powder capable of being sintered onto a substrate (such as a core or frame material for dental restorations) can be used. Examples of glass powder (A) include, for example, amorphous potassium aluminum silicate glass (4SiO2·Al2O3·K2O), leucite crystalline potassium aluminum silicate glass, fluorapatite glass, and lithium silicate glass. Examples of components constituting glass powder (A) include SiO2, Al2O3, B2O3, Li2O, Na2O, K2O, CaO, MgO, and Sb2O3; various components may be selected in appropriate proportions depending on the substrate to which they are applied. Additionally, components such as TiO2, SrO, BaO, ZnO, CeO2, ZrO2, and P2O5 may be added in appropriate proportions. Glass powder (A) can be used alone or in combination of two or more types.

[0035] As a base material, there are no particular limitations as long as it is used in dental applications. Examples include various ceramics (zirconia, alumina, feldspar glass, lithium disilicate, etc., for dental use); and ceramics such as metal-ceramic dental restorations and all-ceramic dental restorations, which are obtained by sintering single or multiple layers of dental porcelain material with ivory or enamel hues on dental metal cores or the aforementioned ceramic cores.

[0036] The linear thermal expansion coefficient of the glass powder (A) used in this invention is preferably approximately the same as that of the substrate to which it is applied. For example, the linear thermal expansion coefficient in the range of 25°C to 500°C can be set to 6.0 × 10⁻⁶. -6 K -1 ~14.0×10 -6 K -1 The linear thermal expansion coefficient can be determined using known methods and apparatus. For example, the linear thermal expansion coefficient can be determined by heating the sample from room temperature to 500°C using a thermomechanical analysis apparatus TMA8311 (manufactured by Rigaku Corporation, with a heating rate of 5°C / min).

[0037] The glass powder (A) used in this invention can be made from a wide range of commonly used ceramic raw materials. There are no particular limitations on the materials, as long as each component can form the aforementioned components when heated in the atmosphere. The glass composition is calculated beforehand, the proportions of each raw material are determined, and the materials are mixed. Furthermore, the method of mixing the raw materials is not particularly limited, but uniform dispersion is preferred.

[0038] The mixed raw materials are melted at temperatures above 1200°C to produce glass. The melting method is not particularly limited, as long as the mixed raw materials are completely melted and uniformly formed into an amorphous substance, and sublimation of components occurs.

[0039] There are no particular limitations on the method of cooling the molten material; quenching in water, etc., are acceptable. The resulting glass block is dried and pulverized to obtain glass powder (A). There are no particular limitations on the method of pulverizing the glass block, nor are there any particular limitations on the method of classifying it into the desired particle size.

[0040] The glass powder (A) used in this invention may contain a colorant. The colorant may be amorphous or crystalline. Alternatively, the glass powder (A) may contain crystalline powder. Examples of colorants include pigments, composite pigments, and fluorescent agents. One type of colorant may be used alone, or two or more may be used in combination.

[0041] Examples of pigments include oxides of at least one element selected from Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Y, Zr, Sn, Sb, Bi, Ce, Pr, Sm, Eu, Gd, Tb, and Er, preferably oxides of at least one element selected from Ti, V, Cr, Mn, Fe, Co, Ni, Pr, Tb, and Er. Examples of oxides include praseodymium oxide, vanadium oxide, iron oxide, nickel oxide, chromium oxide, manganese oxide, cerium oxide, tin oxide, zirconium oxide, zinc oxide, and titanium oxide. Examples of composite pigments include (Zr, V)O2, Fe(Fe, Cr)2O4, (Ni, Co, Fe)(Fe, Cr)2O4·ZrSiO4, and (Co, Zn)Al2O4, preferably (Zr, V)O2. Examples of fluorescent agents include Y₂SiO₅:Ce, Y₂SiO₅:Tb, (Y,Gd,Eu)BO₃, Y₂O₃:Eu, YAG:Ce, ZnGa₂O₄:Zn, and BaMgAl. 10 O 17 Eu et al. In a method for manufacturing a dental glass composition containing a coloring component, the coloring component may be mixed with glass powder (A) alone, or the substance obtained by mixing the coloring component with glass powder (A) and heating and fusing it at 600–1200°C may be micronized.

[0042] Considering the need to achieve a balance between the finest possible particle size to approximate the hue of natural teeth and a certain degree of coarseness for achieving color development, the average particle size of the glass powder (A) used in this invention is preferably 0.05 to 50 μm, more preferably 0.08 to 35 μm, further preferably 0.1 to 20 μm, particularly preferably 0.1 to 10 μm, and most preferably 0.1 to 5 μm.

[0043] When the average particle size is below 50 μm, the dental glass composition adheres well to the frame, does not fall off during porcelain stacking, and the colored particles are not visible to the naked eye, resulting in excellent aesthetics. Furthermore, when the particle size is above 0.05 μm, it will not burn during calcination, allowing for adequate color development.

[0044] In the dental glass composition of the present invention, the content of glass powder (A) is preferably such that it can be mixed with the wax component (B). The content of glass powder (A) is preferably 35% by mass or more, more preferably 45% by mass or more from the viewpoint of superior color development and fixation for dental restorations, further preferably 55% by mass or more, and particularly preferably 68% by mass or more. Furthermore, the content of glass powder (A) is not particularly limited, but is preferably 97% by mass or less, more preferably 95% by mass or less, further preferably 93% by mass or less, and particularly preferably 91% by mass or less. Additionally, when the dental glass composition of the present invention contains an oil component (C), the content of glass powder (A) is not particularly limited, but is preferably 34% by mass or more, more preferably 44% by mass or more from the viewpoint of superior color development and fixation for dental restorations, further preferably 54% by mass or more, and particularly preferably 67% by mass or more. Furthermore, when the dental glass composition of the present invention contains an oil component (C), the content of glass powder (A) is not particularly limited, but is preferably 96% by mass or less, more preferably 94% by mass or less, even more preferably 92% by mass or less, and particularly preferably 90% by mass or less.

[0045] <Wax component (B)>

[0046] Next, the wax component (B) contained in the dental glass composition of the present invention will be described. The wax component (B) is contained to disperse the glass powder and to solidify the dental glass composition at room temperature. The wax component (B) may be used alone or in combination of two or more types.

[0047] The wax component (B) used in this invention preferably comprises a substance that is solid at room temperature (20–35°C) and melts upon heating. In a suitable embodiment, a dental glass composition can be described as follows: it comprises glass powder (A) and a wax component (B), wherein the wax component (B) consists only of a substance that is solid at room temperature and melts upon heating. By using a substance that is solid at room temperature and melts upon heating, changes in properties such as viscosity increasing over time in the glass composition do not occur, and therefore, fixed calcination is not required. This is advantageous compared to the prior art in that repeated fixed calcination is not required. Therefore, the dental glass composition of this invention can be easily and repeatedly colored, and porcelain materials (e.g., dental porcelain materials for surface coloring) can be stacked on it. Furthermore, the dental glass composition of this invention can also be thin-filmed and coated. As the wax component (B), known waxes can be used, such as natural waxes, synthetic waxes, or processed (or modified) waxes.

[0048] Specific examples of wax components (B) include animal-derived waxes such as beeswax, whale wax, tallow, hydrogenated tallow oil, and lard; plant-derived waxes such as carnauba wax, wood wax, hydrogenated palm oil, hydrogenated castor oil, and candelilla wax; petroleum-derived waxes such as paraffin wax, microcrystalline wax, and white petroleum jelly; mineral-derived waxes such as lignite wax; and synthetic waxes such as polyolefin waxes (specifically, polyolefin waxes containing α-olefins such as ethylene and propylene as monomer units) and polyethylene glycol (molecular weight of 1000 or higher). Additionally, wax components (B) can include long-chain fatty acids (stearic acid, behenic acid, etc.) that are solid at room temperature, long-chain fatty acid esters, long-chain fatty acid amides (stearamide, etc.), and ketone waxes (long-chain aliphatic ketones such as dihedrinyl ketone, etc.).

[0049] From the viewpoint of achieving stable preservation in a solid state at room temperature and good fixation of dental restorations, the melting point of the wax component (B) used in this invention is preferably 35–120°C, more preferably 40–110°C, and even more preferably 50–100°C. At melting points below 35°C, it may not be able to maintain a solid state, and may flow out of the drawing during repeated application of the dental glass composition or stacking of surface porcelain. Furthermore, at temperatures above 120°C, adhesion to the dental restoration may be insufficient, resulting in inadequate coloring.

[0050] In the dental glass composition of the present invention, the content of wax component (B) is preferably 3 to 65% by mass, more preferably 5 to 55% by mass, even more preferably 7 to 45% by mass, and particularly preferably 9 to 32% by mass. When the content of wax component is within this range, it is easy to obtain a solid dental glass composition with excellent color development or staining properties, high formability and strength, and good adhesion and fixation to dental restorations. When the content of wax component (B) is less than 3% by mass, it may not be able to remain solid and may flow out from the coating surface during repeated application of the dental glass composition and stacking of surface porcelain materials. On the other hand, when the content of wax component (B) is greater than 65% by mass, the dental glass composition may not fix and thus fail to develop color.

[0051] When the dental glass composition of the present invention includes the oil component (C) described later, the slippage is improved, but the dental glass composition attached to the dental fitting is prone to falling off due to friction, etc. From the viewpoint of improving the fixation of the dental glass composition, it is preferable to include a high melting point wax (B-1) (hereinafter sometimes referred to as "first wax (B-1)") together with the oil component (C).

[0052] Here, the first wax (B-1) refers to a wax among the wax components (B) exemplified above, with a melting point of 75°C or higher and 120°C or lower. By setting the melting point to 75°C or higher, it is possible to achieve conformability to the fine irregularities present on the surface of the substrate when combined with the oil component (C), thereby improving the fixation of the dental glass composition. Examples of the first wax (B-1) include carnauba wax, castor oil (melting point: about 80-90°C), polyolefin wax (wax with a melting point of 75°C or higher, such as low molecular weight polyethylene wax (melting point: about 100-120°C), etc.), long-chain fatty acids (behenic acid, etc.), fatty acid amides (stearamide (melting point: about 98-105°C), etc.), microcrystalline wax (wax with a melting point of about 75-98°C), etc. From the viewpoints of high melting point, solidification in small quantities, and no calcination residue after combustion, behenic acid and carnauba wax are preferred.

[0053] The content of the first wax (B-1) in the wax component (B) is preferably 3 to 100% by mass, more preferably 5 to 80% by mass, even more preferably 7 to 70% by mass, and particularly preferably 10 to 60% by mass. When the content of the first wax (B-1) is within this range, a balance between the slippage and the fixation of the dental glass composition is easily achieved. From the viewpoint of superior slippage and fixation of the dental glass composition, the content of the first wax (B-1) in the dental glass composition containing the first wax (B-1) is preferably less than 15% by mass in the total dental glass composition, more preferably less than 12% by mass, and even more preferably less than 10% by mass.

[0054] The wax component in this invention can be a combination of a first wax (B-1) and a wax component with a melting point less than 75°C (the wax component exemplified above, excluding the first wax (B-1) (hereinafter sometimes referred to as "second wax (B-2)"), etc.). By including the second wax (B-2) in the dental glass composition, the sliding properties when applying the dental glass composition are improved. Especially when the dental glass composition does not contain the oil component (C), by including the second wax (B-2), a dental glass composition with even better sliding properties when applied is obtained.

[0055] The melting point of the second wax (B-2) is preferably 50°C or higher and less than 75°C, more preferably 55-73°C, and even more preferably 60-70°C. The second wax (B-2) is preferably, for example, white petrolatum (melting point: about 38-60°C), stearic acid (melting point: about 69-70°C), candelilla wax (melting point: about 68-72°C), beeswax (melting point: about 63°C), palm oil (melting point: about 59°C), microcrystalline wax (melting point: about 67-70°C), paraffin wax (melting point: about 47-69°C), tallow oil (melting point: about 46°C), ketone wax (melting point: about 60°C or higher and less than 75°C), or polyethylene glycol (molecular weight of 1000 or higher, melting point of 35°C or higher and less than 75°C).

[0056] The wax component (B) in this invention needs to be burned off more thoroughly to the extent that it does not affect the color after calcination when the dental glass composition is coated on the substrate and then dental porcelain is stacked on it and calcined. Therefore, the boiling point is preferably below 400°C, more preferably below 385°C, and even more preferably below 370°C.

[0057] The dental glass composition of the present invention preferably further comprises an oil component (C). The presence of the oil component (C) increases the slippage, thereby improving operability. The oil component (C) can be used alone or in combination of two or more types.

[0058] <Oil Components (C)>

[0059] As an oil component (C), substances that are liquid at room temperature (20–35°C) can be listed. Examples of oil components (C) include, for instance, oils derived from plants and animals such as olive oil; mineral oils such as liquid paraffin; synthetic oils such as silicone oil; long-chain fatty acids that are liquid at room temperature (such as oleic acid and linolenic acid, which have melting points below 35°C); and long-chain alcohols derived from long-chain fatty acids that are liquid at room temperature (such as oleyl alcohol, which have melting points below 35°C). Oil component (C) can be used alone or in combination of two or more.

[0060] As the oil component (C), using a substance compatible with or soluble in the molten wax component (B) easily improves dispersibility. By including the oil component (C), the viscosity of the molten wax component (B) can be adjusted, and the dispersibility of the glass component (A) can also be improved, resulting in uniform coloring with good workability and superior sliding properties during application. Furthermore, by improving the dispersibility of the glass powder (A) and the wax component (B), the fixation of the dental glass composition can be further improved. Among the oil component (C), mineral oils such as liquid paraffin (oils derived from petroleum) and long-chain alcohols derived from long-chain fatty acids that are liquid at room temperature are preferred.

[0061] In this invention, the oil component (C) needs to be burned off more thoroughly during the calcination process after coating a dental glass composition onto a substrate and then stacking dental porcelain on top, to the extent that it does not affect the color tone after calcination. Therefore, its boiling point is preferably below 400°C, more preferably below 385°C, and even more preferably below 370°C. Furthermore, if an oil component (C) with a boiling point less than 100°C is used, it may volatilize at room temperature, leading to accelerated drying and difficulty in maintaining a stable solid state. Therefore, its boiling point is preferably above 100°C. As for the oil component (C), its boiling point is preferably 100–400°C, more preferably 100–385°C, and even more preferably 100–370°C.

[0062] When the dental glass composition of the present invention contains an oil component (C), the content of the oil component (C) is preferably 0.3 to 30% by mass, more preferably 0.5 to 25% by mass, and even more preferably 0.6 to 15% by mass. When the content of the oil component (C) is within this range, it is easy to impart appropriate strength and heat resistance to the resulting dental restorations, and it is easy to improve the sliding and fixing properties of the dental glass composition during application. When the content of the oil component (C) is less than 0.3% by mass, the dental glass composition may not fix and fail to develop color. When the content of the oil component (C) is greater than 30% by mass, the dental glass composition may not fix and fail to develop color. Furthermore, when the dental glass composition of the present invention contains an oil component (C), the content of the oil component (C) is preferably less than the content of the wax component (B).

[0063] From the viewpoint of obtaining a solid dental glass composition, having excellent fixation for dental fittings, and excellent color development, the content of components that are liquid at room temperature (e.g., oil components (C) and organic solvents) is preferably less than 18% by mass, more preferably less than 15% by mass, and even more preferably less than 12% by mass.

[0064] The dental glass composition of the present invention may include, as needed, known additives used in dental glass compositions. Examples of such additives include, for instance, resins (e.g., ethylene-vinyl acetate copolymer), binders, antioxidants, surfactants, preservatives, fungicides, and antibacterial agents. One additive may be used alone, or two or more may be used in combination.

[0065] The dental glass composition of the present invention may, as needed, include an adhesive resin (a known adhesive resin, such as rosin and / or petroleum resins such as rosin modifiers). Examples of rosin modifiers include esters such as rosin esters, hydrogenated rosin esters, and / or polymerized rosin esters. One type of adhesive resin may be used alone, or two or more types may be used in combination.

[0066] The dental glass composition of the present invention can be manufactured using glass powder (A) and a wax component (B) by known methods. The manufacturing method is not particularly limited; the dental glass composition can be obtained, for example, by adding glass powder to molten liquid wax component (B) and mixing, flowing the mixture into a mold, allowing it to cool and solidify, and removing it from the mold.

[0067] According to an embodiment of the present invention, the dental glass composition of the present invention can also be obtained by extruding the mixture.

[0068] The mixing of the components can be carried out while the wax component (B) is in a liquid state. Typically, the components are mixed while heated to a temperature above the melting point of the wax component (B). Alternatively, if an oil component (C) is included, the wax component (B) can be melted at a temperature above its melting point, and the oil component (C) can be mixed with the wax component (B) while the mixture is in a liquid state.

[0069] There is no particular limitation on the order in which the components are mixed, but it is preferable to add glass powder (A) to the liquid wax component (B) and disperse it. If an oil component (C) is included, the glass powder (A) can be dispersed into the wax component (B) before mixing the oil component (C), preferably after pre-mixing the wax component (B) and the oil component (C) before adding the glass powder (A). Alternatively, a portion of the wax component (B) and a portion of the oil component (C) can be pre-mixed, and after adding the glass powder (A) and further mixing, the remaining wax component (B) and oil component (C) can be added. By cooling the mixture containing the constituent components in a mold to a temperature lower than the melting point of the wax component (B), a solid dental glass composition can be obtained.

[0070] The dental glass composition of the present invention may contain a solvent as long as it achieves the effects of the present invention. Examples of solvents include water and organic solvents. The solvent needs to be completely burned off during the calcination process, such that it does not affect the color of the calcined product, when the dental glass composition is coated onto a substrate and then dental porcelain is stacked on top. Therefore, as an organic solvent, the boiling point is preferably below 400°C, more preferably below 385°C, and even more preferably below 370°C. Furthermore, if an organic solvent with a boiling point less than 100°C is used, it may evaporate at room temperature, leading to accelerated drying and difficulty in maintaining a stable solid state; therefore, the boiling point is preferably above 100°C. As an organic solvent, the boiling point is preferably 100–400°C, more preferably 100–385°C, and even more preferably 100–370°C. Examples of organic solvents include, for example, 1-butanol, 2-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-hexanol, 2-hexanol, 3-hexanol propylene glycol monopropyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, 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.; and amine compounds such as diethanolamine and triethanolamine. As one embodiment, a dental glass composition comprising glass powder (A) and wax component (B) and substantially solvent-free is provided. "Substantially solvent-free" means that the solvent content in the dental glass composition may be less than 0.1% by mass or less than 0.01% by mass. As another embodiment, a dental glass composition comprising glass powder (A), a wax component (B), and an amine compound can be cited. It can be considered that in the aforementioned dental glass composition, when the wax component (B) contains, for example, long-chain fatty acids (stearic acid, behenic acid, etc.), a surface-active effect is exhibited by forming a salt with the long-chain fatty acid using the amine compound. As a result, the slippage and fixation of the dental glass composition during application can be improved. In this case, the content of components that are liquid at room temperature (e.g., oil component (C) and organic solvents, etc.) is preferably less than 18% by mass, more preferably less than 15% by mass, and even more preferably less than 12% by mass.

[0071] In addition to glass powder (A), wax component (B), and oil component (C), the dental glass composition of the present invention may further include other components (optional components) as long as they do not impair the effects of the present invention. Examples of such other components include colorants, pH adjusters, polymerization accelerators, polymerization initiators, etc. One of the other components may be used alone, or two or more may be used in combination. Examples of colorants include, for example, colorants that decolorize upon calcination. Examples of colorants that decolorize upon calcination include food dyes that dissolve in organic solvents. Examples of food dyes include organic dyes containing two or more aromatic groups, such as Yellow 4 (tartrazine), Yellow 5 (Sunset Yellow FCF), Red 2 (Amaranth), Red 102 (New Carmine), Blue 1 (Brilliant Blue FCF), Blue 2 (Indigo Carmine), Green 3 (Fast Green FCF), and Red 102 (New Carmine); Acid Red 289, Brominated pyrogallol Red, Rhodamine B, and Rhodamine 6. G, Rhodamine 6GP, Rhodamine 3GO, Rhodamine 123, Eosin, Eosin B, Eosin Y, Fluorescein, Fluorescein isothiocyanate, and other organic dyes containing fused aromatic groups with sulforaphane as the parent nucleus (sulforaphane-based dyes); Carmine dye (carmine acid dye); Betaine red (main components: isobetaine and betaine), betaine, isobetaine, probetainin, neobetaine, and other betaine-based dyes. In one embodiment, a dental glass composition can be listed as follows, which contains glass powder (A) and wax component (B), and further contains oil component (C) as needed, and substantially does not contain coloring agents that decolorize during calcination. The absence of colorants that decolorize during calcination means that the content of colorants that decolorize during calcination relative to the mass of the dental glass composition can be, for example, 1000 ppm by mass or less, preferably 100 ppm by mass or less, more preferably 10 ppm by mass or less, further preferably 1 ppm by mass or less, particularly preferably 0.1 ppm by mass or less, and most preferably 0 ppm by mass. The content of other components is not particularly limited, but is preferably 15.0% by mass or less, more preferably 12.0% by mass or less.

[0072] Next, a method for manufacturing dental restorations using the glass composition of the present invention will be described. The method for manufacturing dental restorations can be appropriately selected according to the oral environment.

[0073] As a method for manufacturing dental restorations according to the present invention, a method for manufacturing dental restorations can be listed below, comprising: a step of coating the aforementioned dental glass composition onto a substrate of a dental restoration having a ceramic surface; and a step of firing the substrate coated with the aforementioned dental glass composition after stacking dental porcelain (firing step). The substrate is as described above. The substrate of a dental restoration having a ceramic surface refers to the substrate (core or frame, etc.) before stacking dental porcelain. The substrate of a dental restoration having a ceramic surface can be manufactured by processing commercially available products (e.g., Catanarconia STML (manufactured by Clarenoritate Dental Co., Ltd.)) using known methods. The method of coating the dental glass composition onto the substrate of a dental restoration having a ceramic surface is not particularly limited, and known methods can be used. Examples of dental restorations obtained using the glass composition of the present invention include, for example, metal-ceramic dental restorations and all-ceramic dental restorations that have been repaired using alumina cores, zirconia cores, etc. Specifically, examples of dental restorations include inlays, full-coverage crowns, fabricated prostheses (bridges), and implant superstructures with a portion of the gum line.

[0074] The dental glass composition of the present invention can be colored by directly applying it to a substrate of a dental restoration with a ceramic surface as a porcelain colorant using both internal and surface colorant methods, followed by firing. Furthermore, when the substrate of a dental restoration with a ceramic surface is zirconia, which has become increasingly transparent in recent years, the zirconia frame itself can be selected to be ivory-colored. Using the internal colorant method as a porcelain colorant, the glass composition of the present invention can be directly applied to the zirconia and fired to achieve color. Here, "direct application" means applying the mixture in its original state without undergoing a paste-forming process involving the addition of a special liquid (including water, ethanol, etc.). From another perspective, the present invention provides the use of a dental glass composition comprising glass powder (A) and a wax component (B) as a porcelain colorant of the "direct application" type. The dental glass composition of the present invention can be solid at room temperature. Even when solid at room temperature, the dental glass composition of the present invention can be used as a porcelain colorant for "direct application". In one embodiment, the dental glass composition of the present invention can be used as a tinting composition for ceramic crown porcelain materials.

[0075] The dental glass composition of the present invention can easily be applied to the substrate of dental restorations with ceramic surfaces, mimicking the characteristics (hereinafter sometimes referred to as "features") of teeth. That is, in addition to being used alone like charcoal or crayons for sketching, the dental glass composition of the present invention can also easily depict fine features such as enamel cracks and capillary cracks by sharpening the tip into a pencil shape. Furthermore, by attaching it to a blush brush, a sponge-like eyeshadow brush, etc., and applying it to the substrate of dental restorations with ceramic surfaces by rubbing, it is possible to achieve variations in tone depth (tone gradation, blending), etc., and these can be developed in various methods. It should be noted that features refer to, for example, the white band of natural teeth; staining, discoloration, fading, enamel cracks, and micro-cracks infiltrated with coloring components at the neck of the tooth, proximal surfaces, etc.

[0076] When using conventional porcelain colorants, a fixed firing process is performed after the colorant is applied. That is, when using conventional porcelain colorants, a fixed firing process is necessary to prevent the colorant from seeping or flowing out after the colorant is applied and before the surface layer of porcelain is stacked. Furthermore, to simulate the internal structure of natural teeth, such as dentin, coloring is required from the incisal edge of the dental restoration towards the cervical region along a vertical direction. The representation of white bands, etc., must be achieved by repeatedly applying porcelain colorant in a mesiodistal (mesiodistal) horizontal direction. Each time the coloring direction is changed, a fixed firing process is required to prevent confusion.

[0077] On the other hand, unlike conventional porcelain colorants, the dental glass composition of the present invention is a non-flowing solid. Therefore, the coated dental glass composition has good fixation, eliminating the need for fixing and firing during each repeated coating. Furthermore, even when dental porcelain is stacked on the surface without fixing and firing after coating the dental glass composition of the present invention, the final dental restoration also exhibits good fixation, preventing seepage or runoff. Additionally, no foaming or blackening occurs during subsequent firing when dental porcelain is stacked, thus eliminating the need for a fixing and firing step. Therefore, in the manufacturing method of the dental restoration of the present invention, a dental restoration can be obtained with only one firing after coating the substrate with the dental glass composition and then stacking the dental porcelain, simplifying the manufacturing process and significantly improving manufacturing efficiency.

[0078] After applying the dental glass composition of the present invention, in the case of the internal coloring agent method, the dental restoration is completed by stacking dental porcelain and firing it, adjusting it to conform to the shape of a natural tooth in order to express the shape of the crown, and performing a polishing (self-polishing) process in which only the surface layer of the dental porcelain melts to obtain a gloss. It should be noted that the dental glass composition of the present invention can also be used in the surface coloring agent method, where coloring is performed simultaneously with glazing using polishing glass with a low melting temperature to reveal a gloss after adjusting to the final shape. There is no particular limitation on the dental porcelain used in the manufacturing method of the dental restoration of the present invention, and known dental porcelain can be used. As known dental porcelain, commercially available products can be used (e.g., Celavian (registered trademark) ZR Premium LF Extinction (manufactured by Clareno Resorts)).

[0079] The calcination temperature (maximum calcination temperature) after stacking dental porcelain materials in this invention can be appropriately varied depending on the type and application of the dental porcelain materials. Therefore, there is no particular limitation as long as the inorganic pigment can develop color. Preferably, it is 700°C or higher, more preferably 730°C or higher, and even more preferably 750°C or higher. The upper limit of the calcination temperature is not particularly limited, but preferably below 1100°C, more preferably below 1050°C, and even more preferably below 1000°C. The heating rate up to the maximum calcination temperature can be appropriately varied depending on the type of porcelain material and is not particularly limited. Preferably, it is about 10–70°C / minute, more preferably about 20–60°C / minute.

[0080] Specifically, dental fittings include crowns, frames, dentures, dentures, orthodontic products, and implant products. Dentures include, for example, crowns, bridges, inlays, onlays, and veneers. Orthodontic products include, for example, braces. Dental implant products include, for example, implants, bridge abutments, implant fixation devices, implant bridges, and implant rods.

[0081] Example

[0082] The present invention will be described in more detail below through embodiments, but the present invention is not limited to the following embodiments.

[0083] Solid dental glass compositions of Examples 1-9 and glass compositions of Comparative Examples 1 and 2 were prepared as follows, and their properties were evaluated. The results are shown in Tables 1-4.

[0084] [Examples 1-9]

[0085] Oil component (C) was added to the wax component (B) that had molten in a container heated on a stirrer at 120°C, in the manner specified in Tables 1-3 by mass%. Then, glass powder (A-1) (CeraVian (registered trademark) ZR Premium LF Extender: manufactured by Clareno Richard Dental Co., Ltd.) or glass powder (A-2) (CeraVian (registered trademark) ZR Premium LF Extender: manufactured by Clareno Richard Dental Co., Ltd.) was added and mixed until homogeneous using a metal spatula. The resulting mixture was poured into a mold with dimensions of 20.0 mm in length, 1.5 mm in width, and 1.5 mm in depth, and allowed to cool and solidify, thereby producing a solid dental glass composition.

[0086] [Comparative Examples 1-2]

[0087] Weigh each component listed in Table 4 onto a glass plate in the manner indicated by the mass percentage listed in the table, and mix directly with a spatula to obtain a paste-like composition.

[0088] [Preparation of Zirconia Sintered Body]

[0089] Commercially available dental zirconia (Katana (registered trademark) zirconia STML: manufactured by Clareno Ritak Dental Co., Ltd.) was processed into a cylindrical shape with a diameter of approximately 18 mm, and calcined at 1550°C for 2 hours using a calcination furnace "Noritak Katana (registered trademark) F-1" manufactured by SK Mediakal Electronics Co., Ltd., thereby obtaining a sintered zirconia body.

[0090] [Evaluation methods for fixedity]

[0091] On the surface of the aforementioned prepared zirconia sintered body, lines were drawn using the aforementioned prepared dental glass composition. A substance obtained by kneading porcelain material (ZR Premium LF Translucent - Center: Clareno Ritage Dental Co., Ltd.) with purified water was then stacked on top. The condition where the shape of the drawn lines was maintained was evaluated as "○", and the condition where the lines flowed with the porcelain material and could not maintain their shape was evaluated as "×" (n=3). The condition where the shape of the lines drawn with the dental glass composition was maintained for all samples was evaluated as "○", and even if only one line flowed with the porcelain material and could not maintain its shape, it was evaluated as "×".

[0092] [Methods for evaluating color development]

[0093] On the surface of the aforementioned zirconia sintered body, lines were drawn using the aforementioned dental glass composition. A substance obtained by kneading porcelain material (CeraVian (registered trademark) ZR Premium LF: manufactured by Clareno Richard Dental Co., Ltd.) with purified water was then stacked on top. After holding at 840°C for 1 minute, the clarity of the drawn lines was evaluated as "○", the lack of clarity and white appearance as "Δ", and the absence of any visible color development as "×" (n=3). The clarity of the lines drawn with the dental glass composition for all samples was evaluated as "○", even if only one line was unclear and white, it was evaluated as "Δ", and the absence of any visible color development was evaluated as "×".

[0094] [Table 1]

[0095]

[0096] [Table 2]

[0097]

[0098] [Table 3]

[0099]

[0100] [Table 4]

[0101]

[0102] As a result, Comparative Examples 1 and 2, which were paste-like, neither fixed nor developed color, thus resulting in compromised aesthetics as dental restorations. It can be inferred that when the paste-like composition originally required fixing and calcination, and porcelain was stacked after the paste composition was applied, the paste-like composition shifted from its original application site due to the influence of some of the porcelain mixed in, thus compromising aesthetics. On the other hand, Examples 1-9, as solid dental glass compositions, exhibited good fixation and color development even without fixing and calcination. Furthermore, in Examples 6-8, due to the high content of liquid components, the dental glass compositions were slightly soft, and their fixation and color development were rated as "Δ". Moreover, in Example 9, since the wax component (B) was only the second wax (B-2) with a lower melting point, the solid state of the dental glass composition was slightly soft, and its fixation and color development were rated as "Δ".

[0103] Industrial practicality

[0104] The glass composition of the present invention, by being made into a solid state with good fixation for dental restorations, exhibits almost no change in the glass composition itself over time. It allows for thin-film coating of dental restorations and has no flowability, thus enabling coating without exudation. It allows for easy fabrication of dental restorations with desired hues with good operability, and is therefore suitable for use as a dental glass composition. Furthermore, especially with the increasing demand for ceramic crowns and rising individual aesthetic requirements, the frequency of use of dental glass compositions is expected to increase; therefore, the dental glass composition of the present invention, which eliminates the need for fixed calcination, is useful.

Claims

1. A dental glass composition for coloring and tinting of dental fittings, comprising glass powder (A), a wax component (B), and an oil component (C), The glass powder (A) has an average particle size of 0.1 μm to 50 μm. The content of the glass powder (A) is 45% by mass or more and 91% by mass or less. The boiling point of the wax component (B) is below 370°C. The melting point of the wax component (B) is 50~100℃. The content of the wax component (B) is 7-65% by mass. The boiling point of the oil component (C) is 100~370℃. The oil component (C) is liquid at room temperature, i.e., 20~35℃. The content of the oil component (C) is 0.5~25% by mass.

2. The composition according to claim 1, wherein, The average particle size of the glass powder (A) is 0.1 μm to 35 μm.

3. The composition according to claim 1 or 2, wherein, The wax component (B) includes a high melting point wax (B-1) with a melting point above 75°C and below 120°C.

4. The composition according to claim 1 or 2, wherein, The content of the wax component (B) is 9-55% by mass.

5. The composition according to claim 1 or 2, wherein, The content of the oil component (C) is 0.6~15% by mass.

6. The composition according to claim 1 or 2, wherein it is a ceramic colorant.

7. A method for manufacturing dental restorations, comprising: The process of applying the composition of any one of claims 1 to 6 to a substrate of a dental restoration having a ceramic surface; and The process involves calcining the substrate coated with the composition, rather than calcining it after stacking dental porcelain.

8. The method for manufacturing dental restorations according to claim 7, wherein, The calcination temperature in the calcination process after stacking the dental porcelain material is 700~1100℃.

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