Hardened components for dental use

Abstract

This invention provides a dental curable composition that exhibits appropriate fluidity in a paste state, possesses fluorescence and high radiopacity similar to natural teeth, and conforms to the color stability test of ISO 4049:2019. [Solution] A dental curable composition comprising a specific amount each of a silica-based composite oxide powder composed of a polymerizable monomer (A), an amine compound, a fluorescent agent containing a phthalate ester, silica-based composite oxide primary particles (d) having a specific average primary particle size, and an X-ray contrast material consisting of crystalline rare earth metal fluoride primary particles (e) having a specific average primary particle size and specific crystallinity, wherein the total amount of (e) blended is 5 to 50 parts by mass per 100 parts by mass of (A), of which 2 to 25 parts by mass are included in the form of primary particles, and the remainder is included as aggregated particles with an average aggregated particle size of 3 to 30 μm.

Description

Technical Field

[0001] The present invention relates to a dental curable composition.

Background Art

[0002] Dental curable compositions mainly contain a polymerizable monomer (monomer), an inorganic filler (filler) composed of an aggregate of inorganic particles (inorganic powder particles), and a polymerization initiator. Among them, composite resin (hereinafter sometimes abbreviated as "CR") is one of the most frequently used materials in dental treatment as a material for repairing cavities after removing tooth defects and caries.

[0003] As composite resin, it is required to be excellent in various physical properties such as operability in a paste state before polymerization curing, aesthetic property (or transparency), mechanical strength, and X-ray contrast of the cured product obtained after polymerization curing. <​​​​​​​​​​In response to such problems, Patent Document 1 discloses a technique for improving various physical properties of a composite resin by using, in a specific quantitative ratio, two types of inorganic fine particles that exhibit zeta potentials (in water) with opposite polarities to each other and each have a specific average particle diameter and specific surface area. Specifically, as a dental curable composition having good dischargeability (having a consistency suitable for discharging from a syringe) and exhibiting appropriate fluidity that suppresses dripping of the paste, an inorganic filler (B) composed of particles such as silica-based composite oxides having an average particle diameter of 50 nm to 1 μm and a negative (minus) zeta potential; and an inorganic filler (C) composed of particles such as rare earth metal fluorides having a specific surface area of 25 to 100 m 2 / g (about 10 to 300 nm in terms of particle diameter) and a positive (plus) zeta potential are disclosed, which are included in amounts of 170 to 270 parts by mass and 5 to 50 parts by mass, respectively, per 100 parts by mass of the polymerizable monomer.

[0007] On the other hand, for the diagnosis of damaged parts of teeth, it is generally common to incorporate rare earth metal fluoride powder particles into dental curable compositions, which have X-ray contrast and are likely to obtain transparency close to that of natural teeth even when incorporated. In addition, in composite resins, there may be an aesthetic problem that the repaired part appears black in an environment that emits ultraviolet light or short-wavelength visible light after repair. To avoid this, a fluorescent agent may be added. Among them, phthalate-based fluorescent agents are widely used because they are easily available, and the repaired part added with this emits fluorescence similar to that of natural teeth and has excellent aesthetics.

[0008] However, when the above-mentioned phthalate ester-based fluorescent agent, an amine compound which is a component of a photopolymerization initiator, and rare-earth metal fluoride powder granules which are an X-ray contrast-enhanced acidic filler are used in combination, strong discoloration may be observed in the cured product after curing. Patent Document 2 discloses a technique to prevent discoloration by specifying the respective blending ratios, including the polymerizable monomer, as a solution to this problem. Specifically, Patent Document 2 describes a "curable composition comprising (A) a polymerizable monomer, (B) an amine compound, (C) a fluorescent agent containing a phthalate ester, and (D) an X-ray contrast-enhanced acidic filler consisting of inorganic particles containing fluorine atoms, wherein the composition contains 0.01 to 3.0 parts by mass of (B) the amine compound, 0.0005 to 0.05 parts by mass of (C) the fluorescent agent containing a phthalate ester, and 1 to 100 parts by mass of the X-ray contrast-enhanced acidic filler consisting of inorganic particles containing fluorine atoms, per 100 parts by mass of (A) the polymerizable monomer."

[0009] Furthermore, it is known that as the amount of rare-earth metal fluoride powders is increased to improve X-ray contrastability, the transparency of the hardened material decreases, making aesthetic restoration difficult. As a technology to solve this problem, Patent Document 3 discloses an X-ray opaque filler that can suppress the decrease in transparency of the hardened material after curing, characterized by comprising "a first powder mainly composed of crystalline rare-earth metal fluoride particles, wherein the full width at half maximum of the maximum intensity peak originating from the crystalline rare-earth metal fluoride particles in the X-ray diffraction pattern is 0.3° or more, and a second powder obtained by surface-treating the first powder," selected from the group comprising these two components. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] International Publication No. 2023 / 085201 brochure [Patent Document 2] Patent No. 6584338 [Patent Document 3] International Publication No. 2023 / 042598 Brochure [Overview of the project] [Problems that the invention aims to solve]

[0011] The present inventors focused on the fact that rare-earth metal fluoride particles with a positive zeta potential function as an X-ray contrast agent in the dental curable composition disclosed in Patent Document 1. They hypothesized that by applying the technology disclosed in Patent Document 2 to impart fluorescence without discoloration after curing, and by applying the technology disclosed in Patent Document 3 to enhance X-ray contrast while ensuring the transparency of the cured body, it would be possible to obtain a dental curable composition with appropriate fluidity in a paste state (with good dispensing properties while suppressing paste dripping, etc.), fluorescence similar to natural teeth, and high X-ray contrast properties, and conducted investigations accordingly.

[0012] However, while the dental curable compositions prepared in this manner exhibit appropriate fluidity, fluorescence, and radiopaquery in paste form, a new problem was discovered when the cured bodies were subjected to the color stability test specified in ISO 4049:2019. This test revealed that the cured bodies discolored over time, sometimes failing to meet the standard. Therefore, the present invention aims to provide a dental curable composition that exhibits appropriate fluidity in paste form, possesses fluorescence and high radiopaquery similar to natural teeth, and further conforms to the color stability test of ISO 4049:2019. [Means for solving the problem]

[0013] The present invention solves the above problems, and the first aspect of the present invention is a silica-based composite oxide powder (D) composed of polymerizable monomer (A): 100 parts by mass, amine compound (B): 0.01 to 3.0 parts by mass, phthalate ester (C): 0.0005 to 0.05 parts by mass, silica-based composite oxide powder (D) composed of silica-based composite oxide primary particles (d) having an average particle size of 50 nm to 1 μm: 170 to 270 parts by mass, and X-ray contrast material (E) composed of fluorine atom-containing inorganic particles: 5 to 50 parts by mass. It contains, The above (E) consists of a plurality of crystalline rare-earth metal fluoride primary particles (e) in which the full width at half maximum of the maximum intensity peak originating from the crystalline rare-earth metal fluoride in the X-ray diffraction pattern obtained by X-ray diffraction measurement is 0.3° or more, and the average primary particle size measured by electron microscopy is 10 to 300 nm. (e1), which is a portion of the plurality of crystalline rare earth metal fluoride primary particles (e), is dispersed in the composition as a plurality of primary particles, and the remainder (e2) is dispersed in the composition as a plurality of aggregated particles consisting only of (e2) whose average aggregated particle diameter, defined as the median diameter in the volume-based particle size distribution measured by laser diffraction-scattering, is 3 to 30 μm, and the amount of (e1) is 2 to 25 parts by mass per 100 parts by mass of polymerizable monomer (A). This is a dental curable composition characterized by the following:

[0014] In the above-described form of the dental curable composition (hereinafter also referred to as "the dental curable composition of the present invention"), it is preferable that (e) consists of ytterbium fluoride primary particles.

[0015] Furthermore, the amine compound (B) is the following general formula (1)

[0016] [ka]

[0017] (In the formula, R 1 and R 2 They are mutually independent, A substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, which may have a hydroxyl group or a halogen atom as a substituent; or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms excluding the substituent, which may have an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a thiomethyl group or a halogen atom as a substituent; R 3 teeth, The above-mentioned substituted or unsubstituted alkyl groups; the above-mentioned substituted or unsubstituted aryl groups; C2-C12 alkenyl groups; C1-C10 alkoxy groups; C1-C10 alkyloxycarbonyl groups; benzoyl groups having 7-12 carbon atoms excluding the substituent, which may have an alkyl-substituted amino group having 1-C6 carbon atoms as a substituent; acetyl groups; carboxyl groups; nitro groups; or cyano groups; n is an integer between 0 and 5. When n is between 2 and 5, there are multiple R 3 They may be different from each other, R 3 They may be joined together to form a ring. Preferably, it contains at least one tertiary aromatic amine compound represented by .

[0018] A second embodiment of the present invention is a method for producing a dental curable composition of the present invention, comprising a mixing step of mixing: 100 parts by mass of polymerizable monomer (A), 0.01 to 3.0 parts by mass of amine compound (B), 0.0005 to 0.05 parts by mass of phthalate ester (C), 170 to 270 parts by mass in terms of the total mass of (d) for a first raw material powder containing only the silica-based composite oxide primary particles (d) as inorganic primary particles, and 5 to 50 parts by mass in terms of the total mass of (e) for a second raw material powder containing only the crystalline rare earth metal fluoride primary particles (e) as inorganic primary particles; As the second raw material powder, a non-aggregated powder (E1) consisting of substantially non-aggregated particles of (e) and an agglomerated powder (E2) composed of agglomerated particles of (e) having an average agglomerated particle diameter of 3 to 30 μm is used, or a powder consisting only of (E2) is used. The aforementioned mixing step is (A): A first step of mixing e, in which 2 to 25 parts by mass of a second raw material powder is added based on the total mass of (e) converted to 100 parts by mass, and then the mixture is mixed so that (e) in the added second raw material powder is dispersed in the form of primary particles, and The process includes a second mixing step in which, after the first mixing step e, the agglomerated powder (E2) containing the remaining amount of (e) is added and then mixed in a manner that does not cause the agglomerated particles constituting (E2) to break down, The first raw material powder is mixed at any time between the start and end of the mixing process. The manufacturing method is characterized by the above.

[0019] Furthermore, a third embodiment of the present invention is a method for producing a dental curable composition of the present invention, comprising a mixing step of mixing a first raw material powder containing only the silica-based composite oxide primary particles (d) as inorganic primary particles, a second raw material powder containing only the crystalline rare earth metal fluoride primary particles (e) as inorganic primary particles, and a composite aggregate powder (F) composed of composite aggregate particles (f) formed by aggregation of (d) and (e), wherein the content of (e) is 2.0 to 92.6% by mass and the average aggregate particle diameter is 1 to 50 μm. In the aforementioned mixing step, As the second raw material powder, a non-aggregated powder (E1) consisting of substantially non-aggregated particles of (e) and an agglomerated powder (E2) composed of agglomerated particles of (e) having an average agglomerated particle diameter of 3 to 30 μm is used, or a powder consisting only of (E2) is used. The amount of the composite aggregated powder (F) blended is such that, when the amounts of (d) and (e) contained in (F) relative to 100 parts by mass of (A) are Q(Fd) and Q(Fe), respectively, Q(Fd) is 2 to 100 parts by mass and Q(Fe) is 2 to 25 parts by mass. The amount of the first raw material powder is such that the sum of the amount of (d) in terms of total mass relative to 100 parts by mass of (A) and Q(Fd) is between 170 and 270 parts by mass. The amount of the second raw material powder is such that the sum of the amount of (e) based on the total mass relative to 100 parts by mass of (A) and Q(Fe) is between 5 and 50 parts by mass. The aforementioned mixing step is The following steps are taken: (F) or (F) and the second raw material powder are blended in an amount equivalent to 2 to 25 parts by mass of the total mass of (e) contained in them relative to 100 parts by mass of (A), and then the mixture is mixed so that the (e) in the blended second raw material powder is dispersed in the form of primary particles; The process includes a second mixing step in which the agglomerated powder (E2) containing the remaining amount of (e) is added after the ed mixing step, and then mixed in a manner that does not cause the agglomerated particles constituting (E2) to break down. The first raw material powder is mixed at any time between the start and end of the mixing process. The manufacturing method is characterized by the above.

[0020] Furthermore, a fourth embodiment of the present invention is a flowable composite resin comprising the dental curing composition of the present invention. [Effects of the Invention]

[0021] According to the present invention, it is possible to obtain excellent effects such as exhibiting appropriate fluidity in a paste state, having fluorescence and high radiopacity similar to natural teeth, and conforming to the color stability test of ISO 4049:2019. [Modes for carrying out the invention]

[0022] The dental curable composition of the present invention is a dental curable composition obtained by applying the technologies of Patent Documents 2 and 3 to the dental curable composition disclosed in Patent Document 1, which is a "dental curable composition containing polymerizable monomer (A): 100 parts by mass, amine compound (B): 0.01 to 3.0 parts by mass, phthalate ester (C): 0.0005 to 0.05 parts by mass, silica-based composite oxide powder (D): 170 to 270 parts by mass composed of silica-based composite oxide particles (d) having an average particle diameter of 50 nm to 1 μm, and X-ray contrast material (E): 5 to 50 parts by mass composed of specific crystalline rare earth metal fluoride primary particles (e)". The present invention was obtained based on the finding that when some of the plurality of crystalline rare earth metal fluoride primary particles (e) are blended in an aggregated state, the composition conforms to the color stability test of ISO 4049:2019.

[0023] The reason why such effects are obtained is not necessarily clear, and the present invention is not bound by any logic, but the inventors believe it is due to the following mechanism.

[0024] In other words, in order to exhibit appropriate paste fluidity and maintain the transparency of the cured product, it is necessary to use crystalline rare-earth metal fluoride powders with a large specific surface area that have undergone mechanochemical treatment. However, Patent Document 2 states that the cause of discoloration is "because the presence of surface acid sites of YbF3 causes the unpaired electrons of the phthalate ester to become unevenly distributed, and hydrogen atoms of the phthalate ester are extracted by the amine compound, generating a colored substance." Therefore, it is thought that when such crystalline rare-earth metal fluoride powders are used, the above reaction originating from the surface acid sites of crystalline rare-earth metal fluoride powders such as YbF3 cannot be sufficiently suppressed, resulting in discoloration of the cured product after long-term storage. In contrast, when YbF3 is present as aggregated particles in the composition, the YbF3 particles inside the aggregated particles cannot react with the surrounding polymerizable monomers and dissolved phthalate ester-based fluorescent agents, and it is thought that discoloration originating from surface acid sites can be suppressed.

[0025] The present invention will be described in detail below. In this specification, unless otherwise specified, the notation "x~y" using numerical values ​​x and y means "x or greater and y or less". If a unit is attached only to the numerical value y in such notation, that unit shall also apply to the numerical value x. In this specification, the term "(meth)acrylic" means both "acrylic" and "methacrylic". Similarly, the term "(meth)acrylate" means both "acrylate" and "methacrylate", and the term "(meth)acryloyl" means both "acryloyl" and "methacryloyl".

[0026] 1. Dental curable composition of the present invention As described above, the dental curable composition of the present invention is based on the dental curable composition disclosed in Patent Document 1, to which the technologies disclosed in Patent Documents 2 and 3 are applied. Its main feature is the specification of the formulation (dispersion state in the composition) of the plurality of crystalline rare-earth metal fluoride primary particles (e) that serve as the X-ray contrast material (E). Therefore, other aspects, such as the various components and their raw materials, are not particularly different from those disclosed in Patent Documents 1 to 3. However, the following will focus on explaining each component of the dental curable composition of the present invention, including these other aspects.

[0027] <Polymerizable monomer (A)> The dental curable composition of the present invention contains a polymerizable monomer. As the polymerizable monomer, any polymerizable monomer used in conventional dental curable compositions, such as radical polymerizable monomers and cationic polymerizable monomers, can be used without particular limitation. Among these, it is preferable to use commonly used (meth)acrylate polymerizable monomers, specifically acidic group-containing (meth)acrylate polymerizable monomers, hydroxyl group-containing (meth)acrylate polymerizable monomers, and monofunctional and polyfunctional (meth)acrylate polymerizable monomers that do not have these substituents.

[0028] Examples of suitably usable (meth)acrylate polymerizable monomers include the following: Acidic group-containing (meth)acrylate polymerizable monomers include (meth)acrylic acid, N-(meth)acryloyl-p-aminobenzoic acid, 2-(meth)acryloyloxybenzoic acid, 2-(meth)acryloyloxyethylphenyl hydrogen phosphate, and 2-(meth)acryloyloxyethylphosphonic acid. Hydroxy group-containing (meth)acrylate polymerizable monomers include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 2,2-bis[(3-methacryloyloxy-2-hydroxypropyloxy)phenyl]propane, and 2,2-bis[4-(4-methacryloyloxy)-3-hydroxybutoxyphenyl]propane. Furthermore, examples of monofunctional and polyfunctional (meth)acrylate polymerizable monomers that do not have the above substituents include methyl (meth)acrylate, ethyl (meth)acrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, 1,6-bis(methacrylateethyloxycarbonylamino)trimethylhexane, and 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane.

[0029] Among these polymerizable monomers, bifunctional or more, and more preferably bifunctional to tetrafunctional polymerizable monomers, are preferred due to their high polymerizability and particularly high mechanical strength of the cured product. Furthermore, these polymerizable monomers may be used individually or mixed together.

[0030] <Amine compound (B)> The amine compound is incorporated as a polymerization initiator for the polymerizable monomer (A). There are no particular restrictions on the amine compound, and it can be appropriately selected depending on the purpose. Primary amine compounds, secondary amine compounds, and tertiary amine compounds can all be used, but among these, the tertiary amine compound is preferred from the viewpoint of odor and other factors.

[0031] Furthermore, there are no particular restrictions on the amine compound, and any compound in which all organic groups bonded to the nitrogen atom are aliphatic groups (however, they may have substituents) (hereinafter also referred to as "aliphatic amine compound") or amine compound in which one or more aromatic groups are directly bonded to the nitrogen atom (hereinafter also referred to as "aromatic amine compound") can be used.

[0032] As the amine compound, at least one amine compound selected from the group consisting of aliphatic amine compounds and aromatic amine compounds may be used. Among these, it is preferable to contain both the aliphatic amine compound and the aromatic amine compound. Furthermore, as will be described later, the curability achieved by using a photoacid generator in combination as a polymerization initiator is higher when both are used together than when the aliphatic amine compound and the aromatic amine compound are used individually, and the curing speed can be further improved. In addition, it is particularly preferable to use an aliphatic tertiary amine compound and an aromatic tertiary amine compound in combination, as this also has the effect of suppressing discoloration when the polymerized cured product is exposed to ultraviolet light such as sunlight.

[0033] There are no particular restrictions on the aliphatic amine compounds, and they can be appropriately selected depending on the purpose. Specifically, examples include aliphatic primary amine compounds such as 2-ethylhexylamine, n-butylamine, n-hexylamine, and n-octylamine; aliphatic secondary amine compounds such as diethylamine, dibutylamine, diallylamine, diisopropylamine, di-2-ethylhexylamine, and di-n-octylamine; and aliphatic tertiary amine compounds such as triethylamine, triethanolamine, tributylamine, triallylamine, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, N-methyldiethanolamine, N-ethyldiethanolamine, triethanolamine, and tri(isopropanol)amine.

[0034] Among these, the aliphatic tertiary amine compound in which two or more of the three saturated aliphatic groups bonded to the nitrogen atom have electron-withdrawing groups as substituents can obtain higher polymerization activity and even better storage stability. Among such aliphatic tertiary amine compounds, those with two electron-withdrawing saturated aliphatic groups, such as N-methyldiethanolamine and N-ethyldiethanolamine, and those with three electron-withdrawing saturated aliphatic groups, such as triethanolamine and tri(isopropanol)amine, are particularly preferred. The aliphatic amine compound may be used alone or in combination of two or more.

[0035] The aromatic amine compound is not particularly limited and can be appropriately selected depending on the purpose. Examples include primary aromatic amine compounds such as aniline and toluidine; secondary aromatic amine compounds such as N-methylaniline and N-methyl-p-toluidine; and tertiary aromatic amine compounds in which at least one aryl group, which may have substituents, is bonded to a nitrogen atom.

[0036] Among these, considering their use in dentistry, the tertiary aromatic amine compound is preferred from the viewpoint of odor and the like. Further, in terms of exhibiting high polymerization activity, maintaining stability against environmental light and short-time polymerization curability by irradiation light, and being able to exhibit high cured product physical properties, it is particularly preferable to use the aromatic tertiary amine compound represented by the general formula (1).

[0037]

Chemical formula

[0038] In the above general formula (1), R 1 and R 2 are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms which may have a hydroxyl group or a halogen atom as a substituent; or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms excluding the carbon atoms of the substituent, which may have an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a thiomethyl group or a halogen atom as a substituent; R 3 is the above substituted or unsubstituted alkyl group; the above substituted or unsubstituted aryl group; an alkenyl group having 2 to 12 carbon atoms; an alkoxy group having 1 to 10 carbon atoms; an alkyloxycarbonyl group having 1 to 10 carbon atoms; an acetyl group, a carboxy group, a nitro group, a cyano group or a benzoyl group having 7 to 12 carbon atoms excluding the carbon atoms of the substituent, which may have an alkyl group having 1 to 6 carbon atoms as a substituent on the amino group. Further, n represents an integer of 0 to 5. When n is 2 or more, a plurality of R 3 may be the same as or different from each other. Further, R 3 may combine with each other to form a ring. In the above formula, it is preferable that n is 1 and the bonding site of R 3 is the para position or the ortho position.

[0039] Examples of the substituted or unsubstituted alkyl groups include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, n-hexyl group, fluoromethyl group, 2-fluoroethyl group, trifluoromethyl group, and 2-hydroxyethyl group. Among these, unsubstituted alkyl groups having 1 to 3 carbon atoms (e.g., methyl group, ethyl group, n-propyl group) and 2-hydroxyethyl group are particularly preferred.

[0040] Examples of the substituted or unsubstituted aryl groups include phenyl group, p-methoxyphenyl group, p-methylthiophenyl group, p-chlorophenyl group, and 4-biphenylyl group.

[0041] Examples of the alkenyl group include vinyl, allyl, and 2-phenylethenyl groups. Examples of the alkoxy group include methoxy, ethoxy, and butoxy groups. Examples of the alkyloxycarbonyl group include methoxycarbonyl, ethoxycarbonyl, butoxycarbonyl, amyloxycarbonyl, isoamyloxycarbonyl, and 2-ethylhexyloxycarbonyl groups. Examples of the benzoyl group which may have an alkyl-substituted amino group include benzoyl and 4-dimethylaminobenzoyl groups.

[0042] Also, if n=1, R 3 The bonding position is preferably the para position, and among them R 3 It is preferable that the group is an alkyloxycarbonyl group. On the other hand, when n is 2 to 3, it is preferable that the bonded position is at least one of the ortho and para positions. In particular, multiple R 3 The bonding of the ortho and para positions improves the sunlight stability of the cured body.

[0043] Specific examples of compounds of the general formula (1) that can be suitably used include N,N-dimethylaniline, N,N-dibenzylaniline, N,N-dimethyl-p-toluidine, N,N-diethyl-p-toluidine, N,N-dimethyl-4-trifluoromethylaniline, N,N-di(β-hydroxyethyl)-p-toluidine, N,N-dimethylaminobenzoic acid, 4-N,N-dimethylaminobenzoate ethyl, 2-N,N-dimethylaminobenzoate ethyl Examples include methyl 3-N,N-dimethylaminobenzoate, amyl 4-N,N-dimethylaminobenzoate, isoamyl 4-N,N-dimethylaminobenzoate, ethylhexyl 4-N,N-dimethylaminobenzoate, 4'-dimethylaminoacetophenone, N,N-dimethyl-4-nitroaniline, 4-dimethylaminobenzonitrile, 4-dimethylaminobenzophenone, and 4,4'-bis(dimethylamino)benzophenone.

[0044] The aromatic amine compound may be used alone or in combination of two or more.

[0045] Furthermore, when the aliphatic amine compound and the aromatic amine compound are used in combination, the preferred mixing ratio of the aliphatic amine compound to the aromatic amine compound is 1:99 to 99:1 by mass, and more preferably 3:97 to 97:3.

[0046] The amount of the amine compound must be 0.01 to 3 parts by mass per 100 parts by mass of the polymerizable monomer. In particular, to better exhibit the effects of the present invention, it is preferable that the amount of the amine compound be 0.02 to 2 parts by mass. When an aliphatic amine compound and an aromatic amine compound are used in combination, the amount of the amine compound is the total amount of the aliphatic amine compound and the aromatic amine compound.

[0047] <Phthalate (C)> The dental curable composition of the present invention contains a phthalate ester (C) that functions as a fluorescent agent. Any known phthalate ester can be used without any limitations. A particularly preferred phthalate ester system is represented by the following general formula (2). Note that R in the formula 4 and R 5 Each of these is independently an alkyl group, preferably an alkyl group having 1 to 3 carbon atoms, and R 6 R is a hydrogen atom, an amino group, or a hydroxyl group. 7 It is an amino group or a hydroxyl group.

[0048] [ka]

[0049] Examples of alkyl groups include methyl, ethyl, n-propyl, and i-propyl groups, with those having 1 to 2 carbon atoms being particularly preferred.

[0050] Specific examples of phthalate esters include dimethyl 2,5-dihydroxyterephthalate, diethyl 2,5-dihydroxyterephthalate, dimethylaminoterephthalate, and diethylaminoterephthalate. Fluorescent agents containing phthalate esters substituted with hydroxyl groups, such as diethyl 2,5-dihydroxyterephthalate, are preferred because they emit fluorescence similar to natural teeth and exhibit strong coloration. These phthalate esters may be used individually or in combination of two or more.

[0051] The amount of phthalate ester added must be 0.0005 to 0.05 parts by mass per 100 parts by mass of polymerizable monomer (A).

[0052] If the amount of phthalate ester is less than 0.0005 parts by mass, sufficient fluorescence close to that of natural teeth cannot be obtained. On the other hand, if it exceeds 0.05 parts by mass, yellow discoloration occurs when the amine compound (B) is used in combination with the X-ray contrast agent (E) described later, making it difficult to achieve aesthetically pleasing restorations that match the color of natural teeth. Therefore, considering fluorescence, aesthetics, etc., the amount of phthalate ester is preferably 0.001 to 0.04 parts by mass per 100 parts by mass of polymerizable monomer (A).

[0053] <Silica-based composite oxide powder (D)> The silica-based composite oxide powder (D) contained in the dental curable composition of the present invention is composed of silica-based composite oxide primary particles (d) having an average primary particle diameter of 50 to 1 μm as measured by an electron microscope.

[0054] Here, the average primary particle diameter refers to a value measured using a scanning or transmission electron microscope as follows: By performing image analysis on 30 or more, preferably 100 or more, primary particles randomly selected from electron microscope images where light and dark are clearly defined and the particle contours can be discerned, the equivalent circular diameter of each primary particle (the diameter of a circle with the same area as the target particle) is calculated: X i Find X from the 1st to the nth item. i 3 Sum: ΣX i 3 Based on this, the formula is: X={(ΣX i 3 ) / n} 1 / 3 This refers to the average particle (volume) diameter: X calculated by [the specified method].

[0055] From the viewpoint of improving the polishability of the cured product when incorporated into dental curable compositions, the average primary particle size of the silica-based composite oxide powder (D) is preferably 0.15 to 1.0 μm, and more preferably 0.15 to 0.8 μm.

[0056] The shape of the silica-based composite oxide primary particles (d) is not particularly limited, and spherical, substantially spherical, or irregularly shaped particles can be used. However, from the viewpoint of excellent wear resistance and surface smoothness of the cured product of the dental curable composition, spherical or substantially spherical particles are preferred. The term "substantially spherical" refers to the maximum length of each particle determined by image analysis performed on 30 or more, preferably 100 or more, primary particles (d) selected from the images used to measure the average particle diameter, with the longest length being the major axis: L i and the minimum width which is the diameter in the direction perpendicular to the major axis: B i Ratio to: B i / L i The sum of the first nth elements: ΣB i / L i Based on this, the formula is: Pr=(ΣB i / L i The mean homogeneity Pr, defined as ) / n, is 0.6 or higher. A mean homogeneity of 0.7 or higher is preferable, and 0.8 or higher is particularly preferable. The upper limit of the mean homogeneity is 1.

[0057] The silica-based composite oxide powder (D) is composed of silica-based composite oxide primary particles (d), but its formulation is not particularly limited. It may be formulated as primary particles, as aggregated particles formed by the aggregation of primary particles (d), as composite aggregated particles (f) formed by aggregation with crystalline rare-earth metal fluoride primary particles (e), or as organic-inorganic composite particles consisting of a composite of resin and primary particles. However, when formulated as organic-inorganic composite particles, it tends to be less likely to interact with crystalline rare-earth metal fluoride primary particles (e). Therefore, it is preferable that the proportion of (d) formulated in other forms that can be dispersed in the composition as primary particles be 70% by mass or less, particularly 60% by mass or less, of the silica-based composite oxide powder (D) {total silica-based composite oxide primary particles (d)}, and that the proportion of (d) formulated in other forms that can be dispersed in the composition as primary particles be 30% by mass or more, particularly 40% by mass.

[0058] The material of the silica-based composite oxide primary particles (d) can be a composite oxide such as silica-zirconia, silica-titania, silica-titania-barium oxide, silica-titania-zirconia, borosilicate glass, aluminosilicate glass, or fluoroaluminosilicate glass, which are commonly used as fillers in conventional dental curing compositions. It is preferable to use a silica-based composite oxide such as silica-zirconia, silica-titania, silica-titania-barium oxide, or silica-titania-zirconia, as these are commonly used and readily available, with silica-zirconia being more preferable.

[0059] Furthermore, it is preferable that (d) is composed of the same type of material, that is, that they have the same chemical structure.

[0060] The amount of silica-based composite oxide powder (D) incorporated into the dental curable composition of the present invention, in other words, the total amount of silica-based composite oxide primary particles (d) regardless of their form of incorporation, is 170 to 270 parts by mass, more preferably 180 to 250 parts by mass, per 100 parts by mass of polymerizable monomer (M). If the above amount is less than 170 parts by mass, the mechanical strength of the cured product of the dental curable composition tends to decrease, and if it exceeds 270 parts by mass, the dischargeability deteriorates.

[0061] Incidentally, silica-based composite oxide primary particles (d) are generally known to have acid spots on their surface. However, silica-based composite oxide powders incorporated into dental curable compositions are surface-treated with surface treatment agents such as silane coupling agents to improve the interfacial strength with the cured body formed by the polymerization of polymerizable monomers. Therefore, the number of acid spots or acid intensity is significantly lower than that of crystalline rare-earth metal fluoride primary particles (e). This can be measured by the following method a * m a and a * m b Difference: a * m a -a * m b Δa defined as* m(=a * m a -a * m b This is evident from the fact that the value of ) is 10-30 for crystalline rare-earth metal fluoride primary particles (e), while it is less than 10 for surface-treated silica-based composite oxide primary particles (d). That is, after drying inorganic powders at 100°C for more than 3 hours, they are stored in a desiccator containing phosphorus pentoxide, 1 g is placed in a sample vial, then 3 g of anhydrous toluene is added and shaken vigorously to disperse without agglomeration, and then the sample vial is allowed to stand to allow the filler to settle, and after complete settling, the colorimeter, which has been pre-measured with a standard on a white background, is placed so that the measurement hole is at the center of the bottom of the sample vial, and the color difference is measured on a black background to obtain a * The value is a * m b The value becomes a * m b After measuring the value, one drop (approximately 0.016 g) of anhydrous toluene solution of 0.004 mol / L methyl red, stored in the light-shielded container, was added to the sample vial, and after shaking and standing, the color difference was measured. * The value is a * m a And so, a before and after dropping of methyl red solution * The difference is Δa * It becomes m.

[0062] Therefore, it is desirable that the silica-based composite oxide primary particles (d) are surface-treated with a surface treatment agent such as a silane coupling agent. Examples of the surface treatment method include known methods, and examples of the silane coupling agent include methyltrimethoxysilane, methyltriethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and hexamethyldisilazane.

[0063] As described above, the silica-based composite oxide primary particles (d) may be incorporated in the form of an organic-inorganic composite powder composed of organic-inorganic composite particles made of a composite (composite material) of a resin and the primary particles. In this case, the content of the silica-based composite oxide primary particles (d) in the composite material is usually 60 to 90% by mass, preferably 70 to 90% by mass. Also, from the viewpoints of dischargeability when discharging with a syringe and mechanical strengths such as the bending strength of the cured body, the average particle diameter of the organic-inorganic composite powder is preferably 1 to 100 μm. The average particle diameter of the organic-inorganic composite powder corresponds to the average value of the particle diameters of a plurality of organic-inorganic composite particles and means the average particle diameter defined as the median diameter in the volume-based particle size distribution measured by the laser diffraction-scattering method.

[0064] The organic-inorganic composite powder may be obtained by polymerizing a mixture of silica-based composite oxide primary particles (d), a polymerizable monomer, and a polymerization initiator and then pulverizing it. Alternatively, it may be a microporous organic-inorganic composite powder obtained by immersing an aggregated powder composed of inorganic aggregated particles in which the silica-based composite oxide primary particles (d) are aggregated in a polymerizable monomer solution containing a polymerizable monomer, a polymerization initiator, and an organic solvent, removing the organic solvent, and then polymerizing and curing the polymerizable monomer. The above aggregated powder can be obtained, for example, by spray-drying an aqueous dispersion containing the powder composed of (d). As the polymerizable monomer, those described as the polymerizable monomer (A) above can be used without particular limitation. As the polymerization initiator, those described as being optionally added to the dental curable composition described later can be used without particular limitation.

[0065] <X-ray contrast agent (E)> The X-ray contrast material (E) is composed of fluorine atom-containing inorganic particles, specifically, multiple crystalline rare-earth metal fluoride primary particles (e) whose maximum intensity peak originating from crystalline rare-earth metal fluorides in the X-ray diffraction pattern obtained by X-ray diffraction measurement has a full width at half maximum of 0.3° or more, and whose average primary particle size measured by electron microscopy is 10 to 300 nm. In other words, the crystalline rare-earth metal fluoride primary particles (e) themselves can be said to have the function of an X-ray contrast material (E).

[0066] Examples of crystalline rare-earth metal compounds include ytterbium fluoride (YbF3), lanthanum fluoride (LaF3), cerium fluoride (CeF3), and gadolinium fluoride (GdF3). However, from the viewpoint of X-ray opacity, ytterbium fluoride is the most preferable. Crystallinity can be determined by whether or not peaks based on crystal planes are observed during X-ray diffraction measurements.

[0067] In the dental curable composition of the present invention, in order to provide the cured body with high radiopaqueness and good aesthetics, the amount of crystalline rare earth metal fluoride primary particles (e) that function as an X-ray contrast agent (E) must be 5 to 50 parts by mass per 100 parts by mass of polymerizable monomer (A). Furthermore, in order to obtain the above effects while also conforming to the color stability test of ISO 4049:2019, a portion of the plurality of crystalline rare earth metal fluoride primary particles (e), namely (e1), is dispersed in the composition as a plurality of primary particles, and the remainder, namely (e2), is dispersed in the composition as aggregated particles consisting only of (e2) whose average aggregated particle diameter, defined as the median diameter in the volume-based particle size distribution measured by laser diffraction-scattering, is 3 to 30 μm, and the amount of (e1) must be 2 to 25 parts by mass per 100 parts by mass of polymerizable monomer (A).

[0068] The above-mentioned crystalline rare-earth metal fluoride primary particles (e) function as "inorganic filler (C) consisting of particles such as rare-earth metal fluorides with a positive zeta potential" in Patent Document 1 and "X-ray contrast-enhancing acidic filler" in Patent Document 2, and correspond to the particles constituting "a first powder that mainly contains crystalline rare-earth metal fluoride particles and has a full width at half maximum of the maximum intensity peak originating from the crystalline rare-earth metal fluoride particles in the X-ray diffraction pattern of 0.3° or more" which becomes an X-ray opaque filler in Patent Document 3. Therefore, even if a relatively large amount is added, the transparency of the cured product is not likely to decrease, however, as mentioned above, Δa * Because it has surface acid sites where m is between 10 and 30, if it is blended in an amount exceeding 50 parts by mass per 100 parts by mass of (A) in a form that uniformly disperses it in the composition, the formation of colored substances due to the reaction of coexisting amine compounds with phthalate esters is unavoidable. Furthermore, even if it is less than 50 parts by mass, if it is included in an amount exceeding 25 parts by mass, discoloration will occur after long-term storage of the cured product. On the other hand, if (e) is blended as aggregated particles, the influence of surface acid sites can be reduced and the above problems can be prevented, but the interaction with silica-based composite oxide primary particles (d) decreases, making it difficult to obtain good paste properties.

[0069] Therefore, from the viewpoint of effectiveness, in the dental curable composition of the present invention, the amount of (e1) in which crystalline rare earth metal fluoride primary particles (e) are uniformly dispersed in the composition is limited to the above range, and the remaining (e2) is dispersed in the composition as aggregated particles. The amounts of X-ray contrast agent (E) {total amount of crystalline rare earth metal fluoride primary particles (e)} and (e1) per 100 parts by mass of polymerizable monomer (A) are particularly preferably (E): 10 to 40 parts by mass and (e1): 5 to 20 parts by mass, respectively.

[0070] Furthermore, from the viewpoint of the transparency of the cured body, the full width at half maximum of the maximum intensity peak originating from the crystalline rare earth metal fluoride in the X-ray diffraction pattern of the crystalline rare earth metal fluoride primary particles (e) is preferably 0.4° or more, and more preferably 0.5° or more.

[0071] Since the full width at half maximum of the maximum intensity peak of industrially available crystalline rare-earth metal fluoride powders is usually less than 0.3°, it is necessary to perform a mechanochemical treatment as disclosed in Patent Document 3 in order to make the full width at half maximum of the maximum intensity peak 0.3° or more. Treatment using a wet bead mill is particularly preferred due to its productivity and ease of handling.

[0072] The content (dispersion state) of (e1) and (e2) in the dental curable composition of the present invention can be confirmed by FE-SEM image observation or the like.

[0073] Furthermore, the form of the crystalline rare earth metal fluoride primary particles (e), that is, the control of the amounts of (e1) and (e2), can be controlled by the form of the raw material powder used as the source of crystalline rare earth metal fluoride primary particles (e) during the preparation of the dental curable composition of the present invention and by the kneading method during preparation. This point will be explained in detail in the description of the manufacturing method of the present invention, but (e) is preferably a raw material powder in one of two or three forms: "aggregated powder (E2) composed of aggregated particles of (e) with an average aggregated particle diameter of 3 to 30 μm", "non-aggregated powder (E1) consisting of (e) in a substantially non-aggregated state", and / or "composite aggregated powder (F) composed of composite aggregated particles (f) formed by the aggregation of (d) and (e), with an (e) content of 7.4 to 98.1% by mass and an average aggregated particle diameter of 1 to 50 μm", and it is particularly preferable that it be a form that includes (E2) and (F).

[0074] In other words, it is preferable to use composite agglomerated powder (F) because it facilitates interaction between (d) and (e1). When composite agglomerated powder (F) is used, the crystalline rare earth metal fluoride (e1) and silica-based inorganic compound primary particles (d) are in contact with each other within the composite agglomerated particles (f), which is thought to facilitate interaction.

[0075] Furthermore, from the viewpoint of dispersibility, the average composition of the individual composite aggregate particles (f) constituting the composite aggregate powder (F), that is, the total mass of (e1) relative to the total mass of (d) in the composite aggregate powder (F): 100 parts by mass, is preferably in the range of 20 to 300 parts by mass {expressed as the content of (e), it is preferably in the range of 16.7 to 75% by mass}, and the average aggregate particle diameter is preferably 1 to 50 μm.

[0076] <Photopolymerization initiator> The dental curable composition of the present invention may contain components other than (B) above that function as a photopolymerization initiator, or more specifically, a reducing agent for the photopolymerization initiator. The photopolymerization initiator can be any that is commonly used in direct dental filling and restoration applications, which often involve curing in the oral cavity. Examples of such photopolymerization initiators include benzoin alkyl ethers such as benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; benzyl ketals such as benzyl dimethyl ketal and benzyl diethyl ketal; benzophenones such as benzophenone, 4,4'-dimethylbenzophenone, and 4-methacryloxybenzophenone; α-diketones such as diacetyl, 2,3-pentadione benzyl, camphorquinone, 9,10-phenanthraquinone, and 9,10-anthraquinone; and 2,4-diethoxythioxanthone. Examples include thioxanthone compounds such as 2-chlorothioxanthone and methylthioxanthone, and bisacylphosphine oxides such as bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

[0077] Furthermore, other reducing agents besides the amine compound (B) can be used as photopolymerization initiators. Examples include aldehydes such as lauryl aldehyde, dimethylaminobenzaldehyde, and terephthalaldehyde, and sulfur-containing compounds such as 2-mercaptobenzoxazole, 1-decanethiol, thiosalicylic acid, and thiobenzoic acid.

[0078] Furthermore, in addition to the above-mentioned photopolymerization initiator and reducing agent, a photoacid generator may also be added. Examples of such photoacid generators include diaryliodonium salt compounds, sulfonium salt compounds, sulfonic acid ester compounds, halomethyl-substituted S-triazine derivatives, and pyridinium salt compounds.

[0079] These photopolymerization initiators may be used individually, but two or more may also be used in combination. The amount of photopolymerization initiators other than (B) above should be selected as an effective amount depending on the purpose, but it is usually used in a ratio of 0.01 to 10 parts by mass per 100 parts by mass of polymerizable monomer, and more preferably in a ratio of 0.1 to 5 parts by mass.

[0080] <Other additives> In the dental curable composition of the present invention, additives such as chemical polymerization initiators, polymerization inhibitors, pigments, and ultraviolet absorbers can be incorporated, as long as they do not impair its effect.

[0081] 2. Method for producing the dental curable composition of the present invention The dental curable composition of the present invention can be prepared by thoroughly mixing predetermined amounts of each of the above components and any optional components to obtain a paste, and then degassing this paste under reduced pressure to remove air bubbles. For mixing each component, it is preferable to use either method 1 or 2 described below.

[0082] Method 1: A mixing step comprising mixing 100 parts by mass of polymerizable monomer (A), 0.01 to 3.0 parts by mass of amine compound (B), 0.0005 to 0.05 parts by mass of phthalate ester (C), 170 to 270 parts by mass in terms of total mass of (d) for a first raw material powder containing only the silica-based composite oxide primary particles (d) as inorganic primary particles, and 5 to 50 parts by mass in terms of total mass of a second raw material powder containing only the crystalline rare earth metal fluoride primary particles (e) as inorganic primary particles, As the second raw material powder, a non-aggregated powder (E1) consisting of substantially non-aggregated particles of (e) and an agglomerated powder (E2) composed of agglomerated particles of (e) having an average agglomerated particle diameter of 3 to 30 μm is used, or a powder consisting only of (E2) is used. The aforementioned mixing step is (A): A first step of mixing e, in which 2 to 25 parts by mass of a second raw material powder is added based on the total mass of (e) converted to 100 parts by mass, and then the mixture is mixed so that (e) in the added second raw material powder is dispersed in the form of primary particles, and The process includes a second mixing step in which, after the first mixing step e, the agglomerated powder (E2) containing the remaining amount of (e) is added and then mixed in a manner that does not cause the agglomerated particles constituting (E2) to break down, A method comprising mixing the first raw material powder at any time between the start and end of the mixing process. Furthermore, (B) and (C) may be mixed at any time between the start and end of the mixing process. Also, in the first mixing step, it is possible to use a powder made of agglomerated particles of (e) with a different average agglomerated particle size instead of (E2) or together with (E2), but in Method 1, agglomerated powders other than (E2) are not used from the viewpoint of reducing the number of types of powders used.

[0083] Method 2: A mixing step comprising mixing a first raw material powder containing only the silica-based composite oxide primary particles (d) as inorganic primary particles, a second raw material powder containing only the crystalline rare earth metal fluoride primary particles (e) as inorganic primary particles, and a composite aggregate powder (F) composed of composite aggregate particles (f) formed by the aggregation of (d) and (e), wherein the content of (e) is 2.0 to 92.6% by mass and the average aggregate particle diameter is 1 to 50 μm. In the aforementioned mixing step, As the second raw material powder, a non-aggregated powder (E1) consisting of substantially non-aggregated particles of (e) and an agglomerated powder (E2) composed of agglomerated particles of (e) having an average agglomerated particle diameter of 3 to 30 μm is used, or a powder consisting only of (E2) is used. The amount of the composite aggregated powder (F) blended is such that, when the amounts of (d) and (e) contained in (F) relative to 100 parts by mass of (A) are Q(Fd) and Q(Fe), respectively, Q(Fd) is 2 to 100 parts by mass and Q(Fe) is 2 to 25 parts by mass. The amount of the first raw material powder is such that the sum of the amount of (d) in terms of total mass relative to 100 parts by mass of (A) and Q(Fd) is between 170 and 270 parts by mass. The amount of the second raw material powder is such that the sum of the amount of (e) based on the total mass relative to 100 parts by mass of (A) and Q(Fe) is between 5 and 50 parts by mass. The aforementioned mixing step is The following steps are taken: (F) or (F) and the second raw material powder are blended in an amount equivalent to 2 to 25 parts by mass of the total mass of (e) contained in them relative to 100 parts by mass of (A), and then the mixture is mixed so that the (e) in the blended second raw material powder is dispersed in the form of primary particles; The process includes a second mixing step in which the agglomerated powder (E2) containing the remaining amount of (e) is added after the ed mixing step, and then mixed in a manner that does not cause the agglomerated particles constituting (E2) to break down. A method comprising mixing the first raw material powder at any time between the start and end of the mixing process. Furthermore, (B) and (C) may be mixed at any time between the start and end of the mixing process. In addition, in the first ed mixing step, it is possible to use a powder made of agglomerated particles of (e) with a different average agglomerated particle size instead of (E2) or together with (E2), but in Method 2, agglomerated powders other than (E2) are not used from the viewpoint of reducing the number of types of powders used. In the ed mixing step, it is preferable to mix only (F).

[0084] The various powders and granules used as raw materials for the X-ray contrast material (E) in these manufacturing methods, as well as the mixing process, will be described in detail below.

[0085] <Constituent particles of the second raw material powder (e), (E1), and (E2)> As mentioned above, (e) contained in the second raw material powder corresponds to the "constituent particles of crystalline rare earth metal fluoride powder in which the maximum intensity peak of the X-ray diffraction pan derived from crystalline rare earth metal fluoride is 0.3° or higher by mechanochemical treatment" in Patent Document 3. (e), and furthermore, non-aggregated powder (E1) and aggregated powder (E2) which become the second raw material powder, can be prepared by the method (mechanochemical treatment) described in Patent Document 3. Specifically, a crystalline rare earth metal fluoride powder in which the full width at half maximum of the maximum intensity peak derived from crystalline rare earth metal fluoride in the X-ray diffraction pattern is less than 0.3° is used as the raw material powder for (e), and after wet bead milling treatment using water as the medium (dispersion medium), drying treatment is performed.

[0086] Wet bead milling is a type of mechanochemical treatment in which a slurry, obtained by mixing the powder to be treated with a medium (dispersion medium), is brought into contact with a media (beads) that has been moved by stirring or vibration, thereby imparting a crushing and pulverizing action to the powder. Examples of materials that can be used as the media include glass, alumina, zircon, zirconia, steel, and resin, but it is preferable to use alumina or zirconia beads because they have excellent wear resistance and relatively little contamination. The size of the beads used can be selected according to the average particle size of the target (e), and there are no particular restrictions, but it is preferable to use beads with a diameter of φ0.01 to 0.5 mm in order to obtain (e) which is suitable for incorporation into dental curable compositions. Furthermore, it is preferable to use water as the dispersion medium, but it is also possible to use water with an organic solvent added as needed. Examples of the organic solvent include ethanol, isopropyl alcohol, chloroform, and dimethylformamide.

[0087] Wet bead mills come in various operating methods, including batch type, where slurry and beads are directly fed into the machine for processing; circulating type, where slurry circulates between a tank and the machine; and pass type, where slurry passes through the machine a predetermined number of times. The appropriate operating method should be selected based on the amount of raw material powder used for processing. Circulating or pass-type bead mills are preferable due to their high productivity and ability to process relatively large quantities of inorganic powder.

[0088] Depending on the operating method, such as the circulation type or pass type described above, it may be necessary to separate the slurry and beads when performing mechanochemical treatment. Examples of bead separation methods include the slit type, screen type, and centrifugal separation type. These bead separation methods can be selected according to the particle size of the beads used, and any of these methods can be used without particular restriction. The concentration of the slurry used for mechanochemical treatment is usually 40 to 900 parts by mass of the dispersion medium per 100 parts by mass of the raw material powder.

[0089] Drying can be performed using an evaporator or a spray dryer, and by spray drying, it is possible to prepare only agglomerated powder (E2). For spray drying, methods such as using a high-speed airflow to atomize the slurry into fine droplets and spray them for drying, or dropping the mixed slurry onto a disc-shaped rotating body rotating at a speed of 1,000 to 50,000 rpm and using centrifugal force to atomize and dry it, can be employed. With such methods, it is difficult to obtain powder with an average (aggregated) particle diameter of 3 μm or less; therefore, the average agglomerated particle diameter of the agglomerated powder (E2) can be brought within the above range by cutting the coarser particles. Since an average agglomerated particle diameter exceeding 30 μm may reduce the mechanical strength, such as the bending strength, of the hardened dental hardening composition; therefore, an average agglomerated particle diameter of 3 to 25 μm is preferable.

[0090] The non-aggregated granular material (E1) consisting of (e) in a substantially non-aggregated state may contain a small amount of particles with a smaller aggregate particle diameter than the constituent particles of (E2). (E1) can be obtained, for example, by grinding the granular material obtained after drying as needed, and further removing aggregate particles with an aggregate particle diameter of 3 μm or more by classification.

[0091] <Composite agglomerated powder (F)> The composite aggregated powder (F) composed of the composite aggregated particles (f) can be suitably produced by spray drying a mixed slurry containing (d) and (e).

[0092] Specifically, it can be obtained by mixing a slurry 1 in which 100 parts by mass of (d) is dispersed in a dispersion medium and a slurry 2 in which 20 to 300 parts by mass of (e) is dispersed in a dispersion medium using a stirrer or the like, and then spray-drying the resulting homogeneous mixed slurry. By a manufacturing method including such a spray-drying step, a composite aggregated powder (F) can be obtained, which is composed of composite aggregated particles (f) in which (e) is uniformly dispersed among inorganic particles (d).

[0093] Slurry 1 is preferably obtained by dispersing a mixture of a dispersion medium and granular material consisting of (d). Water is preferably used as the dispersion medium, but water with an organic solvent added as needed may also be used. Examples of the organic solvent include ethanol, isopropyl alcohol, chloroform, and dimethylformamide. The amount of dispersion medium used is usually 40 to 900 parts by mass per 100 parts by mass of granular material consisting of (d).

[0094] The dispersion process can be carried out using a mixing device such as a bead mill. As slurry 2, the slurry obtained by the mechanochemical process can be used.

[0095] Examples of usable surface treatment agents include silane coupling agents such as vinyltriethoxysilane, vinyltrimethoxysilane, vinyltrith(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, κ-methacryloyloxidedecyltrimethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, γ-glycidoxypropyl-trimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl-trimethoxysilane, γ-ureidopropyl-triethoxysilane, γ-chloropropyltrimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, and methyltriethoxysilane, as well as titanate-based coupling agents.

[0096] The amount of surface treatment agent added is, for example, 0.1 to 10 parts by mass, preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the total of (d) and (e).

[0097] The spray drying method can involve using a high-speed airflow to atomize the mixed slurry into fine droplets and dry them, or dropping the mixed slurry onto a disc-shaped rotating body rotating at a rotational speed of 1,000 to 50,000 rpm and using centrifugal force to eject it in a mist for drying. From the viewpoint of obtaining a composite aggregated powder (F) consisting of composite aggregated particles (f) of uniform particle size, it is preferable to immediately dry the atomized mixed slurry with high-temperature air or an inert gas, and the temperature of the gas used for drying is preferably 60 to 300°C, and particularly preferably 80 to 250°C.

[0098] The composite aggregated powder (F) obtained by spray drying is preferably subjected to vacuum drying after spray drying, from the viewpoint of removing any remaining dispersion medium. Vacuum drying is generally carried out under reduced pressure of 0.01 to 100 hectopascals at 20 to 150°C for 1 to 48 hours. The inorganic powder obtained by spray drying may be pulverized as needed to adjust to an appropriate average particle size. As a pulverizing method, a vibrating ball mill, bead mill, jet mill, etc., can be used.

[0099] <Mixing process> In Method 1, the first raw material powder may be mixed at any time between the start and end of the mixing process, but it is preferable to mix the entire amount of the first raw material powder at the same time as or before the first mixing step e, so that at least a portion of (d) constituting the first raw material powder is uniformly dispersed as primary particles. Similarly, in Method 2, the first raw material powder may be mixed at any time between the start and end of the mixing process, but it is preferable to mix the entire amount of the first raw material powder at the same time as or before the mixing step ed, so that at least a portion of (d) constituting the first raw material powder is uniformly dispersed as primary particles.

[0100] Furthermore, in the first mixing step e in Method 1 and the ed mixing step ed in Method 2, it is preferable to perform the mixing (kneading) under conditions where the paste hardness, measured using a rheometer, is 3 kg or more, in order to ensure that (e) or (e) and (d) are reliably dispersed uniformly in the composition as primary particles. This can be done by confirming the dispersion state with an electron microscope and then terminating the mixing, or by adopting mixing conditions that have been confirmed to yield the desired dispersion state by checking the dispersion conditions with an electron microscope over time. Paste hardness refers to the maximum load when a pressure-sensitive rod with a diameter of 4 mm is compressed into the hole filled with paste at a loading speed of 240 mm / min to a loading depth of 2 mm using a rheometer (Sun Science Co., Ltd.). When this paste hardness is 3 kg or more, shear is easily applied to the paste, and (e) or (e) and (d) are easily dispersed uniformly in the composition as primary particles. The paste hardness is determined by the ratio of the polymerizable monomer solution to each powder. Therefore, after performing the first mixing step e in Method 1 and the ed mixing step ed in Method 2 in appropriate ratios, the remaining polymerizable monomer solution can be added in the second mixing step e in Methods 1 and 2. Here, the paste hardness is a value that varies depending on the desired dental curable composition and does not necessarily have to be this value. However, in that case, it is preferable to confirm the dispersion state using an electron microscope or the like, to ensure that (e) or (e) and (d) are reliably and uniformly dispersed in the composition as primary particles.

[0101] Furthermore, regarding the mixing in the second step (e) of Method 1 and Method 2, in order to ensure that the aggregated particles are uniformly dispersed in the composition without being destroyed, it is preferable to perform the mixing (kneading) under conditions where the viscosity measured using a CS rheometer is 150 Pa·s or less, confirm the dispersion state with an electron microscope, and then terminate the mixing, or to adopt mixing conditions that have been confirmed in advance to obtain the desired dispersion state by checking the dispersion conditions with an electron microscope over time. The viscosity was defined as the maximum viscosity measured using a CS rheometer (Anton Paar, MCR302) with a parallel plate, at a measurement temperature of 25°C and a shear rate of 5 / s. When this viscosity is 150 Pa·s or less, shear is less likely to occur in the paste, and the aggregated particles are more likely to be uniformly dispersed in the composition without being destroyed. Since the viscosity can be adjusted by the ratio of the polymerizable monomer solution to each granular material, an appropriate amount of polymerizable monomer solution can be added before adding the aggregated particles in the second step (e) of mixing in Method 1 and Method 2. Note that viscosity is a value that varies depending on the dental curing composition being sought, and it is not necessarily required to be this value. However, in such cases, it is preferable to check the dispersion state using an electron microscope or similar device to ensure that the aggregated particles are not destroyed. [Examples]

[0102] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. First, the substances used as raw materials for the compositions prepared in the examples and comparative examples, their abbreviations, and the methods for evaluating the above raw materials and the prepared compositions will be described.

[0103] 1. Raw materials and their abbreviations / codes (1) Polymerizable monomer (A) UDMA: 1,6-bis(methacrylateethyloxycarbonylamino)-2,2-4-trimethylhexane • 3G: Triethylene glycol dimethacrylate GMA: 2,2-bis[(3-methacryloyloxy-2-hydroxypropyloxy)phenyl]propane · D-2.6E: 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane.

[0104] (2) Amine compound (B) (2-1) Aliphatic amine compounds • N,N-dimethylaminoethyl methacrylate (DMEM) • N-methyldiethanolamine (MDEOA) Triethanolamine (TEOA).

[0105] (2-2) Aromatic amine compounds • 4-N,N-dimethylaminobenzoate ethyl (DMBE) • N,N-dimethyl-p-toluidine (DMPT) ·4'-Dimethylaminoacetophenone (DMA) ·4-Dimethylaminobenzophenone (DMB) 4-Dimethylaminobenzoic acid (DMBA) • N,N-dimethyl-4-nitroaniline (DMNA) • 4-Dimethylaminobenzoate isoamyl (DMBI) · 4,4'-bis(dimethylamino)benzophenone (BDAB) ·4-Dimethylaminobenzonitrile (DMBN) • N,N-dimethyl-4-trifluoromethylaniline (DMTFA).

[0106] (3) Fluorescent agents containing phthalates (C) • 2,5-Diethyl dihydroxyterephthalate (DHTP) • Dimethylaminoterephthalate (DATP).

[0107] (4) Silica-based composite oxide powder (D) • FD-1: Powdered material consisting of spherical silica-zirconia particles manufactured by the sol-gel method (average primary particle diameter 260 nm, average uniformity: 0.95) • FD-2: Powder / granular material consisting of amorphous silica-zirconia particles manufactured by the sol-gel method (average primary particle diameter 1000 nm, average uniformity: 0.95) • FD-3: Powdered material consisting of spherical silica-zirconia particles manufactured by the sol-gel method (average primary particle diameter: 40 nm, average uniformity: 0.90) • FD-4: Powdered material consisting of spherical silica-zirconia particles manufactured by the sol-gel method (average primary particle diameter 150 nm, average uniformity: 0.95) • FD-5: A powder / granular material consisting of amorphous silica-zirconia particles manufactured by the sol-gel method (average primary particle diameter 400 nm).

[0108] The average primary particle diameter is a value determined based on the method shown below. Furthermore, for each (D), the acidity (Δa * m) was measured using the method shown below. The physical properties of each (D) are shown in Table 1 along with the measurement results.

[0109] <Method for measuring the average primary particle diameter> A scanning electron microscope (Philips XL-30S) was used to take photographs of the powder at magnifications of 5,000 to 100,000 times. The captured images were processed using image analysis software (IP-1000PC, product name; manufactured by Asahi Kasei Engineering Co., Ltd.), and the average primary particle diameter was determined based on the number of particles (100 or more) observed within the unit field of view of the photograph.

[0110] Measurement of the acidity of the surface of inorganic particles constituting inorganic granules (Δa using methyl red) * )> After drying at 100°C for more than 3 hours, 1 g of inorganic granules stored in a desiccator containing phosphorus pentoxide was placed in a sample tube with an inner diameter of approximately 16 mm. Then, 3 g of anhydrous toluene was added and the sample tube was shaken vigorously to disperse the material without any aggregates. The sample tube was then allowed to stand to allow the inorganic granules to settle. After complete settling, a colorimeter (TC-1800MKII, manufactured by Tokyo Denshoku Co., Ltd.), which had previously measured a standard against a white background, was placed so that its measuring hole was centered at the bottom of the sample tube, and the color difference was measured against a black background. * The value a * mb The following was done. After measuring the color difference, one drop (approximately 0.016 g) of anhydrous toluene solution of 0.004 mol / L methyl red (Tokyo Chemical Co., Ltd.), stored under light shielding, was added to the sample vial, and after shaking and standing, the color difference was measured again. * The value a * m a The formula is: Δa * m=a * m a -a * m b From, Δa * We found m.

[0111] [Table 1]

[0112] (5) Crystalline rare earth metal fluoride powder • YbF3-40:3 Ytterbium fluoride (average primary particle size 46 nm, manufactured by Treibacer) • YbF3-300:3 Ytterbium fluoride (average primary particle size 270 nm, manufactured by Treibacer).

[0113] (6) Photopolymerization initiator Camphorquinone (CQ).

[0114] 2. Manufacturing Examples (1) Production and analysis of organic-inorganic composite powders consisting of silica-based composite oxide powders (D) and resins. Using a wet bead mill SC50 (manufactured by Mitsui Mining Co., Ltd.), a slurry was prepared by mixing 400 parts by mass of each inorganic powder with 600 parts by mass of ion-exchanged water. This slurry was then dispersed using 100 g of φ0.3 mm zirconia beads at a rotation speed of 3000 rpm for 10 minutes to prepare slurry (SD-1) in which (D) was dispersed. SD-1 was supplied onto a high-speed rotating disk and granulated by spray drying. Spray drying was performed using a spray dryer TSR-2W (manufactured by Sakamoto Giken Co., Ltd.) equipped with a rotating disk that atomizes by centrifugal force. The disk rotation speed was 10,000 rpm, and the temperature of the drying atmosphere air was 200°C. Subsequently, the powder obtained by spray drying was vacuum dried at 60°C for 18 hours to obtain a granular material (aggregated granular material) composed of approximately spherical aggregated particles.

[0115] Next, 30 g of the above-mentioned agglomerated powder was immersed in a polymerizable monomer solution prepared by mixing 7 g of UDMA as a polymerizable monomer, 0.015 g of azobisisobutyronitrile (AIBN) as a thermal polymerization initiator, and 12.4 g of ethanol as an organic solvent. After thorough stirring to confirm that the mixture had become a slurry, it was left to stand for 1 hour. The above mixture was dried in a vacuum dryer under reduced pressure of 10 hectopascals and heating conditions of 40°C for 1 hour to remove the organic solvent. After removal of the organic solvent, a non-aggregating, highly fluid powder was obtained. The above powder was heated under reduced pressure of 10 hectopascals and 140°C for 20 minutes to polymerize and harden the polymerizable monomers in the powder. Next, it was sieved through a 100 μm mesh to obtain an organic-inorganic composite powder: FD-6, which consists of approximately spherical organic-inorganic composite particles, the surface of which of the obtained spherical aggregates is coated with an organic polymer. The average particle size (median diameter in the volume-based particle size distribution) was determined for the obtained organic-inorganic composite powder and granules as follows. The results are shown in Table 2.

[0116] <Evaluation of average particle size of organic-inorganic composite powders and granules> 0.1 g of organic-inorganic composite powder was dispersed in 10 mL of ethanol and irradiated with ultrasound for 20 minutes. Using a laser diffraction-scattering particle size analyzer "LS230" (Beckman Coulter), the optical model "Fraunhofer" was applied, and the average particle size was determined from the median diameter of the volume statistics.

[0117] [Table 2]

[0118] (2) Manufacturing and analysis of X-ray contrast material (E) Mechanochemical treatment was performed on inorganic powders (YbF3-40, YbF3-300) consisting of the aforementioned crystalline rare-earth metal fluorides to obtain slurries (SE-1 to SE-3) in which primary particles (e) that serve as X-ray contrast materials (E) were dispersed. The mechanochemical treatment was performed using a wet bead mill SC50 (manufactured by Mitsui Mining Co., Ltd.) by dispersing a slurry of inorganic powders consisting of 400 parts by mass of each crystalline rare earth fluoride in 600 parts by mass of ion-exchanged water with 100 g of φ0.3 mm zirconia beads as the media at a rotation speed of 3000 rpm.

[0119] Furthermore, the obtained slurry was dried using a nozzle-type spray dryer (MiniSprayDryer B-290 Advanced; manufactured by Nippon Buch Co., Ltd.). The obtained granular material was spread on a tray and vacuum-dried at 80°C for 15 hours. Granular materials consisting of aggregated primary particles (e) that will serve as X-ray contrast material (E) were prepared as shown in Table 3, with the material of the crystalline rare-earth metal fluoride particles and the processing time for the dispersion treatment as shown. FE-1 was obtained only from the cyclone recovery section, and FE-2 and FE-3 were obtained only from the main unit's lower recovery section. For these granular materials, the average primary particle diameter and the acidity of the inorganic particle surface constituting the inorganic granular material (Δa measured by methyl red) were determined in the same manner as described above. * In addition to measuring the ), the average aggregated particle diameter (median diameter in the volume-based particle size distribution), the 2θ of the peak of the crystal plane (1,1,1) in the X-ray diffraction pattern, and the full width at half maximum (deg:°) were measured as follows. The results are shown in Table 3.

[0120] <Measurement of average particle size> 0.1g each of FE-1 to FE-3 was added to 10mL of water and shaken well by hand to disperse. Using a laser diffraction-scattering particle size analyzer "LS230" (Beckman Coulter), the optical model "Fraunhofer" was applied, and the average particle size was determined from the median diameter of the volume statistics.

[0121] <Method for measuring 2θ and full width at half maximum (deg:°) of crystal plane (1,1,1)> The aforementioned granular material was packed into a sample stage, and an X-ray diffraction pattern (chart) was obtained by measuring it using an X-ray diffractometer {Rigaku Corporation's "Smartlab"}, with the horizontal axis representing 2θ (°) and the vertical axis representing diffraction intensity. Here, CuKα rays were used as the X-rays for the X-ray diffraction measurement. When the material of the crystalline rare earth metal fluoride particles is YbF3, the peak with the greatest intensity is the peak originating from the (1,1,1) plane (a peak observed around 2θ = 28°), so the full width at half maximum (deg:°) of this peak was determined.

[0122] [Table 3]

[0123] (3) Production and analysis of composite aggregated powder (F) consisting of composite aggregated particles formed by the aggregation of silica-based composite oxide particles and crystalline rare earth metal fluoride particles. 100g of slurry SD-1 and 25g of slurry SE-2 were mixed to obtain a mixed slurry. Next, 1.6g (0.006mol) of γ-methacryloyloxypropyltrimethoxysilane and 20g of water were added, and then acetic acid was added to adjust the pH to 4. The mixture was stirred for 1 hour and 30 minutes to obtain a homogeneous solution. This solution and 50g of deionized water for concentration adjustment were added to the mixed slurry and mixed uniformly. Then, while lightly mixing the dispersion, the inorganic powder was spray-dried using a spray dryer (Spray Dryer "FOC-20", manufactured by Okawara Chemical Machinery Co., Ltd.) at a disk rotation speed of 26,000 rpm and a drying atmosphere air temperature of 200°C, and the resulting inorganic powder was recovered from the cyclone recovery section and the main body lower recovery section. Subsequently, the inorganic powder recovered from the cyclone recovery section was vacuum-dried at 80°C for 17 hours to obtain composite aggregated powder (F): FF-1. Furthermore, the inorganic powder recovered from the recovery section at the bottom of the main unit was similarly vacuum-dried to obtain composite aggregated powder (F): FF-2. As shown in Table 4, inorganic powder (F): FF-3 and FF-4 were prepared in the same manner as FF-1, except that the type and proportion of crystalline rare earth metal fluoride slurry used in the preparation and the amount of ion-exchanged water added for concentration adjustment were changed. Furthermore, when the amount of crystalline rare-earth metal fluoride was small and the viscosity of the slurry was high, the slurry clogged the nozzle during spray drying and spraying was not possible (FF-5).

[0124] For the obtained composite agglomerated powder (F), the average agglomerated particle diameter (median diameter in the volume-based particle size distribution) was measured in the same manner as in (1) the method for measuring the average particle diameter of organic-inorganic composite powder, except that ultrasonic irradiation was not performed. The formation of agglomerated particles in the composite agglomerated powder (F) was confirmed by scanning electron microscopy. Furthermore, for inorganic powders FF-1 to FF-5, the parts by mass of crystalline rare earth metal fluoride primary particles (e) relative to 100 parts by mass of silica-based composite oxide particles (d) in (F) are as shown in Table 4.

[0125] [Table 4]

[0126] 3. Examples and Comparative Examples Example 1 A polymerizable monomer solution was prepared by completely dissolving a polymerizable monomer consisting of 60 parts by mass of UDMA and 40 parts by mass of 3G, a photopolymerization initiator consisting of 0.30 parts by mass of CQ and 0.5 parts by mass of DMBE, an amine compound, and a fluorescent agent consisting of 0.025 parts by mass of DHTP, a phthalate ester. Subsequently, 210 parts by mass of silica-based composite oxide powder FD-1 surface-treated with γ-methacryloyloxypropyltrimethoxysilane, 10 parts by mass of FE-1 which will be an X-ray contrast material (E), and a portion of the polymerizable monomer solution were kneaded in a mortar until (e) was dispersed as primary particles (e1) to form a paste. The remaining polymerizable monomer solution was added and homogenized, and then 13 parts by mass of FE-1 was added and kneaded to maintain the state of aggregated particles (e2), and degassed to prepare a paste-like dental curable composition. The prepared paste-like dental hardening composition was filled into a cylindrical syringe, and a plunger for dispensing the contents of the syringe and a cap were attached. The obtained dental curable compositions were evaluated for their flowability, contrast ratio, radiopacity, color stability, fluorescence, and dispensing properties in paste form using the method described below. The results are shown in Table 5.

[0127] <Method for measuring flow rate> A 20G needle tip was attached to the tip of a syringe filled with the prepared paste-like dental hardening composition. Next, it was left to stand in a 25°C constant temperature room for 30 minutes. Then, a 5mm diameter circle was drawn on a glass plate, and 0.1g of the dental hardening composition was dispensed into the circle. The syringe was then left to stand horizontally in a 37°C incubator for 2 minutes. The spread of the paste was measured by its vertical and horizontal diameters, and the average of these two measurements was calculated. This evaluation was performed twice, and the average value was defined as the paste's flowability.

[0128] <Method for evaluating the contrast ratio (Yb / Yw) of hardened dental compositions> The prepared dental curable composition was placed in a mold having a through-hole with a diameter of 7 mm and a thickness of 1 mm, and the distance was adjusted so that the irradiation intensity on the surface of the polyester film pressure-bonded to both sides was 1000 mW / cm2, and both sides were irradiated with light for 20 seconds each using a dental light irradiator (Elipar Deep Cure, manufactured by 3M). After curing the dental curable composition, it was taken out of the mold, and the Y value (background colors black and white) of the tristimulus values of the cured body was measured using a color difference meter (TC-1800MKII, manufactured by Tokyo Denshoku). The following formula, Contrast ratio (Yb / Yw) = Y value in the case of background color black / Y value in the case of background color white Based on this, the contrast ratio (Yb / Yw) was calculated.

[0129] <Method for measuring X-ray contrast>[ The paste was filled into a polyethylene terephthalate mold having a hole with a diameter of 15 mm and a thickness of 1 mm, and while being pressure-bonded with a polypropylene film, it was irradiated with visible light using a visible light irradiator (Elipar Deep Cure, manufactured by 3M) five times in total by changing the location so that the entire surface was illuminated and closely adhered to the polypropylene film. The polypropylene film was removed, and the cured body was removed from the mold to obtain a sample. The prepared sample was observed using a desktop X-ray transmission inspection device (μB1300, Matsuda Precision). Also, when observing the sample, an aluminum step wedge with a thickness of 1 to 4 mm was observed simultaneously. The observed image was captured using dedicated image capture software (μRayVision, Matsuda Precision), and the luminance of the sample and the aluminum step wedge was measured. A calibration curve was created from the luminance of the aluminum step wedge at each thickness, and the X-ray contrast of the sample was calculated as the equivalent aluminum thickness (Al%).

[0130] <Color tone stability>[ Based on the color stability test of ISO 4049:2019, paste was filled into a polyacetal mold with a φ15 mm, 1 mm thick hole, and pressed with a polypropylene film. A dental light curing unit (Ellipper Deep Cure, 3M) was then placed in close contact with the polypropylene film and irradiated with light while shifting its position until the entire paste was irradiated, thereby preparing a cured body. After irradiation, the mold and test specimens were placed in a 37°C incubator and removed from the mold after 15 minutes. Two cured bodies were prepared; the specimen stored in a 37°C desiccator was designated as the reference specimen, and the specimen immersed in 37°C water was designated as the water absorption test specimen. After 7 days, the test specimens were removed, and the color of the reference specimen and the water absorption test specimen was visually evaluated for discoloration according to the following evaluation criteria. ○: No obvious discoloration is observed. ×: Items showing obvious discoloration.

[0131] <Evaluation of fluorescence> A polytetrafluoroethylene mold with a 7mmφ × 3.0mm pore was filled with paste and pressed with a polypropylene film. A dental light curing unit (Ellipa Deep Cure, 3M) was placed in close contact with the polypropylene film and irradiated for 30 seconds to prepare a cured body. The fluorescence emission state of the obtained cured body was observed using a UV light curing unit (MINERALIGHT LAMP, Funakoshi Pharmaceutical Co., Ltd.; maximum absorption wavelength 366nm), and the fluorescence of the paste was evaluated according to the following evaluation criteria. 1: Those that exhibited particularly excellent fluorescence. 2: Those in which good fluorescence was confirmed. 3: Those in which fluorescence could not be detected.

[0132] <Evaluation of the sensation of discharge> A 20G needle tip was attached to the tip of the aforementioned syringe container, and by pressing the plunger, 0.2g of paste was dispensed from the tip of the needle tip onto a glass plate (5cm x 10cm). The ease of pressing the plunger at this time was checked, and the feel of dispensing the paste was evaluated according to the following evaluation criteria. A dispensing feel of 1 to 3 was considered acceptable. 1: Paste can be dispensed even with light pressure, and the dispensing performance is excellent. 2: The paste can be dispensed without difficulty, and the dispensing performance is good. 3: The paste can be dispensed by pressing a little harder, so the dispensing performance is acceptable. 4. While it is possible to dispense the paste by pressing hard, the dispensing performance is poor. 5: The paste cannot be dispensed at all.

[0133] Example 2 Similar to Example 1, a portion of the polymerizable monomer solution was mixed with FD-1 to obtain 187 parts by mass of surface-treated silica-based composite oxide powder FD-1, and 23 parts by mass of FF-1, which is a composite aggregate powder (F). These were kneaded in a mortar until (e) and (d) in the composite aggregate powder (F) were dispersed as primary particles to form a paste. The remaining polymerizable monomer solution was added and homogenized. Then, 23 parts by mass of FE-1, which is an X-ray contrast material (E), was added and kneaded while maintaining the aggregate particle state, and degassed to prepare a paste-like dental curable composition. The prepared paste-like dental curable composition was filled into a cylindrical syringe, and a plunger for pushing out the contents of the syringe and a cap were attached. The obtained dental curable composition was evaluated in the same manner as in Example 1.

[0134] Example 3 Similar to Example 1, a portion of the polymerizable monomer solution and FD-1 were surface-treated silica-based composite oxide powder granules FD-1: 105 parts by mass and FD-6: 117 parts by mass, and FE-1: 5 parts by mass, which will be the X-ray contrast material (E), were kneaded in a mortar until (e) was dispersed as primary particles (e1) to form a paste. The remaining polymerizable monomer solution was added and homogenized, and then 7 parts by mass of FE-1: which will be the X-ray contrast material (E), were added and kneaded to maintain the aggregated particle state, and then degassed to prepare a paste-like dental curable composition. The prepared paste-like dental curable composition was filled into a cylindrical syringe, and a plunger for pushing out the contents of the syringe and a cap were attached. The obtained dental curable composition was evaluated in the same manner as in Example 1.

[0135] Example 4 Similar to Example 1, a portion of the polymerizable monomer solution was surface-treated with FD-1 to obtain surface-treated silica-based composite oxide powder granules: 54 parts by mass of FD-1, 135 parts by mass of FD-6, and 54 parts by mass of FF-1, which is a composite aggregate powder granule (F). These were kneaded in a mortar until (e) and (d) in the composite aggregate powder granule (F) were dispersed as primary particles to form a paste. The remaining polymerizable monomer solution was added and homogenized, and then 27 parts by mass of FE-1, which is an X-ray contrast material (E), was added and kneaded while maintaining the aggregate particle state, and then degassed to prepare a paste-like dental curable composition. The prepared paste-like dental curable composition was filled into a cylindrical syringe, and a plunger for pushing out the contents of the syringe and a cap were attached. The obtained dental curable composition was evaluated in the same manner as in Example 1.

[0136] Examples 5-26, Comparative Examples 1-8 The polymer monomer (A), amine compound (B), fluorescent agent containing phthalate ester (C), silica-based composite oxide powder (D), X-ray contrast agent (E), and composite aggregate powder (F) used were changed as shown in Tables 5 to 8. After kneading to form a paste, the amount of (e) that will become the X-ray contrast agent (E), excluding the amount that will be dispersed in an aggregated state (e2), was kneaded so that (e) was uniformly dispersed in a state of (e1). Then, the amount of powder that will become the X-ray contrast agent (E) to be added was kneaded while maintaining the aggregated particles, and a paste-like dental curable composition was prepared in the same manner as in Example 4. The composition obtained was evaluated in the same manner as in Examples 1 to 4. The results are shown in Tables 5 to 8.

[0137] [Table 5]

[0138] [Table 6]

[0139] [Table 7]

[0140] [Table 8]

[0141] As can be seen from the results of Examples 1 to 26, dental curable compositions that satisfy the requirements of the present invention exhibit appropriate fluidity in a paste state, have fluorescence and high radiopacity similar to natural teeth, and pass color stability tests.

[0142] As can be seen from Comparative Examples 1 and 2, if the amount of fluorescent agent containing phthalate ester does not satisfy the requirements of the present invention, fluorescence is not observed or discoloration is observed in terms of color stability.

[0143] As can be seen from Comparative Examples 3 and 4, if the total amount of (e) constituting the X-ray contrast material (E) does not satisfy the requirements of the present invention, proper fluidity is not imparted in the paste state, resulting in reduced X-ray contrast properties or discoloration in color stability.

[0144] As can be seen from Comparative Example 5, if the amount of (E1) dispersed in the composition as primary particles (e) constituting the X-ray contrast material (E) does not satisfy the requirements of the present invention, discoloration is observed in terms of color stability.

[0145] As can be seen from Comparative Example 6, when a powder or granular material consisting of particles having a full width at half maximum of the maximum intensity peak derived from crystalline rare-earth metal fluoride is used instead of (e) which constitutes the X-ray contrast material (E), the contrast ratio of the hardened material increases and the dental hardening composition becomes opaque.

[0146] As can be seen from Comparative Examples 7 and 8, when silica-based composite oxide powder (D) that does not satisfy the requirements of the present invention is used, the dispensing performance deteriorates.

Claims

1. Polymerizable monomer (A): 100 parts by mass, Amine compound (B): 0.01 to 3.0 parts by mass, Phthalate ester (C): 0.0005 to 0.05 parts by mass, Silica-based composite oxide powder (D) composed of silica-based composite oxide primary particles (d) having an average particle size of 50 nm to 1 μm: 170 to 270 parts by mass, and X-ray contrast material (E) composed of fluorine atom-containing inorganic particles: 5 to 50 parts by mass It contains, The above (E) consists of a plurality of crystalline rare-earth metal fluoride primary particles (e) in which the full width at half maximum of the maximum intensity peak originating from the crystalline rare-earth metal fluoride in the X-ray diffraction pattern obtained by X-ray diffraction measurement is 0.3° or more, and the average primary particle size measured by electron microscopy is 10 to 300 nm. (e1), which is a portion of the plurality of crystalline rare earth metal fluoride primary particles (e), is dispersed in the composition as a plurality of primary particles, and the remainder (e2) is dispersed in the composition as a plurality of aggregated particles consisting only of (e2), which has an average aggregated particle diameter of 3 to 30 μm, defined as the median diameter in the volume-based particle size distribution measured by laser diffraction-scattering, and the amount of (e1) is 2 to 25 parts by mass per 100 parts by mass of polymerizable monomer (A). A dental hardening composition characterized by the following features.

2. The dental curable composition according to claim 1, wherein (e) comprises ytterbium fluoride primary particles.

3. The amine compound (B) is given by the following general formula (1) 【Chemistry 1】 (In the formula, R １ and R ２ They are mutually independent, A substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, which may have a hydroxyl group or a halogen atom as a substituent; or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms excluding the substituent, which may have an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a thiomethyl group or a halogen atom as a substituent; R ３ teeth, The above-mentioned substituted or unsubstituted alkyl groups; the above-mentioned substituted or unsubstituted aryl groups; C2-C12 alkenyl groups; C1-C10 alkoxy groups; C1-C10 alkyloxycarbonyl groups; benzoyl groups having 7-12 carbon atoms excluding the substituent, which may have an alkyl-substituted amino group having C1-C6 as a substituent; acetyl groups; carboxyl groups; nitro groups; or cyano groups; n is an integer between 0 and 5. When n is between 2 and 5, there are multiple R ３ They may be different from each other, R ３ They may be joined together to form a ring. The compound comprises at least one tertiary aromatic amine compound represented by The dental curable composition according to claim 1 or 2.

4. A method for producing the dental curable composition described in claim 1, The process includes a mixing step of mixing: 100 parts by mass of polymerizable monomer (A), 0.01 to 3.0 parts by mass of amine compound (B), 0.0005 to 0.05 parts by mass of phthalate ester (C), 170 to 270 parts by mass in terms of total mass of (d) for a first raw material powder containing only the silica-based composite oxide primary particles (d) as inorganic primary particles, and 5 to 50 parts by mass in terms of total mass of (e) for a second raw material powder containing only the crystalline rare earth metal fluoride primary particles (e) as inorganic primary particles; As the second raw material powder, a non-aggregated powder (E1) consisting of substantially non-aggregated particles of (e) and an aggregated powder (E2) composed of aggregated particles of (e) having an average aggregated particle diameter of 3 to 30 μm is used, or a powder consisting only of (E2) is used. The aforementioned mixing step is (A): A first mixing step of e, in which 2 to 25 parts by mass of a second raw material powder or granules is added in total mass equivalent to (e) per 100 parts by mass, and then the mixture is mixed so that (e) in the added second raw material powder or granules is dispersed in the form of primary particles, and The process includes a second step of mixing e, in which the agglomerated powder (E2) containing the remaining amount of (e) is added after the first step of mixing e, and then mixed in a manner that does not cause the agglomerated particles constituting (E2) to break down. The first raw material powder is mixed at any time between the start and end of the mixing process. The manufacturing method characterized by the above.

5. A method for producing the dental curable composition described in claim 1, The process includes a mixing step of mixing a first raw material powder containing only the silica-based composite oxide primary particles (d) as inorganic primary particles, a second raw material powder containing only the crystalline rare earth metal fluoride primary particles (e) as inorganic primary particles, and a composite aggregate powder (F) composed of composite aggregate particles (f) formed by the aggregation of (d) and (e), wherein the content of (e) is 2.0 to 92.6% by mass and the average aggregate particle diameter is 1 to 50 μm. In the aforementioned mixing step, As the second raw material powder, a non-aggregated powder (E1) consisting of substantially non-aggregated particles of (e) and an aggregated powder (E2) composed of aggregated particles of (e) having an average aggregated particle diameter of 3 to 30 μm is used, or a powder consisting only of (E2) is used. The amount of the composite aggregated powder (F) is such that, when the amounts of (d) and (e) contained in (F) relative to 100 parts by mass of (A) are Q(Fd) and Q(Fe), respectively, Q(Fd) is 2 to 100 parts by mass and Q(Fe) is 2 to 25 parts by mass. The amount of the first raw material powder is such that the sum of the amount of (d) in terms of total mass relative to 100 parts by mass of (A) and Q(Fd) is between 170 and 270 parts by mass. The amount of the second raw material powder is such that the sum of the amount of (e) in terms of total mass relative to 100 parts by mass of (A) and Q(Fe) is between 5 and 50 parts by mass. The aforementioned mixing step is The following steps are taken: (F) or (F) and the second raw material powder are blended in an amount that is 2 to 25 parts by mass when calculated based on the total mass of (e) contained in them relative to 100 parts by mass of (A), and then the mixture is mixed so that (e) is dispersed in the blended second raw material powder in the form of primary particles; The process includes a second mixing step in which the agglomerated powder (E2) containing the remaining amount of (e) is added after the ed mixing step, and then mixed in a manner that does not cause the agglomerated particles constituting (E2) to break down. The first raw material powder is mixed at any time between the start and end of the mixing process. The manufacturing method characterized by the above.

6. A flowable composite resin comprising the dental curing composition described in claim 1.

Images