JP7175542B1 - dental curable composition - Google Patents

Abstract

[Problem] To provide a dental curable composition that enables restoration with high color tone compatibility with natural teeth, has small polymerization shrinkage, and provides a cured product with high surface hardness. SOLUTION: (a) a cationic polymerizable monomer, (b) a photoacid generator, (d) a thiophene compound, and (f1) an average primary particle size in the range of 230 nm or more and 1000 nm or less, and a number-based particle size In the distribution, the ratio of particles existing in the range of 5% before and after the average primary particle size to the total number of particles is 90% or more, and the inorganic spherical filler (f1) has a refractive index at 25 ° C. A dental curable composition, wherein nFa is greater than the refractive index nP at 25° C. of the polymer of the cationic polymerizable monomer (a). [Selection figure] None

Description

The present invention relates to dental hardenable compositions. More specifically, it relates to a dental curable composition that enables restoration with high color tone compatibility with natural teeth, has small polymerization shrinkage, and provides a cured product with high surface hardness.

A dental curable composition containing a polymerizable monomer can be cured by an external stimulus such as light irradiation and used to repair a tooth damaged by caries, fracture, or the like.
In recent years, there is an increasing demand for tooth restoration not only for restoration of occlusion but also for aesthetic restoration that looks like natural teeth. Therefore, there is a demand for a dental curable composition that enables restoration of natural teeth with high color matching.

In Patent Document 1, a curable composition containing a polymerizable monomer component, a spherical filler having an average particle size in the range of 230 nm to 1000 nm, and a polymerization initiator, a cured body having a thickness of 1 mm is formed and measured. curable compositions having specific ranges of lightness and chroma under a black background and a white background. Further, it is described that the hardened body of the curable composition has excellent color tone compatibility with natural teeth. The spherical filler contained in the curable composition has a specific average particle size, a narrow particle size distribution, and a predetermined refractive index. It enables restoration with high color matching to natural teeth.

In the invention described in Patent Document 1, the polymerizable monomer component used in the examples is a (meth)acrylate-based radically polymerizable monomer. Although such a radically polymerizable monomer has good photopolymerizability, it has a problem of large polymerization shrinkage. After filling a dental curable composition into a tooth cavity requiring restoration, the surface of the filled curable dental composition is irradiated with light to polymerize and cure to form a cured product. Due to the shrinkage associated with polymerization, stress acts on the body to separate it from the tooth interface. As a result, there is a tendency for a gap to easily form between the tooth and the hardened body of the curable dental composition. Therefore, there is a demand for a dental curable composition that has a small polymerization shrinkage and is less likely to cause gaps during curing.

Cationic polymerizable monomers such as epoxides and vinyl ethers are known as polymerizable monomers with small polymerization shrinkage. need to proceed. Cationic polymerizable monomers are generally polymerized using photocationic polymerization initiators containing photoacid generators, photosensitizers, and the like, and from the viewpoint of causing rapid polymerization, highly active light is used. A cationic polymerization initiator is desired.

For example, in Patent Document 2, as a cationic polymerizable monomer photoinitiator system, when measured based on an iodonium salt, a visible light photosensitizer, and a saturated calomel electrode, it is higher than 0, 1,4 - A photoinitiator system has been proposed that includes an electron-donating compound with an oxidation potential lower than that of dimethoxybenzene and has a constant photoinduced potential. Polycyclic aromatic compounds such as anthracene compounds are disclosed as the electron-donating compound.

Further, Patent Document 3 contains an epoxy resin, an iodonium salt, a visible light photosensitizer, and a photoinitiator system containing an electron-donating compound, and the photoinitiator system has a specific photoinduced potential. Photopolymerizable compositions have been proposed. Aromatic amines, alkylaryl polyethers and the like are disclosed as the electron-donating compounds.

WO2017/069274 WO2003/059295 WO 98/47046

However, from the viewpoint of reducing polymerization shrinkage, when a cationically polymerizable monomer is used instead of the radically polymerizable monomer used in the invention described in Patent Document 1, the original purpose of color tone It has been found that problems such as difficulty in repairing with high adaptability and a decrease in surface hardness of the cured product have been found. For example, even if the photoinitiator system described in Patent Document 2 is used, the resulting cured product is confirmed to have blue fluorescence by ultraviolet rays, and compared to yellow to red colored light, blue coloration It was confirmed that the color tone compatibility with natural teeth deteriorated during restoration, such as when the light became stronger. Also, it was confirmed that the surface hardness of the cured body is lowered even when the photoinitiator system described in Patent Document 3 is used.
Accordingly, an object of the present invention is to provide a dental curable composition that enables restoration with high color tone compatibility with natural teeth, has small polymerization shrinkage, and provides a cured product with high surface hardness.

The present inventors have made intensive studies in order to achieve the above object. As a result, the refractive index nF _a of the inorganic spherical filler at 25° C. was The inventors have found that the above problems can be solved by a dental curable composition having a refractive index nP larger than the polymer of the cationic polymerizable monomer at 25°C, and have completed the present invention.

The present invention relates to the following [1] to [8].
[1] (a) a cationically polymerizable monomer, (b) a photoacid generator, (d) a thiophene compound, and (f ₁ ) an average primary particle size in the range of 230 nm or more and 1000 nm or less, and a number-based particle size In the distribution, the ratio of particles existing in the range of 5% before and after the average primary particle size to the total number of particles is 90% or more, and the refraction of the (f ₁ ) inorganic spherical filler at 25 ° C. A dental curable composition, wherein the index nF _a is greater than the refractive index nP at 25° C. of the polymer of the cationic polymerizable monomer (a).
[2] The curable dental composition according to [1] above, wherein the (d) thiophene compound is a compound having one or more π-conjugated substituents on the thiophene skeleton.
[3] The curable dental composition according to [1] or [2] above, wherein the π-conjugated substituent contains one or more benzene rings or thiophene rings.
[4] The dental curable composition according to any one of [1] to [3] above, further comprising (c) a photosensitizer.
[5] The above [1], wherein the difference between the refractive index nF _a of the inorganic spherical filler (f ₁ ) and the refractive index nP of the polymer of the cationic polymerizable monomer (a) is 0.001 or more. The curable dental composition according to any one of [4].
[6] The dental curability according to any one of [1] to [5], wherein the (a) cationic polymerizable monomer contains at least one compound selected from epoxy compounds and oxetane compounds. Composition.
[7] The dental curable composition according to any one of [1] to [6] above, wherein the (b) photoacid generator is an iodonium salt compound.
[8] The dental curable composition according to any one of [1] to [7] above, further comprising a phenolic antioxidant.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a dental curable composition that enables restoration with high color tone compatibility with natural teeth, has small polymerization shrinkage, and gives a cured product with high surface hardness.

[Dental curable composition]
The dental curable composition of the present invention comprises (a) a cationic polymerizable monomer, (b) a photoacid generator, (d) a thiophene compound, and (f ₁ ) range, and in the number-based particle size distribution, the ratio of particles existing in the range of 5% before and after the average primary particle size to the total number of particles is 90% or more, and the inorganic spherical filler ( The refractive index nF _a of f ₁ ) at 25° C. is higher than the refractive index nP at 25° C. of the polymer of the cationic polymerizable monomer (a).

The dental curable composition of the present invention contains (d) an inorganic spherical filler having an average primary particle size within a specific range, a narrow particle size distribution, and a refractive index higher than that of the cationic polymerizable monomer polymer. This enables highly tonal matching restorations. In addition, since the dental curable composition of the present invention uses (a) a cationically polymerizable monomer in place of a conventional radically polymerizable monomer, polymerization shrinkage is suppressed.
The dental curable composition of the present invention is characterized by further comprising (d) a thiophene compound. (d) The thiophene compound, like the aromatic amine and the anthracene compound, functions as an electron-donating compound to highly activate a photocationic polymerization initiator such as a photoacid generator. As a result, (a) poor curing of the cationically polymerizable monomer is suppressed, and furthermore, compared to the case where an aromatic amine, an anthracene compound, or the like is used as the electron-donating compound, (f ₁ ) the inorganic spherical filler is used. The blending does not impair the effect of color matching, and the surface hardness of the cured product is increased.
The reason for this is not clear, but compared to other electron-donating compounds such as aromatic amines and anthracene compounds, thiophene compounds are less likely to leave substances that cause coloration and color tone changes over time during the curing process. It is presumed that this is related to the rapid progress of hardening.

<(a) Cationic polymerizable monomer>
The dental curable composition of the present invention contains (a) a cationic polymerizable monomer. (a) The cationically polymerizable monomer can make polymerization shrinkage smaller than when a (meth)acrylate-based radically polymerizable monomer is used. Therefore, when a tooth is restored with the dental curable composition, it is possible to make it difficult for a gap to form between the tooth and the hardened body.

(a) The cationically polymerizable monomer is not particularly limited as long as it is a compound polymerized by an acid generated by decomposition of the photoacid generator. Examples include epoxy compounds, oxetane compounds, cyclic ether compounds, vinyl ether compounds, bicyclic ortho Ester compounds, cyclic acetal compounds, bicyclic acetal compounds, cyclic carbonate compounds and the like can be mentioned.
From the viewpoints of easy availability, small volume shrinkage, and rapid polymerization reaction, (a) as the cationically polymerizable monomer, it is preferable to include at least one compound selected from epoxy compounds and oxetane compounds.

Specific examples of epoxy compounds that can be preferably used include 1,2-epoxypropane, methyl glycidyl ether, cyclohexene oxide, exo-2,3-epoxynorbornene, 4-vinyl-1-cyclohexene-1,2-epoxide. , limonene oxide, α-pinene oxide, styrene oxide, (2,3-epoxypropyl)benzene, epoxy compounds having one epoxy functional group such as phenylglycidyl ether; 1,3-butadiene dioxide, ethylene glycol diglycidyl ether , diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, diglycidyl glutarate, 4-vinyl-1-cyclohexene diepoxide, limonene diepoxide, methylbis[2-(7-oxa Epoxy compounds having two epoxy functional groups such as bicyclo[4.1.0]hept-3-yl)ethyl]phenylsilane; glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol triglycidyl ether, pentaerythritol Epoxy compounds having three or more epoxy functional groups such as tetraglycidyl ether and dipentaerythritol hexaglycidyl ether can be mentioned.

As the epoxy compound, compounds having a cyclic siloxane and silsesquioxane structure such as the compounds shown below and having an epoxy functional group can also be mentioned. In the following structural formulas (excluding structural formulas specifying R), the bond marked with *1 indicates that it is bonded to the O atom of the adjacent repeating structural unit, and the bond marked with *2 A hand indicates a bond with the Si atom of the adjacent repeating unit.

Among the above epoxy compounds, epoxy compounds having two or more epoxy functional groups in one molecule are particularly preferably used from the viewpoint of the physical properties of the resulting cured product.

Specific examples of oxetane compounds that can be preferably used include trimethylene oxide, 3-methyl-3-oxetanylmethanol, 3-ethyl-3-oxetanylmethanol, 3-ethyl-3-phenoxymethyloxetane, 3, Oxetane compounds having one oxetane ring such as 3-diethyloxetane, 3-ethyl-3-(2-ethylhexyloxy)oxetane; 1,4-bis(3-ethyl-3-oxetanylmethyloxy)benzene, 4,4 '-bis(3-ethyl-3-oxetanylmethyloxy)biphenyl, 4,4'-bis(3-ethyl-3-oxetanylmethyloxymethyl)biphenyl, ethylene glycol bis(3-ethyl-3-oxetanylmethyl)ether , diethylene glycol bis(3-ethyl-3-oxetanylmethyl) ether, and oxetane compounds having two or more oxetane rings such as the compounds shown below. In the structural formulas shown below, the bond marked with *1 in the structural formula on the left side of the bottom row indicates that it is bonded to the O atom of the adjacent repeating structural unit, and the bond marked with *2 is It indicates that it is bonded to the Si atom of the adjacent repeating structural unit.

Among the above oxetane compounds, oxetane compounds having two or more oxetane rings in one molecule are particularly preferably used from the viewpoint of the physical properties of the resulting cured product.

These (a) cationic polymerizable monomers may be used alone or in combination of two or more. Among them, (a) the cationically polymerizable monomer preferably contains both an epoxy compound and an oxetane compound. B moles of an epoxy compound having epoxy functional groups were mixed and prepared so that (a × A): (b × B) was in the range of 90:10 to 10:90, and the curing speed was It is suitable in that it is fast and resistant to polymerization inhibition due to moisture.

A compound having a cationically polymerizable functional group and a radically polymerizable functional group in the same molecule can also be used as the cationically polymerizable monomer. Examples of such compounds include glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 2-vinyloxyethyl (meth)acrylate, 6-vinyloxyhexyl (meth)acrylate, 3- ethyl-3-(meth)acryloxymethyloxetane, 3-ethyl-3-(2-(meth)acryloxyethyloxymethyl)oxetane, p-(meth)acryloxymethylstyrene, and the like.

In the present invention, as the cationic polymerizable monomer (a), a plurality of polymerizable monomers can be used in order to adjust the physical properties (mechanical properties and adhesion to tooth substance) of the cured product. At this time, it is desirable to set the kind and mixing ratio of the polymerizable monomer so that the refractive index of the cationic polymerizable monomer (a) is within the range of 1.38 to 1.55. That is, (a) by setting the refractive index of the cationically polymerizable monomer within the range of 1.38 to 1.55, (a) the refractive index nP of the polymer obtained from the cationically polymerizable monomer is , can be set within a range of approximately 1.40 to 1.57. In some cases, a plurality of types of cationic polymerizable monomers (a) are used. In this case, the refractive index of a mixture of a plurality of types of polymerizable monomers should be within the above range. , the refractive index of each polymerizable monomer does not necessarily fall within the above range. In the present invention, the refractive index is measured using an Abbe refractometer at 25°C.

<(b) Photoacid generator>
The dental curable composition of the present invention contains (b) a photoacid generator. (b) By containing a photoacid generator, the polymerization reaction of the cationic polymerizable monomer can be advanced. (b) The photoacid generator is not particularly limited as long as it is generally used as a photocationic polymerization initiator, and a compound that generates a strong acid by reaction due to light irradiation is used.
(b) As the photoacid generator, for example, onium salt compounds such as iodonium salt compounds, sulfonium salt compounds, bismuthonium salt compounds, and pyridinium salt compounds can be used. Among these, it is preferable to use an iodonium salt compound as the photoacid generator (b) because it is readily available and has high polymerization activity. (b) The photoacid generator may be used alone, or two or more of them may be used in combination.

Specific examples of the (b) photoacid generator that is preferably used include onium salt compounds in which the cation or cation moiety and the anion or anion moiety are selected from those shown below.

[Cation or cationic moiety]
Diphenyliodonium, bis(p-chlorophenyl)iodonium, ditolyliodonium, bis(p-tert-butylphenyl)iodonium, p-isopropylphenyl-p-methylphenyliodonium, bis(m-nitrophenyl)iodonium, p-tert- Butylphenylphenyliodonium, p-methoxyphenylphenyliodonium, bis(p-methoxyphenyl)iodonium, p-octyloxyphenylphenyliodonium, p-phenoxyphenylphenyliodonium, bis(p-dodecylphenyl)iodonium, triphenylsulfonium, tri tolylsulfonium, p-tert-butylphenyldiphenylsulfonium, diphenyl-4-phenylthiophenylsulfonium, diphenyl-2,4,6-trimethylphenylsulfonium, tetraphenylbismutonium, triphenyl-2,4,6-trimethylphenyl bismuthonium, 1-methylpyridinium, 1-methyl-2-chloropyridinium and the like.

[Anion or anion part]
tetrakispentafluorophenylborate, tetra(nonafluoro-tert-butoxy)aluminate, hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, tetrafluoroborate, trifluoromethanesulfonate, perchlorate and the like.

(b) The content of the photoacid generator is not particularly limited as long as it is an amount capable of initiating polymerization by light irradiation. In order to achieve both weather resistance and hardness, it is generally 0.01 to 20 parts by mass, preferably 0.05 to 10 parts by mass, relative to 100 parts by mass of the cationic polymerizable monomer (a) described above. parts by mass, more preferably 0.1 to 5 parts by mass.

<(c) Photosensitizer>
The dental curable composition of the present invention preferably contains (c) a photosensitizer. (c) The photosensitizer is not particularly limited as long as it absorbs light energy and accelerates the decomposition of the photoacid generator. Examples include ketone compounds (especially α-diketone compounds), coumarin dyes, Cyanine dyes, merocyanine dyes, thiazine dyes, azine dyes, acridine dyes, xanthene dyes, squalium dyes, pyrylium salt dyes, and the like can be used. Among these, camphorquinone, benzyl, diacetyl, acetylbenzoyl, 2,3-pentadione, 2,3-octadione, 4,4′-dimethoxybenzyl, and 4,4′-oxybenzyl are used from the viewpoint of suppressing the coloring of the cured product. , 9,10-phenanthrenequinone, acenaphthenequinone and the like are preferably used, and camphorquinone is particularly preferably used.

(c) Photosensitizers may be used alone, or two or more of them may be used in combination. (c) The amount of the photosensitizer used varies depending on the other components to be combined and the type of the polymerizable monomer, but usually (a) per 100 parts by mass of the cationic polymerizable monomer, for example 0.001 to 10 parts by mass may be used, preferably 0.01 to 5 parts by mass.

<(d) Thiophene compound>
The dental curable composition of the present invention contains (d) a thiophene compound. (d) The thiophene compound functions as an electron-donating compound, and by containing it, the polymerization of the cationic polymerizable monomer is facilitated, and poor curing is suppressed. Furthermore, the (d) thiophene compound has a color tone compatibility that is expressed by blending the (f ₁ ) inorganic spherical filler, compared to the case where an aromatic amine, anthracene compound, or the like is used as the electron-donating compound. The surface hardness of the cured product is increased without lowering the effect.

As the thiophene compound (d), any known compound can be used without particular limitation as long as it is a compound having a thiophene ring in the molecule. In the present invention, a thiophene compound is used as an electron-donating compound, so a compound with high electron-donating properties is desirable. It is known that extension of the π-conjugated system is effective for enhancing the electron-donating property. Therefore, as (d) the thiophene compound, a compound having one or more π-conjugated substituents on the thiophene skeleton can be preferably used.
Examples of the partial structure constituting the π-conjugated substituent include a benzene ring and heteroaryl rings such as a thiophene ring, a furan ring, and a pyrrole ring. The thiophene compound in the present invention preferably has a π-conjugated substituent, and it is particularly preferable that the π-conjugated substituent has one or more benzene rings or thiophene rings. Also, the π-conjugated system composed of thiophene and the above partial structure may be substituted with other substituents such as an alkyl group or an alkoxy group. Such (d) thiophene compounds include 2-phenylthiophene derivatives, 2,2′-bithiophene derivatives, 2-thienylfuran derivatives, 2-thienylpyrrole derivatives and the like. 2) is preferably used.

In the above formulas (1) and (2), R ¹ to R ¹¹ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkylthio group, an aryl group, or a thienyl group, and R ³ and R ⁴ and R ³ and R ⁹ may combine with each other to form a ring. The alkyl group, alkenyl group, alkynyl group, alkoxy group, and alkylthio group are preferably straight or branched alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, and alkylthio groups having 1 to 12 carbon atoms. The aryl group and thienyl group may have a substituent such as an alkyl group having 1 to 12 carbon atoms, an alkenyl group, an alkynyl group, an alkoxy group, or a halogen atom such as bromine. When R3 and ^R4 or R3 and ^{R9 are} respectively bonded to form a ring ^, the ring is preferably cyclopentadiene, thiophene, furan, cyclohexadiene, or benzene.

Specific examples of the compounds represented by the general formula (1) or (2) include 2,5-diphenylthiophene, 2,3,4,5-tetraphenylthiophene, 2,2′-bithiophene, 5- hexyl-2,2'-bithiophene, 5-octyl-2,2'-bithiophene, 3,3'-dihexyl-2,2'-bithiophene, 4,4'-dihexyl-2,2'-bithiophene, 5, 5′-dihexyl-2,2′-bithiophene, 2,2′:5′,2″-terthiophene, 5,5″-dibromo-2,2′:5′,2″-terthiophene, 4H-cyclopenta[2,1-b:3,4-b']dithiophene, dithieno[3,2-b:2',3'-d]thiophene and the like. Among these, 5-octyl-2,2'-bithiophene is preferable as (d) the thiophene compound.

(d) The thiophene compound may be used alone or in combination of two or more. The amount of the thiophene compound (d) used varies depending on the other components to be combined and the type of the polymerizable monomer. , preferably 0.01 to 5 parts by mass, more preferably 0.1 to 4 parts by mass, still more preferably 0.2 to 3 parts by mass.
The curable dental composition of the present invention may contain (d) an electron-donating compound other than the thiophene compound as long as it does not adversely affect the effects of the present invention. However, in particular, the content of the electron-donating compound comprising an anthracene compound and/or an aromatic amine compound is 0.2 parts by mass or less, particularly 0.1 parts by mass, per 1 part by mass of (d) the thiophene compound. It is preferable to make it less than a part, and more preferable not to contain it.

<(f ₁ ) Inorganic Spherical Filler>
The dental curable composition of the present invention has an average primary particle size in the range of 230 nm or more and 1000 nm or less. It contains inorganic spherical fillers ((f ₁ ) inorganic spherical fillers) whose ratio to the number of particles is 90% or more.

(f ₁ ) The inorganic spherical filler is composed of a large number of primary particles, and the range of 5% before and after the average primary particle diameter of the large number of primary particles (the numerical value ±5% of the particle size range), 90% or more of the total number of primary particles are present. Particles present in the range of 5% before and after the average primary particle size account for preferably 91% or more, more preferably 93% or more, of the total number of particles.
(f ₁ ) The inorganic spherical filler has such a narrow particle size distribution that it emits colored light with structural colors based on light interference, diffraction, refraction, scattering, etc. (hereinafter simply referred to as “interference, scattering, etc.”). can be generated. Such color development by structural color utilizing interference, scattering, etc. is preferable because there is no fading or discoloration phenomenon seen when pigment substances, dye substances, etc. are used. That is, the dental curable composition of the present invention can improve the color tone compatibility with natural teeth by utilizing colored light due to structural color. There is an advantage that it is not necessary to use a coloring substance such as a dye substance.

Colored light that exhibits a structural color that appears due to interference, scattering, etc., is diffracted and interfered according to the Bragg condition, and light of a specific wavelength is emphasized, and light other than light of a specific wavelength is scattered, resulting in light of a specific wavelength. When the inorganic spherical filler having the above average primary particle size and particle size distribution is blended, the cured body of the curable dental composition has a yellow color according to the average primary particle size. ~ Reddish colored light appears. From the viewpoint of further enhancing the effect of developing colored light due to the interference, scattering, etc., the average primary particle size of the inorganic spherical filler (f ₁ ) is preferably 230 nm or more and 800 nm or less, more preferably 230 nm or more and 500 nm or less. , 260 nm or more and 350 nm or less. When an inorganic spherical filler having an average primary particle diameter of less than 230 nm is used, the coloring becomes bluish and does not match the color tone of dentin. In addition, when an inorganic spherical filler having an average primary particle size of less than 100 nm is used, structural color hardly occurs. On the other hand, when spherical fillers having an average primary particle diameter of more than 1000 nm are used, light interference and scattering can be expected, but sedimentation of the inorganic spherical fillers and a decrease in polishability occur. Not good as a material.

As described above, the inorganic spherical filler (f ₁ ) has an average primary particle size of 230 nm to 1000 nm, and depending on the average primary particle size, the cured product of the dental curable composition emits yellow to red colored light. Express. Among them, when inorganic spherical fillers having an average primary particle diameter in the range of 230 nm to 260 nm are used, the obtained colored light is yellowish, and the tooth surface color tone around the restored tooth is the shade guide "VITAPAN Classic (registered trademark)". )” is useful for the repair of cavities in the B series (red-yellow) category. When inorganic spherical fillers with an average particle size of 260 nm to 350 nm are used, the resulting colored light is reddish, and the tooth surface color tone around the restored tooth is A in the shade guide "VITAPAN Classic (registered trademark)". It is useful for the restoration of cavities in the category of (reddish brown). Since most of the dentin has a reddish hue, the embodiment using inorganic spherical fillers with an average particle size of 260 nm to 350 nm is preferable because it is widely compatible with restoration teeth of various color tones.

It is important that the inorganic spherical filler (f ₁ ) has an average primary particle size within the above range, and the individual primary particles may exist as agglomerated particles to some extent as long as the particles satisfy this requirement. . However, it is preferable that the particles are present as independent particles as much as possible, and specifically, aggregated particles of 10 μm or more are preferably less than 10% by volume.

In the present invention, the average primary particle size of the (f ₁ ) inorganic spherical filler is the number of all particles (30 or more) observed in a unit field of view of a photograph of the powder taken with a scanning electron microscope. and the primary particle diameter (maximum diameter) of all particles are measured, and the average value calculated by the following formula based on the measured values obtained.

（ｎ：粒子の数、Ｘ_ｉ：ｉ番目の粒子の一次粒子径（最大径））

(n: number of particles, X _i : primary particle diameter (maximum diameter) of i-th particle)

In the present invention, (f ₁ ) In the number-based particle size distribution of the inorganic spherical filler, the ratio (%) of particles existing in a range of 5% before and after the average primary particle size to the total number of particles (%) is within the unit field of view of the above photograph. Of all the particles (30 or more) in the above, the number of particles having a primary particle diameter (maximum diameter) outside the particle diameter range of ± 5% of the average primary particle diameter obtained above is measured, and the value is By subtracting from the number of particles, the number of particles within the range of average particle diameter ±5% in the unit field of view of the photograph is obtained, and the number is calculated by the following formula.
Percentage (%) of particles existing in the range of 5% before and after the average primary particle size to the total number of particles = [(Present in the range of 5% before and after the average primary particle size in the unit field of the scanning electron micrograph number of particles) / (total number of particles in a unit field of scanning electron micrograph)] × 100
can be calculated according to

Here, the spherical shape of the inorganic spherical filler may be substantially spherical, and does not necessarily have to be a perfect sphere. In general, a photograph of particles is taken with a scanning electron microscope, and for each particle (30 or more) within the unit field of view, the particle diameter in the direction perpendicular to the maximum diameter is divided by the maximum diameter. , and the average degree of symmetry obtained by averaging them should be 0.6 or more, more preferably 0.8 or more. The upper limit of the average degree of uniformity is 1 because it includes the case of a perfect spherical shape. The average degree of uniformity can be determined by the method described in Examples.

As the inorganic spherical filler (f ₁ ), as long as the requirements for the average primary particle size and particle size distribution are satisfied, those used as components of general curable compositions in the dental field can be used without limitation. Specifically, inorganic materials such as amorphous silica, silica-titanium oxide-based composite oxide particles (silica-zirconia, silica-titania, etc.), quartz, alumina, barium glass, zirconia, titania, lanthanoids, colloidal silica, etc. powder. Among them, silica/titanium group oxide-based composite oxide particles are preferable because the refractive index can be easily adjusted.

Silica-titanium group oxide-based composite oxide particles are composite oxides of silica and titanium group (group IV element of the periodic table) oxide, and are silica-titania, silica-zirconia, silica-titania-zirconia. etc. Of these, silica-zirconia is preferable because it allows adjustment of the refractive index of the filler and also imparts high X-ray opacity. The compound ratio is not particularly limited, but from the viewpoint of imparting sufficient X-ray opacity and setting the refractive index in a suitable range described later, the content of silica is 70 to 95 mol%, and the titanium group It is preferable that the oxide content is 5 to 30 mol %. In the case of silica/zirconia, the refractive index can be freely changed by changing each compound ratio in this manner.

These silica/titanium group oxide-based composite oxide particles may also contain metal oxides other than silica and titanium group oxides as long as they are in small amounts. Specifically, alkali metal oxides such as sodium oxide and lithium oxide may be contained within 10 mol %.

The method for producing such silica/titanium group oxide-based composite oxide particles is not particularly limited, but in order to obtain the specific inorganic spherical filler of the present invention, A so-called sol-gel method, in which a mixed solution containing a titanium group metal compound is added to an alkaline solvent and hydrolyzed to precipitate a reaction product, is preferably employed.

These silica/titanium group oxide-based composite oxide particles may be surface-treated with a silane coupling agent. Surface treatment with a silane coupling agent provides excellent interfacial strength between the polymerizable monomer component and the polymer portion. Typical silane coupling agents include organosilicon compounds such as γ-methacryloyloxyalkyltrimethoxysilane and hexamethyldisilazane. The surface treatment amount of these silane coupling agents is not particularly limited, and the optimum value may be determined after confirming the mechanical properties of the obtained dental curable composition by experiments in advance. Then, it is in the range of 0.1 to 15 parts by mass with respect to 100 parts by mass of particles.

In the present invention, the refractive index nF _a of the inorganic spherical filler (f ₁ ) at 25° C. is greater than the refractive index nP of the polymer of the cationic polymerizable monomer (a) at 25° C. This makes it easier to develop good color matching with natural teeth.
(f ₁ ) The difference between the refractive index nF _a (25° C.) of the inorganic spherical filler and the refractive index nP (25° C.) of the polymer of (a) the cationic polymerizable monomer is 0.001 or more. is preferred, 0.002 or more is more preferred, and 0.005 or more is most preferred. In addition, since the colored light is more clearly expressed when the transparency of the cured product is high, (f ₁ ) the refractive index nF _a (25 ° C.) of the inorganic spherical filler and (a) the cationic polymerizable monomer The difference from the refractive index nP (25° C.) of the polymer is preferably 0.1 or less, more preferably 0.05 or less.

The content of the inorganic spherical filler (f ₁ ) in the present invention is preferably 50 to 1500 parts by mass with respect to 100 parts by mass of the cationic polymerizable monomer (a). By blending 50 parts by mass or more of the inorganic spherical filler (f ₁ ), colored light due to interference, scattering and the like can be favorably expressed. The amount of the (f ₁ ) inorganic spherical filler to be blended is more preferably 100 to 1,300 parts by mass, more preferably 150 to 1,000 parts by mass, per 100 parts by mass of the cationic polymerizable monomer (a).

(f ₁ ) Among the inorganic spherical fillers, the silica-based filler, particularly the silica-titanium group oxide-based composite oxide, has a refractive index in the range of about 1.45 to 1.58 depending on the silica content. . That is, (a) the refractive index of the cationically polymerizable monomer is set within the above-described range (1.38 to 1.55) to satisfy the requirements of the present invention (f ₁ ) inorganic spherical The filler can be easily selected. That is, it is preferable to use a silica-titanium group oxide-based composite oxide (for example, silica-titania or silica-zirconia) containing an appropriate amount of silica.

<Organic-inorganic composite filler>
The dental curable composition of the present invention may contain an organic-inorganic composite filler. By using the organic-inorganic composite filler together with the inorganic spherical filler (f ₁ ) described above, the filling rate of the filler can be increased. Therefore, the polymerization shrinkage rate can be reduced, and the surface hardness of the cured product can be improved. The organic-inorganic composite filler contains (m) an organic resin matrix and (f ₂ ) an inorganic spherical filler, and more specifically, (m) consists of a plurality of primary particles (f ₂ ) contains an inorganic spherical filler, and (m) an organic resin matrix covers the surface of the primary particles that constitute the (f ₂ ) inorganic spherical filler.

(m) The organic resin matrix may be formed from a polymer of a radically polymerizable monomer, may be formed from a polymer of a cationically polymerizable monomer, or may be formed from a polymer of a radically polymerizable monomer. and a cationic polymerizable monomer.
As the inorganic spherical filler (f ₂ ), those described for the inorganic spherical filler (f ₁ ) can be used without particular limitation.
The content of the organic-inorganic composite filler is preferably 50 to 1000 parts by mass, more preferably 70 to 600 parts by mass, based on 100 parts by mass of the cationic polymerizable monomer (a).

<Phenolic antioxidant>
The dental curable composition of the present invention may contain a phenolic antioxidant as an additive for suppressing decomposition of the photoacid generator. Conventionally known phenolic antioxidants can be used without any restrictions. Examples include 4-methoxyphenol, hydroquinone, 2,6-di-t-butylphenol, dibutylhydroxytoluene, 2,4-di-t-butylphenol, 2-t-butyl-4,6-dimethylphenol and the like. The above phenolic antioxidants may be used singly or in combination of two or more as needed. The content of the phenolic antioxidant is usually, for example, 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight, per 100 parts by weight of the cationic polymerizable monomer (a).

<Other additives>
The dental curable composition of the present invention may contain known additives used in dental restorative materials. Such additives include ultraviolet absorbers, antistatic agents, fragrances, organic solvents, thickeners, and the like.

<Application>
Although the use of the dental curable composition of the present invention is not particularly limited, it is preferably used as a dental composite resin as a material for repairing teeth damaged by caries, breakage or the like. In tooth restoration, the curable dental composition of the present invention enables restoration of all kinds of cavities with high color matching to natural teeth. In general, it is difficult to match the color tone and the restoration operation is complicated. The dental curable composition of the present invention also enables restoration with high color matching.

<Manufacturing method>
The method for producing the dental curable composition of the present invention is not particularly limited, and any known method for producing a dental curable composition may be employed as appropriate. Specifically, in a dark place, the cationically polymerizable monomer, the photoacid generator, the thiophene compound, the inorganic spherical filler and, if necessary, the light-increasing compound that constitutes the dental curable composition of the present invention. Predetermined amounts of other ingredients such as a sensitizer may be weighed and mixed to form a paste. The curable dental composition of the present invention thus produced is stored in the dark until use.

As a means for curing the dental curable composition of the present invention, a known polymerization means may be suitably adopted according to the polymerization initiation mechanism of the photoacid generator type photopolymerization initiator used. Light irradiation by a light source such as arc, xenon lamp, metal halide lamp, tungsten lamp, fluorescent lamp, sunlight, helium cadmium laser, argon laser, or heating using a heat polymerization device, or a combination of these methods, etc. used without When polymerizing by light irradiation, the irradiation time varies depending on the wavelength and intensity of the light source, and the shape and material of the cured product. It is preferable to adjust the mixing ratio of the various components so that the time is in the range of about 5 to 60 seconds.

EXAMPLES The present invention will be specifically illustrated by examples below, but the present invention is not limited to these examples.

<(a) Cationic polymerizable monomer>
・ KR-470: a compound represented by the following formula (manufactured by Shin-Etsu Chemical Co., Ltd.)
· OXT-121: a compound represented by the following formula (manufactured by Toagosei)

<(b) Photoacid generator>
DPIB: iodonium salt with tetrakispentafluorophenylborate as a counter anion represented by the following formula (manufactured by Tokyo Chemical Industry Co., Ltd.)

<(c) Photosensitizer>
・CQ: Camphorquinone (manufactured by Tokyo Chemical Industry Co., Ltd.)

<(d) Thiophene compound (electron-donating compound)>
・ Th2: 2,2'-bithiophene (manufactured by Tokyo Chemical Industry Co., Ltd.)
・ Th3: 5-octyl-2,2′-bithiophene (manufactured by Tokyo Chemical Industry Co., Ltd.)

<Electron donating compound other than thiophene compound>
・DMAn: 9,10-dimethylanthracene (manufactured by Tokyo Chemical Industry Co., Ltd.)
・DMBE: ethyl p-dimethylaminobenzoate (manufactured by Tokyo Chemical Industry Co., Ltd.)
Structural formulas of the above compounds are shown below.

<(f ₁ ) Inorganic Spherical Filler>
F1 to F4 shown in Table 1 below were used.

The inorganic spherical fillers (F1 to F4) are prepared by the method described in JP-A-58-110414, JP-A-58-156524, etc., by adding a hydrolyzable organosilicon compound (tetraethylsilicate, etc.) and water. A mixed solution containing a decomposable organic titanium group metal compound (tetrabutyl zirconate) is added to an ammoniacal alcohol (e.g., methanol, ethanol, isopropyl alcohol, isobutyl alcohol, etc.) solution into which ammonia water has been introduced, It was prepared using a so-called sol-gel method in which hydrolysis was performed to precipitate a reaction product.
F1, F2, and F3 were surface-treated with a silane coupling agent represented by S-1 below. F4 was surface-treated with a silane coupling agent represented by S-2 below.

<Other ingredients: Phenolic antioxidant>
・BHT: Dibutyl hydroxytoluene (manufactured by Tokyo Chemical Industry Co., Ltd.)
・HQME: hydroquinone monomethyl ether (manufactured by Wako Pure Chemical Industries)

<Other components: Radically polymerizable monomer>
• UDMA: 1,6-bis(methacrylethyloxycarbonylamino)trimethylhexane • 3G: triethylene glycol dimethacrylate The structural formulas of the above compounds are shown below.

Various measuring methods in the present invention are as follows.

(1) Average primary particle size of inorganic spherical filler A photograph of the powder is taken with a scanning electron microscope ("XL-30S" manufactured by Philips), and all particles (30 or more) observed in the unit field of view of the photograph ) and the primary particle diameter (maximum diameter) of all particles were measured, and the average primary particle diameter was calculated by the following formula based on the measured values obtained.

（ｎ：粒子の数、Ｘ_ｉ：ｉ番目の粒子の一次粒子径（最大径））

(n: number of particles, X _i : primary particle diameter (maximum diameter) of i-th particle)

(2) Average Uniformity of Inorganic Spherical Filler A photograph of the powder is taken with a scanning electron microscope. Li) and the minor axis (Bi), which is the diameter in the direction orthogonal to the major axis, were determined, and the average degree of uniformity was calculated by the following formula.

（ｎ：粒子の数、Ｂｉ：ｉ番目の粒子の短径、Ｌｉ：ｉ番目の粒子の長径）

(n: number of particles, Bi: short diameter of i-th particle, Li: long diameter of i-th particle)

(3) Percentage of particles existing in the range of average primary particle diameter ± 5% to the total number of particles Measure the number of particles having a primary particle diameter (maximum diameter) outside the particle diameter range of ±5% of the average primary particle diameter, subtract this value from the number of all particles, and average in the unit field of view of the photograph Determine the number of particles within the particle size range of the primary particle size ± 5%, the following formula:
Percentage (%) of particles existing in the range of 5% before and after the average primary particle size to the total number of particles = [(Present in the range of 5% before and after the average primary particle size in the unit field of the scanning electron micrograph number of particles)/(total number of particles in unit field of view of scanning electron micrograph)]×100.

(4) Refractive index nP of polymer of polymerizable monomer
The refractive index of the polymer of the polymerizable monomer was measured at a constant temperature of 25° C. using an Abbe refractometer (manufactured by Atago Co., light source wavelength 589 nm) under almost the same conditions as the polymerization conditions in the cavity. Measured in the room. Incidentally, the polymerizable monomer is a mixture of KR-470: 75 parts by mass and OXT-121: 25 parts by mass in Examples 1 to 9 and Comparative Examples 1 and 2, and in Comparative Example 3, UDMA: 80 It is a mixture of parts by weight and 3G:20 parts by weight.

100 parts by mass of the polymerizable monomer used in each example and comparative example, 2 parts by mass of DPIB as a photoacid generator, 0.3 parts by mass of CQ as a photosensitizer, and 0.3 parts by mass of CQ as an electron donor. A composition was prepared by mixing 5 parts by mass. The composition was sandwiched between two polypropylene films to a thickness of about 0.02 to 0.1 mm. Then, light irradiation was performed for 10 seconds using a dental light irradiation device (Tokuso Power Light, manufactured by Tokuyama Corporation). The light irradiator emits light with a wavelength range of 400-500 nm. Irradiation was performed so that the light intensity on the irradiated surface was 400 mW/cm ² . After the light irradiation, the film-like polymer of the polymerizable monomer was removed from the polypropylene film. When setting the polymer in an Abbe refractometer (manufactured by Atago, light source wavelength 589 nm), a solvent (bromo Naphthalene) was dropped on the sample and measured.

(5) Refractive index nF _a of inorganic spherical filler
The refractive index nF _a of the inorganic spherical filler used was measured by a liquid immersion method using an Abbe refractometer (manufactured by Atago, light source wavelength 589 nm).
That is, 1 g of inorganic spherical filler was dispersed in 50 ml of anhydrous toluene in a 100 ml sample bottle in a constant temperature room at 25°C. The refractive index nF _a of the inorganic spherical filler was measured by adding 1-bromotoluene little by little while stirring the dispersion with a stirrer and measuring the refractive index of the dispersion when the dispersion became most transparent. did.

(6) Surface Hardness The curable dental compositions prepared in Examples and Comparative Examples were filled in a polyacetal mold having holes of 7 mmφ×1.0 mm and pressed with a polypropylene film. Then, using a dental light irradiator (Tokuso Power Light, manufactured by Tokuyama Corporation), light irradiation was performed for 10 seconds (light intensity on the irradiation surface: 400 mW/cm ² ). Immediately after the light irradiation, the state of the filling was checked to confirm whether or not the entire composition was cured. When the composition as a whole is cured, the obtained cured product is removed from the mold, and a Vickers indenter is used with a microhardness tester (MMT-X7 type, manufactured by Matsuzawa Seiki Co., Ltd.) with a load of 100 gf and a load retention time of 30. The diagonal point length (d) of the dent formed in the test piece was measured under the load condition of 1 second, and the surface hardness Hv of the test piece was determined. The surface hardness Hv was obtained using the following formula (1).
Hv=1854.37×100/d ² Formula (1)

(7) Polymerization Shrinkage A SUS plunger with a diameter of 3 mm and a height of 7 mm was inserted into a SUS split mold having a hole with a diameter of 3 mm and a height of 7 mm to make the height of the hole 3 mm. This was filled with the curable dental compositions prepared in Examples and Comparative Examples, and pressed against a polypropylene film from above. Place the film face down on a glass stand equipped with a dental light irradiator (Tokuso Power Light, manufactured by Tokuyama Co., Ltd.). A short needle that can be measured was brought into contact. Polymerize and harden with a dental irradiator (light intensity on the irradiated surface: 800 mW/cm ² ), shrinkage (%) 3 minutes after the start of irradiation is calculated from the vertical movement distance of the short needle, and this is the polymerization shrinkage rate ( %).

(8) Colored Light Visual Evaluation The pastes of the curable dental compositions prepared in Examples and Comparative Examples were placed in a mold having a hole of 7 mmφ×1 mm, and both sides were pressed with a polyester film. After curing by irradiating both sides with a visible light irradiator (Power Light, manufactured by Tokuyama) for 30 seconds each, remove from the mold, place it on the adhesive surface of a black tape (carbon tape) of about 10 mm square, and visually color it. Check the color of the light.

(9) Fluorescent Visual Evaluation Pastes of the curable compositions prepared in Examples and Comparative Examples were placed in a mold having a through hole of 7 mmφ×1 mm, and polyester films were pressed against both sides. Both surfaces were irradiated with light for 30 seconds each with a dental light irradiator (Tokuso Power Light, manufactured by Tokuyama Co., Ltd.) for curing, and then the cured product was removed from the mold. When the cured body was irradiated with ultraviolet light (wavelength: 365 nm) from an ultraviolet light lamp (manufactured by Spectronics Corporation, handy UV lamp), it was confirmed whether or not there was specific color development compared to natural teeth.

(10) Spectral Reflectance Ratio The dental curable composition pastes prepared in Examples and Comparative Examples were placed in a mold having a through hole of 7 mmφ×1 mm, and polyester films were pressed against both sides. After curing by irradiating both sides with a visible light irradiator (manufactured by Tokuyama, Powerlight) for 30 seconds each, remove from the mold and use a color difference meter (manufactured by Tokyo Denshoku, "TC-1800MKII") to measure the black background. Measure the spectral reflectance below, obtain the maximum reflectance in the yellow to red region (600-750 nm): SR1 and the maximum reflectance in the blue region (400-500 nm): SR2, and divide SR1 by SR2 By doing so, the spectral reflectance ratio was calculated.
When the spectral reflectance ratio (SR1/SR2) is 0.8 to 2.0, the colored light in the yellow to red range is stronger than the colored light in the blue range, and the color tone is compatible with natural teeth. It becomes easier to perform high-quality repairs.

[Example 1]
2.0 parts by weight of DPIB as a photoacid generator and 0.0 part by weight as a photosensitizer with respect to 100 parts by weight of a cationic polymerizable monomer consisting of 75 parts by weight of KR-470 and 25 parts by weight of OXT-121. 3 parts by weight of CQ, 0.1 parts by weight of Th3 as an electron-donating compound, 150 parts by weight of F1 as an inorganic spherical filler, 0.1 parts by weight of HQME as a phenolic antioxidant, and 0.1 parts by weight of BHT was added and stirred under red light for 6 hours to prepare a dental curable composition.
The resulting curable dental composition was evaluated for surface hardness, polymerization shrinkage, colored light visual evaluation, fluorescent visual evaluation, and spectral reflectance ratio by the methods described above. Table 2 shows the results.

[Examples 2-9, Comparative Examples 1-2]
A dental curable composition was prepared in the same manner as in Example 1, except that the types and amounts of the electron-donating compound and the inorganic spherical filler were changed as shown in Table 2.
The resulting curable dental composition was evaluated for surface hardness, polymerization shrinkage, colored light visual evaluation, fluorescent visual evaluation, and spectral reflectance ratio by the methods described above. Table 2 shows the results.

[Comparative Example 3]
Instead of the cationic polymerizable monomer, 80 parts by mass of UDMA and 20 parts by mass of a radically polymerizable monomer consisting of 3G were used, except that the amount of the electron-donating compound was 0.5 parts by mass. A dental curable composition was prepared in the same manner as in Example 1.
The resulting curable dental composition was evaluated for surface hardness, polymerization shrinkage, colored light visual evaluation, fluorescent visual evaluation, and spectral reflectance ratio by the methods described above. Table 2 shows the results.

As is clear from the results of Examples 1 to 9, the curable dental composition of the present invention has a strong yellow to red colored light, and is capable of restoration with high color tone compatibility with natural teeth. Do you get it. Furthermore, the dental curable composition of the present invention had good physical properties such as small polymerization shrinkage and high surface hardness of the resulting cured product.
On the other hand, the dental curable composition of Comparative Example 1, in which the thiophene compound was not used as the electron-donating compound and the aromatic amine was used, showed a decrease in the surface hardness of the cured product.
The curable dental composition of Comparative Example 2, which used an anthracene compound instead of a thiophene compound as an electron-donating compound, showed blue fluorescence under ultraviolet light and had a low spectral reflectance ratio. It turned out to be difficult to repair with high efficiency.
The curable dental composition of Comparative Example 3, which used a radically polymerizable monomer instead of a cationically polymerizable monomer, resulted in a larger polymerization shrinkage rate than those of Examples.

Claims (7)

(a) a cationically polymerizable monomer,
(b) a photoacid generator;
(d) a thiophene compound, and (f ₁ ) all particles having an average primary particle size in the range of 230 nm or more and 1000 nm or less and existing in a range of 5% before and after the average primary particle size in the number-based particle size distribution Containing an inorganic spherical filler whose ratio to the number of particles is 90% or more,
The (d) thiophene compound is an electron-donating compound represented by the following formula (1) or (2),

(In formulas (1) and (2) above, R ¹ to R ¹¹ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an alkylthio group, an aryl group, or a thienyl group, and R ³ and R ⁴ and R ³ and R ⁹ may combine to form a ring.)
The curable dental composition, wherein the refractive index nF _a of the (f ₁ ) inorganic spherical filler at 25° C. is greater than the refractive index nP of the polymer of the cationic polymerizable monomer (a) at 25° C. (b) the photoacid generator, (d) the thiophene compound, and (f) with respect to 100 parts by mass of the (a) cationic polymerizable monomer ₁ ) The content of the inorganic spherical filler is, respectively, the (b) photoacid generator: 0.01 to 20 parts by mass, the (d) thiophene compound: 0.001 to 10 parts by mass, and the (f) ₁ ) Inorganic spherical filler: 50 to 1500 parts by mass of the dental curable composition according to claim 1. 3. The dental curable composition according to claim 1, further comprising (c) a photosensitizer. 4. The difference between the refractive index nF _a of the (f ₁ ) inorganic spherical filler and the refractive index nP of the polymer of the cationic polymerizable monomer (a) is 0.001 or more. or the dental curable composition according to any one of items. The dental curable composition according to any one of claims 1 to 4, wherein the (a) cationic polymerizable monomer contains at least one compound selected from epoxy compounds and oxetane compounds. The dental curable composition according to any one of claims 1 to 5, wherein the (b) photoacid generator is an iodonium salt compound. The dental curable composition according to any one of claims 1 to 6, further comprising a phenolic antioxidant.