Composite resin tooth containing non-crosslinked polymer particles

Abstract

[Task] A composite resin tooth is provided which is endowed with excellent fracture toughness to withstand the occlusal pressure in the oral cavity while exhibiting good adhesion to the base of the denture. [Solution] A composite resin tooth having a layered structure of one layer or two or more layers, characterized by comprising a composite resin layer comprising a polymerization-cured body of a curable composition containing a polymerizable monomer (A), an organic-inorganic composite filler (B), inorganic fine particles (C), and non-crosslinked polymer particles (D), wherein the content of the non-crosslinked polymer particles (D) in the curable composition is in the range of 1 mass% to 5 mass%, and the average particle diameter of the total of the inorganic fine particles (C) contained in the curable composition is 1 μm or less.

Description

[Technical field]

[0001] The present invention relates to a composite resin tooth as an artificial tooth used in the manufacture of dental prostheses. [Technical background]

[0002] Until now, resin teeth were used as artificial teeth. These were cured by polymerization after mixing methyl methacrylate and polymethyl methacrylate. Although resin teeth offer excellent transparency, moldability, and adhesion to the denture base, they have low surface hardness and are easily worn in the oral cavity.

[0003] In contrast, composite resin teeth have a composite resin layer in which a curable composition containing a multifunctional polymerizable (meth)acrylate monomer, inorganic fine particles and / or organic-inorganic composite fillers is polymerization-cured, thus having high surface hardness and excellent abrasion resistance.

[0004] JP 2517753 B2 and JP 5804517 B2 propose composite resin teeth in which water absorption resistance and discoloration resistance are increased by forming the composite resin layer with a curable composition containing specific polymerizable monomers. [Summary of the invention][Problem to be solved by the invention]

[0005] Although the mechanical properties of the composite resin teeth according to JP 2517753 B2 and JP 5804517 B2 are improved compared to resin teeth, their fracture strength was not sufficient to withstand the occlusal pressure in the oral cavity when the opposing tooth is a prosthesis with very high surface hardness such as ceramic or zirconia, etc.

[0006] Furthermore, the composite resin layer of these composite resin teeth had insufficient adhesion to the base of the denture, and when used in the oral cavity, tiny gaps appeared at the interface between the artificial teeth and the base of the denture, with plaque and pigments depositing in these gaps having a negative impact on the appearance and hygiene.

[0007] Therefore, the object of the present invention is to provide a composite resin tooth having excellent fracture toughness to withstand the occlusal pressure in the oral cavity and having good adhesion to the base of the denture. [Means of solving the problem]

[0008] To achieve the above object, the present inventors conducted thorough studies and, as a result, found that by mixing a certain amount of non-crosslinked polymer particles into the composite resin layer in the composite resin tooth, high fracture resistance and excellent adhesion to the base of the denture are exhibited, thus completing the present invention. Specifically, the composite resin tooth of the present invention suppresses the occurrence of fractures because the non-crosslinked polymer particles mixed into the composite resin layer absorb the stress transmitted to the composite resin layer when subjected to occlusal pressure.Furthermore, the presence of non-crosslinked polymer particles increases the adhesion to the base of the denture more than with a composite resin layer in a previous composite resin tooth, and the occurrence of tiny gaps at the interface between the composite resin layer and the base of the denture, which may be the cause of plaque and pigment deposition, can be suppressed.

[0009] That is, the above object is achieved by implementing the following component structure. Composite resin tooth having a single-layer structure or a layered structure with two or more layers, characterized in that it comprises a composite resin layer comprising a polymerization-cured body of a curable composition comprising a polymerizable monomer (A), an organic-inorganic composite filler (B), inorganic fine particles (C) and non-crosslinked polymer particles (D), wherein the content of the non-crosslinked polymer particles (D) in the curable composition is in the range of 1 mass% to 5 mass%, where the average particle diameter of the total of the inorganic fine particles (C) contained in the curable composition is 1 µm or less. [Advantages of the invention]

[0010] According to the present invention, a composite resin tooth can be provided which is excellent in fracture toughness to withstand the occlusal pressure in the oral cavity and has good adhesion to the base of the denture. [Brief description of the drawings] [ Fig. 1] Schematic view showing the structure of a test specimen. [ Fig. 2] View showing the test state of the test specimen attached to a special clamping device. [Embodiments of the invention]

[0011] The present invention will be explained in detail below.

[0012] In the present specification, the composite resin tooth refers to an artificial tooth having at least one or more composite resin layers as described below. In the present specification, the composite resin layer refers to a single layer constituting the composite resin tooth, formed by polymerization-curing a curable composition containing a polymerizable monomer and an organic-inorganic composite filler and / or inorganic fine particles.

[0013] In the present description, the non-crosslinked polymer particles mean particles of a polymer of one or two or more monofunctional polymerizable monomers, in particular particles of polymers which do not have crosslinking points between the polymers.

[0014] In the present description, (meth)acrylate is referred to as acrylate and methacrylate, (meth)acryloyl as acryloyl and methacryloyl, (meth)acrylic acid as acrylic acid and methacrylic acid and (meth)acrylamide as acrylamide and methacrylamide, each comprehensively.

[0015] In the present specification, the average particle diameter means the particle diameter (D50) when the sum value from the small particle side accounts for 50% of the volume-measured particle size distribution measured using a laser diffraction and scattering particle size distribution measuring device, etc.

[0016] The composite resin tooth of the present invention, which has a single-layer or two or more-layered structure, is formed by polymerization-curing a curable composition in which a composite resin layer contains a polymerizable monomer (A), an organic-inorganic composite filler (B), inorganic fine particles (C), and a specified amount of non-crosslinked polymer particles (D). These components are explained in detail below.

[0017] In the present invention, the average particle diameter of the non-crosslinked polymer particles (D) may be 5 µm to 50 µm.

[0018] In the present invention, the content of inorganic fine particles (C) in the curable composition may be in the range of 15 mass% to 35 mass%, and the content of inorganic fillers (b-1) contained in the organic-inorganic composite fillers (B) is in the range of 10 mass% to 35 mass%.

[0019] In the present invention, the content of methyl methacrylate with respect to the total of the polymerizable monomers (A) may be 5 mass% or less.

[0020] In the present invention, the non-crosslinked polymer particles (D) may comprise polymethyl methacrylate particles.

[0021] The polymerizable monomers (A) that can be used in the curable composition for forming the composite resin layer (hereinafter referred to as "curable composition of the present invention") are not particularly limited in their molecular structure, and they may be known polymerizable monomers. That is, as polymerizable unsaturated groups contained in the polymerizable monomer (A), for example, (meth)acryloyloxy groups, (meth)acrylamide groups, styryl groups, vinyl groups, and allyl groups are cited, but are not limited to these. Among these polymerizable unsaturated groups, (meth)acryloyloxy groups or (meth)acrylamide groups are preferred because of their excellent polymerization rate, with (meth)acryloyloxy groups being even more preferred.Furthermore, no particular limitation is imposed on the number of polymerizable unsaturated groups that the polymerizable monomer (A) has. The hydrocarbon groups bonded to the polymerizable unsaturated groups may be aliphatic hydrocarbon groups, cycloaliphatic hydrocarbon groups, aromatic hydrocarbon groups, or any combination thereof, and these hydrocarbon groups may have any substituents such as acid groups, hydroxyl groups, halogen atoms, sulfur atoms, alkoxy groups, amino groups, glycidyl groups, etc. The following are concrete examples of polymerizable monomers (A).

[0022] Als monofunktionelle polymerisierbare Monomere werden (Meth)acrylsäure, Methyl(meth)acrylat, Ethyl(meth)acrylat, Isopropyl(meth)acrylat, n-Propyl(meth)acrylat, Isobutyl(meth)acrylat, n-Butyl(meth)acrylat, t-Butyl(meth)acrylat, sec-Butyl(meth)acrylat, n-Amyl(meth)acrylat, Isoamyl(meth)acrylat, n-Hexyl(meth)acrylat, Isodecyl(meth)acrylat, Lauryl(meth)acrylat, Stearyl(meth)acrylat, 2-Ethylhexyl(meth)acrylat, Cyclohexyl(meth)acrylat, Adamantyl(meth)acrylat, Phenyl(meth)acrylat, Phenoxydiethylenglycol(meth)acrylat, Methoxypolyethylenglycol(meth)acrylat, Benzyl(meth)acrylat, 2-Phenylethyl(meth)acrylat, o-Phenoxybenzyl(meth)acrylat, m-Phenoxybenzyl(meth)acrylat, p-Phenoxybenzyl(meth)acrylat, Tetrahydrofurfuryl(meth)acrylat, Glycidyl(meth)acrylat, Isobornyl(meth)acrylat, Allyl(meth)acrylat, 2-Methoxyethyl(meth)acrylat, 2-Ethoxyethyl(meth)acrylat, Phenoxyethyl(meth)acrylat, 2-Hydroxyethyl(meth)acrylat, 2-Hydroxypropyl(meth)acrylat, 3-Hydroxypropyl(meth)acrylat, 2-Hydroxybutyl(meth)acrylat,Glycerol (meth)acrylate, (meth)acryloyloxyethyl methylsuccinate, 2-(meth)acryloyloxyethyl propionate, (meth)acrylic acid esters such as acetoacetoxyethyl (meth)acrylate, acetoacetoxypropyl (meth)acrylate, acetoacetoxybutyl (meth)acrylate, etc., silane compounds such as γ-(meth)acryloyloxypropyl-trimethoxysilane, γ-(meth)acryloyloxypropyl-triethoxysilane, etc., amines such as 2-(N,N-dimethylamino)ethyl (meth)acrylate, 2-(N,N-diethylamino)ethyl (meth)acrylate, etc., fluorine-containing (meth)acrylates such as 2,2,2-trifluoroethyl (meth)acrylate, perfluorohexylethyl (meth)acrylate, perfluorooctylethyl (meth)acrylate, etc., as well as their (meth)acrylamides and N-methylol (meth)acrylamide, etc. cited.,

[0023] Als aromatische bifunktionelle polymerisierbare Monomere werden 2,2-Bis[4-[3-(meth)acryloyloxy-2-hydroxypropoxy]phenyl]propan, 2,2-Bis(4-(meth)acryloyloxyphenyl)propan, 2,2-Bis(4-(meta)acryloyloxyethoxyphenyl)propan, 2,2-Bis(4-(meta)acryloyloxydiethoxyphenyl)propan, 2,2-Bis(4-(meta)acryloyloxytetraethoxyphenyl)propan, 2,2-Bis(4-(meth)acryloyloxypentethoxyphenyl)propan, 2,2-Bis(4-(meth)acryloyloxydipropoxyphenyl)propan, 2-(4-(meth)acryloyloxyethoxyphenyl)-2-(4-(meth)acryloyloxy-diethoxyphenyl)propan, 2-(4-(meth)acryloyloxy-diethoxyphenyl)-2-(4-(meth)acryloyloxy-triethoxyphenyl)propan, 2-(4-(meth)acryloyloxy-dipropoxyphenyl)-2-(4-(meth)acryloyloxytriethoxyphenyl)propan, 2,2-Bis(4-(meth)acryloyloxydipropoxyphenyl)propan, 2,2-Bis(4-(meth)acryloyloxyisopropoxyphenyl))propan, 2,2-Bis(4-(meth)acryloyloxypolyethoxyphenyl)propan, 9,9-Bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluoren, sowie deren (Meth)acrylamide usw. angeführt.

[0024] Als aliphatische bifunktionelle polymerisierbare Monomere werden Ethylenglykoldi(meth)acrylat, Diethylenglykoldi(meth)acrylat, Triethylenglykoldi(meth)acrylat, Tetraethylenglykoldi(meth)acrylat, Polyethylenglykoldi(meth)acrylat, Dipropylenglykoldi(meth)acrylat, Tripropylenglykoldi(meth)acrylat, Neopentylglykoldi(meth)acrylat, 3-Methyl-1,5-pentandioldi(meth)acrylat, 1,3-Butandioldi(meth)acrylat, 1,4-Butandioldi(meth)acrylat, 1,6-Hexandioldi(meth)acrylat, 1,9-Nonandioldi(meth)acrylat, 1,10-Decandioldi(meth)acrylat, Tricyclodecandimethanoldi(meth)acrylat, Glycerin-1,3-dimethacrylat, 3-Hydroxypropyl-1,2-di(meth)acrylat, 2-Hydroxy-3-acryloyloxypropyl(meth)acrylat, 1,2-Bis(3-(meth)acryloyloxy-2-hydroxypropoxy)ethan, 1,2-Bis(3-(meth)acryloyloxy-2-hydroxypropoxy)propan, 2-Hydroxy-1,3-Bis(3-(meth)acryloyloxy-2-hydroxypropoxy)propan und deren (Meth)acrylamide usw. angeführt.

[0025] As polymerizable monomers having three or more functional groups, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolmethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, glycerol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate and their (meth)acrylamides, etc. are mentioned.

[0026] As urethane-based polymerizable monomers, (meth)acrylate compounds, etc., which have a urethane compound derived from additives of polymerizable monomers having hydroxyl groups such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 3-chloro-2-hydroxypropyl (meth)acrylate, and isocyanate compounds such as methylcyclohexane diisocyanate, methylenebis(4-cyclohexyl isocyanate), hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, diisocyanate methyl methylbenzene, and 4,4-diphenylmethane diisocyanate are cited.

[0027] In addition to the above polymerizable monomers, oligomers or polymers having at least one polymerizable group or more may also be used. The above polymerizable monomers (A) are not limited to these and may be used individually or in combination.

[0028] There is no particular limitation on the content of the polymerizable monomers (A), but it is preferable that it be in the range of 10 mass% to 50 mass% in the curable composition of the present invention, more preferably in the range of 25 mass% to 50 mass%, and further preferably in the range of 25 mass% to 40 mass%. When the content of the polymerizable monomers (A) is less than 10 mass%, the fracture strength of the composite resin layer tends to be reduced. On the other hand, when it is more than 50 mass%, the surface hardness, abrasion resistance, compressive strength, etc., tends to be reduced.

[0029] Furthermore, when the polymerizable monomer (A) contains methyl methacrylate, it is preferable that the content of methyl methacrylate be 5 mass% or less with respect to the total of the polymerizable monomer (A). If the content of methyl methacrylate is more than 5 mass%, the surface hardness, abrasion resistance, compressive strength, and fracture strength, etc., of the composite resin layer are likely to be reduced. It is preferable that the curable composition of the present invention not contain methyl methacrylate.

[0030] The organic-inorganic composite filler (B) that can be used in the curable composition of the present invention is a composite particle comprising an inorganic part contained in the form of the inorganic filler (b-1) and an organic part in which the polymerizable monomer (b-2) has been cured, wherein the inorganic filler (b-1) is present in a dispersed state in the cured product of the polymerizable monomer (b-2). The organic-inorganic composite filler (B) is obtained by homogenizing the inorganic filler (b-1) and the polymerizable monomer (b-2) containing a polymerization initiator as much as possible, then curing the polymerizable monomer (b-2), and crushing this cured product if necessary.

[0031] Inorganic fillers (b-1) that can be used to prepare organic-inorganic composite fillers (B) are explained. The inorganic fillers (b-1) are not limited to their components, and generally known items can be used. In the specific demonstration of inorganic fillers (b-1), inorganic oxides such as silicon dioxide, aluminum oxide, titanium dioxide, zirconium oxide, strontium oxide, barium oxide, yttrium oxide, lanthanum oxide, ytterbium oxide, etc., inorganic composite oxides such as silicon dioxide-zirconium oxide, silicon dioxide-titania, silicon dioxide-titania-barium oxide, silicon dioxide-titania-zirconium oxide, etc., glasses such as fused silicon dioxide, quartz, aluminum silicate glass, fluoro-aluminum silicate glass, borosilicate glass, aluminum borate glass, boron-aluminum silicate glass, etc., and metal fluorides such as calcium fluoride, barium fluoride, strontium fluoride, yttrium fluoride, lanthanum fluoride, ytterbium fluoride, etc. are mentioned.

[0032] These inorganic fillers (b-1) have no particular restrictions on their shape, and they can be spherical, needle-shaped, plate-shaped, crushed, or flaky, etc., and they can be used in aggregate form. The inorganic fillers (b-1) shown above are not limited to these and can also be used individually or in combination.

[0033] There is no particular restriction on the particle diameter of the inorganic filler (b-1). Considering the balance of various properties in the composite resin layer, an average particle diameter of 0.005 μm to 3 μm is preferred. If the average particle diameter of the inorganic filler (b-1) is less than 0.005 μm, the aggregation of the inorganic filler (b-1) becomes significant, making it difficult to uniformly disperse the inorganic filler (b-1) in the organic-inorganic composite filler (B), and the compressive strength or fracture toughness of the composite resin layer may be reduced. Furthermore, if the average particle diameter of the inorganic filler (b-1) is more than 3 μm, the abrasion resistance of the composite resin layer may be reduced, resulting in a lack of smooth surface and easy coloring.In the curable composition of the present invention, the inorganic filler (b-1) comprising the organic-inorganic composite filler (B) may also comprise only an inorganic filler whose average particle diameter is 0.005 µm to 3 µm.

[0034] It is preferable that these inorganic fillers (b-1) be surface-treated and rendered hydrophobic. This surface treatment enables high filling of the inorganic filler (b-1) in the organic-inorganic composite filler (B), thereby enhancing the mechanical properties of the organic-inorganic composite filler (B) itself. There is no particular limitation on the surface-treating agents that can be used for the surface treatment of the inorganic filler (b-1), and generally known agents such as organic silicon compounds, organic zirconium compounds, organic titanium compounds, and organic aluminum compounds, etc., can be used, with organic silicon compounds being the most conventionally used.When specifically citing examples of organic silicon compounds, methyltrimethoxysilane, ethyltrimethoxysilane, methoxytripropylsilane, propyltriethoxysilane, hexyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, vinyltri(β-methoxyethoxy)silane, γ-(meth)acryloyloxypropyltrimethoxysilane, 8-(meth)acryloyloxyoctyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, methyltrichlorosilane, phenyltrichlorosilane, trimethylsilyl isocyanate, vinylsilyl triisocyanate, phenylsilyl triisocyanate, hexamethyldisilazane, etc. are cited, but are not limited to these. These surface treatment agents can be used individually or in combination. Furthermore, there is no particular limitation on the surface treatment process and generally known processes can be applied.In addition, there is no particular limitation on the amount of the surface treatment agent with respect to the inorganic filler (b-1) when performing the surface treatment, and it suffices if it is appropriately adjusted according to the particle diameter, etc., of the inorganic filler (b-1).

[0035] It is preferable that the content of the inorganic filler (b-1) contained in the raw materials of the organic-inorganic composite filler (B) is 8 mass% to 50 mass%, and it is more preferable that it is 10 mass% to 35 mass%. When the content of the inorganic filler (b-1) in the organic-inorganic composite filler (B) is less than 8 mass%, the surface hardness, abrasion resistance, and compressive strength, etc., of the composite resin layer tend to be reduced. On the other hand, when the content of the inorganic filler (b-1) is more than 50 mass%, the brittleness of the organic-inorganic composite filler (B) tends to increase, and the fracture strength of the composite resin layer tends to be reduced.In the curable composition of the present invention, the organic-inorganic composite filler (B) may also contain 8 mass % to 50 mass % of an inorganic filler (b-1) having an average particle diameter of 0.005 µm to 3 µm. The curable composition of the present invention may also contain, as the organic-inorganic composite filler (B), only an organic-inorganic composite filler in which the content of the inorganic filler (b-1) contained in the raw materials is 8 mass % to 50 mass %. In the curable composition of the present invention, only an organic-inorganic composite filler containing 8 mass % to 50 mass % of an inorganic filler (b-1) having an average particle diameter of 0.005 µm to 3 µm may be contained as the organic-inorganic composite filler (B).

[0036] The polymerizable monomers (b-2) that can be used to prepare the organic-inorganic composite filler (B) have no particular limitation on their molecular structure, and the same polymerizable monomers as the aforementioned polymerizable monomers (A) can be used.

[0037] It is preferable that the content of polymerizable monomers (b-2) contained in the raw materials of the organic-inorganic composite filler (B) is 48 mass% to 90 mass%, and it is more preferable that it is 63 mass% to 88 mass%. When the content of polymerizable monomers (b-2) in organic-inorganic composite fillers (B) is less than 48 mass%, the brittleness of the organic-inorganic composite fillers (B) tends to increase and the fracture strength of the composite resin layer tends to decrease. On the other hand, when the content of polymerizable monomers (b-2) is more than 90 mass%, the surface hardness, abrasion resistance, and compressive strength of the composite resin layer tends to decrease.

[0038] Next, polymerization initiators that can be used to prepare the organic-inorganic composite filler (B) will be explained. There is no particular limitation on the polymerization initiators, and well-known polymerization initiators such as thermal polymerization initiators, chemical polymerization initiators, and light polymerization initiators can be used. Among them, it is preferable to use thermal polymerization initiators because the production efficiency of the organic-inorganic composite filler (B) is excellent. As thermal polymerization initiators, organic peroxides such as benzoyl peroxide and azo compounds such as azobisisobutyronitrile can be suitably used. These polymerization initiators can be used individually or in combination, regardless of the polymerization method.There is also no particular limitation on the amount of the polymerization initiator added, but generally it is 0.1 mass% to 10 mass% with respect to 100 mass% of the total polymerizable monomer (b-2) used for preparing the organic-inorganic composite filler (B).

[0039] Next, the manufacturing process of the organic-inorganic composite filler (B) will be explained using a case where a thermal polymerization initiator was used as an example. The organic-inorganic composite filler (B) is manufactured through the main processes (Process 1) to (Process 4) shown next. (Process 1) A process in which polymerizable monomers, thermal polymerization initiators, inorganic fillers, etc., which are the individual components constituting the organic-inorganic filler, are mixed to obtain a mixture. (Process 2) A process in which this mixture is heated, the polymerizable monomers are polymerized, and a cured product is obtained. (Process 3) A process in which the cured product is crushed as needed to obtain an organic-inorganic composite filler.(Process 4) A process in which surface treatment is performed on the organic-inorganic composite filler as needed. For the composite resin layer, the organic-inorganic composite filler obtained in (Process 3) can be used as it is after crushing, and the organic-inorganic composite filler obtained in (Process 4) can be used after surface treatment. Furthermore, if it is not in a lump form but already in a fine particle form in the step of (Process 2), it can be used as it is as the organic-inorganic composite filler. Furthermore, this organic-inorganic composite filler can be used after surface treatment in (Process 4).

[0040] In the process for obtaining the mixture of the individual components of (Process 1), a method for mixing the individual components such as polymerizable monomers, thermal polymerization initiators, and inorganic fillers using a kneading machine, or a method for agglomerating the inorganic fillers and obtaining agglomerated fillers having pores of several μm to several tens of μm, and then taking these agglomerated fillers into a solution in which the thermal polymerization initiator and the polymerizable monomers have been dissolved in an inorganic solvent and making them into a slurry state, followed by removing the organic solvent at low temperature and under reduced pressure, and then removing the polymerizable monomers, etc.A method of penetrating and coating the interior and surface of the agglomerated filler, thereby mixing the individual components, or a method of subjecting the inorganic fillers to compression molding to obtain inorganic filler molded articles, then immersing these molded articles in polymerizable monomers containing a thermal polymerization initiator, and allowing the polymerizable monomers to penetrate the interior of the molded articles, thereby mixing the individual components, etc., are mentioned, but not limited to these. In the present process, by allowing the aforementioned surface-treating agents such as organic silicon compounds, etc., to be dissolved in polymerizable monomers, the surface treatment of the inorganic fillers and the mixing of the individual components can be carried out simultaneously.This allows the step of surface treatment of the inorganic fillers before mixing the individual components to be omitted.

[0041] In the process for obtaining the cured product of (Process 2), the polymerization temperature and polymerization time can be adjusted according to the characteristics of the thermal polymerization initiator used, and further with the thermal discoloration of the organic-inorganic composite filler and the amount of remaining unpolymerized monomer as indicators, respectively. However, generally, the polymerization temperature is 70°C to 150°C, and the polymerization time is from several minutes to several hours. Furthermore, depending on the polymerization method, the polymerization conditions, such as polymerization in air, polymerization in an inert gas atmosphere such as nitrogen or argon, polymerization under normal pressure, or polymerization under pressure, can be selected as appropriate.

[0042] (Process 3) In the process of obtaining an organic-inorganic composite filler by crushing, the crushing method is not particularly limited, and either a wet or dry method can be used. The crushing machines used for crushing include high-speed mills such as hammer mills or turbo mills; container-driven mills such as ball mills, planetary mills or vibrating mills; and media-stirring mills such as attritors or bead mills, jet mills, etc., but are not limited to these.There is no particular limitation on the average particle diameter of the organic-inorganic composite filler (B), and it can be adjusted as needed according to the desired properties to be imparted to the composite resin layer. However, it is preferable that the average particle diameter be from 1 μm to 100 μm, and it is more preferable that it be from 10 μm to 30 μm. Organic-inorganic composite fillers with an average particle diameter of less than 1 μm require a long time for crushing to obtain the particle diameter, and therefore, discoloration of the organic-inorganic composite fillers themselves is likely to occur, adversely affecting the color tone of the composite resin layer. Furthermore, if it is more than 100 μm, the compressive strength of the composite resin layer is likely to be reduced.The curable composition of the present invention may also contain, as the organic-inorganic composite filler (B), only organic-inorganic composite fillers having an average particle diameter of 1 µm to 100 µm.

[0043] (Process 4) In the process of performing surface treatment on the organic-inorganic composite filler, the same surface treatment agents can be used as those used for the surface treatment of the above-mentioned inorganic filler. Furthermore, the surface treatment method can be applied to the same well-known methods as those used for the surface treatment of inorganic fillers. Furthermore, there is no particular limitation on the amount of the surface treatment agent used with respect to the organic-inorganic composite filler when performing surface treatment. It is sufficient to use it according to the particle diameter of the inorganic-organic composite filler, etc.is adjusted according to the circumstances, but it is preferred that it be 0.1 mass parts to 5 mass parts with respect to 100 mass parts of organic-inorganic composite filler.

[0044] There is no particular limitation on the content of the organic-inorganic composite filler (B), but it is preferable that it be in the range of 30 mass% to 60 mass% in the curable composition of the present invention, and it is more preferable that it be in the range of 35 mass% to 55 mass%. When the content of the organic-inorganic composite filler (B) is less than 30 mass%, the brittleness of the composite resin layer tends to increase and the fracture strength tends to decrease. Furthermore, when it is more than 60 mass%, the surface hardness, abrasion resistance, and compressive strength tend to decrease.

[0045] The inorganic fine particles (C) that can be used in the curable composition of the present invention are not particularly limited in their components, and publicly known ones can be used. Specific examples include silica, alumina, titania, silica-titania, silica-titania-barium oxide, silica-zirconia, silica-alumina, lanthanum glass, borosilicate glass, sodium glass, barium glass, strontium glass, glass-ceramics, aluminosilicate glass, barium boraluminosilicate glass, strontium boraluminosilicate glass, fluoroaluminosilicate glass, calcium fluoroaluminosilicate glass, strontium fluoroaluminosilicate glass, barium fluoroaluminosilicate glass, strontium calcium fluoroaluminosilicate glass, etc.

[0046] These inorganic fine particles (C) have no particular restrictions on their shape, and they can be spherical, needle-shaped, plate-shaped, crushed, or flaky, etc., and they can also be aggregated. The inorganic fine particles (C) shown above are not limited to these and can also be used individually or in combination.

[0047] In the present invention, the average particle diameter of all the inorganic fine particles (C) contained in the curable composition must be 1 μm or less in order to exhibit good fracture strength, excellent abrasion resistance, and surface smoothness in the composite resin layer. If the average particle diameter of the inorganic fine particles (C) is more than 1 μm, the fracture strength of the composite resin layer is reduced. Furthermore, the abrasion resistance is reduced, and therefore a smooth surface is not obtained and coloring is easy to occur. In the present invention, inorganic particles whose average particle diameter is more than 1 μm may be contained, as long as it is in an amount that does not impair the effect of the present invention.The amount of inorganic particles having an average particle diameter of more than 1 µm in the curable composition of the present invention, at which the effect of the present invention is not impaired, may be less than 1 mass%, less than 0.5 mass%, less than 0.1 mass%, less than 0.05 mass%, less than 0.01 mass%, and less than 0.001 mass%. In the present invention, inorganic particles having an average particle diameter of more than 1 µm may also not be contained. Furthermore, inorganic particles having a particle diameter of more than 1 µm may also not be contained in the present invention.

[0048] Furthermore, the inorganic fine particles (C) can be surface-treated using a surface-treating agent. Specific examples of surface-treating agents include surfactants, organic acids, inorganic acids, organic silicon compounds, organic zirconium compounds, organic titanium compounds, organic aluminum compounds, metal alkoxide compounds, etc., but organic silicon compounds are most commonly used. The same organic silicon compounds that can be used for the surface treatment of the above-mentioned inorganic fillers (b-1) can be used as the organic silicon compounds. Specific examples of surface-treating methods include spraying surface-treating agents onto the inorganic fine particles while they are kept in motion, and / or spraying the surface-treating agent onto the inorganic fine particles.Methods in which the inorganic fine particles are dispersed in a solution containing the surface treatment agent, etc. are cited. The surface treatment agents and surface treatment methods are not limited to these and can be used individually or in combination. Furthermore, there are no particular restrictions on the amount of the surface treatment agent relative to the inorganic fine particles (C) when performing the surface treatment, and it can be adjusted according to the particle diameter of the inorganic fine particles (C), etc., as needed.

[0049] There is no particular limitation on the content of inorganic fine particles (C), but it is preferable that it be in a range of 10 mass % to 50 mass % in the curable composition of the present invention, and it is more preferable that it be in a range of 15 mass % to 35 mass %. When the content of inorganic fine particles (C) is less than 10 mass %, the surface hardness, abrasion resistance, and compressive strength of the composite resin layer tend to be reduced. Furthermore, when it is more than 50 mass %, the brittleness of the composite resin layer tends to be increased and the fracture strength tends to be reduced.

[0050] In the non-crosslinked polymer particles (D) that can be used in the curable composition of the present invention, particles of a homopolymer of a monofunctional polymerizable monomer having the above-mentioned (meth)acryloyloxy groups or (meth)acrylamide groups, particles of a copolymer in which two or more kinds are combined, and particles of a copolymer in which monofunctional polymerizable monomers having (meth)acryloyloxy groups or (meth)acrylamide groups and other monofunctional polymerizable monomers such as styrene, α-methylstyrene, isoprene, butadiene, isobutylene, vinyl acetate, vinyl chloride, vinyl alcohol, ethylene, propylene, maleic acid, itaconic acid, maleic anhydride, etc. are combined, can be used without any limitation.Furthermore, it is also perfectly acceptable to use particles of homopolymers of other monofunctional polymerizable monomers and copolymers combining two or more types. Furthermore, the copolymer particles can be any copolymers, such as random copolymers, alternating copolymers, block copolymers, etc.

[0051] Among these non-crosslinked polymer particles (D), it is preferable to use particles of a homopolymer of a monofunctional polymerizable monomer having a (meth)acryloyloxy group, which is most widely used in dental materials, or particles of a copolymer in which two or more types are combined. When specifically citing examples of these non-crosslinked polymer particles (D), homopolymer particles such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate, as well as copolymer particles in which two or more types are combined, etc., are cited, but they are not limited to these. These non-crosslinked polymer particles (D) can be used not only individually but also in combination with plural ones.Furthermore, it is more preferable that polymethyl methacrylate particles or copolymer particles of methyl methacrylate and ethyl methacrylate be used as the non-crosslinked polymer particles (D), and it is most preferable that polymethyl methacrylate particles be used. When these non-crosslinked polymer particles (D) are used, the fracture strength and compressive strength in the composite resin layer can be increased in a good balance. In the curable composition of the present invention, as the non-crosslinked polymer particles (D), particles of homopolymers of (meth)acryloyloxy group-containing monofunctional polymerizable monomers and / or particles of copolymers in which two or more types are combined may be contained, only polymethyl methacrylate particles and / or copolymer particles of methyl methacrylate and ethyl methacrylate may be contained, and only polymethyl methacrylate particles may be contained.

[0052] There is no particular limitation on the polymerization method for producing these non-crosslinked polymer particles (D), and there is no problem at all if they are produced by a polymerization method such as emulsion polymerization and suspension polymerization. Furthermore, these non-crosslinked polymer particles (D), although they have a shape that is either spherical, broken, or hollow, etc., can be used without any limitation, but a spherical shape is preferred. There is no particular limitation on the weight-average molecular weight of the non-crosslinked polymer particles (D), but it is preferred that it be 1 μm or more and be in a range of 150,000 to 1,500,000. Here, the weight-average molecular weight is the average molecular weight calculated based on the molecular weight distribution measured by gel permeation chromatography.The curable composition of the present invention may also contain, as the non-crosslinked polymer particles (D), only non-crosslinked polymer particles having a weight-average molecular weight of 10,000 to 2,000,000, only non-crosslinked polymer particles having a weight-average molecular weight of 50,000 to 1,500,000, and only non-crosslinked polymer particles having a weight-average molecular weight of 100,000 to 1,500,000.

[0053] Furthermore, it is preferable that the average particle diameter of the non-crosslinked polymer particles (D) be in the range of 1 μm to 100 μm, even more preferable that it be in the range of 1 μm to 80 μm, and further preferable that it be in the range of 5 μm to 50 μm. If the average particle diameter of the non-crosslinked polymer particles (D) is less than 1 μm, the compressive strength of the composite resin layer is likely to be reduced. If it is more than 100 μm, the adhesion of the composite resin layer to the base of the denture is likely to be reduced.The curable composition of the present invention may contain, as non-crosslinked polymer particles (D), only non-crosslinked polymer particles having an average particle diameter of 1 µm to 100 µm, only non-crosslinked polymer particles having an average particle diameter of 3 µm to 80 µm, and only crosslinked polymer particles having an average particle diameter of 5 µm to 50 µm. The curable composition of the present invention may contain, as non-crosslinked polymer particles (D), only non-crosslinked polymer particles having a weight-average molecular weight of 10,000 to 2,000,000 and an average particle diameter of 1 µm to 100 µm.

[0054] The content of non-crosslinked polymer particles (D) in the curable composition of the present invention must be in the range of 1 mass% to 5 mass%. If the content of non-crosslinked polymer particles (D) is less than 1 mass%, the fracture strength and adhesion to the base of the denture of the composite resin layer are reduced. Furthermore, if it is more than 5 mass%, the surface hardness, abrasion resistance, and compressive strength of the composite resin layer are reduced.

[0055] It is preferable that the curable composition of the present invention contains a polymerization initiator. As polymerization initiators, there are those that initiate radical polymerization by heating (thermal polymerization initiators), those that initiate radical polymerization by the action of compounds containing two or more components, such as redox initiators (sometimes referred to as "chemical polymerization initiators" in the field of dentistry. hereinafter referred to as "chemical polymerization initiators"), those that initiate radical polymerization by light irradiation (light polymerization initiators), etc., but in the present invention, all polymerization initiators can be used without any limitation.However, it is preferred that a thermal polymerization initiator is used because the formation of the composite resin layer is simple and high mechanical properties are easily obtained.

[0056] When specifically citing thermal polymerization initiators, organic peroxides such as benzoyl peroxide, parachlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, acetyl peroxide, lauroyl peroxide, tertiary butyl peroxide, cumene hydroperoxide, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dihydroperoxide, methyl ethyl ketone peroxide, tertiary butyl peroxybenzoate, etc., and azo compounds such as azobisisobutyronitrile, azobismethyl isobutyrate, azobiscyanovaleric acid, etc. are mentioned, but are not limited to these. These thermal polymerization initiators can be used not only individually but also in combination with several. Among these thermal polymerization initiators, benzoyl peroxide and / or azobisisobutyronitrile are most preferred.

[0057] Chemical polymerization initiators listed include organic peroxides / amine compounds, organic peroxides / amine compounds / sulfinates, or organic peroxides / amine compounds / boron compounds, etc., but are not limited to these. These chemical polymerization initiators can be used not only individually but also in combination with several.

[0058] Photopolymerization initiators include α-diketones, benzophenones, acylphosphine oxides, α-aminoacetophenones, ketals, coumarins, titanocenes, etc., but are not limited to these. Furthermore, photopolymerization accelerators include tertiary amines, triazines, diaryliodonium salts, tin compounds, aldehyde compounds, and sulfur-containing compounds, etc., but are not limited to these. These photopolymerization initiators and photopolymerization accelerators can be used not only individually but also in combination with several.

[0059] There is no particular limitation on the content of polymerization initiators, but it should be 0.1 mass part to 1.5 mass parts with respect to the sum of 100 mass parts of the polymerizable monomers (A) and the polymerization initiators. If the content of polymerization initiators is less than 0.1 mass part, the polymerization of the curable composition of the present invention is insufficient, and various mechanical properties in the composite resin layer are likely to be reduced, or the composite resin layer is likely to be colored. Furthermore, if it is more than 1.5 mass parts, the composite resin layer is likely to be colored.

[0060] Further, to the curable composition of the present invention, in addition to the above components (A) to (D), ultraviolet absorbers such as 2-hydroxy-4-methylbenzophenone, polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, 2,5-ditertiary-butyl-4-methylphenol, chain transfer agents, coloring inhibitors, antibacterial agents, color pigments and other already well-known additives, etc., may be arbitrarily added as needed.

[0061] The composite resin tooth of the present invention can have a single-layer structure, or it can have a layered structure of two or more layers. When it has a layered structure of two or more layers, at least one layer is a composite resin layer in which the curable composition of the present invention has been polymerization-cured. The composite resin tooth of the present invention can be implemented as a single-layer structure consisting only of the composite resin layer, or as a layered structure consisting only of two or more composite resin layers.For the layers other than the composite resin layer, there are no particular restrictions on the materials used to construct them, but it is preferable that they be acrylic resin layers whose main component is polymethyl methacrylate, just like the conventional composite resin teeth. A liquid whose main component is methyl methacrylate and a powder whose main component is polymethyl methacrylate are mixed and then polymerized. When a layered structure of two or more layers is used, it is preferable that the outermost layer containing the labial lateral surface for anterior teeth and the outermost layer containing the occlusal surface for molar teeth be made of a composite resin layer. This can reduce the wear rate in the oral cavity of the composite resin tooth of the present invention.

[0062] In the composite resin tooth of the present invention, there is no particular limitation on its shape or size and on the shape or size of the individual layers, and furthermore, it is no problem at all if it has retaining holes for obtaining mechanical engagement with the base of the denture.

[0063] There is no particular limitation on the manufacturing method of the composite resin tooth of the present invention, and it can be manufactured by methods such as compression molding, injection molding, and injection molding, etc., but no limitation is imposed on these. [Examples of implementation]

[0064] In the following, the present invention will be explained in more detail using working examples and comparative examples, but the present invention is not limited to these working examples. The various components used to prepare the curable compositions of the working examples and comparative examples, as well as their abbreviations, are as follows. [Polymerizable monomer (A)] - UDMA: Urethane dimethacrylate - UDA: 1,6-Bis[(2-phenoxy-2'-acryloxy)isopropyl-oxycarbonylamino]hexane - Bis-GMA: 2,2-bis[4-[2-hydroxy-3-(methacryloyloxy)propyloxy]phenyl]propane - TEGDMA: Triethylene glycol dimethacrylate - MMA: Methyl methacrylate [Organic-inorganic composite filler (B)] - O1: Organic-inorganic composite filler 1 (average particle diameter: 23 µm, content of inorganic filler (b-1): 18 mass%, average particle diameter of inorganic filler (b-1): 16 nm) - O2: Organic-inorganic composite filler 2 (average particle diameter: 20 µm, inorganic filler content (b-1): 32.5 mass%, average particle diameter of inorganic filler (b-1): 9 nm) - O3: Organic-inorganic composite filler 3 (average particle diameter: 28 µm, inorganic filler content (b-1): 50 mass%, average particle diameter of inorganic filler (b-1): 16 nm) - O4: Organic-inorganic composite filler 4 (average particle diameter: 20 µm, inorganic filler content (b-1): 12 mass%, average particle diameter of inorganic filler (b-1): 16 nm) - O5: Organic-inorganic composite filler 5 (average particle diameter: 25 µm, inorganic filler content (b-1): 35 mass%, average particle diameter of inorganic filler (b-1): 16 nm) - O6: Organic-inorganic composite filler 6 (average particle diameter: 30 µm, inorganic filler content (b-1): 10 mass%, average particle diameter of inorganic filler (b-1): 16 nm) - O7: Organic-inorganic composite filler 7 (average particle diameter: 55 µm, inorganic filler content (b-1): 75 mass%, average particle diameter of inorganic filler (b-1): 4 µm) - O8: Organic-inorganic composite filler 8 (average particle diameter: 22 µm, inorganic filler content (b-1): 50 mass%, average particle diameter of inorganic filler (b-1): 3 µm) [Inorganic fine particles (C) with an average particle diameter of 1 µm or less] - I1: Pyrogenic silicon dioxide (Aerosil OX-50 (Evonik Industries), average particle diameter: 40 nm) - I2: Pyrogenic silicon dioxide (Aerosil R-972 (Evonik Industries), average particle diameter: 16 nm) [Other inorganic fine particles (C')] - I'1: Spherical silicon dioxide (average particle diameter: 3 µm) - I'2: Crushed silicon dioxide (average particle diameter: 1.5 µm) [Non-crosslinked polymer particles (D)] - nCP1: Polymethyl methacrylate (average particle diameter: 8 µm, weight-average molecular weight: approx. 800,000, shape: spherical) - nCP2: Polymethyl methacrylate (average particle diameter: 50 µm, weight average molecular weight: approx. 1,000,000, shape: spherical) - nCP3: Polymethyl methacrylate (average particle diameter: 80 µm, weight-average molecular weight: approx. 1,000,000, shape: spherical) - nCP4: Polymethyl methacrylate (average particle diameter: 4 µm, weight-average molecular weight: approx. 800,000, shape: spherical) - nCP5: Copolymer of methyl methacrylate (MMA) and ethyl methacrylate (EMA) (MMA / EMA = 70 / 30) (average particle diameter: 65 µm, weight-average molecular weight: approx. 350,000, shape: spherical) - nCP6: Polyethyl methacrylate (average particle diameter: 4 µm, weight-average molecular weight: approx. 40,000, shape: spherical) - nCP7: Polymethyl methacrylate (average particle diameter: 1.5 µm, weight-average molecular weight: approx. 150,000, shape: spherical) - nCP8: Polymethyl methacrylate (average particle diameter: 0.4 µm, weight-average molecular weight: approx. 1,500,000, shape: spherical) - nCP9: Polymethyl methacrylate (average particle diameter: 120 µm, weight-average molecular weight: approx. 1,600,000, shape: spherical) - nCP10: Polymethyl methacrylate (average particle diameter: 5 µm, weight-average molecular weight: approx. 300,000, shape: spherical) - nCP11: Polymethyl methacrylate (average particle diameter: 100 µm, weight-average molecular weight: approx. 1,000,000, shape: spherical) [Crosslinked polymer particles (D')] - CP1: Cross-linked polymethyl methacrylate (average particle diameter: 2.2 µm, shape: spherical) - CP2: Cross-linked polyurethane (average particle diameter: 6 µm, shape: spherical) [Polymerization initiator] - BPO: Benzoyl peroxide [Preparation of the organic-inorganic composite filler (B)]<Herstellung des organisch-anorganischen Verbundfüllstoffs 1 (O1)>

[0065] 80 parts by mass of UDMA, 20 parts by mass of ethylene glycol dimethacrylate, and 0.3 parts by mass of BPO were mixed to obtain a resin mixture. 82 parts by mass of this resin mixture and 18 parts by mass of Aerosil R972 were kneaded until uniform, and then the kneaded mixture was heated at 100°C for four hours under a nitrogen atmosphere to obtain a cured product. The resulting cured product was ground to an average particle diameter of 23 µm, yielding an organic-inorganic composite filler 1 (O1). The average particle diameter was measured using a laser diffraction particle sizer (Microtrac MT3300EXII: MicrotracBEL). <Herstellung des organisch-anorganischen Verbundfüllstoffs 2 (O2)>

[0066] 80 parts by mass of UDMA, 20 parts by mass of ethylene glycol dimethacrylate, and 0.5 parts by mass of BPO were mixed to obtain a resin mixture. 67.5 parts by mass of this resin mixture and 32.5 parts by mass of Aerosil R711 were kneaded until uniform, and then the kneaded mixture was heated at 100°C for four hours under a nitrogen atmosphere to obtain a cured product. The resulting cured product was crushed until an average particle diameter of 20 µm was reached, yielding an organic-inorganic composite filler 2 (O2). The average particle diameter was measured using a laser diffraction particle sizer (Microtrac MT3300EXII: MicrotracBEL). <Herstellung des organisch-anorganischen Verbundfüllstoffs 3 (O3)>

[0067] Fifty parts by mass of UDMA, 50 parts by mass of neopentyl glycol dimethacrylate, and 1.0 parts by mass of BPO were mixed to obtain a resin mixture. Fifty parts by mass of this resin mixture and 50 parts by mass of Aerosil R972 were kneaded until uniform, and then the kneaded mixture was heated at 100°C for four hours under a nitrogen atmosphere to obtain a cured product. The resulting cured product was ground to an average particle diameter of 28 µm, yielding an organic-inorganic composite filler 3 (O3). The average particle diameter was measured using a laser diffraction particle sizer (Microtrac MT3300EXII: MicrotracBEL). <Herstellung des organisch-anorganischen Verbundfüllstoffs 4 (O4)>

[0068] 80 parts by mass of UDMA, 20 parts by mass of ethylene glycol dimethacrylate, and 0.3 parts by mass of BPO were mixed to obtain a resin mixture. 88 parts by mass of this resin mixture and 12 parts by mass of Aerosil R972 were kneaded until uniform, and then the kneaded mixture was heated at 100°C for four hours under a nitrogen atmosphere to obtain a cured product. The resulting cured product was crushed until an average particle diameter of 20 µm was reached, yielding an organic-inorganic composite filler 4 (O4). The average particle diameter was measured using a laser diffraction particle sizer (Microtrac MT3300EXII: MicrotracBEL). <Herstellung des organisch-anorganischen Verbundfüllstoffs 5 (O5)>

[0069] 80 parts by mass of UDMA, 20 parts by mass of ethylene glycol dimethacrylate, and 0.3 parts by mass of BPO were mixed to obtain a resin mixture. 65 parts by mass of this resin mixture and 35 parts by mass of Aerosil R972 were kneaded until uniform, and then the kneaded mixture was heated at 100°C for four hours under a nitrogen atmosphere to obtain a cured product. The resulting cured product was ground to an average particle diameter of 25 µm, yielding organic-inorganic composite filler 5 (O5). The average particle diameter was measured using a laser diffraction particle sizer (Microtrac MT3300EXII: MicrotracBEL). <Herstellung des organisch-anorganischen Verbundfüllstoffs 6 (O6)>

[0070] 80 parts by mass of UDMA, 20 parts by mass of ethylene glycol dimethacrylate, and 0.3 parts by mass of BPO were mixed to obtain a resin mixture. 90 parts by mass of this resin mixture and 10 parts by mass of Aerosil R972 were kneaded until uniform, and then the kneaded mixture was heated at 100°C for four hours under a nitrogen atmosphere to obtain a cured product. The resulting cured product was ground to an average particle diameter of 30 µm, yielding an organic-inorganic composite filler 6 (O6). The average particle diameter was measured using a laser diffraction particle sizer (Microtrac MT3300EXII: MicrotracBEL). <Herstellung des organisch-anorganischen Verbundfüllstoffs 7 (O7)>

[0071] 3.0 mass parts of γ-methacryloyloxypropyltrimethoxysilane, 0.5 mass parts of ion-exchange water, and 8.0 mass parts of anhydrous ethanol were mixed to prepare a surface treatment liquid (total mass: 11.5 mass parts). Next, various raw materials such as silicon dioxide, alumina, aluminum phosphate, sodium fluoride, and strontium carbonate (glass composition: SiO2 26.4 mass%, Al2O3 29.3 mass%, SrO 20.5 mass%, P2O5 10.9 mass%, Na2O 2.5 mass%, F 10.4 mass%) were mixed, and then this raw material mixture was melted in a melting furnace at 1400°C. The melt was removed from the melting furnace and rapidly cooled in water to obtain fluoroaluminosilicate glass. The obtained fluoroaluminosilicate glass was crushed until 50% of the particle diameter (D50) reached 4 µm, and fluoroaluminosilicate glass powder was obtained.Subsequently, the surface treatment liquid and 100 mass parts of fluoroaluminosilicate glass powder were dry-mixed, and then heat-treated using a hot air dryer at 110°C for 5 hours to obtain a surface treatment glass powder. Furthermore, 50 mass parts of Bis-GMA, 50 mass parts of triethylene glycol dimethacrylate, and 0.2 mass parts of BPO were mixed to obtain a resin mixture. 25 mass parts of this resin mixture and 75 mass parts of the surface treatment glass powder were kneaded until uniform, and the kneaded mixture was heated at 100°C for 4 hours in a nitrogen atmosphere to obtain a cured product. The resulting cured product was crushed until 50% of the particle diameter (D50) reached 55 μm, and an organic-inorganic composite filler 7 (O7) was obtained.

[0072] Particle diameter (D50) was measured using a laser diffraction particle size measuring machine (Microtrac MT3300EXII: MicrotracBEL). <Herstellung des organisch-anorganischen Verbundfüllstoffs 8 (O8)>

[0073] 3.0 mass parts of γ-methacryloyloxypropyltrimethoxysilane, 0.5 mass parts of ion-exchange water, and 8.0 mass parts of anhydrous ethanol were mixed to prepare a surface treatment liquid (total mass: 11.5 mass parts). Next, various raw materials such as silicon dioxide, alumina, aluminum phosphate, sodium fluoride, and strontium carbonate (glass composition: SiO2 26.4 mass%, Al2O3 29.3 mass%, SrO 20.5 mass%, P2O5 10.9 mass%, Na2O 2.5 mass%, F 10.4 mass%) were mixed, and then this raw material mixture was melted in a melting furnace at 1400°C. The melt was removed from the melting furnace and rapidly cooled in water to obtain fluoroaluminosilicate glass. The obtained fluoroaluminosilicate glass was crushed until 50% of the particle diameter (D50) reached 3 µm, and fluoroaluminosilicate glass powder was obtained.Subsequently, the surface treatment liquid and 100 mass parts of fluoroaluminosilicate glass powder were dry-mixed and then heat-treated using a hot-air dryer at 110°C for 5 hours to obtain a surface treatment glass powder. Furthermore, 50 mass parts of Bis-GMA, 50 mass parts of triethylene glycol dimethacrylate, and 0.2 mass parts of BPO were mixed to obtain a resin mixture. 50 mass parts of this resin mixture and 50 mass parts of the surface treatment glass powder were kneaded until uniform, and the kneaded mixture was heated at 100°C for 4 hours under a nitrogen atmosphere to obtain a cured product. The resulting cured product was crushed until 50% of the particle diameter (D50) reached 40 μm, and an organic-inorganic composite filler 8 (O8) was obtained.50% of the particle diameter (D50) was measured using a laser diffraction particle size measuring machine (Microtrac MT3300EXII: MicrotracBEL).

[0074] By mixing the various components in the proportions shown in Tables 1 to 3, the curable compositions of the working examples and comparative examples were prepared, respectively. The surface hardness, compressive strength, compressive displacement amount, and adhesion of the prepared curable compositions to the denture base material were evaluated according to the test method shown below. In this specification, the compressive displacement amount was considered as an indicator of the fracture strength of the material, and it was judged that the greater the compressive displacement amount, the more excellent the fracture strength. [Surface hardness]

[0075] Surface hardness was measured according to ISO 6507-1:2018 using the following procedure. Each curable composition was filled into a mold (diameter 25 mm, thickness 2.5 mm), and then molded under pressure and heat (pressing pressure: 3 t, mold temperature 120°C, pressing time 5 minutes). The resulting cured products were ground in an area where a thickness of 2 mm or more remained, and these were used as test specimens. Using a Micro Vickers hardness tester HM-102 (Mitsutoyo) under conditions of 23 ± 5°C and HV 0.2, the surface hardness of each specimen was measured. As a result, it was judged that excellent surface hardness was exhibited when the surface hardness was 30 or more. [Compressive strength and compressive displacement quantity]

[0076] The compressive strength and compressive displacement amount were measured according to JIS T 6603:1994 using the following procedure. Each curable composition was filled into a mold (diameter 6 mm, height 12 mm), and then molded under pressure and heat (molding pressure: 3 t, mold temperature 120°C, pressing time 5 minutes). The resulting cured products were immersed in 37°C water for 24 hours and used as test specimens. Using an Instron universal testing machine (Type: 5567A), the compressive strength and compressive displacement amount of each specimen were measured under conditions of a crosshead speed of 1 mm / min. When the compressive strength and compressive displacement amount were evaluated according to the following evaluation criteria, A or B was judged to have good compressive strength and fracture toughness. <bewertungskriterien> < <druckfestigkeit>> A: 500 MPa or more B: 430 MPa or more but less than 500 MPa C: less than 430 MPa < <druckverschiebungsmenge>> A: 4.0 mm or more B: 3.5 mm or more but less than 4.0 mm C: less than 3.5 mm [Liability with regard to the material for the base of the denture]

[0077] The adhesion of the denture base material was evaluated according to ISO 22112:2017 using the following procedure. Each curable composition was poured into a mold of NC Veracia Anterior (Shofu Inc.) with an outer shape of upper anterior teeth, and then molded under pressure and heat (molding pressure: 3 tons, mold temperature: 120°C, pressing time: 5 minutes), thereby producing artificial teeth. A wax measuring 30 x 10 x 6 (mm) was prepared, and a surface measuring 10 x 6 mm was melted on a hot plate. The central portion of the lingual lateral surface of the artificial tooth was pressed into the wax by approximately 2.5 mm. The wax was then held until the wax cooled, thus fixing the artificial tooth in the wax. The artificial tooth was embedded in plaster using a dental bottle, and the wax was then rinsed off with boiling water.The denture base material "Shofu Urban Color 8S" (Shofu Inc.) was poured into the wax-removed areas, a clamp was attached to the bottle, and then it was immersed in 70°C hot water for 90 minutes and then in boiling water for 30 minutes, whereby the denture base material was polymerized, and this was used as a test specimen (. Fig. 1) used. As in Fig. As shown in Figure 2, the test specimen was suspended from the lingual lateral surface of the artificial tooth on a special jig, and the end of the denture base material was fixed by a clamp. Then, a load was applied to the bonding interface in the tensile direction at a displacement rate of 1 mm / min, causing a fracture at the bonding portion of the test specimen. An Instron universal testing machine (Type: 5567A) was used to apply the tensile load to the test specimen. For each curable composition, ten specimens were tested, and the fracture modes of each specimen were observed. When evaluated according to the following criteria, A or B was judged to exhibit good adhesion to the denture base material. <bewertungskriterien> A: Test specimens with aggregate breakage are 10 or 9 out of 10 teeth B: Test specimens with aggregate fracture are 8 or 7 out of 10 teeth C: Test specimens with aggregate fracture are 6 or less out of 10 teeth

[0078] The results of evaluation of the curable compositions of the working examples and comparative examples are shown in Tables 1 to 4.

[0079] Curable composition used in the working examples (mass%) and evaluation results [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 From example 6 Example 7 Example 8 Example 9 Example 10 Polymerizable monomer (A) UDMA 21,0 - 21,0 - 20,1 - - - 21,0 21,0 UDA - 21,0 - - - 24,2 - - - - Bis-GMA - - - 21,0 - - 22,8 22,8 - - TEGDMA 9,0 9,0 7, 5 9,0 8,8 10,4 9, 8 9, 8 9,0 9,0 MMA - - 1,5 - - - - - - - Amount of MMAin (A) - - 5,0 - - - - - - - Organic-inorganic composite filler (B) O1 45,0 45,0 45,0 45,0 40,0 45,0 - - - 45,0 O2 - - - - - - 42,5 - - - O3 - - - - - - - - - - O4 - - - - - - - 42,5 - - O5 - - - - - - - - 45,0 - O6 - - - - - - - - - - O7 - - - - - - - - - - O8 - - - - - - - - - - Inorganic fine particles (C) I1 3,7 3,7 3,7 3,7 5,0 - 3,7 3,7 3,7 3,7 I2 18,0 18,0 18,0 18,0 25,0 15,0 18,0 18,0 18,0 18,0 Other inorganic fine particles (C') I'1 - - - - - - - - - - I'2 - - - - - - - - - - Non-crosslinked polymer particles (D) nCP1 3,0 3,0 3,0 3,0 1,0 5,0 3,0 3,0 3,0 - nCP2 - - - - - - - - - 3,0 nCP3 - - - - - - - - - - nCP4 - - - - - - - - - - nCP5 - - - - - - - - - - nCP6 - - - - - - - - - - nCP7 - - - - - - - - - - nCP8 - - - - - - - - - - nCP9 - - - - - - - - - - nCP10 - - - - - - - - - - nCP11 - - - - - - - - - - cross-linked polymer particles (D') CP1 - - - - - - - - - - CP2 - - - - - - - - - - polymerization initiator BPO 0,3 0,3 0,3 0,3 0,1 0,4 0,2 0,2 0,3 0,3 Polymerization initiator / (A) +polymerization initiator (mass%) 1,0 1,0 1,0 1,0 0,3 1,1 0,6 0,6 1,0 1,0 sum 100,0 100,0 100,0 100, 0 100,0 100,0 100,0 100,0 100,0 100,0 Surface hardness (HVO,2) 34 35 32 34 37 31 39 30 40 34 Compressive strength (MPa) 529 521 514 532 528 509 529 502 539 512 Evaluation A A A A A A A A A A Pressure displacement amount (mm) 4,3 4,3 4,5 4,2 4,1 4,0 4,1 4,5 4,0 4,1 Evaluation A A A A A A A A A A Liability with regard to the material for the base of the denture A A A A A A A A A A

[0080] Curable composition used in the working examples (mass%) and evaluation results [Table 2] Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Example 19 Example 20 Polymerizable monomer (A) UDMA 21,0 21,0 - 20,8 - - 21,0 19,6 21,0 - UDA - - 23,6 - 21,0 21,0 - - - - Bis-GMA - - - - - - - - - 32,0 TEGDMA 9,0 9,0 10,0 8, 9 9,0 9,0 6,0 4,2 9,0 8,0 MMA - - - - - - 3,0 4,2 - - Amount of MMAin (A) - - - - - - 10,0 15,0 - - Organic-inorganic composite filler (B) O1 45,0 45,0 50,0 30,0 - - 42,5 48,4 45,0 - O2 - - - - - - - - - - O3 - - - - 45,0 - - - - - O4 - - - - - - - - - - O5 - - - - - - - - - - O6 - - - - - 40,0 - - - - O7 - - - - - - - - - 30,0 O8 - - - - - - - - - - Inorganic fine particles (C) I1 3,7 3,7 - 27,0 3,7 3,7 4,2 3,4 3,7 4,0 I2 18,0 18,0 13,0 10,0 18,0 23,0 20,0 17,0 18,0 22,6 Other inorganic fine particles (C') I'1 - - - - - - - - - - I'2 - - - - - - - - - - Non-crosslinked polymer particles (D) nCP1 - - 3,0 3,0 3,0 3,0 3,0 - - 3,0 nCP2 - - - - - - - - - - nCP3 3,0 - - - - - - - - - nCP4 - 3,0 - - - - - - - - nCP5 - - - - - - - 3,0 - - nCP6 - - - - - - - - 3,0 - nCP7 - - - - - - - - - - nCP8 - - - - - - - - - - nCP9 - - - - - - - - - - nCP10 - - - - - - - - - - nCP11 - - - - - - - - - - cross-linked polymer particles (D') CP1 - - - - - - - - - - CP2 - - - - - - - - - - BPO 0,3 0,3 0, 4 0,3 0,3 0,3 0,3 0,2 0,3 0, 4 polymerization initiator Polymerization initiator / (A) +polymerization initiator (mass%) 1,0 1,0 1, 2 1,0 1,0 1,0 1,0 0,7 1,0 1,0 sum 100,0 100,0 100,0 100,0 100,0 100,0 100,0 100,0 100,0 100,0 Surface hardness (HV0.2) 34 32 30 41 45 32 30 31 30 41 Compressive strength (MPa) 504 487 452 521 529 486 491 465 471 468 Evaluation A B B A A B B B B B Pressure displacement amount (mm) 4,2 4,1 4,5 3,6 3, 8 4,4 4,0 4,0 3,5 3,5 Evaluation A A A B B A A A B B Liability with regard to the material for the base of the denture B A A A A A A A B A

[0081] Curable composition used in the working examples (mass%) and evaluation results [Table 3] From example 21 Example 22 Example 23 Example 24 Example 25 Example 26 Example 27 Example 28 Example 29 Example 30 Polymerizable monomer (A) UDMA - - 21,0 21,0 21,0 21,0 21,0 20,8 20,8 21,0 UDA 40,0 - - - - - - - - - Bis-GMA - 21,4 - - - - - - - - TEGDMA 10,0 9, 3 9,0 9,0 9,0 9,0 9,0 9,0 8,9 9,0 MMA - - - - - - - - - - Amount of MMAin (A) - - - - - - - - - - Organic-inorganic composite filler (B) O1 - - 45,0 45,0 45,0 45,0 45,0 45,0 45,0 45,0 O2 - 55,0 - - - - - - - - O3 - - - - - - - - - - O4 - - - - - - - - - - O5 - - - - - - - - - - O6 - - - - - - - - - - - - - - - - - - - - O7 - - - - - - - - - - O8 25,0 - - - - - - - - - Inorganic fine particles (C) I1 - - 3, 7 3, 7 3, 7 3, 7 3, 7 3, 7 3, 7 3, 7 I2 21,5 9,0 18,0 18,0 18,0 18,0 18,0 18,0 18,0 18,0 Other inorganic fine particles (C') I'1 - - - - - - - - - - I'2 - - - - - - - - - - Non-crosslinked polymer particles (D) nCP1 3,0 5,0 - - - - - 3,0 3,0 1,5 nCP2 - - - - - - - - - - nCP3 - - - - - - - - - - nCP4 - - - - - - - - - - nCP5 - - - - - - - - - - nCP6 - - - - - - - - - - nCP7 - - 3,0 - - - - - - - nCP8 - - - 3,0 - - - - - - nCP9 - - - - 3,0 - - - - - nCP10 - - - - - 3,0 - - - - nCP11 - - - - - - 3,0 - - - cross-linked polymer particles (D') CP1 - - - - - - - - - 1,5 CP2 - - - - - - - - - - BPO 0,5 0,3 0,3 0,3 0,3 0,3 0,3 0,5 0,6 0,3 polymerization initiator Polymerization initiator / (A) +polymerization initiator (mass%) 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,5 2,1 1,0 sum 100,0 100,0 100,0 100,0 100,0 100,0 100,0 100,0 100,0 100,0 Surface hardness (HV0.2) 38 37 31 31 32 33 34 36 37 30 Compressive strength (MPa) 479 439 471 458 512 517 506 508 477 491 Evaluation B B B B A A A A B B Pressure displacement amount (mm) 3,7 3,9 4,1 4,1 4,0 4,1 4,0 4,1 3,6 3,9 Evaluation B B A A A A A A B B Liability with regard to the material for the base of the denture A A A A B A B A A A

[0082] Curable composition (mass%) used in the comparative examples and evaluation results [Table 4] Comparison example 1 Comparison example 2 Comparison example 3 Comparison example 4 Comparison example 5 Comparison example 6 Comparison example 7 Comparison example 8 Comparison example 9 Comparison example 10 Polymerizable monomer (A) UDMA 23,1 21,0 21,0 21,0 19,6 20,7 21,8 - - - UDA - - - - - - - 14,7 27,1 18,4 Bis-GMA - - - - - - - 8,8 16,3 11,0 TEGDMA 9,9 9,0 9,0 7,5 4,2 8,9 9,4 5,9 10,8 7,3 MMA - - - 1,5 4,2 - - - - - Amount of MMAin (A) - - - 5,0 15,0 - - - - - Organic-inorganic composite filler (B) O1 45,0 45,0 45,0 46,0 40,0 40,0 42,5 30,0 - - 60,0 O2 - - - - - - - - - - O3 - - - - - - - - - - O4 - - - - - - - - - - O5 - - - - - - - - - - O6 - - - - - - - - - - O7 - - - - - - - - - - O8 - - - - - - - - - - Inorganic fine particles (C) I1 3, 7 3, 7 3, 7 4,2 4, 0 3,0 - - 12,5 - I2 18,0 18,0 18,0 19,0 20,7 17,2 18,0 - 30,0 - Other inorganic fine particles (C') I'1 - - - - - - 5,0 - - - I'2 - - - - - - - 37,5 - - Non-crosslinked polymer particles (D) nCP1 - - - 0,5 7,0 - 3,0 3,0 3,0 3,0 nCP2 - - - - - 10,0 - - - - nCP3 - - - - - - - - - - nCP4 - - - - - - - - - - nCP5 - - - - - - - - - - nCP6 - - - - - - - - - - nCP7 - - - - - - - - - - nCP8 - - - - - - - - - - nCP9 - - - - - - - - - - - - - - - - - - - - nCP10 - - - - - - - - - - nCP11 - - - - - - - - - - cross-linked polymer particles (D') CP1 - 3, 0 - - - - - - - - CP2 - - 3,0 - - - - - - - polymerization initiator BPO 0,3 0,3 0,3 0,3 0,3 0,2 0,3 0, 1 0,3 0,3 Polymerization initiator / (A) +polymerization initiator (mass%) 0,9 1,0 1,0 1,0 1,1 0,7 1,0 0,3 0,6 0,8 sum 100,0 100,0 100,0 100,0 100,0 100,0 100,0 100,0 100,0 100,0 Surface hardness (HV0.2) 34 31 29 31 30 28 37 45 38 27 Compressive strength (MPa) 507 487 458 474 428 416 526 506 442 398 Evaluation A B B B C C A A B C Pressure displacement amount (mm) 3,4 3,2 3,7 3, 8 3, 4 3,1 3,2 2,1 2,6 4,2 Evaluation C C B B C C C C C A Liability with regard to the material for the base of the denture C C C C A A B B A A

[0083] As shown in Tables 1 to 4, the curable compositions of the present invention of Working Examples 1 to 29 exhibit high surface hardness and compressive strength, and are difficult to fracture even due to a large amount of compressive displacement. Furthermore, the adhesion to the denture base material was also excellent. On the other hand, in the curable compositions of Comparative Examples 1 to 10, some of the surface hardness, compressive strength, compressive displacement amount (fracture strength), or adhesion to the denture base material were deficient compared to the curable compositions of Working Examples 1 to 29.

[0084] In the present specification, although the disclosed components have been explained either singly or plurally, or have been explained without limitation as singly or plurally, they may be either singly or plurally, unless the context requires otherwise.

[0085] The present disclosure has been explained with reference to detailed embodiments, but those skilled in the art should understand that various changes or modifications are possible based on the features disclosed in the present description. Accordingly, it is intended that any changes or modifications be included within the scope of the embodiments of the present disclosure. [Industrial applicability]

[0086] The composite resin tooth of the present invention can be used for making dentures such as full denture dentures or partial denture dentures. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2517753 B2 [0004, 0005] JP 5804517 B2 [0004, 0005] Cited non-patent literature

[0000] JIS T 6603:1994

[0076] < / bewertungskriterien> < / druckverschiebungsmenge> < / druckfestigkeit> < / bewertungskriterien>

Claims

[1] Composite resin tooth having a single-layer structure or a layered structure with two or more layers, characterized by , that it comprises a composite resin layer comprising a polymerization-cured body of a curable composition containing a polymerizable monomer (A), an organic-inorganic composite filler (B), inorganic fine particles (C) and non-crosslinked polymer particles (D), wherein the content of the non-crosslinked polymer particles (D) in the curable composition is in the range of 1 mass% to 5 mass%, where the average particle diameter of the total of the inorganic fine particles (C) contained in the curable composition is 1 µm or less. [2] The composite resin tooth according to claim 1, wherein the average particle diameter of the non-crosslinked polymer particles (D) is 5 µm to 50 µm. [3] A composite resin tooth according to claim 1 or 2, wherein the content of the inorganic fine particles (C) in the curable composition is in the range of 15 mass% to 35 mass%, and wherein the content of inorganic fillers (b-1) contained in the organic-inorganic composite filler (B) is in the range of 10 mass% to 35 mass%. [4] The composite resin tooth according to claim 1 or 2, wherein the content of methyl methacrylate with respect to the total of the polymerizable monomers (A) is 5 mass% or less. [5] The composite resin tooth according to claim 3, wherein the content of methyl methacrylate with respect to the total of the polymerizable monomer (A) is 5 mass% or less. [6] Composite resin tooth according to any one of claims 1, 2 or 5, wherein the non-crosslinked polymer particles (D) contain polymethyl methacrylate particles. [7] Composite resin tooth according to claim 3, wherein the non-crosslinked polymer particles (D) contain polymethyl methacrylate particles. [8] Composite resin tooth according to claim 4, wherein the non-crosslinked polymer particles (D) contain polymethyl methacrylate particles.

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