JP2017036224A - Resin block for dental cutting processing and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin block for dental cutting processing with excellent appearance in which crack generation is reduced, the resin block being used to make orthoprosthesis.SOLUTION: A resin block for dental cutting processing comprises (A) resin matrix and (B) spherical or approximately spherical organic inorganic composite particles. Preferably the organic inorganic composite particles have a pore volume of 0.01 to 0.30 cm/g, and preferably the resin matrix is an acrylate resin.SELECTED DRAWING: None

Description

  The present invention relates to a resin block for dental cutting for producing a dental prosthesis by cutting and a method for producing the same.

  In dental treatment, as one method for producing dental prostheses such as inlays, onlays, crowns, bridges, and implant superstructures, there is a method of cutting using a dental CAD / CAM system. The CAD / CAM system is a system for designing a dental prosthesis based on three-dimensional coordinate data using a computer and creating a crown restoration using a cutting machine. Various materials such as glass ceramics, zirconia, titanium, and resin are used as the cutting material. As a resin material for dental cutting, a block shape, a disk obtained by curing a curable composition containing an inorganic filler such as silica, a polymerizable monomer such as a methacrylate resin, a polymerization initiator, etc. Cured products such as shapes are provided. Resin-based materials for dental cutting are gaining interest from the viewpoints of high workability, aesthetics, and strength, and various materials have been proposed.

  For example, Patent Document 1 describes an invention related to a resin block for dental cutting, and specifically, a polymerizable monomer and a spherical inorganic filler having an average primary particle size of 0.1 μm or more and less than 1 μm. Disclosed is a dental mill blank (resin block for dental cutting) made of a cured product of a curable composition containing such a dental mill blank, which has excellent mechanical strength and is similar to natural teeth for a long time in the oral cavity. It has been described that it has a sliding durability capable of maintaining the gloss of the film.

International Publication No. 2012/042911 Pamphlet

  However, it has been found that such a resin block for dental cutting may cause a crack, and the crack is particularly likely to occur particularly in a dental cutting block having a large volume. Since the crack defect causes a reduction in mechanical strength of a dental prosthesis produced by cutting a dental cutting block, it is desired to reduce it as much as possible. Resin block for dental cutting process comprising resin matrix and filler such as inorganic particles is manufactured by mixing resin matrix that is polymer and filler, or monomer that is a raw material for resin matrix that is polymer (Polymerizable monomer) and filler are mixed, and then the monomer / filler composition is polymerized and cured. In either case, cracks occur although there are differences in degree. In some cases, especially in the latter case.

  The subject of this invention is providing the resin-type block for dental cutting which suppressed defects, such as a crack.

  The present inventors have intensively studied to solve the above problems. As a result, it was found that the above-mentioned problems can be solved by blending organic-inorganic composite particles as a filler for a resin block for dental cutting and making the particle shape spherical or substantially spherical, thereby completing the present invention. It was.

  That is, the present invention is a resin block for dental cutting processing comprising (A) a resin matrix and (B) spherical or substantially spherical organic-inorganic composite particles.

One preferable embodiment of the present invention is a resin block for dental cutting in which the pore volume of the (B) organic-inorganic composite particles is 0.01 to 0.30 cm ³ / g.

  One preferable embodiment of the present invention is a resin block for dental cutting, wherein the resin matrix (A) is an acrylic resin.

  One preferable embodiment of the present invention is a resin block for dental cutting which further contains (C) inorganic particles.

A preferred embodiment of the present invention, the volume of the block is dental cutting for resin-based block is a 10cm ³ ~200cm ^3.

  Another aspect of the present invention is a dental cutting process characterized by polymerizing and curing a curable composition comprising a polymerizable monomer, (B) spherical or substantially spherical organic-inorganic composite particles, and a polymerization initiator. It is a manufacturing method of the resin system block.

  The resin block for dental cutting according to the present invention has few cracks and good appearance. In addition, when the resin block for machining according to the present invention is used, a dental prosthesis having high mechanical strength can be produced.

  The dental cutting resin block of the present invention is a dental cutting resin block comprising (A) a resin matrix and (B) spherical or substantially spherical organic-inorganic composite particles.

The resin block for dental cutting in the present invention is a resin (resin) matrix used when a dental prosthesis is produced by a cutting machine based on three-dimensional coordinate data acquired on a computer. It refers to the block body as a component. There is no limitation on the size and shape, and a size and shape that suits the purpose may be selected. As the size, the length of one side is usually selected from the range of 5 mm to 150 mm. The shape is arbitrarily selected from a rectangular parallelepiped, a columnar shape, a disk shape and the like according to the application and the cutting apparatus. The volume is usually selected from the range of 1.8 cm ³ to 200 cm ³ . Effect of reducing cracks of the present invention is remarkable in especially large volume hardened molded body, it is preferable volume of the shaped body is a 10cm ³ ~200cm ³ from this point of ^view, 25cm 3 ^{~200cm 3} is more preferable.

(A) Resin matrix (A) The resin matrix in the present invention is a component having a role as a dispersion medium in which (B) organic-inorganic composite particles are dispersed. The resin matrix is not particularly limited as long as it is a resin, and either a thermoplastic resin or a thermosetting resin can be used, but a resin having high transparency is preferable from the viewpoint of aesthetics of a dental prosthesis. Specific examples include acrylic resins such as polymethyl methacrylate, polyester resins such as polystyrene, polyamide, polycarbonate, and polyethylene terephthalate, methyl methacrylate / butadiene / styrene resins, acrylonitrile / butadiene / styrene resins, cycloolefin polymers, epoxy resins, and oxetane resins. Alternatively, these copolymers are preferably used. In particular, acrylic resin, epoxy resin, and oxetane resin are preferably used because safety, high transparency, and refractive index control are easy.

  As the resin matrix, in order to easily disperse the organic-inorganic composite particles, those exhibiting fluidity in the step of mixing the organic-inorganic composite particles are preferable. In addition, the organic-inorganic composite particles are dispersed in the polymerizable monomer for producing the resin matrix, and the polymerizable monomer is polymerized and cured to obtain a mixture of the resin matrix and the organic-inorganic composite particles, that is, the present You may obtain the resin block for dental cutting of invention.

  The polymerizable monomer that is a raw material of the resin matrix is not particularly limited, and examples thereof include radical polymerizable monomers, and cationic polymerizable monomers such as epoxy compounds and oxetane compounds. As the radical polymerizable monomer, a (meth) acrylate monomer is preferably used from the viewpoint of good polymerizability. Specific examples of the (meth) acrylate polymerizable monomer include the following.

(A1) Monofunctional radically polymerizable monomer Methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-lauryl (meth) acrylate, n-stearyl (Meth) acrylate, tetrafurfuryl (meth) acrylate, glycidyl (meth) acrylate, methoxyethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxy-triethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate , Ethoxyethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, ethoxytriethylene glycol (meth) acrylate, ethoxypolyethylene Liethylene glycol (meth) acrylate, phenoxyethylene glycol (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxytriethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate Monofunctional polymerizable monomers having an acidic group, such as isobornyl (meth) acrylate and trifluoroethyl (meth) acrylate, include (meth) acrylic acid, N- (meth) acryloylglycine, and N- (meth) acryloyl. Aspartic acid, N- (meth) acryloyl-5-aminosalicylic acid, 2- (meth) acryloyloxyethyl hydrogen succinate, 2- (meth) acryloyl Oxyethyl hydrogen phthalate, 2- (meth) acryloyloxyethyl hydrogen maleate, 6- (meth) acryloyloxyethyl naphthalene-1,2,6-tricarboxylic acid, O- (meth) acryloyl tyrosine, N- (meth) Acryloyl tyrosine, N- (meth) acryloylphenylalanine, N- (meth) acryloyl-p-aminobenzoic acid, N- (meth) acryloyl-o-aminobenzoic acid, p-vinylbenzoic acid, 2- (meth) acryloyloxy Benzoic acid, 3- (meth) acryloyloxybenzoic acid, 4- (meth) acryloyloxybenzoic acid, N- (meth) acryloyl-5-aminosalicylic acid, N- (meth) acryloyl-4-aminosalicylic acid, and the like Acid carboxylation of the carboxyl group of the compound 11- (meth) acryloyloxyundecane-1,1-dicarboxylic acid, 10- (meth) acryloyloxydecane-1,1-dicarboxylic acid, 12- (meth) acryloyloxide decane-1,1-dicarboxylic acid 6- (meth) acryloyloxyhexane-1,1-dicarboxylic acid, 2- (meth) acryloyloxyethyl-3′-methacryloyloxy-2 ′-(3,4-dicarboxybenzoyloxy) propyl succinate, 4 -(2- (meth) acryloyloxyethyl) trimellitate anhydride, 4- (2- (meth) acryloyloxyethyl) trimellitate, 4- (meth) acryloyloxyethyl trimellitate, 4- (meth) acryloyloxy Butyl trimellitate, 4- (meth) acryloyloxy Xyl trimellitate, 4- (meth) acryloyloxydecyl trimellitate, 4- (meth) acryloyloxybutyl trimellitate, 6- (meth) acryloyloxyethylnaphthalene-1,2,6-tricarboxylic acid anhydride, 6- (meth) acryloyloxyethylnaphthalene-2,3,6-tricarboxylic anhydride, 4- (meth) acryloyloxyethylcarbonylpropionoyl-1,8-naphthalic anhydride, 4- (meth) acryloyloxy Ethylnaphthalene-1,8-tricarboxylic acid anhydride, 9- (meth) acryloyloxynonane-1,1-dicarboxylic acid, 13- (meth) acryloyloxytridecane-1,1-dicarboxylic acid, 11- (meth) Acrylamide undecane-1,1-dicarboxylic acid, 2- (meth) acrylo Ruoxyethyl dihydrogen phosphate, 2- (meth) acryloyloxyethyl phenyl hydrogen phosphate, 10- (meth) acryloyloxydecyl dihydrogen phosphate, 6- (meth) acryloyloxyhexyl dihydrogen phosphate 2- (meth) acryloyloxyethyl-2-bromoethyl hydrogen phosphate, 2- (meth) acrylamidoethyl dihydrogen phosphate, 2- (meth) acrylamido-2-methylpropanesulfonic acid, 10-sulfodecyl ( (Meth) acrylate, 3- (meth) acryloxypropyl-3-phosphonopropionate, 3- (meth) acryloxypropylphosphonoacetate, 4- (meth) acryloxybutyl-3-phosphonop Lopionate, 4- (meth) acryloxybutyl phosphonoacetate, 5- (meth) acryloxypentyl-3-phosphonopropionate, 5- (meth) acryloxypentylphosphonoacetate, 6- (meth) acryloxy Hexyl-3-phosphonopropionate, 6- (meth) acryloxyhexyl phosphonoacetate, 10- (meth) acryloxydecyl-3-phosphonopropionate, 10- (meth) acryloxydecylphosphonoacetate 2- (meth) acryloxyethyl-phenylphosphonate, 2- (meth) acryloyloxyethylphosphonic acid, 10- (meth) acryloyloxydecylphosphonic acid, N- (meth) acryloyl-ω-aminopropylphosphonic acid, 2 -(Meth) acryloyloxyethyl phenyl hydro Examples of monofunctional polymerizable monomers having a hydroxyl group such as 2-phosphate, 2- (meth) acryloyloxyethyl-2′-bromoethyl hydrogen phosphate, 2- (meth) acryloyloxyethyl phenylphosphonate include 2-hydroxy Ethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, propylene glycol mono (meth) acrylate, Glycerol mono (meth) acrylate, erythritol mono (meth) acrylate, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N, N- (dihydroxyethyl) (meth) Or the like can be mentioned acrylamide.

(A2) Bifunctional radically polymerizable monomer 2,2-bis (methacryloyloxyphenyl) propane, 2,2-bis (4-methacryloyloxyethoxyphenyl) propane, 2,2-bis [4- (3-methacryloyl) Oxy) -2-hydroxypropoxyphenyl] propane, 2,2-bis (4-methacryloyloxyphenyl) propane, 2,2-bis (4-methacryloyloxypolyethoxyphenyl) propane, 2,2-bis (4-methacryloyl) Oxydiethoxyphenyl) propane, 2,2-bis (4-methacryloyloxytetraethoxyphenyl) propane, 2,2-bis (4-methacryloyloxypentaethoxyphenyl) propane, 2,2-bis (4-methacryloyloxydi) Propoxyphenyl) propane, 2 (4-me Tacryloyloxydiethoxyphenyl) -2 (4-methacryloyloxydiethoxyphenyl) propane, 2 (4-methacryloyloxydiethoxyphenyl) -2 (4-methacryloyloxyditriethoxyphenyl) propane, 2 (4-methacryloyloxydi) Propoxyphenyl) -2- (4-methacryloyloxytriethoxyphenyl) propane, 2,2-bis (4-methacryloyloxypropoxyphenyl) propane, 2,2-bis (4-methacryloyloxyisopropoxyphenyl) propane, and these Acrylates corresponding to other methacrylates; methacrylates such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, or Diadducts obtained from the addition of vinyl monomers having —OH groups such as acrylates corresponding to these methacrylates and diisocyanate compounds having aromatic groups such as diisocyanate methylbenzene and 4,4′-diphenylmethane diisocyanate, etc. Ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, butylene glycol dimethacrylate, neopentyl glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1 , 6-hexanediol dimethacrylate, and acrylates corresponding to these methacrylates; 2-hydroxyethyl methacrylate Methacrylates such as relate, 2-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, etc., or vinyl monomers having —OH groups such as acrylates corresponding to these methacrylates, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diisocyanate Diadducts obtained from addition with diisocyanate compounds such as methylcyclohexane, isophorone diisocyanate, methylenebis (4-cyclohexylisocyanate), for example 1,6-bis (methacrylethyloxycarbonylamino) -2,2-4-trimethylhexane An acrylic acid anhydride, methacrylic acid anhydride, 1,2-bis (3-methacryloyloxy-2-hydroxy) containing an acid group; Roxypropoxy) ethyl, di (2-methacryloyloxypropyl) phosphate, di [2- (meth) acryloyloxyethyl] hydrogen phosphate, di [4- (meth) acryloyloxybutyl] hydrogen phosphate, di [6- (Meth) acryloyloxyhexyl] hydrogen phosphate, di [8- (meth) acryloyloxyoctyl] hydrogen phosphate, di [9- (meth) acryloyloxynonyl] hydrogen phosphate, di [10- (meth) acryloyloxy Decyl] hydrogen phosphate, 1,3-di (meth) acryloyloxypropyl-2-dihydrogen phosphate, and the like.

(A3) Trifunctional radical polymerizable monomer Trimethylolpropan tri (meth) acrylate, trimethylolethane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, ethoxylated trimethylol Propane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, tris (2- (meth) acryloxyethyl isocyanurate) and the like can be mentioned.

(A4) Tetrafunctional radical polymerizable monomer Pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, propoxylated pentaerythritol tetra (meth) acrylate, ethoxylated ditrimethylolpropane tetra (meth) acrylate A tetraisocyanate compound such as hexamethyl diisocyanate, trimethylhexamethylene diisocyanate, and a diisocyanate compound such as diisocyanate such as diisocyanate methylcyclohexane can be suitably used.

  The above radical polymerizable monomers can be used alone or in combination.

  When a polymerizable monomer is used as a raw material for the resin matrix of the present invention, a polymerization initiator is preferably used in order to polymerize and cure the polymerizable monomer. The polymerization method of the curable composition includes a reaction by light energy such as ultraviolet light and visible light (hereinafter referred to as photopolymerization), a chemical reaction between a peroxide and an accelerator, a method by thermal energy (hereinafter referred to as thermal polymerization). Any method may be used. Photopolymerization and thermal polymerization are preferred from the viewpoint that the timing of polymerization can be arbitrarily selected by externally applied energy such as light and heat and the operation is simple. Various polymerization initiators shown below may be appropriately selected and used according to the polymerization method employed.

  For example, as a photopolymerization initiator, benzoin alkyl ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl ketals such as benzyl dimethyl ketal and benzyl diethyl ketal, benzophenone, 4,4′-dimethylbenzophenone, Benzophenones such as 4-methacryloxybenzophenone, diacetyl, 2,3-pentadione benzyl, camphorquinone, α-diketones such as 9,10-phenanthraquinone, 9,10-anthraquinone, 2,4-diethoxy Thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, methylthioxanthone, bis- (2,6-dichlorobenzoyl) phenylphosphine oxide, bis- (2,6-dichloroben) Yl) -2,5-dimethylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -4-propylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -1-naphthylphosphine oxide, 2,4 Acylphosphine oxides such as 1,6-trimethylbenzoyldiphenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide can be used.

  Incidentally, a reducing agent is often added to the photopolymerization initiator. Examples thereof include tertiary amines such as 2- (dimethylamino) ethyl methacrylate, ethyl 4-dimethylaminobenzoate, and N-methyldiethanolamine. , Aldehydes such as lauryl aldehyde, dimethylaminobenzaldehyde, terephthalaldehyde, and sulfur-containing compounds such as 2-mercaptobenzoxazole, 1-decanethiol, thiosalicylic acid, and thiobenzoic acid.

  Examples of the thermal polymerization initiator include benzoyl peroxide, p-chlorobenzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxydicarbonate, and diisopropyl peroxydicarbonate. Peroxides, azo compounds such as azobisisobutyronitrile, tributylborane, tributylborane partial oxide, sodium tetraphenylborate, sodium tetrakis (p-fluorophenyl) borate, triethanolamine tetraphenylborate And boron compounds such as 5-butyl barbituric acid, 1-benzyl-5-phenyl barbituric acid and the like, and sulfinates such as sodium benzenesulfinate and sodium p-toluenesulfinate. .

  These polymerization initiators may be used alone or in combination of two or more. It is preferable that the compounding quantity of a polymerization initiator is 0.01-5 mass parts with respect to 100 mass parts of resin matrices.

(B) Organic-inorganic composite particles (B) Organic-inorganic composite particles in the present invention are particles in which (B-2) inorganic particles are dispersed in (B-2) organic resin, and (B-1) inorganic Particles and (B-2) organic resin are composited. (B) The organic-inorganic composite particles are characterized by being spherical or substantially spherical.

  Note that the term “substantially spherical” as used herein means that the average degree of homogeneity obtained in image analysis of a photographed image of a scanning or transmission electron microscope is 0.6 or more. The average uniformity is more preferably 0.7 or more, and further preferably 0.8 or more. The average uniformity is measured using a scanning or transmission electron microscope.

Specifically, the average uniformity is obtained from the maximum length and the minimum width of the organic-inorganic composite particles by image analysis of the captured image of the organic-inorganic composite particles. As an image taken with an electron microscope, an image that is clear in brightness and capable of discriminating the particle outline is used. Image analysis is performed using image analysis software capable of measuring at least the maximum length and the minimum width of particles. With respect to 100 randomly selected organic-inorganic composite particles, the maximum length and the minimum width of the particles are obtained by the above method, and the average uniformity of the organic-inorganic composite particles is calculated by the following formula.

  In the above formula, the number of organic-inorganic composite particles is defined as (n), the maximum length of the i-th organic-inorganic composite particles is defined as the major axis (Li), and the diameter perpendicular to the major axis is defined as the minimum width (Bi).

  When spherical or nearly spherical organic-inorganic composite particles are used, the organic-inorganic composite particles and the resin matrix are easily compatible, and air bubbles are less likely to be included at the interface between the organic-inorganic composite particles and the resin matrix, thereby suppressing the occurrence of cracks. It is estimated that Therefore, from the viewpoint of exhibiting the above effects more highly, the average uniformity of the organic-inorganic composite particles used is preferably 0.7 or more, and more preferably 0.8 or more.

  Although there is no restriction | limiting in the particle size of (B) organic-inorganic composite particle in this invention, it is preferable that the average particle diameter of organic-inorganic composite particle is 1-50 microns from a viewpoint of machinability and aesthetics, 7-16 More preferably, it is micron. The average particle diameter of the organic-inorganic composite particles indicates the median diameter determined based on the particle size distribution by the laser diffraction-scattering method. A sample used for measurement is prepared by uniformly dispersing 0.1 g of organic-inorganic composite particles in 10 mL of ethanol.

  The material of (B-1) inorganic particles used for (B) organic-inorganic composite particles in the present invention is not particularly limited, and any materials used as fillers in ordinary dental curable compositions should be used. Can do. Specifically, simple substances of metals selected from Group I, II, III, IV, and transition metals, oxides and composite oxides of these metals, fluorides, carbonates, sulfates, silicates, hydroxides Metal salts composed of chlorides, chlorides, sulfites and phosphates, and composites of these metal salts. Preferably, amorphous silica, quartz, alumina, titania, zirconia, barium oxide, yttrium oxide, lanthanum oxide, ytterbium oxide and other metal oxides, silica-zirconia, silica-titania, silica-titania-barium oxide, silica -Silica-based composite oxides such as titania-zirconia, glass such as borosilicate glass, aluminosilicate glass, fluoroaluminosilicate glass, metal such as barium fluoride, strontium fluoride, yttrium fluoride, lanthanum fluoride, ytterbium fluoride Inorganic carbonates such as fluoride, calcium carbonate, magnesium carbonate, strontium carbonate, and barium carbonate, and metal sulfates such as magnesium sulfate and barium sulfate are used.

Among these, the metal oxide and the silica-based composite oxide are preferably fired at a high temperature in order to obtain a dense material. In order to improve the effect, it is preferable to contain a small amount of a Group I metal oxide such as sodium.
Among the inorganic particles of the above materials, the silica-based composite oxide particles can be easily adjusted in refractive index. Furthermore, since it has a large amount of silanol groups on the particle surface, it is particularly preferable because surface modification can be easily performed using a silane coupling agent or the like.

  The above exemplified particles of silica-zirconia, silica-titania, silica-titania-barium oxide, silica-titania-zirconia, etc. are suitable because they have strong X-ray contrast properties. Furthermore, silica-zirconia particles are most preferred because a cured product with better wear resistance can be obtained.

  The average particle size of primary particles of (B-1) inorganic particles used in (B) organic-inorganic composite particles of the present invention is not particularly limited as long as the particle size is smaller than that of organic-inorganic composite particles, but has high glossiness, Since mechanical strength is high, it is preferable that it is 10-1000 nm, 40-800 nm is more preferable, and 50-600 nm is the most preferable. In addition, since the shape of the (B-1) inorganic particles is spherical, a cured product of a curable composition that is particularly excellent in abrasion resistance, surface lubricity, and gloss durability can be obtained. Preferably used.

  In addition, the average particle diameter of the inorganic particle (B-1) in the present invention is a circle equivalent diameter of the primary particle diameter (a circle having the same area as the area of the target particle) from a scanning image of a scanning or transmission electron microscope. Is measured by image analysis. As an electron microscope image used for measurement, an image that is clear and bright and capable of discriminating the outline of the particle is used. As an image analysis method, an image that can measure at least the area of the particle, the maximum length of the particle, and the minimum width is used. Use analysis software. Moreover, the average particle diameter and average uniformity of these primary particles are calculated from the primary particle diameter measured as described above by the following formula.

Here, the number of particles (n), the maximum length of the particles is the major axis (Li), and the diameter perpendicular to the major axis is the minimum width (Bi). When calculating these values, it is necessary to measure at least 40 or more particles in order to maintain measurement accuracy, and it is desirable to measure 100 or more particles.
These (B-1) inorganic particles may be inorganic particles produced by any known method. For example, as long as it is an inorganic oxide or a composite oxide, it may be manufactured by any of a wet method, a dry method, and a sol-gel method. Considering that it is advantageous to industrially produce fine particles having a spherical shape and excellent monodispersibility, and that it is easy to adjust refractive index and impart X-ray contrast properties, It is preferable to manufacture by a sol-gel method.

  The method for producing spherical silica-based composite oxide particles by the sol-gel method is disclosed in, for example, JP-A Nos. 58-110414, 58-151321, 58-156524, 58-156. It is described in Japanese Patent No. 156526 and so on.

  In this method, first, a hydrolyzable organosilicon compound or a mixed solution in which another hydrolyzable organometallic compound is added is prepared. Next, the mixed solution is added to an alkaline solvent in which these organic compounds are dissolved but the product inorganic oxides are not substantially dissolved, and the mixture is hydrolyzed to precipitate inorganic oxides. After filtration, the precipitate is dried.

  The inorganic particles obtained by such a method may be baked at a temperature of 500 to 1000 ° C. after drying in order to impart surface stability. During firing, some of the inorganic particles may aggregate. In this case, it is preferable to use after agglomerated particles are broken up into primary particles using a jet mill, a vibrating ball mill or the like, and the particle size is adjusted to a predetermined range. By treating in this way, the abrasiveness of the composition when used as a dental composition is improved.

  (B-1) The inorganic particles may be a mixture of a plurality of inorganic particles having different average particle diameters, materials, and shapes.

  The inorganic agglomerated particles used for the organic-inorganic composite particles are preferably surface-treated with a hydrophobizing agent in order to improve the wettability with respect to the polymerizable monomer.

  A conventionally well-known thing is used without a restriction | limiting as a hydrophobizing agent. Examples of suitable hydrophobizing agents are vinyltriethoxysilane, vinyltrimethoxysilane, vinyl-tris (β-methoxyethoxy) silane, γ-methacryloyloxypropyltrimethoxysilane, κ-methacryloyloxidedecyltrimethoxysilane, β -(3,4-epoxycyclohexyl) -ethyltrimethoxysilane, γ-glycidoxypropyl-trimethoxysilane, N-β- (aminoethyl) -γ-aminopropyl-trimethoxysilane, γ-ureidopropyl-tri Examples include silane coupling agents such as ethoxysilane, γ-chloropropyltrimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, and methyltriethoxysilane, and titanate coupling agents.

  There is no restriction | limiting in particular in the usage-amount of the hydrophobizing agent used for the hydrophobization of an inorganic particle, If the usage-amount of a suitable hydrophobizing agent is illustrated, the said hydrophobizing agent 1-30 mass parts with respect to 100 mass parts of inorganic particles. It is.

  The surface treatment method is not particularly limited, and a known method is adopted without limitation. As an example of a typical treatment method, there is a method in which inorganic particles and a hydrophobizing agent are dispersed and mixed in a suitable solvent using a ball mill or the like, dried by an evaporator or air drying, and then heated to 50 to 150 ° C. is there. Furthermore, there is a method in which the inorganic particles and the hydrophobizing agent are heated to reflux for several hours in a solvent such as alcohol. Furthermore, there is a method of graft polymerization of a hydrophobizing agent on the particle surface.

  The surface treatment may be performed on inorganic particles or inorganic aggregated particles. In the case of producing inorganic agglomerated particles by spray drying, it is efficient to perform a surface treatment simultaneously with this treatment. A method for producing the aggregated particles will be described later.

  As (B-2) organic resin of (B) organic-inorganic composite particles, known resins can be used without particular limitation, and (A) the same kind of resin as described above can be used as the resin matrix. The types of (A) resin matrix and (B) organic-inorganic composite particles (B-2) organic resin are not necessarily the same and may be different. Since it is easy to produce the (B) organic-inorganic composite particles of the present invention, the (B-2) organic resin is preferably a polymerized and cured polymerized monomer, particularly acetone. It is preferable to form an organic resin (B-2) using a polymerizable monomer having compatibility with an organic solvent such as ethanol or ethanol as a raw material. Moreover, since the mechanical strength, ecological safety, etc. of the obtained (B-2) organic resin are favorable, it is preferable to use a (meth) acrylate type polymerizable monomer as a raw material. In addition, the (meth) acrylate type | system | group polymerizable monomer can use the same kind polymerizable monomer as what was demonstrated in the said (A) resin matrix. Furthermore, it is preferably a bifunctional or more, more preferably a bifunctional to tetrafunctional polymerizable monomer for reasons such as high polymerizability and particularly high mechanical properties of the cured product. These polymerizable monomers may be used alone or in a mixture of different types.

In (B) organic-inorganic composite particles, the content of (B-2) organic resin is not particularly limited, but is preferably 1 to 40 parts by mass with respect to 100 parts by mass of inorganic particles because the mechanical strength is increased. 5 to 25 parts by mass is more preferable. The content of the organic resin can be determined from the weight loss when simultaneous differential thermal-thermogravimetric measurement is performed.
(Method for producing organic-inorganic composite particles)
The method for producing the organic / inorganic composite particles (B) used in the resin block for dental cutting according to the present invention is not particularly limited, and any method can be selected as long as a spherical or substantially spherical shape can be obtained. Examples thereof include a suspension polymerization method, a spray drying method, and a method of spheroidizing organic-inorganic composite particles obtained by pulverization by a mechanochemical method.

  In the spray drying method, (B-1) an aqueous suspension of inorganic particles is granulated by spray drying to produce inorganic aggregated particles obtained by agglomerating the inorganic particles into a spherical shape or a substantially spherical shape. (B-1) When the inorganic particles are dry-type for dispersing the agglomerates generated during the steps of synthesis or the like, or those that have undergone a wet-dispersion step are used, the shape of the (B) organic-inorganic composite particles is spherical. Alternatively, it is preferable because a substantially spherical shape is easily obtained.

  The method for preparing the aqueous suspension of inorganic primary particles used in the spray drying method is not particularly limited, but a mixing device such as a bead mill is used because it is easy to uniformly disperse the inorganic primary particles in the aqueous medium. A method of preparing a slurry is preferable.

  The concentration of the inorganic primary particles in the aqueous suspension is not limited as long as it can be sprayed by spray drying. Usually, the concentration of the inorganic primary particles is preferably 5 to 50% by mass, and more preferably 20 to 45% by mass.

  Examples of the spray drying method include a method of spraying the aqueous suspension prepared by the above method onto fine droplets by using a high-speed air stream and drying it. The sprayed aqueous suspension is immediately dried with high-temperature air or inert gas to obtain inorganic aggregated particles having a uniform particle size. The temperature of the gas used for drying is preferably from 60 to 300 ° C, particularly preferably from 80 to 250 ° C. As the aqueous solvent volatilizes, a large number of inorganic primary particles dispersed within the droplets aggregate to form substantially one spherical inorganic aggregated particle. In the granulation method using spray drying, the particle size and particle size distribution of the aggregated particles can be controlled according to the spraying format and spraying conditions. These control methods are known techniques.

In the inorganic agglomerated particles prepared by spray drying, pores composed of agglomerated gaps of inorganic primary particles are formed. Range of the pore volume being formed, 0.015~0.35cm ³ / g and is more preferably 0.03~0.33cm ³ / g. The pore volume in the inorganic agglomerated particles is a value measured by a gas adsorption method in which an inert gas is adsorbed.

  Nitrogen gas is generally used in the measurement of the pore volume by the gas adsorption method. A predetermined amount of the inorganic particles is put in a measurement container, and the amount of nitrogen gas adsorbed at a pressure corresponding to the diameter of each pore in the aggregation gap of the inorganic particles is measured using BELSORP-mini II of Nippon Bell Co., Ltd. The pore volume may be calculated from the nitrogen gas adsorption amount.

  When producing organic-inorganic composite particles using the aggregated inorganic aggregated particles, it is preferable to prepare organic-inorganic composite particles by allowing a polymerizable monomer to enter the aggregation gap of the inorganic aggregated particles as the organic resin described above. . Examples of the method for allowing the polymerizable monomer to enter the inorganic aggregated particles include a method of immersing the inorganic aggregated particles in the polymerizable monomer solution. As the organic solvent contained in the polymerizable monomer solution, a known solvent can be used without limitation, but it has high volatility so that the solvent can be easily removed, and can be easily obtained. From the viewpoint of low cost and high safety to the human body during production, alcohol solvents such as methanol and ethanol, acetone, dichloromethane and the like are preferably used. The same polymerization initiator as that described above can be used as the polymerization initiator to be contained in the polymerizable monomer solution. Photopolymerization initiators or thermal polymerization initiators are preferred because the timing of polymerization can be arbitrarily selected by externally applied energy, and the operation is simple, and can be used without any restrictions on the work environment such as light shielding or red light. In this respect, a thermal polymerization initiator is more preferable.

  When immersing the inorganic aggregated particles in the polymerizable monomer solution, it is generally preferable to carry out under normal temperature and pressure. The mixing ratio of the inorganic agglomerated particles and the polymerizable monomer solution is preferably 30 to 500 parts by mass of the polymerizable monomer solution with respect to 100 parts by mass of the inorganic agglomerated particles so that the content of the organic resin described above is obtained. 50-200 mass parts is more preferable. In order to sufficiently infiltrate the polymerizable monomer into the inorganic aggregated particles, it is preferable that the mixture is allowed to stand after mixing. The standing temperature is not particularly limited, but is usually room temperature. The standing time is preferably 30 minutes or longer, and more preferably 1 hour or longer. In order to promote the penetration of the polymerizable monomer solution into the agglomeration gap of the inorganic agglomerated particles, the mixture of the organic resin solution and the inorganic agglomerated particles is subjected to shaking agitation, centrifugal agitation, pressurization, reduced pressure, and heating. Also good.

  After the polymerizable monomer solution is immersed in the aggregation gap of the inorganic aggregated particles, the organic solvent is removed from the polymerizable monomer solution. In the removal of the organic solvent, substantially the entire amount of the organic solvent (usually 95% by mass or more) invading the inorganic aggregated particles is removed. Visually, removal may be performed until there is no coagulum formed by the inorganic aggregated particles sticking to each other and a powder in a fluid state is obtained. The organic solvent may be removed by any known drying operation, but in order to shorten the drying time, a method of heating and drying under reduced pressure is preferred. The degree of vacuum and the drying temperature may be appropriately selected in consideration of the volatility and boiling point of the organic solvent to be removed. After removing the organic solvent, the polymerizable monomer is polymerized and cured to prepare organic-inorganic composite particles.

Inside the organic-inorganic composite particles obtained by the above preparation method, pores composed of agglomeration gaps of the inorganic agglomerated particles are present, and the range of the pore volume is preferably 0.01 to 0.30 cm ³ / g. 015-0.20 cm < ³ > / g is more preferable. The average pore diameter of the pores of the organic / inorganic composite particles is not particularly limited, but is preferably 3 to 300 nm, more preferably 10 to 200 nm. In the case of this average pore diameter range, an agglomeration gap having the pore volume can be easily formed. In addition, the average pore diameter of the pores composed of the agglomerated gaps indicates the median pore diameter determined based on the pore volume distribution in the pores in the pore diameter range of 1 to 500 nm measured by the gas adsorption method.

  When the organic / inorganic composite particles having the pore volume are mixed with a curable composition containing a polymerizable monomer and a polymerization initiator, the polymerizable monomer fills the pores by capillary action in the pores. By intruding in the state of being made to be polymerized and cured in this state, the inside and outside of the organic-inorganic composite particles are integrally covered with the resin matrix, and the adhesion between the organic-inorganic composite particles and the resin matrix becomes strong. This is far stronger than the conventional adhesion between the filler and the resin matrix, which is bonded only on the filler surface, so that the resin block for dental cutting processing blended with the organic-inorganic composite particles in the present invention Is given high mechanical strength. Moreover, since the organic-inorganic composite particles and the resin matrix are closely adhered during polymerization, it is presumed that generation of cracks during polymerization is more effectively suppressed.

When producing a resin block for dental cutting according to the present invention by polymerizing and curing a curable composition containing organic-inorganic composite particles having a pore volume of 0.01 to 0.30 cm ³ / g, organic-inorganic composite particles Since the resin matrix is easily adhered closely and the organic-inorganic composite particles themselves are strengthened, it is easy to obtain the effect of suppressing the occurrence of the cracks described above. Therefore, from the viewpoint of more highly exhibit the above effects, the pore volume of the organic-inorganic composite particles used, 0.01~0.30cm ³ / g are preferred, 0.015~0.20cm ³ / g Gayori preferable.

  The organic-inorganic composite particles in the present invention may be subjected to surface treatment. By performing the surface treatment, higher mechanical strength is imparted to the cured body of the dental curable composition containing the organic-inorganic composite particles. The hydrophobizing agent and the surface treatment method used for the surface treatment are the same as the surface treatment of the inorganic particles described above.

  The blending amount of (B) organic-inorganic composite particles used in the resin block for dental cutting according to the present invention is preferably 50 to 500 parts by mass with respect to 100 parts by mass of (A) resin matrix. More preferably, it is part by mass. (B) When there are too few compounding quantities of organic-inorganic composite particle | grains, it is difficult to obtain the crack suppression effect which is an effect of this invention. (B) When there are too many compounding quantities of an organic inorganic composite particle, it may become difficult to disperse | distribute uniformly in (A) resin matrix.

  In the case where a polymerizable monomer is used as a raw material for the resin matrix (A), a polymerizable monomer for preparing a curable composition containing a polymerizable monomer, organic-inorganic composite particles, and a polymerization initiator. May be adjusted as described above. That is, preferably 50 to 500 parts by mass of (B) organic-inorganic composite particles are blended with respect to 100 parts by mass of the polymerizable monomer, more preferably 100 to 300 parts by mass, and a necessary amount of polymerization initiator is added. The resin composition block for dental cutting of the present invention may be obtained by adjusting the blended curable composition and polymerizing and curing it.

  The resin block for dental cutting according to the present invention can contain an optional component in addition to the resin matrix and the organic-inorganic composite particles. Examples include (B) fillers other than (B) organic-inorganic composite particles, polymerization initiators, polymerization inhibitors, fluorescent agents, ultraviolet absorbers, antioxidants, pigments, antibacterial agents, and X-ray contrast agents.

  (C) A filler is mix | blended from viewpoints, such as the improvement of the mechanical strength in the block of this invention, the improvement of abrasion resistance, the reduction | decrease of a thermal expansion coefficient, water absorption, and a solubility reduction.

  (C) As a filler, a well-known filler can be used without a restriction | limiting, You may use any of inorganic particles and organic particles, and (B) organic-inorganic composite particles other than organic-inorganic composite particles. From the viewpoint of reducing the coefficient of thermal expansion and improving the mechanical strength, it is preferable to use an inorganic filler. As an inorganic filler, the same thing as the (B-2) inorganic particle contained in the (B) organic inorganic composite particle mentioned above can be used. Of these, composite oxides mainly composed of silica and zirconia, silica and titania, or silica and barium oxide are preferably used because they have high X-ray contrast properties. In addition, since the filler has a spherical shape, a cured product of a curable composition that is particularly excellent in wear resistance, surface smoothness, and gloss durability can be obtained. The average particle diameter of the filler is preferably 0.001 to 1 μm, and more preferably 0.01 to 0.5 μm from the viewpoints of wear resistance, surface smoothness, and gloss durability.

  In the embodiment of the present invention, the blending amount of (C) filler may be selected according to the purpose, but (A) it is usually a ratio of 10 to 1000 parts by mass with respect to 100 parts by mass of the resin matrix, More preferably, it is used in a proportion of 100 to 500 parts by mass.

(Manufacturing method of resin block for dental cutting)
There is no restriction | limiting in particular in the manufacturing method of the resin type block for dental cutting of this invention, What is necessary is just to use a manufacturing method properly by the material to be used. For example, when the resin matrix is a thermoplastic resin, a mixed kneaded product of (A) resin matrix and (B) organic-inorganic composite particles is heated and melted and sequentially injected into the mold. A sequential press molding method can be employed. (A) Compound (B) organic / inorganic composite particles and a polymerization initiator are mixed with a polymerizable monomer that is a raw material for a resin matrix, a curable composition is prepared, and this is polymerized and cured for dental cutting. Resin blocks can also be manufactured. In this case, in the manufacturing process, the mold is weighed, filled, shaped, degassed, etc., and if necessary, preliminarily polymerized by heating or light, and then finalized by heating or light. A block body may be produced. Further, if necessary, the obtained block body can be subjected to treatment such as polishing and heat treatment.

(Usage of resin block for dental cutting)
The block produced in this way can be used as a CAD / CAM block by joining pins to be held in the CAD / CAM device as necessary. By connecting this to a CAD / CAM device and performing cutting based on the design, a restoration of a crown can be obtained.

  Examples and comparative examples relating to the present invention are shown below, but the present invention is not limited to these examples. The materials and test methods used in the examples are shown below.

(Polymerizable monomer)
M-1: 1,6-bis (methacrylethyloxycarbonylamino) trimethylhexane M-2: triethylene glycol dimethacrylate

(Organic inorganic composite particles)
The organic-inorganic composite particles used in the examples are shown in Table 1 below. P-1 and P-2 in Table 1 are obtained by granulating inorganic particles by spray drying with a nozzle-type spray dryer RL-8 (manufactured by Okawara Chemical Co., Ltd.), and γ-methacryloyloxypropyltrimethoxy as a surface treatment agent. Silane was used. (Spray drying conditions: spray pressure 0.1 MPa, supply slurry amount 17 kg / h) With respect to 100 parts by mass of the obtained inorganic particles, 19 parts by mass of polymerizable monomer M-1 and I-1 as a polymerization initiator Was mixed at 0.5 parts by mass and polymerized at a nitrogen pressure of 0.4 MPa at 120 ° C. to prepare spherical organic-inorganic composite particles. P-3 is equipped with a rotating disk, and sprayed with a spray dryer TSR-2W (manufactured by Sakamoto Giken Co., Ltd.) that atomizes by centrifugal force. Granulates inorganic particles (spray drying conditions: disk rotation speed 10000 rpm, drying) Spherical organic-inorganic composite particles were prepared by the same method as P-1, except that the temperature was 200 ° C. P-4 granulates inorganic particles in the same manner as P-3, and then 100 parts by mass of the obtained inorganic particles 33 parts by mass of polymerizable monomer M-1 as a polymerization initiator I-1 was blended to 0.5 parts by mass and kneaded to prepare a paste-like mixture. This paste-like mixture was defoamed under reduced pressure, polymerized at 100 ° C., and the polymerized cured product was pulverized with a vibration ball mill (zirconia ball particle size: 5 mm) to prepare amorphous organic-inorganic composite particles.

(Polymerization catalyst)
I-1: Benzoyl peroxide (filler)
F-1: γ-methacryloyloxypropyltrimethoxysilane surface-treated product of spherical silica zirconia having an average particle size of 0.2 microns F-2: Reolosil MT-10 (manufactured by Tokuyama Corporation)
(Appearance test)
Visual evaluation and X-ray observation of the cured product composition were carried out, and the cured product composition was evaluated as “◯” when there was no crack or the like, and “X” when the crack was observed.

(Bending strength)
A test piece having a length of 2 mm, a width of 2 mm, and a height of 25 mm was cut out from the cured composition and polished in the length direction with water-resistant abrasive paper No. 1500 to obtain a test piece having a thickness of ± 0.1 mm and a thickness of 2 ± 0.1 mm. . Using a universal tensile tester Autograph (manufactured by Shimadzu Corporation), a three-point bending test was performed in the atmosphere at room temperature under the conditions of a distance between supporting points of 20 mm and a crosshead speed of 1 mm / min. The bending strength was evaluated for five test pieces, and the average value was defined as the bending strength.

[Production Example 1]
0.4 parts by mass of the polymerization initiator I-1 was mixed and dissolved in 100 parts by mass of the polymerizable monomer mixture obtained by mixing the polymerizable monomers M-1 and M-2 at a weight ratio of 75/25. A curable composition was obtained by adding 240 parts by mass of P-1 as organic-inorganic composite particles to 100 parts by mass of the polymerizable monomer mixture and well dispersing using a planetary mixer. This was degassed in vacuum to give composition 1.

[Production Example 2]
0.4 parts by mass of the polymerization initiator I-1 was mixed and dissolved in 100 parts by mass of the polymerizable monomer mixture obtained by mixing the polymerizable monomers M-1 and M-2 at a weight ratio of 75/25. By adding 230 parts by mass of P-1 as an organic-inorganic composite particle and 230 parts by mass of F-1 as a filler with respect to 100 parts by mass of this polymerizable monomer mixture, the mixture is well dispersed using a planetary mixer. A curable composition was obtained. This was degassed in vacuum to make composition 2.

[Production Example 3]
0.4 parts by mass of the polymerization initiator I-1 was mixed and dissolved in 100 parts by mass of the polymerizable monomer mixture obtained by mixing the polymerizable monomers M-1 and M-2 at a weight ratio of 75/25. To 100 parts by mass of this polymerizable monomer mixture, 230 parts by mass of P-1 as organic-inorganic composite particles, 225 parts by mass of F-1 as fillers, and 5 parts by mass of F-2 are added, and a planetary mixer A curable composition was obtained by thoroughly dispersing the composition. This was degassed in vacuum to give composition 3.

[Production Example 4]
0.4 parts by mass of the polymerization initiator I-1 was mixed and dissolved in 100 parts by mass of the polymerizable monomer mixture obtained by mixing the polymerizable monomers M-1 and M-2 at a weight ratio of 75/25. By adding 230 parts by mass of P-2 as organic-inorganic composite particles and 230 parts by mass of F-1 as a filler to 100 parts by mass of this polymerizable monomer mixture, and thoroughly dispersing them using a planetary mixer A curable composition was obtained. This was degassed in vacuum to obtain Composition 4.

[Production Example 5]
0.4 parts by mass of the polymerization initiator I-1 was mixed and dissolved in 100 parts by mass of the polymerizable monomer mixture obtained by mixing the polymerizable monomers M-1 and M-2 at a weight ratio of 75/25. By adding 230 parts by mass of P-3 as organic-inorganic composite particles and 230 parts by mass of F-1 as a filler to 100 parts by mass of this polymerizable monomer mixture, well dispersed using a planetary mixer A curable composition was obtained. This was degassed in vacuum to give composition 5.

[Production Example 6]
0.4 parts by mass of the polymerization initiator I-1 was mixed and dissolved in 100 parts by mass of the polymerizable monomer mixture obtained by mixing the polymerizable monomers M-1 and M-2 at a weight ratio of 75/25. By adding 237 parts by mass of P-1 as an organic-inorganic composite particle and 3 parts by mass of F-2 as a filler with respect to 100 parts by mass of this polymerizable monomer mixture, it is well dispersed using a planetary mixer. A curable composition was obtained. This was degassed in vacuum to make composition 6.

[Production Example 7]
0.4 parts by mass of the polymerization initiator I-1 was mixed and dissolved in 100 parts by mass of the polymerizable monomer mixture obtained by mixing the polymerizable monomers M-1 and M-2 at a weight ratio of 75/25. A curable composition was obtained by adding 240 parts by mass of the filler F-1 to 100 parts by mass of the polymerizable monomer mixture and well dispersing it using a planetary mixer. This was degassed in vacuum to give composition 7.

[Production Example 8]
0.4 parts by mass of the polymerization initiator I-1 was mixed and dissolved in 100 parts by mass of the polymerizable monomer mixture obtained by mixing the polymerizable monomers M-1 and M-2 at a weight ratio of 75/25. Cured by adding 230 parts by mass of P-4 and 230 parts by mass of filler F-1 as organic-inorganic composite particles to 100 parts by mass of this polymerizable monomer mixture, and dispersing well using a planetary mixer. Sex composition was obtained. This was degassed in vacuum to make a composition 8.

[Example 1]
The composition 1 was filled up to a height of 150 mm so as not to entrain air bubbles in a 14 × 18 mm mold, and the upper surface was smoothed. Then, using a heat and pressure polymerization device, the pressure was 3 kgf / cm ² , 120 ° C. 30 Heating and pressure polymerization were performed under the conditions of minutes. The cured product composition was taken out from the mold to obtain a resin block for dental cutting including a resin matrix and organic-inorganic composite particles. The results of appearance test and bending strength are summarized in Table 2.

[Examples 2 to 6]
A resin block for dental cutting was produced in the same manner as in Example 1 except that the composition shown in Table 2 was used. The results of appearance test and bending strength are summarized in Table 2.

[Comparative Examples 1-2]
A resin block for dental cutting was produced in the same manner as in Example 1 except that the composition shown in Table 2 was used. The results of appearance test and bending strength are summarized in Table 2.

In Comparative Example 1, generation of cracks was observed in the visual evaluation of the appearance test. Therefore, the bending strength cannot be evaluated.

Claims (6)

  A resin block for dental cutting comprising (A) a resin matrix and (B) spherical or substantially spherical organic-inorganic composite particles. (B) The resin-based block for dental cutting according to claim 1, wherein the organic-inorganic composite particles have a pore volume of 0.01 to 0.30 cm ³ / g.   The resin block for dental cutting according to claim 1, wherein the resin matrix (A) is an acrylic resin.   (C) The resin block for dental cutting as described in any one of Claims 1-3 containing an inorganic particle. Dental for cutting resin based block according to any one of claims 1 to 4 volume block, characterized in that it is 10cm ³ ~200cm ^3.   A method for producing a resin block for dental cutting, comprising polymerizing and curing a curable composition comprising a polymerizable monomer, (B) spherical or substantially spherical organic-inorganic composite particles, and a polymerization initiator.