JP2019116438A - Dental curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dental curable composition capable of producing a cured product having an initial strength maintained even after being immersed in water. SOLUTION: It contains (A) a polymerizable monomer, (B) a polymerization initiator, and (C) silica-based inorganic particles having an average particle diameter of 50 to 400 nm and a surface silanol group number of 5 / nm2 or less. A dental curable composition, a cured product of the dental curable composition, a dental curable composition for producing a resin-based material for dental cutting processing comprising the dental curable composition, and the dental cutting. It is a resin-based material for dental cutting, which comprises a cured product of a dental curable composition for producing a resin-based material for processing. [Selection diagram] None

Description

  The present invention relates to a dental hardenable composition, and more particularly to a dental hardenable composition useful for a dental cutting resin-based block for producing a dental prosthesis by cutting.

  A dental curable composition is generally composed mainly of a polymerizable monomer (monomer), a filler, and a polymerization initiator, and as a composite resin, hard resin, artificial tooth, cement, resin material for cutting, etc. It is applied. Although dental hardenable compositions are widely used as dental materials due to their ease of handling and low harmfulness to the living body, the harsh oral environment, especially when compared to other materials such as metals and ceramics It is difficult to say that it is sufficient in terms of mechanical strength to function in a long-term wet environment, and improvement is still needed from the viewpoint of coexistence with other physical properties such as aesthetics and operability. ing.

  In Non-Patent Document 1, although the CAD / CAM composite resin block for dental use has a bending strength equivalent to that of a ceramic material, the ceramic material is affected by the water immersion in the three-point bending strength after 7 days of immersion in water. On the other hand, it has been shown that the CAD / CAM composite resin block for dental use is reduced to about 80% of the initial level. However, while studies for improvement of initial physical properties have been actively conducted, studies for solving such a problem of bending strength reduction after water absorption imitating the inside of the oral cavity have hardly been made up to now.

Dental Materials Journal 2014; 33 (5): 705-710

  The problem to be solved by the present invention is to provide a dental hardenable composition capable of producing a hardened body whose initial strength is maintained even after immersion in water.

  The present inventors diligently studied to solve the above problems. As a result, it is found that a curable composition capable of obtaining a cured product having high strength and capable of suppressing a decrease in strength due to immersion in water to a minimum can be obtained by adding a specific amount of a specific filler. The present invention has been completed.

That is, the present invention
Dental curing comprising (A) polymerizable monomer, (B) polymerization initiator, and (C) silica-based inorganic particles having an average particle diameter of 50 to 400 nm and a surface silanol group number of 5 / nm ² or less Sex composition.

  The dental curable composition of the present invention comprises (B) 0.1 to 10 parts by mass of a polymerization initiator, (C) silica-based inorganic particles 150 to 600, per 100 parts by mass of the (A) polymerizable monomer. It is preferable that they are 0-600 mass parts of fillers other than a mass part and (D) and (C).

  A second aspect of the present invention is a cured product of the above-mentioned dental curable composition.

  A third aspect of the present invention is a dental hardenable composition for producing a resin-based material for dental cutting, which comprises the above-mentioned dental hardenable composition.

  A fourth aspect of the present invention is a resin-based material for dental cutting, comprising a cured product of a dental curable composition for producing the resin-based material for dental cutting.

  The dental curable composition of the present invention can produce a cured product having a high flexural strength of the cured product, minimal reduction in strength due to immersion in water, and maintaining the initial strength even under wet conditions It becomes. The cured product of the dental curable composition of the present invention is particularly effective as a crown restorative material of a molar portion to which high bite pressure is applied, and for producing such crown restorative material by cutting. It is suitable as a resin-based material for dental cutting.

<(A) Polymerizable monomer>
The dental curable composition of the present invention comprises (A) a polymerizable monomer. A well-known polymerizable monomer can be used for a (A) polymerizable monomer. Examples of the polymerizable monomer include radical polymerizable monomers and cationic polymerizable monomers, but in general, radical polymerizable monomers are suitably used. As a radically polymerizable monomer, a radical having a (meth) acrylic acid ester group, a (meth) acrylamide group, a vinyl ester group, a vinyl ether group, a styryl group etc. as a polymerizable functional group which is a functional group having a polymerizing property A polymerizable monomer is mentioned. When plural polymerizable functional groups are contained in one molecule, the respective polymerizable functional groups may be the same or different in one molecule. Particularly preferred polymerizable monomers have a (meth) acrylic acid ester-based polymerizable monomer having a (meth) acrylic acid ester group as a polymerizable functional group from the viewpoint of biological safety, or a (meth) acrylamide group It is a (meth) acrylamide derivative, and from the viewpoint of good polymerizability, a (meth) acrylic acid ester type polymerizable monomer is most preferable. In the present invention, the expression "(meth) acrylic" is used to mean that both of methacrylic and acrylic are included. Specific examples of the (meth) acrylic acid ester-based polymerizable monomer include the following.

  As a monofunctional radically polymerizable monomer, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-lauryl (meth) acrylate, n-stearyl ( Meta) acrylate, tetrafurfuryl (meth) acrylate, glycidyl (meth) acrylate, methoxyethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxy-triethylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, Ethoxyethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, ethoxytriethylene glycol (meth) acrylate, ethoxy ester Ethylene glycol (meth) acrylate, phenoxyethylene glycol (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxytriethylene glycol (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate And N- (meth) acryloyl glycine, N- (meth) acryloyl aspartic acid, and N- (mono) as monofunctional polymerizable monomers having an acidic group such as isoboronyl (meth) acrylate and trifluoroethyl (meth) acrylate. Meta) acryloyl-5-aminosalicylic acid, 2- (meth) acryloyloxyethyl hydrogen succinate, 2- (meth) acryloyloxyethyl hydride Gen phthalate, 2- (meth) acryloyloxyethyl hydrogen malate, 6- (meth) acryloyloxyethyl naphthalene-1,2,6-tricarboxylic acid, O- (meth) acryloyl tyrosine, N- (meth) acryloyl tyrosine, N- (meth) acryloyl phenylalanine, N- (meth) acryloyl-p-aminobenzoic acid, N- (meth) acryloyl-o-aminobenzoic acid, p-vinylbenzoic acid, 2- (meth) acryloyloxybenzoic acid, 3- (Meth) acryloyloxybenzoic acid, 4- (Meth) acryloyloxybenzoic acid, N- (Meth) acryloyl-5-aminosalicylic acid, N- (Meth) acryloyl-4-aminosalicylic acid, etc. and carboxyls of these compounds A compound in which an acid anhydride group is formed, 11- ( Ta) Acryloyloxyundecane-1,1-dicarboxylic acid, 10- (meth) acryloyloxydecane-1,1-dicarboxylic acid, 12- (meth) acryloyl oxydecan-1,1-dicarboxylic acid, 6- (meth) Acryloyloxyhexane-1,1-dicarboxylic acid, 2- (meth) acryloyloxyethyl-3′-methacryloyloxy-2 ′-(3,4-dicarboxybenzoyloxy) propyl succinate, 4- (2- (metha) ) Acryloyloxyethyl) trimellitate anhydride, 4- (2- (meth) acryloyloxyethyl) trimellitate, 4- (meth) acryloyloxyethyl trimellitate, 4- (meth) acryloyloxybutyl trimellitate, 4 -(Meth) acryloyloxyhexyl trimellite 4- (meth) acryloyloxydecyl trimellitate, 4- (meth) acryloyloxybutyl trimellitate, 6- (meth) acryloyloxyethyl naphthalene-1,2,6-tricarboxylic anhydride, 6- ( (Meth) acryloyloxyethylnaphthalene-2,3,6-tricarboxylic acid anhydride, 4- (meth) acryloyloxyethylcarbonylpropionoyl-1,8-naphthalic acid anhydride, 4- (meth) acryloyloxyethylnaphthalene 1,8-tricarboxylic acid anhydride, 9- (meth) acryloyloxynonane-1,1-dicarboxylic acid, 13- (meth) acryloyloxytridecane-1,1-dicarboxylic acid, 11- (meth) acrylamidoundecane- 1,1-dicarboxylic acid, 2- (meth) acryloyloxyethyl di Idorogen phosphate, 2- (meth) acryloyloxyethyl phenyl hydrogen phosphate, 10- (meth) acryloyl oxydecyl dihydrogen phosphate, 6- (meth) acryloyl oxyhexyl dihydrogen phosphate, 2- ( Meta) acryloyloxyethyl 2-bromoethyl hydrogen phosphate, 2- (meth) acrylamidoethyl dihydrogen phosphate, 2- (meth) acrylamido-2-methylpropane sulfonic acid, 10-sulfodecyl (meth) acrylate, 3- (meth) acryloxypropyl-3-phosphonopropionate, 3- (meth) acryloxypropylphosphonoacetate, 4- (meth) acryloxybutyl-3-phosphonopropionate, 4- (Meth) acryloxybutylphosphonoacetate, 5- (meth) acryloxypentyl-3-phosphonopropionate, 5- (meth) acryloxypentylphosphonoacetate, 6- (meth) acryloxyhexyl-3- Phosphonopropionate, 6- (meth) acryloxyhexyl phosphonoacetate, 10- (meth) acryloxydecyl-3-phosphonopropionate, 10- (meth) acryloxydecyl phosphonoacetate, 2- ( Meta) acryloxyethyl-phenylphosphonate, 2- (meth) acryloyloxyethylphosphonic acid, 10- (meth) acryloyloxydecylphosphonic acid, N- (meth) acryloyl-ω-aminopropylphosphonic acid, 2- (meth) Acryloyloxyethyl phenyl hydrogen phosphate As a monofunctional polymerizable monomer having a hydroxyl group such as 2- (meth) acryloyloxyethyl-2'-bromoethyl hydrogen phosphate, 2- (meth) acryloyloxyethyl phenyl phosphonate, 2-hydroxyethyl (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) acrylamide, etc. Can be mentioned.

  As a bifunctional radically polymerizable monomer, ethylene glycol di (meth) acrylate, diethylene glycol dimethacrylate, glycerin dimethacrylate, propylene glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, di [2- (meth) acryloyl] Oxyethyl! Hydrogen phosphate, di [4- (meth) acryloyloxybutyl] hydrogen phosphate, 3,3,4,4-hexafluoro-1,5-pentyl dimethacrylate, 2-hydroxy-1,3-di Methacryloxypropane, di [6- (meth) acryloyloxyhexyl] hydrogen phosphate, di [8- (meth) acryloyloxyoctyl] hydrogen phosphate, di [9- (meth) acryloyloxyno [L] Hydrogen phosphate, di [10- (meth) acryloyloxydecyl] hydrogen phosphate, 1,3-di (meth) acryloyloxypropyl-2-dihydrogen phosphate, 1,5-pentanediol di (meth) Acrylates, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, tricyclode Candimethanol di (meth) acrylate, 2,2-bis ((meth) acryloyloxyphenyl) propane, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate (polyethylene glycol # 200 di (meth) acrylate Acrylate, nona ethylene glycol dimethacrylate (polyethylene glycol # 400 di (meth) acrylate), tetradecaethylene glycol di (meth) acrylate (polyethylene glycol # 600 di (meth) acrylate), polypropylene glycol # 400 di (meth) acrylate , Polypropylene glycol # 700 di (meth) acrylate, etc., 2,2-bis (4-((meth) acryloyloxypolyethoxy) phenyl) propane (ethylene oxide 6 mol), 2,2-bis (4-((meth) acrylate ) Acryloyloxypolyethoxy) phenyl) propane (ethylene oxide 10 mol), 2,2-bis (4-((meth) acryloyloxypolyethoxy) phenyl) propane (ethylene oxide 17 mol), 2, 2, 2-bis (4-((meth) acryloyloxypolyethoxy) phenyl) propane (ethylene oxide 30 mol), 2,2-bis (4- (meth) acryloyloxyethoxyphenyl) propane, 2,2-bis [4 -(3- (Meth) acryloyloxy) -2-hydroxypropoxyphenyl] propane, 2,2-bis ((4- (meth) acryloyloxyethoxy) phenyl) propane (ethylene oxide 2.3 mol), 2,2 -Bis ((4- (meth) acryloyloxyethoxy) phenyl) propane (ethylene oxide 2.6 mol), dimethacryloxyethoxylated 9,9'-bis (4-hydroxyphenyl) fluorene, 2-hydroxyethyl (meth) ) Acrylate, 2-hydroxypropyl (meth) acrylate, 3-g (Meth) acrylates having —OH group such as 2-hydroxypropyl (meth) acrylate and diisocyanate compounds such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diisocyanate methylcyclohexane, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate) and the like Diaduct (eg, 1,6-bis ((meth) acrylethyloxycarbonylamino) -2,2-4-trimethylhexane) and the like obtained from the addition thereof.

  Trifunctional radically polymerizable monomers such as trimethylolpropan tri (meth) acrylate, trimethylol ethane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, ethoxylated trimethylol proper And tri- (meth) acrylate, propoxylated trimethylol propane tri (meth) acrylate, tris (2- (meth) acryloxyethyl isocyanurate) and the like.

  Examples of tetrafunctional radically polymerizable monomers include pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, propoxylated pentaerythritol tetra (meth) acrylate, ethoxylated ditrimethylolpropane tetra (meth) acrylate, etc. Tetra (meth) acrylate compounds, (OH) -containing (meth) acrylates such as glycerol di (meth) acrylate and hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diisocyanate methylcyclohexane, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate) Diaducts obtained from the addition with diisocyanate compounds such as Hexamethylene) bis [2- (aminocarboxy) propane-1,3-diol] tetra (meth) acrylate), and the like.

  The above-mentioned polymerizable monomers can be used alone or in combination. Specific examples of suitable polymerizable monomers include 2,2-bis [4- (3- (meth) acryloyloxy) -2-hydroxypropoxyphenyl] propane and 1,6-bis ((meth) acrylic acid. Ethyloxycarbonylamino) -2,2-4-trimethylhexane, 2,2-bis ((4- (meth) acryloyloxyethoxy) phenyl) propane (ethylene oxide 2.6 mol), neopentyl glycol di (meth) Acrylate, tricyclodecanedimethanol di (meth) acrylate, triethylene glycol di (meth) acrylate, 2,2-bis (4-((meth) acryloyloxypolyethoxy) phenyl) propane (ethylene oxide 6 mol), etc. It can be mentioned.

<(B) polymerization initiator>
The dental curable composition of the present invention comprises (B) a polymerization initiator. The (B) polymerization initiator is added to polymerize and cure the (A) polymerizable monomer. The polymerization method of the dental curable composition of the present invention includes reaction by light energy such as ultraviolet light and visible light (hereinafter referred to as photopolymerization), chemical reaction between peroxide and accelerator, and thermal energy (Hereafter, it is called thermal polymerization) etc., and any method may be used. From the viewpoint that the timing of polymerization can be arbitrarily selected by the energy given from the outside such as light and heat, and the operation is simple, a photopolymerization initiator and a thermal polymerization initiator are preferable. In addition, when the dental curable composition of the present invention is cured and the cured product is used as a resin material for dental cutting, it is necessary to obtain a cured product having a large thickness and a toned color. A thermal polymerization initiator is preferred because it may be difficult to transmit light to the inside of the composition. Various polymerization initiators shown below may be appropriately selected and used according to the polymerization method to be 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, benzyl diethyl ketal, benzophenone, 4,4'-dimethyl benzophenone, Benzophenones such as 4-methacryloxybenzophenone, diacetyl, 2,3-pentadione benzyl, camphorquinone, 9,10-phenanthraquinone, α-diketones such as 9,10-anthraquinone, 2,4-diethoxy Thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, methyl thioxanthone, bis- (2,6-dichlorobenzoyl) phenyl phosphine oxide, bis- (2,6-dichloroben Yl) -2,5-dimethylphenyl phosphine oxide, bis- (2,6-dichlorobenzoyl) -4-propylphenyl phosphine oxide, bis- (2,6-dichlorobenzoyl) -1-naphthyl phosphine oxide, 2,4 Acyl phosphine oxides such as 6,6-trimethyl benzoyl diphenyl phosphine oxide and bis (2,4,6-trimethyl benzoyl) -phenyl phosphine oxide can be used.

  Although 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. And sulfur-containing compounds such as 2-mercaptobenzoxazole, 1-decanethiol, thiosalicylic acid, thiobenzoic acid and the like, and aldehydes such as lauryl aldehyde, dimethylamino benzaldehyde and terephthalaldehyde.

  Also, as a thermal polymerization initiator, for example, benzoyl peroxide, p-chlorobenzoyl peroxide, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxydicarbonate, diisopropylperoxydicarbonate and the like Peroxides, azo compounds such as azobisisobutyronitrile, tributylborane, tributylborane partial oxide, sodium tetraphenylborate, sodium tetrakis (p-fluorophenyl) borate, triethanolamine tetraphenylborate salt And boron compounds such as 5-butyl barbituric acid, 1-benzyl-5-phenyl barbituric acid, barbituric acids, sodium benzenesulfinate, sulfinates such as sodium p-toluenesulfinate, etc. . From the viewpoint of obtaining a cured product of high strength, it is preferable to use a peroxide such as benzoyl peroxide.

  These polymerization initiators may be used alone or in combination of two or more. It is preferable that it is 0.1-10 mass parts with respect to 100 mass parts of (A) polymerizable monomers, and, as for the compounding quantity of a polymerization initiator, it is more preferable that it is 0.2-1 mass part.

<(C) Silica-based inorganic particles having an average particle diameter of 50 to 400 nm and a surface silanol group number of 5 / nm ² or less>
The dental curable composition of the present invention comprises (C) silica-based inorganic particles having an average particle diameter of 50 to 400 nm and a surface silanol group number of 5 / nm ² or less (hereinafter abbreviated as (C) silica-based inorganic particles) It will be. (C) The dental curable composition of the present invention has a bending strength of a cured product by including, as a filler, silica-based inorganic particles having an average particle diameter of 50 to 400 nm and a surface silanol group number of 5 / nm ² or less. It is possible to produce a cured product which is high, the strength reduction due to immersion in water is minimized, and the initial strength is maintained even under wet conditions.

<(C) Definition and Material of Silica-Based Inorganic Particles>
In the present invention, the silica-based inorganic particles are inorganic particles in which the amount of the silica component is 51 to 100 mol%, and silica is present at least in the outermost layer. The preferred amount of silica component is 80 to 100 mol%. As components other than silica, any inorganic particle component used as a known filler can be used. The composition ratio of the components other than silica and the components other than silica and silica may be appropriately selected depending on the purpose such as adjustment of refractive index, improvement of X-ray contrast property, and ion release property.

  The silica-based inorganic particles of the present invention are preferable in order to reduce the elution component from the cured product of the dental curable composition obtainable as silica and to enhance the water resistance. In particular, it is preferable that the amount of metal element components other than silica be small. Specifically, it is preferable that iron is less than 20 ppm, aluminum is less than 5 ppm, sodium is less than 3 ppm, and chlorine is less than 3 ppm. More preferably, iron is less than 1 ppm, aluminum is less than 1 ppm, sodium ions are less than 1 ppm, and chloride ions are less than 1 ppm. The measurement of the metal element component amount is performed by the following method. 2 g of the dried silica-based inorganic particle powder is precisely weighed and transferred to a platinum dish, and 10 ml of concentrated nitric acid and 10 ml of hydrofluoric acid are added in this order. This is placed on a hot plate set at 200 ° C. and heated to dry the contents. After cooling to room temperature, 2 mL of concentrated nitric acid is further added, and the solution is placed on a hot plate set at 200 ° C. and heated to dissolve. After cooling to room temperature, the solution which is the contents of the platinum dish is transferred to a 50 mL volumetric flask, diluted with ultrapure water, and brought to the marked line. Using this as a sample, the amount of metal element component is measured by an ICP emission analyzer.

<Particle diameter of (C) silica-based inorganic particles>
The average particle diameter of the (C) silica-based inorganic particles used in the dental curable composition of the present invention is 50 to 400 nm. By using the silica-based inorganic particles having such an average particle size, it is possible to produce a cured product in which the initial strength is maintained even under wet conditions. The more preferable range of the average particle size is 100 to 300 nm, and most preferably 150 to 200 nm. The particle size distribution is not particularly limited.

  The average particle diameter of the silica-based inorganic particles in the present invention refers to the equivalent circle diameter of the primary particles (the diameter of a circle having the same area as the target particles) from the photographed image of the scanning or transmission electron microscope. It means what was measured by image analysis. As an electron microscopic image used for measurement, one that can clearly distinguish light and dark and distinguish the contour of particle is used, and as a method of image analysis, an image capable of measuring at least the area of particle, maximum length of particle, and minimum width Perform using analysis software. Moreover, the average particle diameter of these primary particles is calculated by the following formula from the primary particle diameter measured by the above.

  When calculating these values, it is necessary to measure at least 40 particles or more in order to maintain measurement accuracy, and it is desirable to measure 100 particles or more.

<Specific surface area of (C) silica-based inorganic particles>
The specific surface area of the (C) silica-based inorganic particles used in the dental curable composition of the present invention is not particularly limited. Generally, the specific surface area changes depending on the particle size, and the larger the particle size, the smaller the specific surface area and the less the influence of deterioration due to the penetration of water, but the basic performance as a dental curable composition Since the surface lubricity which is one tends to decrease, it is preferable to be a silica-based inorganic particle having an appropriate specific surface area. The preferred specific surface area is 10 to 70 m ² / g, more preferably 13 to 37 m ² / g, and most preferably 19 to 26 m ² / g.

  The specific surface area of the (C) silica-based inorganic particles of the present invention can be measured using a BET specific surface area meter.

<Number of surface silanol groups on (C) silica-based inorganic particles>
The (C) silica-based inorganic particles used in the dental curable composition of the present invention have silanol groups on the surface, and the number of surface silanol groups is 5 / nm ² or less. By using such silica-based inorganic particles, it is possible to produce a cured product which maintains its initial strength even under wet conditions. The more preferable number of surface silanol groups is 1 to 4 / nm ² , and more preferably 2 to 3 / nm ² . The (C) silica-based inorganic particles of the present invention are preferably those which have been subjected to silane treatment with a silane coupling agent, but the number of surface silanol groups at this time is the (C) silica before surface treatment. The number of surface silanol groups present on the surface of the inorganic particles is meant.

  The number of surface silanol groups of the (C) silica-based inorganic particles of the present invention refers to a value measured by the Karl Fischer method. That is, the silica sample is left for 45 days in an atmosphere of 25 ° C. and 80% relative humidity. Thereafter, the sample is dried at 120 ° C. for 12 hours, the silica sample is dispersed in a methanol solvent, and the water content is measured using a Karl Fischer moisture meter (for example, “MKS-210 type” manufactured by Kyoto Denshi Kogyo Co., Ltd.) Titrate. As a titration reagent, for example, “HYDRANAL COMPOSITE 5K” (manufactured by Riedel-deHaen) is used. The number of surface silanol groups is calculated from the water content (% by mass) measured by the above-mentioned method according to the following method. That is, first, the number (number / g) of silanols per 1 g of silica is determined by the following equation.

Number of silanols per gram of silica (parts / g) = moisture content (mass%) x 0.01 x number of silanols to generate one water molecule (= 2) x Avogadro constant / molecular weight of water = water content (mass %) × 0.01 × 2 × 6.02 × 10 ²³ /18.0
= Moisture content (mass%) x 6.689 x 10 ²⁰

Next, the number of silanol groups per unit specific surface area (number / nm ² ; number of surface silanol groups) is determined from the number (number / g) of silanols per 1 g of the obtained silica according to the following formula.

Number of surface silanol groups (number / nm ² ) = water content (mass%) × 6.689 × 10 ²⁰ / (specific surface area (m ² / g) × 10 ¹⁸ )
= 668.9 x moisture content (wt%) / specific surface area (m ² / g)

<(C) Shape of Silica-Based Inorganic Particles>
As the shape of the (C) silica-based inorganic particles used in the dental curable composition of the present invention, known ones can be used without limitation. A variety of shapes such as spherical, approximately spherical, irregular shape, hemispherical, lens, concave, mushroom, aggregate, cluster, dimple, plate and fiber can be used. The specific surface area is small relative to the size of the silica-based inorganic particles, and the packing ratio of the (C) silica-based inorganic particles can be increased, and it is hard to be affected by the deterioration due to hydrolysis of the surface treatment, , It is preferable that it is substantially spherical shape. The term "substantially spherical shape" as used herein means that the average uniformity obtained by the following equation is 0.6 or more in the image analysis of the primary particles of the scanning or transmission electron microscopic image. The average uniformity is more preferably 0.7 or more, and still more preferably 0.8 or more.

  Here, the number (n) of the particles, the maximum length of the particles is the long diameter (Li), and the diameter in the direction orthogonal to the long diameter is the minimum width (Bi). When calculating these values, it is necessary to measure at least 40 particles or more in order to maintain measurement accuracy, and it is desirable to measure 100 particles or more.

  The (C) silica-based inorganic particles may be contained as organic-inorganic composite particles.

<(C) Method for producing silica-based inorganic particles>
The (C) silica-based inorganic particles of the present invention may be inorganic particles produced by any known method, but silica having an average particle diameter of 50 to 400 nm and a surface silanol group number of 5 pieces / nm ² or less The dry silica-based inorganic particles are preferably produced by a flame reaction method of a silicon compound because it is relatively easy to obtain the system-based inorganic particles. As a silicon compound, a siloxane compound (such as octamethyl cyclotetrasiloxane) can be used.

<(C) Surface treatment of silica-based inorganic particles>
The (C) silica-based inorganic particles of the present invention improve the wettability to the (A) polymerizable monomer to form a covalent bond with the polymerizable monomer, and increase the strength and decrease the strength after immersion in water It is preferable to surface-treat with a surface treatment agent in order to suppress As a surface treatment agent, a silane coupling agent is preferable. By performing the surface treatment using a silane coupling agent, the number of surface silanol groups on the (C) silica-based inorganic particles is further reduced.

  As the surface treating agent, conventionally known ones are used without any limitation. Examples of suitable surface treatment agents include vinyltriethoxysilane, vinyltrimethoxysilane, vinyl-tris (β-methoxyethoxy) silane, γ-methacryloyloxypropyltrimethoxysilane, κ-methacryloyloxydodecyltrimethoxysilane, β -(3,4-epoxycyclohexyl) -ethyltrimethoxysilane, γ-glycidoxypropyl-trimethoxysilane, N-β- (aminoethyl) -γ-aminopropyl-trimethoxysilane, γ-ureidopropyl-tri Silane coupling agents, such as an ethoxysilane, (gamma) -chloropropyl trimethoxysilane, a methyl trimethoxysilane, an ethyl trimethoxysilane, a methyl triethoxysilane, etc. are mentioned.

  There is no particular limitation on the amount of the surface treatment agent used for the surface treatment of the (C) silica-based inorganic particles of the present invention, and the optimum amount may be selected from the results of several preliminary experiments. If the amount is too large or too small, the strength after immersion in water may be reduced. If the usage-amount of a suitable surface treatment agent is illustrated, it is 1-30 mass parts of said surface treatment agents with respect to 100 mass parts of (C) silica type inorganic particle.

  The surface treatment method is not particularly limited, and known methods may be adopted without limitation. As an example of a typical treatment method, (C) silica-based inorganic particles and a surface treatment agent are dispersed and mixed in a suitable solvent using a ball mill or the like, and dried by a spray dryer, an evaporator, air-drying, etc. There is a method of heating to 50 to 150 ° C. Furthermore, there is a method of heating and refluxing (C) the silica-based inorganic particles and the surface treatment agent in a solvent such as alcohol for several hours. Furthermore, there is a method of graft polymerizing a surface treatment agent on the particle surface, a method of integral blending, and the like.

  The surface treatment may be performed on primary particles in the case of using agglomerated or cluster-like particles produced by aggregating inorganic particles as (C) silica-based inorganic particles and performing heat treatment or condensation treatment as necessary. And may be applied to the agglomerated particles. For example, in the case of producing agglomerated particles by spray drying, it is efficient to perform surface treatment simultaneously with this treatment. In particular, in the case of surface treatment using a silane coupling agent, the hydrolysis group such as alkoxysilane is surely hydrolyzed by using acid and alkali in combination, and then it is subjected to dehydration condensation reaction with the silanol group on the silica surface by heating. According to the invention, it is possible to produce a cured product having high flexural strength of the cured product of the dental curable composition of the present invention, minimizing the decrease in strength due to immersion in water, and maintaining initial strength even under wet conditions It is preferable in that

<(C) Compounding Amount of Silica-Based Inorganic Particles>
In the embodiment of the present invention, the blending amount of the (C) silica-based inorganic particles may be selected according to the purpose. Preferably it is 150-600 mass parts with respect to 100 mass parts of (A) polymerizable monomers. When used as a resin material for dental cutting, since the resin material for dental cutting is generally highly polymerized, the adhesion is poor, so that the silane coupling agent is likely to act, (C) Silica-based The compounding amount of the inorganic particles is preferably high. The amount is more preferably 200 to 500 parts by mass, and most preferably 300 to 450 parts by mass.

<Fillers other than (D) (C)>
(C) In addition to silica-based inorganic particles having an average particle diameter of 50 to 400 nm and a surface silanol group number of 5 / nm ² or less, other inorganic particles (average particle diameter less than 50 nm or over 400 nm) as a filler A silica-based inorganic particle, a surface-silanol group number includes a silica-based inorganic particle having a number of more than 5 / nm ² ), an organic particle, and an organic-inorganic composite particle including at least a filler other than (C) may be included. Fillers other than (D) and (C) enhance the mechanical strength of the dental curable composition, enhance the aesthetics, impart X-ray contrast and fluorine release properties, and improve the operability. And the like, to the extent that the effects of the present invention are not hindered. The compounding amount of the filler other than (D) and (C) is preferably 0 to 600 parts by mass, and more preferably 250 to 400 parts by mass with respect to 100 parts by mass of the polymerizable monomer (A). . A filler, which is the total of (C) silica-based inorganic particles and (D) (C), while the dental curable composition of the present invention contains a sufficient amount of a polymerizable monomer to give paste properties. The higher the content of B, the easier it is to obtain high bending strength.

<Other optional components>
The dental curable composition of the present invention has (A) a polymerizable monomer, (B) a polymerization initiator, and (C) an average particle diameter of 50 to 400 nm, and a surface silanol group number of 5 / nm ² or less. In addition to the filler other than the above (D) and (C), other optional components can be contained as optional components other than the silica-based inorganic particles. For example, polymerization inhibitors, chain transfer agents, fluorescent agents, ultraviolet light absorbers, antioxidants, pigments, antibacterial agents, X-ray contrast agents and the like can be mentioned. As these optional components, known ones used in dental curable compositions can be used.

<Method for Preparing Dental Curable Composition>
The preparation method of the dental hardenable composition of this invention can use a well-known method. In general, it can be obtained by sufficiently mixing a predetermined amount of each essential component and each optional component to be added if necessary, and further degassing the paste to remove air bubbles.

<Applications of the dental curable composition>
The use of the dental curable composition of the present invention is not particularly limited, and is suitably used for dental restorative materials and dental prostheses such as composite resins, hard resins, artificial teeth, cements, resin materials for cutting and the like. can do.

  The cured product of the dental curable composition of the present invention is obtained by polymerizing and curing the dental curable composition. The provided form may be a dental curable composition, such as a composite resin, hard resin, cement, etc., if the user shapes the shape in situ and polymerizes and hardens it by an appropriate polymerization method, and the dental cutting composition may be used. When a desired shape is formed by cutting from a block-like cured body as in a processing resin, the provided form may be a cured body of a dental curable composition.

<Resin based materials for dental cutting>
The cured product of the dental curable composition of the present invention has a high initial strength and is inhibited from being lowered in strength after immersion in water, so it is particularly suitable for use in dental materials where high strength is required. It is suitable as a resin-based material for dental cutting which is used. The cutting method is characterized in that even materials of high strength and hardness can be machined by mechanical cutting. Specifically, the resin material for dental machining of the present invention is suitable for dentures, dentures, artificial teeth, implant fixtures, abutments, upper structures, inlays, onlays, crowns, bridges, abutment construction materials, etc. It is suitable for use as a crown material and a bridge material because it can be used in particular, and in particular it can be used for high strength and high strength even after immersion in water.

  The size of the dental cutting resin material of the present invention is desirably processed to an appropriate size so that it can be set in a commercially available dental CAD / CAM system. Examples of desirable sizes are, for example, 40 mm × 20 mm × 15 mm prisms suitable for making a single-tooth defect bridge; 17 mm × 10 mm × 10 mm prisms suitable for making an inlay, onlay; suitable for making a full crown 14 mm × 18 mm × 20 mm, 10 mm × 12 mm × 15 mm or 14.5 mm × 14.5 mm × 18 mm prismatic; long span bridge, suitable for making denture base, diameter 90 to 100 mm, thickness 10 to 28 mm Although a disk shape etc. are mentioned, it is not limited to these sizes.

  The resin material for dental cutting of the present invention may be provided with a fixture for fixing to a cutting machine. The fixture is not particularly limited as long as it can be connected to a cutting machine. The material of the fixture is stainless steel, brass, aluminum or the like. The method of fixing the fixing tool to the resin material for dental cutting may be bonding, fitting, screwing, etc. There is no particular limitation on the above bonding method, and isocyanate type, epoxy type, urethane type, silicone type, acrylic Various commercially available adhesives such as a system can be used.

  There is no restriction | limiting in particular in the manufacturing method of the resin-type material for dental cutting from the dental curable composition of this invention, What is necessary is just to use a manufacturing method suitably according to the desired objective and the material to be used. For example, (A) a polymerizable monomer, (B) a polymerization initiator, (C) a silica-based inorganic particle, and an optional component are mixed, dissolved and dispersed by stirring and kneading, weighing, mold filling, defoaming, Perform operations such as shaping, perform temporary polymerization by heating and light as necessary, and then perform operations such as external energy application according to the initiation mechanism of the polymerization initiator (B), for example, using a thermal polymerization initiator In this case, polymerization and curing can be performed by heating or, if necessary, pressure heating with nitrogen or the like to produce a resin-based material for dental cutting. In addition, post-treatments such as polishing, surface drawing, printing, heat treatment and the like of the obtained resin-based material for dental cutting may be performed.

  The method for producing a machined product using the resin-based material for dental cutting according to the present invention will be described below.

  First, a dentist forms an abutment in the patient's mouth. For example, the abutment is formed by shaving the teeth. Next, an impression of the abutment, the adjacent teeth, the paired teeth, etc. is taken by the dentist. The impression is taken using an alginate-based impression material, a silicone-based impression material, a digital impression device or the like. Thereafter, a plaster model is produced from the obtained impression by a dental technician or dentist, and the shape of the plaster model is digitized using a scanning machine or the like. Alternatively, a digital model is created from data obtained by digital impression.

  Then, based on the measurement data of the gypsum model, digital data of the prosthesis is created using design software. Based on the digital data of the prosthesis, digital data for cutting with a cutting machine is created. Under the present circumstances, it is confirmed on software that preferably the to-be-cut part of the resin-type material for dental cutting of this invention has sufficient size with respect to the prosthesis to produce.

  Thereafter, the block of the resin-based material for dental cutting according to the present invention is installed in a cutting machine, and cutting is performed. It is preferred to use commercially available dental cutting machines. Cutting requires a cutting tool (bar) and cutting (CAM) software. The CAM software controls the movement of the cutting tool and the movement of the fixed block through the fixing tool, and representative parameters include position information, feed speed, and rotational speed. As a cutting tool, it is preferable to use a general dental cutting bar. It is preferable that a coating such as a diamond coat is applied to prevent wear. Generally, a cutting bar is used in combination of a plurality of cutting bars depending on the stage of cutting, such as for rough cutting, middle cutting, fine cutting, and the like. For simplicity, rough crown shapes are formed using rough cutting (for example, 2 mm diameter), and then surface properties are smoothed using fine cutting (for example, 0.8 mm diameter), or fine surfaces such as occlusal surfaces etc. To express a simple structure. When cutting by the cutting machine is completed, the portion connecting the dental cutting block main body and the object to be cut is cut to recover the object to be cut. At this time, the burr remaining on the workpiece side is removed. After shape correction and polishing, pretreatment of the inner surface of the prosthesis (roughing by sand blasting or the like) is performed as necessary. The prosthesis thus produced is adhered to a support in the patient's oral cavity after pretreatment of the inner surface (primer application, etc.) is carried out as required.

  Hereinafter, the present invention will be more specifically described by way of examples, but the present invention is not limited to these examples. The materials, test methods, etc. used in the examples and comparative examples are shown below.

<(A) Polymerizable monomer>
UDMA: 1,6-bis (methacrylicethyloxycarbonylamino) -trimethylhexane TEGDMA: triethylene glycol dimethacrylate HD: 1,6-hexanediol dimethacrylate

<(B) polymerization initiator>
BPO: benzoyl peroxide

<(C) Silica-based inorganic particles>
(C-1) Spherical silica (Silfil NSS-3N manufactured by Tokuyama, average particle size 125 nm, surface silanol group number 2 / nm ² , specific surface area 30 m ² / g, amount of 5 μm or more <0.) By flame reaction method of silicon compound 01%, particle size distribution 10-300 nm, average uniformity 0.9, Fe <1 ppm, Al <1 ppm, Na ⁺ <1 ppm, Cl ⁻ <1 ppm, U <0.1 ppb) of γ-methacryloyloxypropyltrimethoxysilane Processed material.

(C-2) Spherical silica (average particle diameter 240 nm, surface silanol group number 2 / nm ² , specific surface area 18 m ² / g, amount of 5 μm or more <0.01%, average uniformity 0) by flame reaction method of silicon compound .9, [gamma] -methacryloyloxypropyltrimethoxysilane-treated product of Fe <1 ppm, Al <1 ppm, Na ⁺ <1 ppm, Cl < ^- <1 ppm, U <0.1 ppb).

(C-3) Spherical silica (Silfil NSS-5N manufactured by Tokuyama, average particle diameter 70 nm, surface silanol group number 5 / nm ² , specific surface area 50 m ² / g, amount of 5 μm or more <0.) By flame reaction method of silicon compound 01%, particle size distribution 10 to 120 nm, average uniformity 0.9, Fe <1 ppm, Al <1 ppm, Na ⁺ <1 ppm, Cl ⁻ <1 ppm, U <0.1 ppb) of γ-methacryloyloxypropyltrimethoxysilane Processed material.

(C-4) Spherical silica (average particle diameter 360 nm, surface silanol group number 2 / nm ² , specific surface area 11 m ² / g, amount of 2 μm or more <0.01%, average uniformity 0) by flame reaction method of silicon compound .9, [gamma] -methacryloyloxypropyltrimethoxysilane-treated product of Fe <1 ppm, Al <1 ppm, Na ⁺ <1 ppm, Cl < ^- <1 ppm, U <0.1 ppb).

(C-5) Spherical silica (Silfil NSS-3N manufactured by Tokuyama, average particle diameter 125 nm, surface silanol group number 2 / nm ² , specific surface area 30 m ² / g, amount of 5 μm or more <0.) By flame reaction method of silicon compound 01%, particle size distribution 10-300 nm, average uniformity 0.9, Fe <1 ppm, Al <1 ppm, Na ⁺ <1 ppm, Cl ⁻ <1 ppm, U <0.1 ppb) in aqueous dispersion Cured by mixing and dissolving 100 parts by mass of UDMA and 0.5 parts by mass of BPO in the aggregate obtained by adding an acetic acid hydrolyzate of roxypropyltrimethoxysilane, drying by spray drying and drying by a vacuum dryer at 80 ° C. for 15 hours Part is impregnated with 17 parts by mass with respect to 100 parts by mass of an aggregate, and heated at 120 ° C. for 2 hours to polymerize and cure, and an organic having an average particle diameter of 12 microns Aircraft composite particles.

<Fillers other than (D) (C)>
(D-1) Amorphous silica-zirconia according to sol-gel method (zirconia content: 15 mol%, average particle diameter: 3.5 microns, surface silanol group number 6 / nm ² , specific surface area: 3.5 m ² / g, particle size distribution 0. 3 to 10 microns) of [gamma] -methacryloyloxypropyl trimethoxysilane treated product.

(D-2) γ-methacryloyloxypropyltrimethoxysilane-treated spherical silica (average particle diameter 125 nm, surface silanol group number 8 / nm ² , specific surface area 30 m ² / g) by sol-gel method.

(Average particle size of inorganic particles)
Take a photograph of inorganic particles at a magnification of 5000 to 100000 times with a scanning electron microscope ("Phillips", "XL-30S"), and use image analysis software ("IP-1000PC", trade name; manufactured by Asahi Kasei Engineering Co., Ltd.) And process the photographed image, measure the number (100 or more) of particles observed in the unit field of view of the photograph, and the equivalent circle diameter of the primary particles, and calculate the average particle diameter according to the above equation based on the measured value. Calculated.

(Number of surface silanol groups)
The sample was left for 45 days in an atmosphere of 25 ° C. and 80% relative humidity. Thereafter, the sample was dried at 120 ° C. for 12 hours, then the silica sample was dispersed in a methanol solvent, and the water content was titrated using a Karl Fischer moisture meter (MKS-210 type manufactured by Kyoto Denshi Kogyo Co., Ltd.). HYDRANAL COMPOSITE 5K (manufactured by Riedel-deHaen) was used as a titration reagent. The amount of surface silanol groups was calculated from the water content (mass%) measured by the above method, according to the following equation.
Number of surface silanol groups (number / nm ² ) = 668.9 × water content (wt%) / specific surface area (m ² / g)

(surface treatment)
A 20 g sample was dispersed in 40 ml of ion-exchanged water using a wet disperser to obtain a dispersion. Silane coupling agent γ-methacryloyloxypropyltrimethoxysilane was weighed in an amount yg calculated based on the following formula, and hydrolyzed in 100 mL of acetic acid adjusted to pH 4.0 for 2 hours.

Amount of silane coupling agent used: y (g) = 20 (g) x X / Y
X: specific surface area of composite oxide particles (m ² / g)
Y: Minimum coverage area of silane coupling agent (m ² / g)

  The silane coupling agent hydrolyzate was mixed with the above dispersion and stirred for 1 hour. After stirring, water was removed by a spray dryer, and the obtained white powder was dried at 80 ° C. under vacuum for 15 hours for surface treatment.

(Bending test)
From the cured product of the dental curable composition, 20 pieces of 1.2 mm × 4.0 mm × 18 mm test pieces were cut out, and each side of the test pieces was finished with a P2000 water-resistant abrasive paper. About ten of the produced test pieces, they were used as the test pieces before immersion in water. The remaining 10 pieces were immersed in purified water, stored in a 37 ° C. thermostat for 7 days, and used as specimens after immersion in water.

  Three-point bending test on a 4.0 mm × 18 mm surface under the conditions of 12.0 mm distance between supporting points and a crosshead speed of 1.0 mm / min in room temperature air using a universal testing machine autograph (manufactured by Shimadzu Corporation) Did. The bending strength [MPa] was calculated from the following equation for each of ten test pieces before and after immersion in water, and was determined as an average value.

Flexural strength [MPa] = 3 FS / ( ² bh ² )
Where F: maximum load applied to the test piece [N], S: distance between supporting points [mm], b: width of the test piece measured immediately before the test [mm], h: test piece measured immediately before the test Thickness [mm].

  From the determined flexural strength, the ratio of the flexural strength to the initial flexural strength (bending strength ratio) after 7 days of immersion in water at 37 ° C. was calculated.

Example 1
A curable polymerizable monomer composition was prepared by mixing 80 parts by mass of UDMA, 20 parts by mass of TEGDMA, and 0.5 parts by mass of BPO. To 100 parts by mass of the above curable polymerizable monomer composition, 230 parts by mass of (C-1) is added, and mixing is carried out until uniform using a planetary mixer to form a paste and vacuum degassing A dental hardenable composition was prepared. This dental curable composition is filled in a 14.5 mm × 14.5 mm × 18 mm mold and polymerized and cured by heating at 120 ° C. for 2 hours under 0.4 MPa nitrogen pressure to obtain a dental curable composition A cured product was obtained and subjected to a bending test. The results of the bending test are shown in Table 2.

(Examples 2 to 7)
The same as in Example 1 except that the used filler (A), the polymerizable monomer (C), the silica-based inorganic particles, and the filler other than (D) and (C) are changed to those described in Table 1 and the blending ratio. A cured product was produced by the method and subjected to a bending test. The results are shown in Table 2.

(Comparative example 1)
A cured product was produced in the same manner as in Example 1 except that the used (A) polymerizable monomer and (C) silica-based inorganic particles were changed to those shown in Table 1 and the compounding ratio, and a bending test was conducted. Did. The results are shown in Table 2.

Claims (5)

Dental curing comprising (A) polymerizable monomer, (B) polymerization initiator, and (C) silica-based inorganic particles having an average particle diameter of 50 to 400 nm and a surface silanol group number of 5 / nm ² or less Sex composition. (A) 0.1 to 10 parts by mass of (B) polymerization initiator, (C) 150 to 600 parts by mass of silica-based inorganic particles, (D) fillers other than (C) with respect to 100 parts by mass of the polymerizable monomer The dental curable composition according to claim 1, which is 0 to 600 parts by mass. A cured product of the dental curable composition according to any one of claims 1 to 2. A dental hardenable composition for producing a resin-based material for dental cutting comprising the dental hardenable composition according to claim 1. A resin-based material for dental cutting comprising a cured product of a dental hardenable composition for producing the resin-based material for dental cutting according to claim 4.