JP2019116471A - Dental resin composition and resin block for dental cutting consisting of the same - Google Patents

Abstract

To provide dental resin compositions that have high strength and such a high surface hardness as to be able to withstand intraoral abrasion, and are aesthetic.SOLUTION: The present invention provides a dental resin composition comprising resin matrix, and 25 to 1000 parts by mass of inorganic filler with respect to 100 parts by mass of resin matrices, the resin matrix of the dental resin composition consisting of polyurethane, the inorganic fillers having an average particle diameter of 0.001 to 100 μm, a method of producing the dental resin composition, and a resin block for dental cutting consisting of the dental resin composition.SELECTED DRAWING: None

Description

  The present invention relates to a dental resin composition that can be suitably used in a resin-based block for dental cutting for producing a dental prosthesis by cutting.

  In dental treatment, there is a method of cutting using a dental CAD / CAM system as one method of producing a dental prosthesis such as inlay, onlay, crown, bridge, and implant superstructure. The dental 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 or the like. As materials for cutting, various materials such as glass ceramics, zirconia, titanium and resin are used. As a resin-based material for dental cutting, a block shape, a disc obtained by curing a curable composition containing an inorganic filler such as silica, a polymerizable monomer such as methacrylate resin, a polymerization initiator and the like Cured products such as shapes are provided. Resin-based materials for dental cutting are of increasing interest in terms of their high workability, aesthetics and strength.

  Such a resin-based material for dental cutting is applied in the crown portion, and when used as a molar or a bridge, higher strength is required. However, current resin materials for dental cutting are based on (meth) acrylic resin, and their strength is limited. For example, in Patent Document 1, 15 to 70 parts by weight of a (meth) acrylic polymerizable monomer, 30 to 85 parts by weight of a 0.9 .mu.m and 5 to 7 .mu.m silica filler, and a catalyst etc. are blended. Although resin materials are disclosed, their flexural strength is not sufficient.

  Patent Document 2 discloses a dental composition comprising a polyamide used as a mill blank. However, since the polyamide is opaque, it is insufficient in aesthetics for use in dental treatment. Moreover, there existed a subject that it was inferior to cutting processability.

  On the other hand, polyurethane resins are generally known to have high strength. For example, Patent Document 3 discloses a polyurethane resin comprising an isocyanate having a norbornane skeleton, a polyol having two or more hydroxy groups or thiol groups in one molecule, or a polythiol.

Unexamined-Japanese-Patent No. 2016-13997 JP-A-2017-48121 Japanese Patent Application Publication No. 2007-191598

  An object of the present invention is to provide a dental resin composition having high strength and high surface hardness that can withstand abrasion in the oral cavity and which is aesthetic.

  As a result of various investigations by the present inventor, the polyurethane resin has a soft resin hardness on the surface and does not have a strength that can withstand abrasion with an intraoral tooth. In addition, it was found that there is a problem that the resin is easily seized and the like, and the machinability and the abradability are inferior. As a result of conducting various studies in order to solve the above problems, a dental resin composition having higher strength, higher surface hardness, and excellent aesthetics is provided by blending an inorganic filler with a polyurethane matrix. I found that it was possible.

  That is, the present invention provides a dental resin composition comprising 25 parts by mass to 1000 parts by mass of the inorganic filler with respect to 100 parts by mass of the resin matrix, and the resin matrix of the dental resin composition is made of polyurethane. The dental resin composition, wherein the inorganic filler has an average particle size of 0.001 to 100 μm.

  The polyurethane constituting the resin matrix comprises an isocyanate compound having two or more isocyanate groups in one molecule, a polyol compound having two or more hydroxy groups in one molecule, or two or more thiol groups in one molecule. It is preferable that it is a polyurethane produced | generated by polyaddition with the polythiol compound which it has.

  The inorganic filler is preferably silica, alumina, titania, zirconia, or a composite thereof.

  Another invention of the present invention is a composition containing an isocyanate compound and a polyol compound or a polythiol compound separately, compounding an inorganic filler in one or both of the compositions, and a composition containing an isocyanate compound After preparing a composition (b) containing a) and a polyol compound or a polythiol compound, the compositions (a) and (b) are mixed to prepare a curable composition, and the dental resin composition to be reacted Manufacturing method.

  Moreover, it is a resin system block for dental cutting which consists of said resin composition for dental treatment.

  The dental resin composition of the present invention has high strength and high surface hardness that can withstand abrasion in the oral cavity, and has high transparency, and is made of the dental resin composition of the present invention. The resin-based block for dental cutting has high strength and can withstand abrasion in the oral cavity, and can produce an aesthetic dental prosthesis. Furthermore, the dental resin composition of the present invention is excellent in machinability, and the dental cutting resin-based block made of the dental resin composition of the present invention can be easily manufactured into a dental prosthesis.

  The dental resin composition of the present invention is a dental resin composition having high strength and high surface hardness that can withstand abrasion in the oral cavity, and having high transparency, and is made of a resin matrix comprising polyurethane. And an inorganic filler.

  The resin matrix, which is one component of the resin composition of the present invention, comprises a polyurethane produced by polyaddition, which is produced by polyaddition from an isocyanate compound and a polyol compound or a polythiol compound.

(A) Isocyanate Compound In the present invention, the isocyanate compound is a compound having two or more isocyanate groups in one molecule, and the isocyanate compound is a compound having two or more isocyanate groups in one molecule. There is no particular limitation, and any known ones can be used in any combination. Specific examples of the isocyanate compound include the following.

(A1) Bifunctional Isocyanate Compound 1,3-Bis (2-isocyanato-2-propyl) benzene, 2,2-Bis (4-isocyanatophenyl) hexafluoropropane, 1,3-Bis (isocyanatomethyl) cyclohexane 4,4,4'-methylene diisocyanate, 3,3'-dichloro-4,4'-diisocyanatobiphenyl, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, dicyclohexylmethane 4,4'- Diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, norbornane diisocyanate, isophorone diisocyanate, 1,5-diisocyanatonaphthalene, 1,3-phenylene diisocyanate, trimethylhexamethylene diisocyanate, tolylene-2,4-diisocyanate And tolylene-2,6-diisocyanate, m-xylylene diisocyanate and the like.

(A2) Trifunctional or Higher Functional Isocyanate Compound: lysine triisocyanate, 4,4 ′, 4 ′ ′-methylidine tris (isocyanatobenzene), polymethylene polyphenyl polyisocyanate, etc. can be mentioned.

  The above isocyanate compounds can be used alone or in combination.

(B) Polyol Compound or Polythiol Compound The polyol compound or the polythiol compound is not particularly limited as long as it is a compound having two or more hydroxy groups or thiol groups in one molecule, and known compounds may be freely combined. Can be used. Specific examples of the polyol compound or the polythiol compound include the following.

(B1) Bifunctional polyol compound α, ω-alkanediol (ethylene glycol, 1,3-propanediol etc.), 1,2-propanediol, 1,3-adamantanediol, 2,3-butanediol, 2-butene 1,4-diol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10 -Tetraoxaspiro [5.5] undecane, 1,3-bis (hexafluoro-α-hydroxyisopropyl) benzene, bis [3,5-dibromo-4- (2-hydroxyethoxy) phenyl] sulfone, bis [4 -(2-hydroxyethoxy) phenyl] sulfone, 4,4'-bicyclohexanol, 2,2'-bis (hydroxymethyl) diphenyl Nil ether, 1,8-bis (hydroxymethyl) anthracene, 2-benzyloxy-1,3-propanediol, 4,4'-biphenyldimethanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, 1 2,3-cyclohexanediol, 1,3-cyclopentanediol, 2,5-dimethyl-2,5-hexanediol, 3,7-dithia-1,9-nonanediol, 2,2,3,3,4, 4,5,5,6,6,7,7-dodecafluoro-1,8-octanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, tricyclodecanedimethanol, 1, 2-benzenedimethanol, glycerol mono (meth) acrylate, bisphenol A diglycidyl di (meth) acrylate, trimethylo Le propane mono (meth) acrylate, polyether polyols such as polyethylene glycol and polytetramethylene glycol, polyester polyols such as polycaprolactone polyol and polyethylene 1,6-hexamethylene adipate diol, and polycarbonate diol.

(B2) Bifunctional polythiol compound α, ω-alkanedithiol (1,4-butanedithiol, 1,10-decanedithiol etc.), 2,3-butanedithiol, 1,4-butanediol bis (thioglycollate), 3,6-dioxa-1,8-octanedithiol, 3,7-dithia-1,9-nonane dithiol, ethylene bis (thioglycollate), ethylene glycol bis (3-mercaptopropionate), 1,4- Bis (3-mercaptobutyryloxy) butane and the like can be mentioned.

(B3) Trifunctional Polyol Compounds Trimethylolethane, trimethylolpropane, glycerin, trimethylolpropane ethoxylate, glycerol tripropoxylate, 1,3,5-adamantanetriol, tris (2-hydroxyethyl) isocyanurate, etc. Can.

(B4) Trifunctional Polythiol Compounds Trimethylolpropane tris (thioglycollate), trimethylolpropane tris (3-mercaptopropionate), trimethylolpropane tris (3-mercaptobutyrate), trimethylolethane tris (3-mercapto) And butyrate), 1,3,5-tris (3-mercaptobutyryloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione and the like.

(B5) Polyol compound having four or more functions: Pentaerythritol, ditrimethylol ethane, pentaerythritol ethoxylate, pentaerythritol propoxylate, ditrimethylol propane, dipentaerythritol, sugar alcohols such as sorbitol, saccharides such as sucrose, and hydroxy group-containing polyrotaxane And the like.

(B6) Tetrafunctional or higher polythiol compound pentaerythritol tetra (3-mercaptopropionate), pentaerythritol tetrakis (mercaptoacetate), dipentaerythritol hexakis (3-mercaptopropionate), pentaerythritol tetrakis (3- Mercaptobutyrate etc. can be mentioned.

  The above-mentioned polyol compounds or polythiol compounds may be used alone or in combination or in combination with each other. When a polyol compound and a polythiol compound are used in combination, the refractive index of the dental resin composition of the present invention can be easily adjusted, and the transparency can be adjusted.

  From the viewpoint of odor, it is preferable to use a polyol compound as the above-mentioned polyol compound or polythiol compound.

  The isocyanate compound, and the polyol compound or the polythiol compound are preferably liquid at normal temperature and pressure when they are individually or mixed, for ease of handling.

  As specific (A) isocyanate compounds which are liquid alone, pentamethylene diisocyanate, hexamethylene diisocyanate, norbornane diisocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6- Diisocyanate, m-xylylene diisocyanate, polymethylene polyphenyl polyisocyanate and the like can be mentioned.

  As a specific (B) polyol compound or polythiol compound which is liquid alone, 1,2-propanediol, 1,3-adamantanediol, neopentyl glycol, tricyclodecanedimethanol, trimethylolpropane mono (meth) Acrylate, polyether polyol having a number average molecular weight of 1000 or less, polyester polyol having a number average molecular weight of 1000 or less, polycarbonate diol having a number average molecular weight of 800 or less, ethylene bis (thioglycollate), ethylene glycol bis (3-mercaptopropionate), Glycerin, trimethylolpropane ethoxylate, glycerol tripropoxylate, trimethylolpropane tris (thioglycollate), trimethylolpropane tris (3-mercaptopropioner ), Pentaerythritol ethoxylate, pentaerythritol propoxylate, pentaerythritol tetrakis (3-mercapto butyrate), dipentaerythritol hexakis (3-mercaptopropionate) and the like.

  The use ratio of (A) the isocyanate compound and (B) the polyol compound or the polythiol compound is (A) the average number of functional groups of the isocyanate group in the isocyanate compound is A, the number of moles of the isocyanate compound is C mole, (B) the polyol compound Or (A × C) / (B × D) is usually 0.5, where B is the average functional group number of hydroxy groups or thiol groups of the polythiol compound, and D moles of the polyol compound or polythiol compound. It is in the range of -3.0, preferably in the range of 0.5 to 2.0, more preferably in the range of 0.5 to 1.5.

  The isocyanate compound and the polyol compound or the polythiol compound may be pre-reacted and prepolymerized in order to facilitate handling and to reduce shrinkage upon curing.

  The isocyanate compound and the polyol compound or the polythiol compound are preferably those having a chemical crosslinking structure in the polyurethane after the reaction in order to make the strength of the dental resin composition sufficient. That is, when the average number of functional groups of isocyanate groups per molecule in the isocyanate compound is A, and the average number of functional groups of hydroxyl groups or thiol groups of one molecule of a polyol compound or polythiol compound is B, (A + B) It is preferable that /2≧2.5, and more preferably (A + B) /2≧3.0.

(C) Monofunctional Isocyanate Compound, Alcohol Compound, Thiol Compound Also, monofunctional isocyanate compound, alcohol compound, or thiol compound may be added for the purpose of imparting functionality to the resin composition after reaction. It is possible. However, from the viewpoint of the strength of the resin composition, the addition amount thereof is preferably 10% by mass or less in each compound. Specific examples of the isocyanate compound, alcohol or thiol compound include the following.

(C1) Isocyanate compound 2-isocyanatoethyl (meth) acrylate, 3-isocyanatopropyltriethoxysilane, 2-isocyanatodiethylene glycol (meth) acrylate, 1,1- (bisacryloyloxymethyl) ethyl isocyanate, etc. it can.

(C2) Alcohol Compound Hydroxyl (meth) acrylate, hydroxyethyl (meth) acrylamide, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate and the like can be mentioned.

(C3) Thiol Compound Mercaptoethyl (meth) acrylate, mercaptoethyl (meth) acrylamide, 3-mercaptopropyltrimethoxysilane and the like can be mentioned.

  Moreover, it is preferable to make the structure of chemical crosslinking by the said isocyanate compound, and a polyol compound or a polythiol compound more dense. That is, it is preferable that the molecular weight per functional group be smaller. When the average molecular weight of the isocyanate compound is M1, and the average molecular weight of the polyol compound or the polythiol compound is M2, M1 / A <200 and M2 / B <300 are preferable, and M1 / A <100 and It is more preferable that M2 / B <200.

  An inorganic filler is mix | blended from a viewpoint of the improvement of the mechanical strength of the dental resin composition of this invention, an abrasion resistance improvement, etc. As the filler, an inorganic filler such as inorganic particles is used.

  As such an inorganic filler, it is preferable to consist of inorganic particles such as silica, alumina, titania, zirconia or composites thereof, and glass. When an inorganic salt (for example, calcium carbonate or the like) is used as the inorganic filler, there is a possibility of dissolution in the intraoral environment, which is not preferable as the dental resin composition of the present invention. The inorganic filler may be blended as organic-inorganic composite particles. The organic-inorganic composite particles referred to herein are materials obtained by combining the above-mentioned inorganic particles and an organic resin.

  Specific examples of the inorganic particles include spherical particles or irregularly shaped particles such as amorphous silica, silica-zirconia, silica-titania, silica-titania-zirconia, quartz and alumina.

  As the organic resin used for the organic-inorganic composite particles, known ones can be used without limitation. Specifically, (meth) acrylic resin, urethane resin, urea resin, epoxy resin, polycarbonate resin, polyamide resin, polyester etc. may be mentioned, but from the viewpoint of strength and aesthetics, (meth) acrylic resin, urethane It is preferable that it is resin, a urea resin, and an epoxy resin.

  From the viewpoint of aesthetics, the refractive index of the inorganic filler in the present invention is preferably closer to the refractive index of polyurethane that is a resin matrix. Specifically, the refractive index of the inorganic filler is preferably 1.2 to 1.8, and more preferably 1.4 to 1.6. Specific examples of the inorganic filler include amorphous silica, silica-zirconia, silica-titania, silica-titania-zirconia, quartz and the like. The transparency of the dental resin composition can be adjusted to be opaque by blending a pigment, specifically, a white pigment such as zinc oxide or titanium oxide. Therefore, having the pigment transparent in the unblended state can be freely adjusted to the desired transparency, and a prosthesis with excellent aesthetics can be obtained. Moreover, as a preferable range of the transparency of the dental resin composition, if it is in the range of 0.1 to 0.6, more preferably in the range of 0.2 to 0.5, the enamel which is transparent and relatively relatively Adjustment in the range which expresses the two layers of dentine which is opaque from one hardening composition is possible, and a prosthesis excellent in aesthetics can be obtained.

  The inorganic filler is particularly preferably in the form of a sphere since a resin composition having particularly excellent abrasion resistance, surface lubricity and gloss retention can be obtained. The term “spherical shape” as used herein means that the average uniformity obtained in image analysis of a photographed image of a scanning or transmission type electron microscope is 0.6 or more. The average uniformity is more preferably 0.7 or more, and still more preferably 0.8 or more. The average uniformity is the number (n) of particles, the major diameter (Li) which is the maximum diameter of particles, and the minor diameter (Bi) which is the diameter orthogonal to the major diameter in image analysis of photographed images of scanning or transmission type electron microscopes. ) Was calculated by the following equation.

  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 average particle diameter of the filler is preferably 0.001 to 100 μm, and more preferably 0.01 to 20 μm from the viewpoints of abrasion resistance, surface lubricity, and gloss maintenance.

  The filler is preferably surface-treated to improve compatibility with the matrix of the isocyanate compound and the polyol compound or the polythiol compound and to improve the mechanical strength and water resistance. As a surface treatment agent, a silane coupling agent is generally used, and particularly in the case of a filler based on an inorganic particle based on silica, the effect of the surface treatment with the silane coupling agent is high. The surface treatment may be carried out by a known method, and as a silane coupling agent, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-glycidoxypropyl Trimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) -3- Aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- Aminopropyltriethoxy Down, 3-mercaptopropyltrimethoxysilane, and 3-isocyanate propyl triethoxysilane is preferably used. The above silane coupling agents can be used alone or in combination of two or more.

  In the embodiment of the present invention, the blending amount of the filler is a ratio of 25 to 1000 parts by mass, preferably 60 to 600 parts by mass with respect to 100 parts by mass of the resin matrix.

  The dental resin composition of the present invention may contain fillers other than the inorganic filler according to the purpose. Specifically, organic particles such as polymethyl methacrylate particles and polyethyl methacrylate particles and hyperbranched polymers, and organic fibers such as cellulose fibers and carbon nanofibers can be mentioned.

  The dental resin composition of the present invention may further contain other optional components. For example, fluorescent agents, ultraviolet light absorbers, antioxidants, pigments, antibacterial agents, X-ray contrast agents and the like can be mentioned.

  In the method for producing a dental resin composition of the present invention, it is preferable to use cast polymerization. Specifically, a step of preparing a curable composition comprising an isocyanate compound, a polyol compound or a polythiol compound, and an inorganic filler, and a step of polymerizing and curing the curable composition after molding it into a mold. , At least.

  In the step of preparing the curable composition, after mixing the isocyanate compound, the polyol compound and the polythiol compound in advance, a method (method 1) of preparing the curable composition by blending an inorganic filler may be used. A composition separately containing an isocyanate compound and a polyol compound or a polythiol compound, an inorganic filler blended in one or both of the compositions, and a composition (a) containing an isocyanate compound and a polyol compound or After the composition (b) containing the polythiol compound is prepared, a method (method 2) of preparing the curable composition by mixing the compositions (a) and (b) may be used. It is preferable to use method 2 from the viewpoint of the reactivity of the isocyanate compound and the polyol compound or the polythiol compound.

  In the method 1, in the step of mixing the isocyanate compound and the polyol compound or the polythiol compound, the average functional group number of the isocyanate group in the isocyanate compound is A, the hydroxy group of the polyol compound or polythiol compound, or the average functional group of the thiol group Assuming that the number of groups is B, the number of moles of isocyanate compound is C mole, and the number of moles of alcohol or thiol compound is D mole, (A × C) / (B × D) is 0.5 to 2.0. The range is preferably, and more preferably 0.5 to 1.5.

  The method of mixing the isocyanate compound, the polyol compound or the polythiol compound in advance is not particularly limited, and the isocyanate compound, the polyol compound or the polythiol compound is added, and mixed uniformly using a magnetic stirrer, a stirring blade, a centrifugal mixer, etc. The method of stirring and mixing etc. are used. The method of mixing the obtained mixture with the inorganic filler to form a curable composition is also not particularly limited, but the inorganic filler is added to the mixed isocyanate compound, polyol compound or polythiol compound, and the liquiing machine, planetary mixer The curable composition may be prepared by mixing using a centrifugal mixer or the like. The curable composition thus prepared is preferably defoamed to remove air bubbles contained therein prior to polymerization and curing. As a method of degassing, known methods are used, and methods such as pressure degassing, vacuum degassing, centrifugal degassing and the like can be optionally used.

  In Method 2, the average number of functional groups of isocyanate groups in the composition (a) containing an isocyanate compound is A, and the average number of functional groups of hydroxy groups or thiol groups in the composition (b) containing a polyol compound or a polythiol compound is B When the number of moles of isocyanate groups in the composition (a) containing an isocyanate compound is C, and the number of moles of hydroxy groups or thiol groups in the composition (b) containing a polyol compound or a polythiol compound is D moles, A × C) / (B × D) is preferably in the range of 0.5 to 2.0, and more preferably 0.5 to 1.5.

  The method of mixing the inorganic filler with the isocyanate compound, the polyol compound or the polythiol compound is not limited, and the compositions (a) and (b) are prepared by mixing using a liquifier, a planetary mixer, a centrifugal mixer, etc. You may In the compositions (a) and (b) prepared in this manner, it is preferable to eliminate air bubbles contained therein by degassing before mixing the two. As a method of degassing, known methods are used, and methods such as pressure degassing, vacuum degassing, centrifugal degassing and the like can be optionally used.

  In the composition (a) containing an isocyanate compound and the composition (b) containing a polyol compound or a polythiol compound, the composition (a) and (b) is used for the purpose of uniform mixing in the mixing step. It is preferable to keep the viscosity close. A composition (a) containing an isocyanate compound and a composition containing a polyol compound or a polythiol compound (because the viscosity of the compositions (a) and (b) can be easily brought close and they can be uniformly mixed. It is preferable to mix | blend an inorganic filler with both b).

  There is no particular limitation on the method of preparing a curable composition by mixing the composition (a) containing an isocyanate compound and the composition (b) containing a polyol compound or a polythiol compound, but the mixing of bubbles and the like is prevented. Preferably, a mixing device such as a static mixer is used.

  In the present invention, in order to polymerize and harden the curable composition obtained above into a desired shape, it is preferable to use cast polymerization for filling the mold and then performing polymerization and curing. A mold having a desired shape may be prepared, the curable composition may be filled into the inside of the mold, and polymerization curing may be performed, or filling into a mold having a larger size than desired and polymerization curing to obtain a bulk body It may be manufactured, and punching, cutting, etc. may be performed to obtain a desired shape. Similarly, the shape of the mold may be a prism, a cylinder, a square plate, or a disc, and is not particularly limited.

  When the curable composition is polymerized and cured, the dental resin composition may be obtained by heat curing. In addition, a polymerization catalyst may be added to the curable composition. As a polymerization catalyst, a known polymerization catalyst for producing polyurethane by polyaddition is not particularly limited, and can be used. Specifically, tin catalysts such as dibutyltin laurate, amine catalysts such as triethylenediamine, and the like can be mentioned. These polymerization catalysts may be used alone or in combination of two or more. In the method 2, the polymerization catalyst may be added to any of the compositions (a) and (b), or may be added to both of them.

  In the curable composition for producing the dental resin composition of the present invention, the curing temperature is controlled at the time of polymerization curing in order to generate heat when the isocyanate group and the hydroxy group or the thiol group react with each other. Is preferred. Moreover, it is preferable to heat at 80 degreeC or more in order to advance reaction sufficiently.

  In the polymerization and curing step, pressure may be applied to suppress the generation of air bubbles in the dental resin composition of the present invention. The method of pressurization is not limited, and mechanical pressurization may be performed, or pressurization with a gas such as nitrogen may be performed.

  Any post-process may be performed after the above-mentioned heat polymerization process. For example, heat treatment for relieving the residual stress of the obtained dental resin composition, cutting for correction to a required shape or a more convenient shape, or processing such as polishing may be performed.

  The dental resin composition thus produced can be used as a resin-based block for dental cutting by bonding fixtures such as pins for holding to a CAD / CAM device as necessary. A crown restoration can be obtained by connecting this to a CAD / CAM device and performing cutting based on the design.

  Although the Example and comparative example regarding this invention are shown below, this invention is not limited to this Example.

  Bending strength evaluation, surface hardness evaluation, cutting processability evaluation, and transparency evaluation for samples of Examples and Comparative Examples described later are as follows.

1. Bending Strength Evaluation A dental resin composition obtained by the method described later is cut out with a low speed diamond cutter (manufactured by Buehler), and a # 800 water resistant abrasive paper is used to measure a corner of 1.0 mm × 3.0 mm × 18 mm. Test pieces were obtained by arranging in a column shape. The test piece was attached to an autograph (manufactured by Shimadzu Corporation), and a 3-point bending test was performed under the conditions of a distance between supporting points of 14 mm and a crosshead speed of 1 mm / min.

  The bending strength σ was calculated by the following equation (1). In addition, ten pieces of the test pieces were prepared for each of the example and the comparative example, and the average value was used as the bending strength of the dental resin composition. The flexural strength of these dental resin compositions is shown in Table 2 below.

σ = 3 PS / ² WB ² Equation (1)
P: bending load at the maximum point (N), S: distance between supporting points (14 mm), W: width (3.0 mm), B: thickness (1.0 mm)

2. Surface hardness evaluation The dental resin composition obtained by the method described later is cut out with a low speed diamond cutter (manufactured by Buehler), polished with a # 1500 water-resistant abrasive paper, 0.3 μm alumina particles, 12 mm × 14 mm × A test piece was obtained by arranging into a prism of 1.0 mm. Then, using a microhardness tester (MHT-1, manufactured by Matsuzawa Seiki), measure the diagonal point length (d) of a recess made under a load condition of 100 gf and 30 seconds, and determine the surface hardness of the test piece The The surface hardness Hv was determined using the following equation (2). The surface hardness of these dental resin compositions is shown in Table 2 below.
Hv = 1854.37 × 100 / d ² equation (2)

3. Evaluation of Cutting Processability The dental resin composition obtained by the method described later was installed in a low speed diamond cutter (manufactured by Buehler) so as to be able to cut the surface of 12 mm × 14 mm. At this time, a load of 200 gf was applied for cutting out, and the time until the cutting was completed was evaluated. The obtained machining time was regarded as machinability. The machinability of these dental resin compositions is shown in Table 2 below.

4. Transparency evaluation The dental resin composition obtained by the method described later is cut out with a low speed diamond cutter (made by Buehler), and polished with a # 1500 water-resistant abrasive paper, 0.3 μm alumina particles, 12 mm × 14 mm × A test piece was obtained by arranging into a prism of 1.0 mm. The Y-value of tristimulus value was measured with background color black and white using the obtained test piece using a color difference meter (made by Tokyo Denshoku, TC-1800MKII). The value of the following formula (3) was taken as transparency. The transparency of these dental resin compositions is shown in Table 2 below.
Transparency = Y value for black background color / Y value for white background color Formula (3)

<Dental resin composition>
1. Isocyanate compound TDI: tolylene diisocyanate (2,4-about 80%, 2, 6 to about 20%) (molecular weight = 174, functional group number 2)
XDI: m-xylylene diisocyanate (molecular weight = 188, functional group number 2)

2. Polyalcohol compound or polythiol compound GTP: glycerol tripropoxylate (average molecular weight = 266, number of functional groups 3)
PETP: pentaerythritol propoxylate (average molecular weight = 426, functional group number 4)
PEMA: pentaerythritol tetrakis (mercapto acetate) (molecular weight = 432, functional group number 4)

3. Inorganic filler F1: silica-zirconia (spherical mean particle diameter 0.2 μm, 3-glycidoxypropyltrimethoxysilane surface treated product, average uniformity 0.94)
F2: silica-zirconia (spherical mean particle diameter 0.2 μm, 3-methacryloyloxypropyltrimethoxysilane surface treated product, average uniformity 0.94)

4. Methacrylic polymerizable monomer and polymerization catalyst UDMA: 1,6-bis (methacrylicethyloxycarbonylamino) -2,2-4-trimethylhexane 3G: triethylene glycol dimethacrylate BPO: benzoyl peroxide

Example 1
A composition (a) was obtained by charging 240 g of TDI and 160 g of F1 into a planetary mixer (manufactured by Inoue Seisakusho) and kneading. Similarly, 240 g of GTP and 160 g of F1 were charged into a planetary mixer (manufactured by Inoue Seisakusho Co., Ltd.) and kneaded to obtain a composition (b). Each composition obtained was placed in a desiccator and depressurized for 60 minutes to remove air bubbles in the composition. Then, it was filled in a mixing cartridge (CDA, manufactured by MIXPAC). Attach a mixer syringe (MA 4.0-17S, manufactured by MIXPAC), and while extruding, the curable composition in which the above-mentioned compositions (a) and (b) are mixed is 12 × 18 × 14 mm thick After filling in the mold of (1), it was allowed to stand for 1 hour under nitrogen pressure (0.3 MPa) at After that, the temperature was raised to 150 ° C. over 20 hours while being pressurized, and held for 6 hours. Thereafter, it was taken out from the mold to obtain a dental resin composition. The flexural strength, surface hardness, machinability and transparency of the obtained dental resin composition are shown in Table 2.

(Examples 2 to 4)
It produced by the method similar to Example 1 except performing using the curable composition of the composition described in Table 1. The flexural strength, surface hardness, machinability and transparency of the obtained dental resin composition are shown in Table 2.

(Comparative example 1)
180 g of the polymerizable monomer UDMA and 60 g of 3G were mixed. Next, 2.4 g of thermal polymerization initiator BPO was added, and after stirring, solution 1 was obtained. Then, 240 g of solution 1 and 160 g of F2 were charged into a planetary mixer (Inoue Seisakusho Co., Ltd.) and kneaded to obtain a curable composition.

  The resulting curable composition was placed in a desiccator and depressurized for 60 minutes to remove air bubbles in the curable composition. Then, the curable composition was filled in a mold of length 12 × width 18 × thickness 14 (mm), and then allowed to stand at 23 ° C. under nitrogen pressure (0.3 MPa) for 1 hour. After that, the temperature was raised to 150 ° C. over 20 hours while being pressurized, and held for 6 hours. Thereafter, it was taken out from the mold to obtain a dental resin composition. The flexural strength, surface hardness, machinability and transparency of the obtained dental resin composition are shown in Table 2.

(Comparative example 2)
10 g of TDI and 10 g of GTP were mixed by a magnetic stirrer, and then filled in a mold of 12 × 18 × 14 (mm) in length. After leaving to stand at 23 ° C. under nitrogen pressure (0.3 MPa) for 1 hour, the temperature was raised to 150 ° C. over 20 hours while maintaining pressure, and held for 6 hours. Thereafter, it was taken out from the mold to obtain a dental resin composition. The flexural strength, surface hardness, machinability and transparency of the obtained dental resin composition are shown in Table 2.

  From the comparison of Examples 1 to 4 and Comparative Example 1, it can be seen that the dental resin composition made of polyurethane resin has a bending strength higher than that of the dental resin made of methacrylic resin, and has the same transparency. From the comparison of Examples 1 to 4 and Comparative Example 2, it is understood that the surface hardness and the machinability are improved by blending the inorganic filler. From the comparison of Examples 1 and 2, it can be seen that the surface hardness is high and the cutting processability is excellent when the inorganic filling rate is high. From the comparison between Example 1 and Examples 3 and 4, it can be seen that the larger the (A + B) / 2, the higher the bending strength.

  According to the present invention, a dental resin composition comprising a polyurethane resin is suitably used as a resin-based block for dental cutting, as a transparent material having higher strength and resistance to wear in the oral cavity and excellent cutting ability. be able to.

Claims (5)

  A dental resin composition comprising 25 parts by mass to 1000 parts by mass of an inorganic filler with respect to a resin matrix and 100 parts by mass of the resin matrix, wherein the resin matrix of the dental resin composition is made of polyurethane, A dental resin composition, wherein the inorganic filler has an average particle size of 0.001 to 100 μm.   The polyurethane constituting the resin matrix is an isocyanate compound having two or more isocyanate groups in one molecule, a polyol compound having two or more hydroxy groups in one molecule, or two or more thiol groups in one molecule. The dental resin composition according to claim 1, which is a polyurethane produced by polyaddition with a polythiol compound having the compound.   The dental resin composition according to claim 1, wherein the inorganic filler according to claim 1 comprises silica, alumina, titania, zirconia, or a composite thereof.   Composition (a) containing an isocyanate compound and a polyol compound or a polythiol compound, wherein an isocyanate compound and a polyol compound or a polythiol compound are separately contained, and an inorganic filler is blended in one or both of the compositions. The method for producing a dental resin composition according to claim 1, wherein the compositions (a) and (b) are mixed after preparing the composition (b) containing (c) to prepare a curable composition and to react.   A resin-based block for dental cutting comprising the dental resin composition according to claim 1.