JP2017039665A - Manufacturing method of resin-based mill blank for dental cutting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide production methods of a mill blank for dental cutting, the methods being able to efficiently produce a mill blank (cured body) which reduces a defect, such as a crack at the time of production, and has strength needed as a resin material for dental cutting.SOLUTION: A production method of a resin mill blank for dental cutting obtained by heat polymerization of a polymerizable monomer and a thermal polymerization initiator-containing curable composition, comprises a step of polymerization curing by heating the curable composition for 10 hours or more at a 10 hour half-life period temperature of the thermal polymerization initiator of -10°C to +20°C.SELECTED DRAWING: None

Description

  The present invention relates to a method for manufacturing a resin-based mill blank for dental cutting for producing a dental prosthesis by cutting.

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

  For example, in Patent Document 1, 20 to 70% by weight of an inorganic filler having an average particle size of 0.01 to 0.04 μm, a methacrylate or acrylate monomer having at least one unsaturated double bond, and a heat polymerization initiator are included. A method for producing a dental resin material by polymerizing and curing a mixture comprising a combination under pressure and heating under conditions of a pressure of 50 to 300 MPa and a temperature of 100 to 200 ° C. is disclosed.

  For example, Patent Document 2 discloses a mill blank for making a dental prosthesis, which includes a polymer resin and a filler, which is manufactured so as to pass a thermal shock test substantially without cracks. Here, it is described to apply pressure to the composite material during the curing process and to select a mill blank component that does not shrink in order to minimize the internal stress of the material. Further, as a preferable curing method, light is used to cure the composite at high speed, heat treatment is subsequently performed for stress relaxation, and the heat treatment raises the temperature of the blank above the glass transition temperature of the resin component of the blank. It is described that it is preferable.

For example, Patent Document 3 discloses a step of preparing a molding composition containing a radical polymerizable monomer, a polymerization initiator, and an inorganic filler, and the molding composition has a volume of 40 cm ³ or more and 700 cm ³ or less inside. A method for producing a resin material for dental cutting, comprising the steps of filling the cavity in a mold in which the cavity is formed and dielectrically heating the molding composition filled in the space. ing. According to this manufacturing method, it is described that a large-sized resin material for dental cutting can be efficiently manufactured, and breakage such as cracks hardly occurs.

  When such a resin material for dental cutting is produced from a polymerizable monomer such as a methacrylate monomer, there is a case where defects such as cracks occur in a molded product due to shrinkage that occurs during curing. In particular, when manufacturing a resin material for dental cutting with a large volume, the risk is great and there is a problem in the manufacturing process. As a method for solving this problem, it is considered that the method of performing polymerization under high pressure described in Patent Document 1 and Patent Document 2 is effective, but when such polymerization under high pressure is adopted, There is a problem that productivity is reduced due to the increase in size. In addition, as described in Patent Document 2, in the case of a method in which heat treatment is performed after polymerization by light, a uniform hardened body is obtained because the light for polymerization does not reach the inside of the resin material for dental cutting. Problems such as difficulty in obtaining and a decrease in productivity due to an increase in the number of processes are cited as problems. The problem of inhomogeneity of the hardened body is likely to occur particularly when the volume of the resin material for dental cutting is large or the optical properties of the material are opaque. Moreover, when using the dielectric heating method as described in Patent Document 3, special manufacturing equipment is required.

JP 1998-323353 A Special table 2003-529386 JP2013-202180A

  An object of the present invention is to provide a dental cutting mill capable of efficiently producing a mill blank (hardened body) having a necessary strength as a resin material for dental cutting, suppressing defects such as cracks during manufacturing. The object is to provide a blank manufacturing method.

  In order to solve the above-mentioned problems, the present inventor examined various thermal polymerization initiators and polymerization conditions when using them. As a result, the inventors have found that the effects of the present invention can be obtained with specific thermal polymerization initiators and polymerization conditions, and have completed the present invention.

  That is, the present invention relates to a method for producing a resin-based mill blank for dental cutting obtained by heat polymerization of a curable composition containing a polymerizable monomer and a thermal polymerization initiator, and the curable composition A method for producing a resin-based mill blank for dental cutting, wherein the product is polymerized and cured by heating the product at a temperature of −10 ° C. to + 20 ° C. for 10 hours half-life temperature of the thermal polymerization initiator for 10 hours or more. is there.

Another embodiment of the present invention is characterized in that the thermal polymerization initiator has a 10-hour half-life temperature of 60 to 100 ° C. Further, and wherein the volume of the mill blank is 10cm ³ ~200cm ^3.

  By the production method of the present invention, it becomes possible to efficiently produce a resin material for dental cutting that suppresses defects such as cracks during production.

  The present invention relates to a method for producing a resin-based mill blank for dental cutting obtained by heat polymerization of a curable composition containing a polymerizable monomer and a thermal polymerization initiator, the curable composition comprising Is a method of producing a resin-based mill blank for dental cutting, which is polymerized and cured by heating at a temperature of −10 ° C. to + 20 ° C. for 10 hours half-life temperature of the thermal polymerization initiator for 10 hours or more. .

The resin-based mill blank for dental cutting in the present invention is a cured resin-based molding used when a dental prosthesis is produced by a cutting machine based on three-dimensional coordinate data acquired on a computer. Say about the body. There is no limitation on the size and shape, and a size and shape that suits the purpose may be selected. As the size, the length of one side is usually selected from the range of 5 mm to 150 mm. The shape is selected from a rectangular parallelepiped, a cylindrical shape, a disk shape, and the like according to the application and the cutting device. The volume is usually selected from the range of 1.8 to 200 cm ³ . Effect of the present invention is remarkable in especially large volume hardened molded body, it is preferable volume of the shaped body is a 10cm ³ ~200cm ^3, more preferably 25~200cm ^3.

(Polymerizable monomer)
As the polymerizable monomer which is one component of the curable composition of the present invention, a known polymerizable monomer can be used without particular limitation, but the thermal polymerization initiator of the present invention can be easily dissolved. Preferably, the melting point of the polymerizable monomer is preferably at least 20 ° C. lower than the 10 hour half-life temperature of the thermal polymerization initiator. Further, since the polymerizable monomer does not volatilize during curing by heat polymerization, it is preferable that the boiling point of the polymerizable monomer is at least 20 ° C. higher than the 10-hour half-life temperature of the thermal polymerization initiator. The polymerizable monomer is not particularly limited, and examples thereof include radical polymerizable monomers, cation polymerizable monomers such as epoxy compounds and oxetane compounds. As the radical polymerizable monomer, a (meth) acrylate monomer is preferably used from the viewpoint of good polymerizability. Specific examples of the (meth) acrylate polymerizable monomer include the following.

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

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

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

(A4) Tetrafunctional radical polymerizable monomer Pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, propoxylated pentaerythritol tetra (meth) acrylate, ethoxylated ditrimethylolpropane tetra (meth) acrylate A tetraisocyanate compound such as hexamethyl diisocyanate, trimethylhexamethylene diisocyanate, and a diisocyanate compound such as diisocyanate such as diisocyanate methylcyclohexane can be suitably used. In addition, all the above radical polymerizable monomers can be used alone or in combination.

  Further, from the point that the strength of the resin-based mill blank for dental cutting can be further increased, 50 parts by mass or more in 100 parts by mass of the polymerizable monomer are exemplified in (A2), (A3), and (A4). A polymerizable monomer having the above polymerizable functional group is preferable, and the amount is more preferably 80 parts by mass or more.

  Moreover, it is preferable that the molecular weight of a polymerizable monomer is 200 or more from the point which can suppress defects, such as a crack at the time of superposition | polymerization, more.

(Thermal polymerization initiator)
In order to polymerize and cure the resin material for dental cutting according to the present invention, a thermal polymerization initiator is used. The thermal polymerization initiator is a compound that generates a polymerization initiating species by thermal energy. Usually, the higher the temperature, the higher the rate of formation of the polymerization initiating species, so the reactivity of the thermal polymerization initiator is increased. A 10 hour half-life temperature is used as an index to represent. The 10-hour half-life temperature is a temperature at which the concentration of the thermal polymerization initiator is reduced to half of the initial value in 10 hours. Although there is no restriction | limiting in particular in the 10-hour half life temperature of the thermal-polymerization initiator used for this invention, 60-100 degreeC is preferable, 60-95 degreeC is more preferable, and 70 degreeC-90 degreeC is further more preferable. When the 10-hour half-life temperature is 60 ° C. or lower, the handling is not easy because the stability is low, and the control of polymerization and curing tends to be difficult. On the other hand, when the 10-hour half-life temperature is 100 ° C. or higher, discoloration is likely to occur when exposed to a high temperature during production of the resin-based material mill blank for dental cutting of the present invention.

  As the thermal polymerization initiator, one that matches the polymerization mechanism of the corresponding polymerizable monomer can be arbitrarily used. Specific examples of thermal polymerization initiators for radical polymerizable monomers such as methacrylate series include benzoyl peroxide, p-chlorobenzoyl peroxide, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxy Peroxides such as dicarbonate and diisopropyl peroxydicarbonate, azo compounds such as azobisisobutyronitrile, tributylborane, tributylborane partial oxide, sodium tetraphenylborate, tetrakis (p-fluorofluorophenyl) boric acid Boron compounds such as sodium and tetraphenylborate triethanolamine, 5-butyl barbituric acid, barbituric acids such as 1-benzyl-5-phenylbarbituric acid, sodium benzenesulfinate, p-toluenesulfinate sodium Sulfinic acid salts such as Um like. It is preferable to use a peroxide because of its high polymerizability. Specific examples of a thermal polymerization initiator having a preferable 10-hour half-life temperature include benzoyl peroxide (10-hour half-life temperature 74 ° C.), dilauroyl peroxide (10-hour half-life temperature 62 ° C.), 1,1, 3,3-tetramethylbutylperoxy-2-ethylhexanoate (10-hour half-life temperature 65 ° C), disuccinic acid peroxide 10-hour half-life temperature 66 ° C), tert-hexylperoxy-2-ethylhexanoate Ate (10-hour half-life temperature 70 ° C), tert-butylperoxy-2-ethylhexanoate (10-hour half-life temperature 72 ° C), 1,1-di (tert-butylperoxy) -2-methylcyclohexane (10-hour half-life temperature 83 ° C.), 1,1- (di-tert-hexylperoxy) cyclohexane (half-hour 10 hours) Temperature 87 ° C.), 1,1-di (tert-hexylperoxy) -3,3,5-trimethylcyclohexane (10 hour half-life temperature 87 ° C.), 1,1-di (tert-butylperoxy) cyclohexane ( 10-hour half-life temperature 91 ° C), tert-hexylperoxyisopropyl monocarbonate (10-hour half-life temperature 95 ° C), tert-butylperoxy-3,3,5-trimethylhexanoate (10-hour half-life temperature) 97 ° C.), tert-butyl peroxylaurate (10 hour half-life temperature 98 ° C.), tert-butyl peroxy-2-ethylhexyl monocarbonate (10 hour half-life temperature 99 ° C.), tert-hexyl peroxybenzoate ( 10 hours half-life temperature 99 ° C), tert-butylperoxyisopropyl monocarbo (10-hour half-life temperature 99 ° C), 2,5-dimethyl-2,5-di (benzoylperoxy) hexane (10-hour half-life temperature 100 ° C), azobisisobutyronitrile (10-hour half-life) Temperature 65 ° C.).

  In the production method of the present invention, the setting of the 10-hour half-life temperature of the thermal polymerization initiator is important, and details will be described later.

  These thermal polymerization initiators may be used alone or in admixture of two or more. The blending amount of the thermal polymerization initiator is preferably 0.1 to 2 parts by mass, and more preferably 0.2 to 0.8 parts by mass with respect to 100 parts by mass of the polymerizable monomer. When the amount of the thermal polymerization initiator is small, the effect of the present invention may be difficult to obtain. Moreover, when there are too many thermal-polymerization initiators, there exists a possibility that it may become easy to generate | occur | produce a crack by progress of rapid polymerization hardening.

(Optional component)
The curable composition of the present invention can contain any component in addition to the polymerizable monomer and the thermal polymerization initiator. Examples thereof include fillers, fluorescent agents, ultraviolet absorbers, antioxidants, pigments, antibacterial materials, and X-ray contrast agents.

(Filler)
The filler is blended from the viewpoints of improving mechanical strength, improving wear resistance, reducing thermal expansion coefficient, water absorption, and solubility of the resin-based material mill blank for dental cutting of the present invention. Is preferred.

  As the filler, known fillers can be used without limitation, and any of inorganic particles, organic particles, and organic-inorganic composite particles may be used. From the viewpoint of blending the filler described above, the inorganic filler is used. Is preferably used.

  Specific examples of such inorganic fillers include spherical particles such as amorphous silica, silica-zirconia, silica-titania, silica-titania barium oxide, silica-titania-zirconia, quartz, alumina, and glass, or irregular shapes. Particles can be mentioned. Of these, composite oxides mainly composed of silica and zirconia, silica and titania, or silica and barium oxide are preferably used because they have high X-ray contrast properties. In addition, since the filler has a spherical shape, a cured product of a curable composition that is particularly excellent in wear resistance, surface smoothness, and gloss durability can be obtained. The term “spherical shape” as used herein means that the average degree of uniformity obtained in image analysis of a captured image of a scanning or transmission electron microscope is 0.6 or more. The average uniformity is more preferably 0.7 or more, and further preferably 0.8 or more.

  The average particle size of the filler is preferably 0.001 to 1 micron, more preferably 0.01 to 0.5 micron from the viewpoint of wear resistance, surface lubricity, and gloss durability. preferable.

  The filler may be subjected to surface treatment in order to improve compatibility with the matrix of the polymerizable monomer and improve mechanical strength and water resistance. As the surface treatment agent, a silane coupling agent is generally used. In particular, an inorganic particle-based filler based on silica has a high effect of surface treatment with the silane coupling agent. The surface treatment may be carried out by a known method. Examples of the silane coupling agent include methyltrimethoxysilane, methyltriethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane. , Vinyltrichlorosilane, vinyltriacetoxysilane, vinyltris (2-methoxyethoxy) silane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltris (2-methoxyethoxy) silane, 3-chloropropyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane or the like is preferably used. The said silane coupling agent should just select a suitable thing suitably according to the polymerizable monomer to be used, and can use it 1 type or in combination of 2 or more types.

  In the embodiment of the present invention, the blending amount of the filler may be selected according to the purpose, but is usually a ratio of 10 to 1000 parts by mass, more preferably 100 parts by mass of the polymerizable monomer. Used in a proportion of 100 to 500 parts by mass.

  In the method for producing a resin mill blank for dental cutting according to the present invention, a step of preparing a curable composition comprising a polymerizable monomer and a thermal polymerization initiator, and the thermal polymerization of the curable composition are started. At least a step of polymerizing and curing by heating at a temperature of −10 ° C. to + 20 ° C. for a 10-hour half-life temperature of the agent for 10 hours or more.

  In the method for producing a resin mill blank for dental cutting according to the present invention, a curable composition is prepared. The preparation method is not particularly limited, and a method of stirring and mixing using a magnetic stirrer, a stirring blade, a centrifugal mixer or the like is used until a thermal polymerization initiator is added to the polymerizable monomer and dissolved. In order to suppress decomposition of the thermal polymerization initiator, the temperature during preparation is preferably −20 ° C. or less of the 10-hour half-life temperature of the thermal polymerization initiator used, and the preparation time is preferably 12 hours or less. preferable. Similarly, when the filler is blended, it is not particularly limited, but the filler is added to the polymerizable monomer in which the thermal polymerization initiator is dissolved, and the mixture is prepared by mixing using a reiki machine, a planetary mixer, a centrifugal mixer, or the like. It's okay. In the curable composition thus prepared, it is preferable to eliminate bubbles contained therein by defoaming treatment before polymerization and curing. A known method is used as the defoaming method, and a method such as pressure defoaming, vacuum defoaming or centrifugal defoaming can be arbitrarily used.

In the production method of the present invention, in order to polymerize and cure the curable composition obtained above into a desired shape, it is preferable to perform polymerization and curing after filling the mold. A mold having a desired shape is prepared, and the inside thereof may be filled with the curable composition and polymerized and cured, or a mold having a larger size may be filled to produce a bulk body. Alternatively, punching or cutting may be performed so as to obtain a desired shape. In particular, when the latter method is employed, the effects of the present invention can be remarkably obtained. Volume of the mold may be appropriately selected depending on the purpose, 10 to 50 cm ³ in the case of block shape, in the case of a disc-shaped preferably selected from the range of 50 to 200 cm ^3. Similarly, the shape of the molding die may be a prism, a cylinder, a square plate, or a disc shape, and is not particularly limited.

  As the material of the mold, metal, ceramics, resin, or the like can be used according to the purpose. It is preferable to use a material having higher heat resistance than the polymerization temperature to be carried out. Specific examples include SUS, high-speed tool steel, aluminum alloy, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), and polystyrene (PS).

  The production method of the present invention includes a step of polymerizing and curing the curable composition by heating it at a temperature of −10 ° C. to + 20 ° C. for 10 hours half-life temperature of the thermal polymerization initiator for 10 hours or more. When polymerization is performed at a temperature lower than the lower limit temperature, that is, at a temperature lower than the 10-hour half-life temperature of −10 ° C., the polymerization and curing cannot be sufficiently performed. In the case of polymerization at a temperature higher than the upper limit temperature, that is, a temperature higher than the 10-hour half-life temperature + 20 ° C., molding defects such as cracks are likely to occur due to a rapid polymerization reaction. Even when molding defects do not occur, the required strength cannot be obtained due to residual stress and minute cracks inside the cured body. A preferable temperature range is −10 ° C. to + 15 ° C. with respect to a 10-hour half-life temperature, and a most preferable temperature range is −10 ° C. to + 10 ° C. When the polymerization time is less than 10 hours, the polymerization and curing cannot be performed sufficiently. A preferable polymerization time is 12 to 24 hours from the viewpoint of sufficient polymerization curing and production efficiency.

  Moreover, there is no restriction | limiting in the pressure at the time of superposition | polymerization by this method. Therefore, you may perform pressurization or pressure reduction arbitrarily. The method is not limited, and examples thereof include mechanical pressurization such as pressing, pressurization with gas filled with gas, and decompression under vacuum. The pressure is preferably 1.0 megapascal or less, more preferably atmospheric pressure (0.1 megapascal) to 1.0 megapascal, and still more preferably 0.3 megapascal to 0.8 megapascal.

  Resin system for dental cutting with no molding defects such as cracks by suppressing the generation of distortion and internal stress due to shrinkage at the time of polymerization and curing by selecting a production method based on such a combination of thermal polymerization initiator and polymerization temperature Not only can a material mill blank be obtained, it is also possible to obtain a resin-based material mill blank for dental cutting that has been polymerized and cured to physical properties that sufficiently function as a dental prosthesis. Since this method does not necessarily require polymerization under high pressure or special auxiliary equipment, it is not necessary to increase the size of the equipment in order to ensure the durability and safety of the production equipment. is there.

  Any apparatus can be used as the apparatus used for the heat polymerization in the production method of the present invention. As specific examples, a dryer, a vacuum dryer, an air dryer, an incubator, an inert oven, or the like can be used.

  In the production method of the present invention, any operation can be performed without particular limitation within the range that does not impede the effects of the present invention as long as the above conditions are satisfied. For example, a step of gradually increasing the temperature as preheating before reaching the heating polymerization temperature, a step of gradually decreasing the temperature for the purpose of gradual cooling after completion of the heating polymerization step, and a polymerization environment with nitrogen or argon gas. A step of filling with an active gas, a pressurizing step, a heat treatment step and the like may be added or performed simultaneously.

  Any post-process may be performed after the heat polymerization process. For example, the obtained resin mill blank for dental cutting can be subjected to heat treatment, cutting for correcting to a required shape or a shape that is easier to use, and polishing. The heat treatment temperature at this time may be higher than the polymerization temperature.

  The mill blank produced in this way can be used as a CAD / CAM mill blank by joining a fixture such as a pin for holding it in a CAD / CAM device as required. By connecting this to a CAD / CAM device and cutting based on the design, a restoration of the crown can be obtained.

  Examples and comparative examples relating to the present invention are shown below, but the present invention is not limited to these examples.

(material)
1. Thermal polymerization initiator (10 hours half-life temperature ° C)
BPO: Benzoyl peroxide (74 ° C)
tHPO: tert-hexylperoxyisopropyl monocarbonate (95 ° C.)
AIBN: Azobisisobutyronitrile (65 ° C.)
2. 2. Polymerizable monomer UDMA: 1,6-bis (methacrylethyloxycarbonylamino) -2,2-4-trimethylhexane 3G: triethylene glycol dimethacrylate Filler F1: Silica-zirconia (spherical average particle size 0.40 μm)
F2: Silica-zirconia (spherical average particle size 0.15 μm)
F3: Silica-zirconia (spherical average particle size 0.07 μm)

(Evaluation method and evaluation criteria)
The crack and bending strength evaluation for the samples of Examples and Comparative Examples described later are as follows.
1. Crack evaluation The outside of the mill blank cured by the method described later was visually observed, and the presence or absence of cracks was observed. Next, observation with an X-ray inspection apparatus (manufactured by Matsusada Precision Co., Ltd.) was performed, and the presence or absence of cracks inside was observed. Evaluation was made in two stages: ○ (where no crack was observed) and × (where any crack was observed).
2. Bending strength evaluation A test piece was prepared by cutting a mill blank cured by the method described later with a low-speed diamond cutter (Buehler) and preparing a square column of 2 mm x 2 mm x 25 mm using # 1500 water-resistant abrasive paper. Got. The test piece of the previous period was mounted on an autograph (manufactured by Shimadzu Corporation), and a three-point bending test was performed under the conditions of a distance between supporting points of 20 mm and a crosshead speed of 1 mm / min.

The bending strength σ was calculated by the following formula. In addition, the said test piece produced five pieces for every Example and comparative example, and made the average value the bending strength of a mill blank. The bending strength of these mill blanks is shown in Table 1 below.
σ = 3PS / 2WB2
P: Test force at break, S: Distance between fulcrums (20 mm), W: Width (2 mm), B: Thickness (2 mm)

Example 1
80 parts by mass of the polymerizable monomer UDMA and 20 parts by mass of 3G were mixed so that the total amount was 150 g. Next, 0.3 part by mass of thermal polymerization initiator BPO was added, and after stirring, Solution 1 was obtained. Then, 25 parts by mass of Solution 1 and 75 parts by mass of F2 were charged into a planetary mixer (Inoue Seisakusho) and kneaded to obtain a total amount of 500 g, thereby obtaining a curable composition.

  The obtained curable composition was put in a desiccator and decompressed for 30 minutes to remove bubbles in the curable composition. Then, after filling the curable composition in a SUS mold having a diameter of 10 × thickness 2 (cm), the curable composition was allowed to stand in an incubator (Yamato) set at 80 ° C. for 15 hours. Then, it removed from the metal mold | die and obtained the mill blank.

(Examples 2-9, Comparative Examples 1-3)
Using the curable composition of the composition described in Table 1, it produced by the method equivalent to Example 1 except performing the heating on each condition described in Table 1.

  Although the comparative example 1 is the example performed above the temperature suitable for this invention, the crack generate | occur | produced. Therefore, the bending strength could not be evaluated.

Claims (3)

  A method for producing a resin-based mill blank for dental cutting obtained by heating and polymerizing a curable composition containing a polymerizable monomer and a thermal polymerization initiator, wherein the curable composition is thermally polymerized. A method for producing a resin-based mill blank for dental cutting, which is polymerized and cured by heating at a temperature of −10 ° C. to + 20 ° C. of a 10-hour half-life temperature of an initiator for 10 hours or more.   The method for producing a resin-based mill blank for dental cutting according to claim 1, wherein the 10-hour half-life temperature of the thermal polymerization initiator is 60 to 100 ° C. Method for producing a dental cutting for resin-based mill blank of claim 1 or 2 volumes of mill blank is characterized in that a 10cm ³ ~200cm ^3.