JP6806547B2 - Dental curable composition - Google Patents

Description

The present invention relates to a dental curable composition, a dental mill blank, and a method for producing the same. More specifically, for example, inlays, onlays, onlays, veneers, crowns, bridges, abutment teeth, dental posts, dentures, denture bases, implant members (fixtures, abats) by cutting with a dental CAD / CAM system. The present invention relates to a dental curable composition preferably used for producing a dental mill blank which is suitably used for producing a dental prosthesis such as ment).

Dental curable compositions composed of polymerizable monomers, inorganic fillers and polymerization initiators are dental materials that are often used as materials for repairing tooth defects and tooth decay. Such a dental curable composition is required to have sufficient mechanical strength and hardness that can replace natural teeth, abrasion resistance against occlusion in the oral cavity, and surface sliding durability. Tooth. In recent years, a CAD / CAM system for designing dental prostheses such as inlays and crowns by a computer and cutting them with a milling device has become widespread, and a mill, which is a material to be cut, is used in this system. As a blank material, a dental mill blank manufactured from a dental curable composition is being studied. The dental mill blank produced from the dental curable composition has an appropriate hardness that does not damage the opposing teeth and has excellent impact resistance, so that it has begun to be processed into a dental prosthesis and used clinically. There is.

For example, Patent Document 1 describes a method for producing a mill blank, in which an inorganic filler is press-molded to obtain a molded product, and then a polymerizable monomer component is immersed in the molded product and heat-polymerized. There is. At that time, a method of relaxing the stress strain generated inside the cured product by heat-treating at 80 ° C. to 130 ° C. for 10 to 120 minutes after the polymerization curing is described. By this manufacturing method, nanoparticles can be packed at a high density, and a dental mill blank having excellent mechanical strength and aesthetics can be obtained.

However, as a result of studies by the present inventors, there is a problem that cracks may occur during polymerization in this production method. Dental mill blanks with cracks are not of good quality due to reduced mechanical strength and poor appearance, and details are easily chipped when cutting with CAD / CAM, making them highly accurate for dentistry. No mill blank could be obtained.

Further, Patent Document 2 describes a dental mill blank composed of a polymerizable monomer containing an initiator having a radical generation temperature of 100 to 150 ° C. and a cured product of an inorganic filler. According to the present invention, a dental mill blank having excellent mechanical strength and aesthetics can be obtained. However, it has been found that polymerization at such a high temperature tends to cause polymerization runaway, causes cracks, and has a problem of low yield.

International Publication No. 2014/021343 U.S. Patent Application Publication No. 2014/0162216

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a dental prosthesis having a low risk of cracking during polymerization and excellent mechanical strength and aesthetics. To provide a dental curable composition that can be made. Another object of the present invention is to provide a dental curable composition capable of providing a dental prosthesis having excellent storage stability in water.

The present invention relates to the following inventions.
[1] Containing a polymerizable monomer (A), a heat polymerization initiator (B) and an inorganic filler (C),
The heat polymerization initiator (B) has a monofunctional polymerization initiator (b-1) having a 10-hour half-life temperature (τ1) of 50 to 75 ° C. and a 10-hour half-life temperature (τ2) of 80 to 120 ° C. A dental curable composition containing a polyfunctional polymerization initiator (b-2).
[2] The dental curable composition according to the above [1], wherein the heat polymerization initiator (B) is 0.1 to 5 parts by weight with respect to 100 parts by weight of the polymerizable monomer (A);
[3] The amount of the monofunctional polymerization initiator (b-1) blended in the heat polymerization initiator (B) is 20 to 70% by weight, and the blending amount of the polyfunctional polymerization initiator (b-2) is The dental curable composition according to the above [1] or [2], which is 30 to 80% by weight;
[4] The dental curable composition according to any one of [1] to [3] above, which contains 100 to 400 parts by weight of the inorganic filler (C) with respect to 100 parts by weight of the polymerizable monomer (A). Stuff;
[5] A dental mill blank made of a cured product of the dental curable composition according to any one of the above [1] to [4];
[6] A method for producing a dental mill blank, which comprises a step of heat-polymerizing the dental curable composition according to any one of [1] to [4].
[7] The step of heat polymerization includes first polymerization and second polymerization, the temperature of the first polymerization is (τ1) -25 ° C to (τ1) -15 ° C, and the temperature of the second polymerization is (τ1) -15 ° C. τ2) The method for producing a dental mill blank according to the above [6], which is -10 ° C to (τ2) + 30 ° C;
[8] The method for producing a dental mill blank according to [7], wherein the first polymerization time is 1 to 30 hours and the second polymerization time is 2 to 50 hours.

The dental curable composition of the present invention can provide a dental mill blank having a low risk of cracking during polymerization and excellent mechanical strength and aesthetics. Further, the present invention can provide a dental curable composition which can provide a dental prosthesis having excellent storage stability in water. More specifically, it is possible to provide a dental prosthesis having excellent mechanical strength and aesthetics even after long-term storage in water.

The dental curable composition of the present invention contains a polymerizable monomer (A), a heat polymerization initiator (B) and an inorganic filler (C), and the heat polymerization initiator (B) is used for 10 hours. A monofunctional polymerization initiator (b-1) having a half-life temperature (τ1) of 50 to 75 ° C. and a polyfunctional polymerization initiator (b-2) having a 10-hour half-life temperature (τ2) of 80 to 120 ° C. ) Is contained.

In this specification, the upper limit value and the lower limit value of the numerical range (content of each component, value calculated from each component, each physical property, etc.) can be appropriately combined.

Factors for exhibiting the effects of the present invention are considered as follows. First, by heating the dental curable composition at a low temperature, radicals are generated from the monofunctional polymerization initiator (b-1), and the dental curable composition is cured to some extent. After that, the temperature is raised all at once and heated at a high temperature, so that radicals are generated from the polyfunctional polymerization initiator, and the remaining monomers react to proceed with curing. At this time, it is presumed that the semi-cured product is formed by low-temperature polymerization with the monofunctional polymerization initiator (b-1), becomes a state with some strength, and suppresses the generation of cracks during the subsequent heat polymerization at high temperature. Will be done. Furthermore, by using the polyfunctional polymerization initiator (b-2) during high-temperature polymerization, two polymer chains grow from one molecule of the initiator, and the polymer strength is improved and branched by increasing the molecular weight. It is considered that when the polymer is used, the distance between the polymer chains is increased due to the steric repulsion and polymerization shrinkage is less likely to occur, that is, cracks are less likely to occur due to the suppression of shrinkage stress.

Polymerizable monomer (A)
As the polymerizable monomer (A) used in the present invention, a known polymerizable monomer used for dental composite resins and the like can be used without any limitation, but in general, a radical polymerizable monomer is preferable. Used for. Specific examples of the radically polymerizable monomer include esters such as α-cyanoacrylic acid, (meth) acrylic acid, α-halogenated acrylic acid, crotonic acid, cinnamic acid, sorbic acid, maleic acid, and itaconic acid. Examples thereof include (meth) acrylamide, (meth) acrylamide derivatives, vinyl esters, vinyl ethers, mono-N-vinyl derivatives, styrene derivatives and the like. Among these, (meth) acrylic acid ester and (meth) acrylamide derivative are preferable, and (meth) acrylic acid ester is more preferable. In the present invention, the notation "(meth) acrylic" is used to include both methacrylic and acrylic.

Examples of (meth) acrylic acid ester-based and (meth) acrylamide derivative-based polymerizable monomers are shown below.

(I) Monofunctional (meth) acrylic acid ester and (meth) acrylamide derivative Methyl (meth) acrylate, isobutyl (meth) acrylate, benzyl (meth) acrylate, lauryl (meth) acrylate, 2- (N, N-dimethyl) Amino) ethyl (meth) acrylate, 2,3-dibromopropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, propylene glycol mono ( Meta) acrylate, glycerin mono (meth) acrylate, erythritol mono (meth) acrylate, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N- (dihydroxyethyl) (meth) acrylamide, (meth) acryloyl Examples thereof include oxidodesylpyridinium bromide, (meth) acryloyl oxidedecylpyridinium chloride, (meth) acryloyloxyhexadecylpyridinium chloride, (meth) acryloyloxydecylammonium chloride, and 10-mercaptodecyl (meth) acrylate.

(II) Bifunctional (meth) acrylic acid ester Ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6- Hexadiol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, bisphenol A diglycidyl acrylate (2,2-bis4- [3-acryloyloxy-2-hydroxypropoxy] phenyl] propane, bisphenol A Diglycidyl methacrylate (2,2-bis4- [3-methacryloyloxy-2-hydroxypropoxy] phenyl] propane (commonly known as Bis-GMA)), 2,2-bis [4- (meth) acryloyloxyethoxyphenyl] propane , 2,2-bis [4- (meth) acryloyloxypolyethoxyphenyl] propane, 1,2-bis [3- (meth) acryloyloxy2-hydroxypropoxy] ethane, pentaerythritol di (meth) acrylate, 2, 2,4-trimethylhexamethylenebis (2-carbamoyloxyethyl) dimethacrylate (commonly known as UDMA), 2,2,3,3,4,4-hexafluoro-1,5-pentyldimethacrylate, tricyclodecanedimethanol Di (meth) acrylate and the like can be mentioned.

(III) Trifunctional or higher (meth) acrylic acid ester Trimethylolpropane tri (meth) acrylate, trimethylolethanetri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, pentaerythritol tetra (meth) acrylate, di Pentaerythritol hexa (meth) acrylate, N, N'-(2,2,4-trimethylhexamethylene) bis [2- (aminocarboxy) propan-1,3-diol] tetra (meth) acrylate, 1,7- Examples thereof include diacryloyloxy-2,2,6,6-tetraacryloyloxymethyl-4-oxaheptane.

Further, in addition to these (meth) acrylic acid ester-based and (meth) acrylamide derivative-based polymerizable monomers, cationically polymerizable oxylan compounds and oxetane compounds are also preferably used.

Each of the polymerizable monomers (A) can be used alone or in combination of two or more. Further, the polymerizable monomer (A) used in the present invention is preferably in a liquid state, but it does not necessarily have to be in a liquid state at room temperature, and the polymerizable monomer (A) is used as an inorganic filler (C). ), If it is a liquid in the environment of the process of contacting it, there is no problem. Further, even the solid polymerizable monomer (A) can be mixed and dissolved with other liquid polymerizable monomers before use.

Heat polymerization initiator (B)
The heat polymerization initiator (B) used in the present invention can be selected from the heat polymerization initiators used in the general industry, and among them, the polymerization initiator used for dental applications is preferably used.

The heat polymerization initiator (B) is a monofunctional polymerization initiator (b-1) having a 10-hour half-life temperature of 50 to 75 ° C. and a polyfunctional polymerization initiator (b-1) having a 10-hour half-life temperature of 80 to 120 ° C. Contains the agent (b-2).

Here, the 10-hour half-life temperature represents a temperature at which the half-life of the heat polymerization initiator is 10 hours, and the half-life is until the concentration of the heat polymerization initiator is reduced to half of the initial value. Represents time.

Monofunctional polymerization initiator (b-1) having a 10-hour half-life temperature of 50 to 75 ° C.
Examples of thermal polymerization initiators used as monofunctional polymerization initiators are 2,2'-azobis (2-methylpropionitrile), dicumyl peroxide, di (3,5,5-trimethylhexanoyl). Peroxide, dilauroyl peroxide, dissuccinic acid peroxide, benzoyl peroxide, t-butylperoxybenzoate, t-hexyl peroxide palerate, 2,5-dimethyl-2,5-di (2-ethylhexanoyl) Peroxy) hexane, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate Ate and the like can be mentioned.

Polyfunctional polymerization initiator (b-2) having a 10-hour half-life temperature of 80 to 120 ° C.
Examples of thermal polymerization initiators used as polyfunctional polymerization initiators are n-butyl-4,4-di (t-butylperoxy) valerate, 1,1-di (t-butylperoxy) cyclohexane, 1,1-di (t-hexyl peroxy) cyclohexane, 2,2-bis (4,5-di t-butyl peroxycyclohexyl) propane, 1,1-bis (t-butyl peroxy) -3,3 , 5-trimethylcyclohexane, 2,2-bis (t-butylperoxy) butane and the like.

In the dental curable composition of the present invention, for example, a polymerizable monomer (A) and a heat polymerization initiator (B) are mixed to obtain a polymerizable monomer-containing composition, and then the polymerizable monomer is obtained. It can be obtained by mixing the monomer-containing composition with the inorganic filler (C). Further, the dental curable composition of the present invention can be obtained by mixing a polymerizable monomer (A), a heat polymerization initiator (B) and an inorganic filler (C).

The amount of the heat polymerization initiator (B) blended in the dental curable composition is preferably 0.1 to 5 parts by weight, preferably 0.3 parts by weight, based on 100 parts by weight of the polymerizable monomer (A). ~ 3 parts by weight is more preferable, and 0.5 to 2 parts by weight is further preferable. If the amount of the heat polymerization initiator (B) is too small, unpolymerized monomers may remain and the strength may be lowered, and if it is too large, there is a risk of discoloration of the polymerized cured product.

The blending amount of the monofunctional polymerization initiator (b-1) in the heat polymerization initiator (B) is preferably 20 to 70% by weight, more preferably 30 to 60% by weight. Further, the blending amount of the polyfunctional polymerization initiator (b-2) in the heat polymerization initiator (B) is preferably 30 to 80% by weight, more preferably 40 to 70% by weight. Further, in the heat polymerization initiator (B), the blending amount of the monofunctional polymerization initiator (b-1) is 20 to 70% by weight, and the blending amount of the polyfunctional polymerization initiator (b-2) is The blending amount is preferably 30 to 80% by weight, the blending amount of the monofunctional polymerization initiator (b-1) is 30 to 60% by weight, and the blending amount of the polyfunctional polymerization initiator (b-2) is. It is preferably 40 to 70% by weight.

Inorganic filler (C)
As the inorganic filler (C) used in the present invention, known inorganic particles used as a filler for dental composite resins can be used without any limitation. Specifically, for example, various glasses {silicon dioxide (quartz, quartz glass, silica gel, etc.), silicon as a main component, and boron and / or aluminum contained together with various heavy metals}, alumina, various ceramics, diatomaceous clay, etc. Conventionally known kaolin, clay minerals (montmorillonite, etc.), active white clay, synthetic zeolite, mica, silica, calcium fluoride, itterbium fluoride, calcium phosphate, barium sulfate, zirconium dioxide (zirconia), titanium dioxide (titania), hydroxyapatite, etc. Can be used. Further, an organic-inorganic composite particle (organic-inorganic composite filler) obtained by adding a polymerizable monomer to these inorganic particles in advance to form a paste, curing the polymerization, and pulverizing the mixture may be used. These inorganic particles may be used alone or in combination of two or more.

The inorganic particles used as the inorganic filler (C) in the present invention are not particularly limited in form, and are, for example, crushed, plate-shaped, scaly, fibrous (short fibers, long fibers), needle-shaped, whiskers, and spherical. Various shapes such as are used. The primary particles having these shapes may be aggregated, or may be a combination of different shapes. In the present invention, some treatment (for example, pulverization) may be performed so as to have the above-mentioned shape.

In the present invention, two or more kinds of inorganic particles having different materials, particle size distributions, and morphologies may be mixed or used in combination, and the inorganic particles are unintentionally used as long as the effects of the present invention are not impaired. Particles other than particles may be contained as impurities.

The preferred aspects of the inorganic filler (C) in the present invention are described below.

In a preferred embodiment, the inorganic filler (C) preferably contains inorganic particles (submicron filler) (C1) having an average particle diameter in the range of 0.10 μm or more and less than 1.0 μm. The submicron filler (C1) preferably has a particle size range of 0.05 to 5.0 μm. Among them, inorganic particles having an average particle diameter in the range of 0.10 μm or more and 0.50 μm or less are more preferable, and inorganic particles having an average particle diameter in the range of 0.10 μm or more and 0.30 μm or less are more preferable. Inorganic particles having a range and an average particle size in the range of 0.10 μm or more and 0.30 μm or less are particularly preferable. The application of inorganic particles (C1) having an average particle size in this range to a dental curable composition is a dental prosthesis having an appropriate mechanical strength and aesthetics (wear resistance, smoothness). A dental mill blank to give can be given. The content of the submicron filler (C1) in the inorganic filler (C) in the dental curable composition containing the submicron filler (C1) is preferably 90% by weight or more, more preferably 95% by weight or more. , Substantially 100% by weight is even more preferred.

In this specification, the average particle size of the inorganic particles can be determined by a laser diffraction / scattering method or an electron microscope observation of the particles. Specifically, the laser diffraction / scattering method is convenient for measuring the particle size of particles of 0.10 μm or more, and the electron microscope observation is convenient for measuring the particle system of ultrafine particles of less than 0.10 μm. The 0.10 μm is a value measured by a laser diffraction / scattering method.

Specifically, the laser diffraction / scattering method can be measured by using a laser diffraction type particle size distribution measuring device (SALD-2100: manufactured by Shimadzu Corporation) using a 0.2% sodium hexametaphosphate aqueous solution as a dispersion medium.

Specifically, for electron microscope observation, for example, a transmission electron microscope (manufactured by Hitachi, Ltd., H-800NA type) photograph of particles is taken, and the particle size of the particles (200 or more) observed in the unit field of view of the photograph is determined. It can be obtained by measuring using an image analysis type particle size distribution measurement software (Microscope Co., Ltd.). At this time, the particle diameter of the particles is obtained as the equivalent circle diameter, which is the diameter of a circle having the same area as the particles, and the average primary particle diameter is calculated from the number of particles and the particle diameter.

Further, in the submicron filler (C1) having the particle size range, when the inorganic particles are spherical particles, it is more preferable from the above viewpoint. The sphere includes a substantially sphere and does not necessarily have to be a perfect sphere. In general, a scanning electron microscope is used to take a picture of particles, 30 particles are arbitrarily selected to be observed within the unit field of view of the picture, and the maximum particle size of each particle is perpendicular to the maximum diameter. When the gradual uniformity with the diameter is determined, the average value (average uniformity) is preferably 0.6 or more, more preferably 0.8 or more, and 0.9 or more. Is even more preferable.

As such a spherical submicron filler (C1), an oxide of at least one metal selected from the group consisting of silica particles, Group 2, Group 4, Group 12, and Group 13 of the Periodic Table. Particles or composite oxide particles containing at least one metal atom selected from the group consisting of Group 2, Group 4, Group 12, and Group 13 of the Periodic Table, a silicon atom, and an oxygen atom. Is preferable. Specific examples of these include amorphous silica, quartz, Christovalite, tridimite, alumina, titanium dioxide, strontium oxide, barium oxide, zinc oxide, zirconium oxide, hafnium oxide, silica zirconia, silica titania, silica titania barium oxide, silica. Examples thereof include particles such as alumina, silica titania sodium oxide, silica titania potassium oxide, silica zirconia sodium oxide, silica zirconia potassium oxide, siliceaium oxide, and silica strontium oxide. More preferably as spherical particles, silica particles, oxide particles of a metal of Group 4 of the Periodic Table, and particles of a composite oxide containing a metal atom of Group 4 of the Periodic Table, a silicon atom, and an oxygen atom. Therefore, since a dental mill blank having X-ray contrast property and more excellent wear resistance can be obtained, the particles are more preferably silica zirconia particles. A commercially available product can be used as the submicron filler (C1). Further, as a method for producing the submicron filler (C1), for example, Japanese Patent Application Laid-Open No. 58-110414 is described. In addition, hydroxyapatite can also be used as the spherical submicron filler.

The specific surface area of the submicron filler (C1) is preferably 5 to 25 m ² / g. In the present specification, the specific surface area can be measured according to a conventional method by the specific surface area BET method.

In yet another preferred embodiment, the inorganic filler (C) is an inorganic particle (C2) having an average particle diameter in the range of 1.0 nm or more and less than 0.10 μm and a specific surface area in the range of 30 to 500 m ² / g. ) (Hereinafter, also referred to as inorganic ultrafine particles (C2)). The average particle size of the inorganic ultrafine particles (C2) is more preferably 5.0 nm or more, and further preferably 10 nm or more. The average particle size of the inorganic ultrafine particles (C2) is more preferably 50 nm or less, and further preferably 40 nm or less. The specific surface area of the inorganic ultrafine particles (C2) is more preferably 40 m ² / g or more, and further preferably 50 m ² / g or more. Further, the specific surface area of the inorganic ultrafine particles (C2) is more preferably 400 m ² / g or less, and further preferably 200 m ² / g or less. Further, the average particle size of the inorganic ultrafine particles (C2) is more preferably 5.0 nm or more and 50 nm or less, and further preferably 10 nm or more and 40 nm or less. More preferably a specific surface area of the inorganic ultrafine particles (C2) is 40 to 400 ² / g, more preferably from 50 to 200 m ² / g. As the inorganic ultrafine particles (C2), inorganic ultrafine particles having an average particle size in the range of 5.0 nm or more and 50 nm or less and a specific surface area in the range of 40 to 400 m ² / g are more preferable, and the average particle size is 5. located 50nm below the range of 0 nm, the range inorganic ultrafine particles or the average particle diameter is less 40nm or 10nm in the range a specific surface area of 50 to 200 m ² / g, ranging specific surface area of 40 to 400 ² / g Inorganic ultrafine particles in the above are more preferable, and inorganic ultrafine particles having an average particle diameter in the range of 10 nm or more and 40 nm or less and a specific surface area in the range of 50 to 200 m ² / g are particularly preferable. Such inorganic ultrafine particles (C2) are so-called nanoparticles (ultrafine particle fillers), and can provide a dental mill blank having excellent transparency and polishing smoothness. The content of the inorganic ultrafine particles (C2) in the inorganic filler (C) in the dental curable composition containing the inorganic ultrafine particles (C2) is preferably 90% by weight or more, more preferably 95% by weight or more. , Substantially 100% by weight is even more preferred.

As such nanoparticles (C2), known inorganic ultrafine particles used for dental composite resins and the like can be used without any limitation. Preferably, inorganic oxide particles such as silica (for example, silica produced by a flame thermal decomposition method), alumina, titania, and zirconia, or composite oxide particles composed of these (for example, silica / alumina composite oxide, silica / Zirconia composite oxide), calcium phosphate, hydroxyapatite, ittium fluoride, itterbium fluoride, barium titanate, potassium titanate and the like. Preferably, it is a particle of silica, alumina, titania, a silica / alumina composite oxide, or a silica / zirconia composite oxide produced by a flame thermal decomposition method. Commercially available products can be used for the inorganic ultrafine particles (C2). Examples of the commercially available products include Aerodil (registered trademark) OX-50, Aerodil (registered trademark) 50, and Aerodil (registered trademark) 130 manufactured by Nippon Aerozil. , Aerogil® 200, Aerogil® 380, Aerogil® MOX80, Aerogil® R972, Aerogil® RY50, Aeroxide® Alu C, Aeroxide® TiO ₂ P 25, Aeroxide® TiO ₂ P 25S, VPZirconiumOxide 3-YSZ, VPZirconiumOxide 3-YSZ PH. Further, the shape of the inorganic ultrafine particles is not particularly limited, and can be appropriately selected and used.

In addition, agglomerated particles (C3) formed by aggregating the ultrafine particle fillers (nanoparticles) (C2) can also be suitably used in the present invention. The average particle size of the agglomerated particles (C3) is preferably in the range of 1.0 to 20 μm, preferably in the range of 2.0 to 10 μm, from the viewpoint that a mill blank having excellent mechanical strength can be provided. More preferred. In another preferred embodiment of the present invention, the inorganic filler (C) contains aggregated particles (C3) in which the inorganic ultrafine particles (C2) are aggregated, and the average particle size of the aggregated particles (C3) is 1 to 1. An embodiment of 20 μm is preferred. The content of the agglutinating particles (C3) in the inorganic filler (C) in the dental curable composition containing the agglutinating particles (C3) is preferably 90% by weight or more, more preferably 95% by weight or more, substantially. 100% by weight is more preferable.

Normally, commercially available ultrafine particle fillers exist as aggregates, but 10 mg of inorganic oxide powder is added to 300 mL of water (dispersion medium) to which water or a surfactant such as sodium hexametaphosphate of 5% by weight or less is added. However, when the dispersion treatment is performed for 30 minutes with an ultrasonic intensity of 40 W and a frequency of 39 KHz, it has only a weak cohesive force to disperse to the particle size indicated by the manufacturer. However, the aggregated particles (C3) in the present invention are particles in which particles that are hardly dispersed even under such conditions are strongly aggregated.

As the ultrafine particle filler (C2) constituting the agglomerated particles (C3), known ultrafine particle fillers used in dental curable compositions and the like can be used as long as the average particle size is 1.0 nm or more and less than 0.10 μm. It is used without any limitation, and examples thereof include the above-mentioned ultrafine particle filler (C2). Preferred examples thereof include inorganic oxide particles such as silica, alumina, titania and zirconia, or composite oxide particles composed of these, particles such as calcium phosphate, hydroxyapatite, ittrium fluoride and itterbium fluoride, and these ultrafine particles. The filler (C2) may be used alone or in combination of two or more.

As a method for producing cohesive particles (C3) used in the present invention from commercially available ultrafine particle fillers, in order to further increase the cohesive force, the fillers are heated to near the temperature just before melting, and the fillers in contact with each other are slightly in contact with each other. A method of heating to the extent that the particles are fused to the above is preferably used. Further, in this case, in order to control the shape of the agglomerated particles, the agglomerated morphology may be formed before heating. For example, a method of putting the filler in an appropriate container and pressurizing it, or once dispersing it in a solvent and then removing the solvent by a method such as spray drying can be mentioned.

Further, another suitable method for producing the agglutinated particles (C3) of the ultrafine particle filler is a method such as freeze-drying or spray-drying using silica sol, alumina sol, titania sol, zirconia sol or the like produced by a wet method. By drying with and heat-treating if necessary, agglomerated particles in which the particles are strongly aggregated can be easily obtained. Specific examples of the sol include Seahoster (registered trademark) manufactured by Nippon Shokubai Co., Ltd., OSCAL (registered trademark) manufactured by JGC Catalyst Kasei Co., Ltd., QUEENTITANIC, Snowtex (registered trademark) manufactured by Nissan Chemical Industries, Ltd. Nano-use (registered trademark) and the like can be mentioned. The shape of the ultrafine particle filler is not particularly limited, and can be appropriately selected and used.

Further, as the aggregated particles (C3), the surface of silica-based fine particles described in JP-A-2008-115136 is coated with a composite oxide composed of at least zirconium, silicon and oxygen, and is amorphous. Inorganic oxide fine particles (fillers) can also be preferably used.

In still another preferred embodiment, the inorganic filler (C) has an average particle size in the range of 1.0 nm or more and less than 0.10 μm and a specific surface area in the range of 30 to 500 m ² / g. Contains hybrid inorganic particles (C6) containing fine particles (C4) and inorganic particles (C5) having an average particle size in the range of 0.2 to 2.0 μm and a particle size range of 0.10 to 10 μm. It is preferable to do so. The composition in which both the inorganic ultrafine particles (C4) and the inorganic particles (C5) having an average particle diameter of 0.2 to 2.0 μm are blended (mixed) in this way is called a hybrid inorganic particle (C6). A dental mill blank with better mechanical strength can be provided. The content of the hybrid type inorganic particles (C6) in the inorganic filler (C) is preferably 90% by weight or more, more preferably 95% by weight or more, and substantially further preferably 100% by weight.

As the inorganic ultrafine particles (C4) in the hybrid type, the same ones as those of the ultrafine particle filler (C2) are used. On the other hand, the inorganic particles (C5) preferably have an average particle diameter of 0.2 μm or more, and more preferably 0.4 μm or more. The average particle size of the inorganic particles (C5) is preferably 2.0 μm or less, and more preferably 1.5 μm or less. Further, as the inorganic particles (C5), inorganic particles having a particle size range of 0.1 μm or more and 10 μm or less are preferable, and inorganic particles having a particle size range of 0.1 μm or more and 5.0 μm or less are more preferable. Further, as the inorganic particles (C5), the average particle size is in the range of 0.2 to 2.0 μm, and the particle size range is in the range of 0.1 to 5.0 μm, or the average particle size is Inorganic particles in the range of 0.4 to 1.5 μm and a particle size range of 0.1 to 10 μm are more preferred, with an average particle size in the range of 0.4 to 1.5 μm and grains. Inorganic particles having a diameter range of 0.1 to 5.0 μm are more preferable. As the inorganic particles (C5), inorganic particles having such an average particle size and particle size range and having a composition as exemplified by the submicron filler (C1) are used.

The weight ratio of the inorganic ultrafine particles (C4) to the inorganic particles (C5) (inorganic ultrafine particles (C4) / inorganic particles (C5)) in the hybrid type inorganic particles (C6) is preferably 1/1 to 1/20. / 3 to 1/10 is more preferable.

Specific examples of such hybrid inorganic particles (C6) include the following combinations. For example, as a specific example of the ultrafine particle filler (C4), inorganic oxide fine particles such as silica, alumina, zirconia, and titania, or composite oxide fine particles composed of these are preferable, and among these, high grade represented by the trade name Aerosil. Dispersible silica and highly dispersible alumina, titania, and zirconia represented by the trade name Aeroxide are more preferable. Further, as the inorganic particles (C5) to be combined with these, the above-mentioned barium boroaluminosilicate glass, lantern glass, strontium boroaluminosilicate glass, feldspar, mulite, quartz, Pyrex (registered trademark) glass, silica glass and the like are suitable. Used for.

Further, in the present invention, inorganic particles that have been surface-treated in advance can be used as the inorganic filler. By applying the surface treatment, the mechanical strength of the obtained mill blank is improved. Further, the inorganic filler is pressure-molded, and the obtained aggregate of the inorganic particles (inorganic filler molded product) is brought into contact with a polymerizable monomer described later, and the polymerizable simple substance is formed in the aggregation gap of the inorganic particles. There is also an advantage that the surface of the inorganic particles and the polymerizable monomer become more familiar with each other when the body is invaded, and the polymerizable monomer easily penetrates into the agglomerate gap. When the hybrid type inorganic particles (C6) are surface-treated with a surface treatment agent, the inorganic ultrafine particles (C4) and the inorganic particles (C5) in the hybrid type are surface-treated and then mixed and hybridized. The type inorganic particles may be used, or a mixture of the inorganic ultrafine particles (C4) and the inorganic particles (C5) may be surface-treated.

As such a surface treatment agent, a known surface treatment agent can be used, and an organic silicon compound; an organic metal compound such as an organic titanium compound, an organic zirconium compound, and an organic aluminum compound; and a phosphoric acid group, a pyrophosphate group, and a thiophosphate group can be used. An acidic group-containing organic compound having at least one acidic group such as a group, a phosphonic acid group, a sulfonic acid group, and a carboxylic acid group can be used. When two or more kinds of surface treatment agents are used, the surface treatment layer may be a mixture of two or more kinds of surface treatment agents, or may be a surface treatment layer having a multi-layer structure in which a plurality of surface treatment agent layers are laminated. Further, as the surface treatment method, a known method can be used without particular limitation.

Examples of the organic silicon compound include compounds represented by R ¹ _n SiX _(4-n) (in the formula, R ¹ is a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, and X is a carbon. It represents an alkoxy group, an acetoxy group, a hydroxy group, a halogen atom or a hydrogen atom of the number 1 to 4, and n is an integer of 0 to 3, but when there are a plurality of R ¹ and X, they are the same or different. May be).

Specifically, for example, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, β- (3) , 4-Epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane , Γ-Methacryloxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ- Aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, trimethylsilanol, methyltrichlorosilane, methyl Dichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, vinyltrichlorosilane, trimethylbromosilane, diethylsilane, vinyltriacetoxysilane, ω- (meth) acryloxialkyltrimethoxysilane [(meth) acryloxy Number of carbon atoms between group and silicon atom: 3-12, eg, γ-methacryloxypropyltrimethoxysilane], ω- (meth) acryloxyalkyltriethoxysilane [(meth) acryloxy group and silicon atom Number of carbon atoms between: 3 to 12, eg, γ-methacryloxypropyltriethoxysilane, etc.] and the like. In the present invention, the notation "(meth) acryloxy" is used to include both methacryloxy and acryloxy.

Among these, a coupling agent having a functional group capable of copolymerizing with a polymerizable monomer, for example, ω- (meth) acryloxyalkyltrimethoxysilane [(meth) carbon number between acryloxy group and silicon atom: 3-12], ω- (meth) acryloxyalkyltriethoxysilane [number of carbon atoms between (meth) acryloxy group and silicon atom: 3-12], vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxy Silane, γ-glycidoxypropyltrimethoxysilane and the like are preferably used.

Examples of the organic titanium compound include tetramethyl titanate, tetraisopropyl titanate, tetra n-butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate and the like.

Examples of the organic zirconium compound include zirconium isopropoxide, zirconium n-butoxide, zirconium acetylacetonate, zirconium acetate and the like.

Examples of the organoaluminum compound include aluminum acetylacetonate and aluminum organolate chelate compounds.

Examples of the acidic group-containing organic compound containing a phosphoric acid group include 2-ethylhexyl acid phosphate, stearyl acid phosphate, 2- (meth) acryloyloxyethyl dihydrogen phosphate, 3- (meth) acryloyloxypropyl dihydrogen phosphate, and 4- (Meta) acryloyloxybutyl dihydrogen phosphate, 5- (meth) acryloyloxypentyl dihydrogen phosphate, 6- (meth) acryloyloxyhexyl dihydrogen phosphate, 7- (meth) acryloyloxyheptyl dihydrogen Phosphate, 8- (meth) acryloyloxyoctyldihydrogen phosphate, 9- (meth) acryloyloxynonyldihydrogenphosphate, 10- (meth) acryloyloxydecyldihydrogenphosphate, 11- (meth) acryloyloxyundecyl Dihydrogen phosphate, 12- (meth) acryloyl oxide decyl dihydrogen phosphate, 16- (meth) acryloyloxyhexadecyldihydrogen phosphate, 20- (meth) acryloyloxyicosyl dihydrogen phosphate, bis [2- (Meta) acryloyloxyethyl] hydrogen phosphate, bis [4- (meth) acryloyloxybutyl] hydrogen phosphate, bis [6- (meth) acryloyloxyhexyl] hydrogen phosphate, bis [8- (meth) acryloyloxy Octyl] hydrogen phosphate, bis [9- (meth) acryloyloxynonyl] hydrogen phosphate, bis [10- (meth) acryloyloxydecyl] hydrogen phosphate, 1,3-di (meth) acryloyloxypropyl dihydrogen Phosphate, 2- (meth) acryloyloxyethyl phenylhydrogen phosphate, 2- (meth) acryloyloxyethyl-2-bromoethyl hydrogen phosphate, bis [2- (meth) acryloyloxy- (1-hydroxymethyl) ethyl] Examples thereof include hydrogen phosphate, acid groups thereof, alkali metal salts, ammonium salts and the like.

Further, as the acidic group-containing organic compound having an acidic group such as a pyrophosphate group, a thiophosphate group, a phosphonic acid group, a sulfonic acid group, and a carboxylic acid group, for example, those described in WO2012 / 042911 are preferably used. Can be done.

The above-mentioned surface treatment agent may be used alone or in combination of two or more. In addition, an acidic group-containing organic compound having a functional group that can be copolymerized with the polymerizable monomer in order to enhance the chemical bond between the inorganic filler and the polymerizable monomer and improve the mechanical strength of the cured product. Is more preferable to use.

The amount of the surface treatment agent used is not particularly limited, and for example, 0.1 to 50 parts by weight is preferable with respect to 100 parts by weight of the inorganic filler (C).

Here, the blending amount of the inorganic filler (C) is preferably 100 to 400 parts by weight, more preferably 150 to 300 parts by weight, based on 100 parts by weight of the polymerizable monomer (A).

In addition to the above components, the dental curable composition used in the present invention includes a photopolymerization initiator, a pH adjuster, an ultraviolet absorber, an antioxidant, a polymerization inhibitor, a colorant, a pigment, and an antibacterial agent, depending on the purpose. It is also possible to further add agents, X-ray contrast agents, thickeners, fluorescent agents and the like.

A polymerizable monomer-containing composition containing the polymerizable monomer (A) and the heat polymerization initiator (B) is produced, and the inorganic filler (C) is mixed to produce the dental curable composition of the present invention. In the case of producing a product, the contact method between the polymerizable monomer-containing composition and the inorganic filler (C) is not particularly limited, but a simple and preferable method is 1) the polymerizable monomer-containing composition. Immersing the molded product of the inorganic filler (C) in the mixture, or 2) kneading the polymerizable monomer-containing composition and the inorganic filler (C).

As the contact method of 1) above, specifically, the inorganic filler (C) is filled in a pressing die of a desired size and pressed by a uniaxial press using an upper punch and a lower punch to be inorganic. A filler (C) molded product can be obtained. By immersing the molded product of the inorganic filler (C) in the composition containing a polymerizable monomer, the monomer can gradually permeate into the molded product due to the capillary phenomenon.

At this time, it is preferable to place the surrounding environment in a reduced pressure atmosphere because it promotes the permeation of the liquid monomer. Further, repeating the operation of returning to normal pressure (decompression / normal pressure operation) a plurality of times after the depressurization operation is effective for shortening the time of the step of completely permeating the monomer into the molded product. The degree of decompression at this time is appropriately selected depending on the viscosity of the monomer (A) and the particle size of the inorganic filler (C), but is usually 100 hectopascals (10 kPa) or less, preferably 0.001 to 50 hectopascals (preferably 0.001 to 50 hectopascals). It is in the range of 0.0001 to 5 kPa), more preferably 0.1 to 20 hectopascals (0.01 to 2 kPa). Further, it may be under vacuum (1 × 10 ^-8 to 1 × 10 ^-1 Pa).

Further, as a method other than dipping, a method of feeding the polymerizable monomer-containing composition into the inorganic filler molded product in the mold by applying pressure as it is in the state of being press-molded by the mold can be considered. By adopting this method, the step of polymerization curing can be continued as it is in the mold. The pressurizing condition is preferably 2 MPa or more, more preferably 10 MPa or more, still more preferably 20 MPa or more.

Further, as a method of allowing the polymerizable monomer (A) to penetrate into the inorganic filler (C) molded product without gaps, the inorganic filler (C) molded product apparently impregnated with the polymerizable monomer (A). There is a method of placing the product under pressurization conditions for a certain period of time. That is, it is desirable that the inorganic filler (C) molded product impregnated with the polymerizable monomer (A) is placed under pressure conditions together with the polymerizable monomer (A) using a CIP device or the like. The pressurizing condition is preferably 20 MPa or more, more preferably 50 MPa or more, still more preferably 100 MPa or more. Further, it is more preferable to repeat the pressurization / normal pressure by releasing the pressurization, returning to the normal pressure, and pressurizing again.

In addition, the viscosity of the polymerizable monomer-containing composition affects the permeation rate, and the lower the viscosity, the faster the permeation. The preferable viscosity range (25 ° C.) is 10 Pa · s or less, more preferably 5 Pa · s or less, still more preferably 2 Pa · s or less, but the selection of the polymerizable monomer (A) is mechanical in addition to the viscosity. It is necessary to take into account the strength and refractive index. In addition, the polymerizable monomer-containing composition may be diluted with a solvent and used, and the solvent may be distilled off by a subsequent decompression operation. Further, the viscosity of the polymerizable monomer composition is lowered by raising the temperature to a range of preferably 25 ° C. or higher, more preferably 30 ° C. or higher, preferably 70 ° C. or lower, and more preferably 60 ° C. or lower. It can also accelerate penetration.

The time for contacting the polymerizable monomer-containing composition with the inorganic filler (C) molded product varies depending on the type of the inorganic filler (C), the size of the molded product, the degree of penetration of the monomer, the contact method, and the like. Is not determined and can be adjusted as appropriate. For example, contact by immersion usually takes 1 to 120 hours, immersion under reduced pressure usually takes 0.5 to 12 hours, and contact under pressure usually 0.2 to 6 hours. It's time.

As the contact method of 2) above, specifically, the present invention can be produced from a paste-like composite resin obtained by kneading a polymerizable monomer-containing composition and an inorganic filler (C). is there. At this time, a process such as vacuum defoaming can be performed as needed.

As a molding method, a composite resin may be poured into a mold and press-molded to process the composite resin into a desired shape. Further, the polymerization curing step can be continued as it is in the mold. The pressurizing condition is preferably 2 MPa or more, more preferably 10 MPa or more, still more preferably 20 MPa or more. By heating with the completion of pressurization, it is possible to obtain a mill blank by polymerization curing.

Next, polymerization curing of the dental curable composition containing the polymerizable monomer (A) thermal polymerization initiator (B) is performed.

The polymerization curing can be carried out by heat polymerization, and the conditions thereof can be carried out according to a known method. In particular, in the present invention, from the viewpoint of suppressing the occurrence of cracks and obtaining a mill blank having higher mechanical strength even after long-term storage in water, the temperature of the first heat polymerization after the first heat polymerization is performed. It is preferable to carry out the second heat polymerization at a higher temperature.

The temperature of the first heat polymerization is preferably the half-life temperature (τ1) -25 ° C to (τ1) -15 ° C of the monofunctional initiator (b-1). The temperature of the second heat polymerization is preferably higher than the temperature of the first heat polymerization, and the half-life temperature (τ2) of the polyfunctional initiator is preferably −10 ° C. to (τ2) + 30 ° C. The polymerization time of the first heat polymerization is preferably 1 to 30 hours, more preferably 2 to 10 hours. The polymerization time of the second heat polymerization is preferably 2 to 50 hours, more preferably 3 to 30 hours.

Further, at the time of polymerization curing, by polymerizing the dental curable composition in an inert atmosphere such as nitrogen gas or in a reduced pressure environment, the polymerization rate can be increased and the mechanical strength can be further increased.

Thus, the manufacturing method of the present invention provides a dental mill blank. The obtained mill blank is cut, cut, and surface-polished to a desired size as needed, and then shipped as a product. The dental mill blank obtained by the present invention can realize high mechanical strength without cracking during polymerization as compared with a conventional general dental mill blank. Further, the dental mill blank of the present invention has excellent storage stability in water, and after storage in water for one month, the rate of decrease in bending strength is 15% or less as compared with that before storage in water. preferable.

It is desirable that the size of the dental mill blank of the present invention be processed to an appropriate size so that it can be set in a commercially available dental CAD / CAM system. Desirable sizes include, for example, a 40 mm × 20 mm × 15 mm prism suitable for creating a single tooth missing bridge, a 17 mm × 10 mm × 10 mm prism suitable for creating an inlay or onlay, and a 14 mm suitable for creating a full crown. Examples thereof include a prismatic shape of × 18 mm × 20 mm, a disk shape having a diameter of 100 mm and a thickness of 10 to 28 mm, which is suitable for producing a long span bridge and a denture base, but the size is not limited to these.

Dental prostheses manufactured from the mill blank of the present invention include, for example, crown restorations such as inlays, onlays, onlays, veneers, crowns and bridges, as well as abutment teeth, dental posts, dentures and denture bases. , Implant members (fixtures, abutments) and the like. Further, the cutting process is preferably performed using, for example, a commercially available dental CAD / CAM system. Examples of such a CAD / CAM system include the CEREC system of Sirona Dental Systems and the Katana system of Kuraray Noritake Dental.

Further, the mill blank obtained in the present invention can be used for applications other than dental applications, for example, electronic material applications such as encapsulation materials and laminated plate molding materials, general-purpose composite material members, for example. It can also be used as a part for construction, electrical appliances, household goods, and toys.

The present invention includes various combinations of the above configurations within the technical scope of the present invention as long as the effects of the present invention are exhibited.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples, and many modifications are made in the art within the technical idea of the present invention. It is possible by a person with ordinary knowledge.

Polymerizable monomer (A)
UDMA: 2,2,4-trimethylhexamethylenebis (2-carbamoyloxyethyl) dimethacrylate TEGDMA: triethylene glycol dimethacrylate Bis-GMA: bisphenol A diglycidyl methacrylate (2,2-bis [4- [3-methacryloyl) Oxy-2-hydroxypropoxy] phenyl] propane)

Heat polymerization initiator (B)
Monofunctional polymerization initiator (b-1)
BPO: Benzoyl peroxide (τ1 = 73.6 ° C, manufactured by NOF CORPORATION)
AIBN: 2,2'-azobis (2-methylpropionitrile) (τ1 = 65 ° C., manufactured by Sigma-Aldrich)
Perbutyl Z: t-butylperoxybenzoate (τ1 = 104.3 ° C., manufactured by NOF CORPORATION)
Dikmyl peroxide: (τ1 = 115 ° C, manufactured by Sigma-Aldrich)
Polyfunctional polymerization initiator (b-2)
Perhexa V: n-Butyl-4,4-di (t-Butylperoxy) Valerate (τ2 = 104.5 ° C, manufactured by NOF CORPORATION)
Perhexa C: 1,1-di (t-butylperoxy) cyclohexane (τ2 = 90.7 ° C, manufactured by NOF CORPORATION)
Perhexa HC: 1,1-di (t-hexyl peroxy) cyclohexane (τ2 = 87.1 ° C, manufactured by Nichiyu Co., Ltd.)
Pertetra A: 2,2-bis (4,5-G t-butylperoxycyclohexyl) propane (τ2 = 94.7 ° C, manufactured by NOF CORPORATION)

Inorganic filler (C)
OX 50: Fine particle silica (average primary particle diameter 0.04 μm, BET specific surface area 50 m ² / g, manufactured by Nippon Aerosil)
Si-YbF ₃ : Ytterbium fluoride spherical filler (average primary particle size 0.10 μm, silica coating, manufactured by Suklyung)
UF2.0: Barium glass (average primary particle size 2.0 μm, manufactured by Schott)
NF180: Barium glass (average primary particle size 0.180 μm, manufactured by Schott)

[Production Example 1 of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (m-1) was prepared by dissolving 0.5 part by weight of BPO and 0.5 part by weight of perhexa V as the heat polymerization initiator (B) in 70 parts by weight of UDMA and 30 parts by weight of TEGDMA. ..

[Production Example 2 of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (m-2) was prepared by dissolving 0.5 part by weight of BPO and 0.5 part by weight of perhexa C as a heat polymerization initiator (B) in 70 parts by weight of UDMA and 30 parts by weight of TEGDMA. ..

[Production Example 3 of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (m-3) was prepared by dissolving 0.5 part by weight of BPO and 0.5 part by weight of perhexa HC as the heat polymerization initiator (B) in 70 parts by weight of UDMA and 30 parts by weight of TEGDMA. ..

[Production Example 4 of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (m-4) was prepared by dissolving 0.5 part by weight of BPO and 0.5 part by weight of Pertetra A as the heat polymerization initiator (B) in 70 parts by weight of UDMA and 30 parts by weight of TEGDMA. ..

[Production Example 5 of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (m-5) was prepared by dissolving 0.5 part by weight of AIBN and 0.5 part by weight of perhexa V as a heat polymerization initiator (B) in 70 parts by weight of UDMA and 30 parts by weight of TEGDMA. ..

[Production Example 6 of Polymerizable Monomer-Containing Composition]
The polymerizable monomer-containing composition (m-6) was prepared by dissolving 0.5 part by weight of BPO and 0.5 part by weight of perhexa V as the heat polymerization initiator (B) in 70 parts by weight of Bis-GMA and 30 parts by weight of TEGDMA. Prepared.

[Production Example 7 of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (m-7) was prepared by dissolving 1 part by weight of BPO and 2 parts by weight of perhexa V as the heat polymerization initiator (B) in 70 parts by weight of UDMA and 30 parts by weight of TEGDMA.

[Production Example 8 of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (m-8) was prepared by dissolving 0.1 part by weight of BPO and 0.1 part by weight of perhexa V as the heat polymerization initiator (B) in 70 parts by weight of UDMA and 30 parts by weight of TEGDMA. ..

[Production Example 9 of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (m-9) was prepared by dissolving 0.5 part by weight of BPO and 0.5 part by weight of perbutyl Z as a heat polymerization initiator (B) in 70 parts by weight of UDMA and 30 parts by weight of TEGDMA. ..

[Production Example 10 of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (m-10) was prepared by dissolving 1 part by weight of BPO as the heat polymerization initiator (B) in 70 parts by weight of UDMA and 30 parts by weight of TEGDMA.

[Production Example 11 of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (m-11) was prepared by dissolving 1 part by weight of Perhexa V as a heat polymerization initiator (B) in 70 parts by weight of UDMA and 30 parts by weight of TEGDMA.

[Production Example 12 of Polymerizable Monomer-Containing Composition]
A polymerizable monomer-containing composition (m-12) was prepared by dissolving 1 part by weight of dicumyl peroxide as a heat polymerization initiator (B) in 70 parts by weight of UDMA and 30 parts by weight of TEGDMA.

[Production Example 1 of Inorganic Particles]
100 parts by weight of OX 50 was dispersed in 500 parts by weight of ethanol, 7 parts by weight of γ-methacryloxypropyltrimethoxysilane and 5 parts by weight of water were added, and the mixture was stirred at room temperature for 2 hours. The solvent was distilled off under reduced pressure, and the surface was further treated by drying at 90 ° C. for 3 hours to obtain inorganic particles (c-1).

[Production Example 2 of Inorganic Particles]
100 parts by weight of Si-YbF ₃ was dispersed in 500 parts by weight of ethanol, 4 parts by weight of γ-methacryloxypropyltrimethoxysilane and 5 parts by weight of water were added, and the mixture was stirred at room temperature for 2 hours. The solvent was distilled off under reduced pressure, and the surface was further treated by drying at 90 ° C. for 3 hours to obtain spherical inorganic particles (c-2).

[Production Example 3 of Inorganic Particles]
80 parts by weight of UF2.0 and 20 parts by weight of NF180 are dispersed in 300 parts by weight of ethanol, and 5 parts by weight of γ-methacryloxypropyltrimethoxysilane, 0.15 parts by weight of acetic acid, and 5 parts by weight of water are added at room temperature. Stirred for 2 hours. The solvent was distilled off under reduced pressure, and the surface was further treated by drying at 90 ° C. for 3 hours to obtain inorganic particles (c-3).

[Example 1]
4.5 g of the surface-treated inorganic particles (c-1) obtained in the above production example was laid on a lower punch rod of a pressing die having a rectangular hole of 14.5 mm × 18 mm. The powder of the inorganic particles (c-1) was smoothed by tapping, the upper punch rod was set on the top, and a uniaxial press (press pressure 38.3 MPa, time was 2 minutes) was performed using a table press machine. The upper punch rod and the lower punch rod were removed from the mold, and the press-molded product in which the powder was agglomerated was taken out. The size of the press-molded product was a rectangular parallelepiped of 14.5 mm × 18 mm × 15 mm. The press-molded product was immersed in the polymerizable monomer composition (m-1). After allowing to stand in a dark place for 24 hours at room temperature, the pressure was reduced and degassed (10 hectopascals, 10 minutes) while being immersed. The reduced pressure was released, and the molded product impregnated with the polymerizable monomer was taken out to obtain a translucent polymerized monomer-impregnated molded product. When this translucent polymerizable monomer-impregnated molded product was visually confirmed, no bubbles were observed inside. Next, the molded product impregnated with the polymerizable monomer was heated at 55 ° C. for 4 hours using a hot air dryer, and then heat-treated at 110 ° C. for 7 hours to obtain a mill blank.

[Examples 2 to 6]
The same operation as in Example 1 was carried out except that the polymerizable monomer compositions (m-2) to (m-6) were used instead of the polymerizable monomer composition (m-1). A rectangular parallelepiped mill blank free from bubbles and defects similar to Example 1 was obtained as Examples 2 to 6.

[Example 7]
11 g of a mixed powder of the inorganic particles (c-1) and the inorganic particles (c-2) was laid on a lower punch rod of a pressing die having a rectangular hole of 24 mm × 33 mm. The mixed powder was smoothed by tapping, the upper punch rod was set on the top, and a uniaxial press (press pressure 38.9 MPa, time was 5 minutes) was performed using a table press machine. The upper punch rod and the lower punch rod were removed from the mold, and the press-molded product in which the powder was agglomerated was taken out. The size of the press-molded body was a rectangular parallelepiped of 24 mm × 33 mm × 11.5 mm. The press-molded product was immersed in the polymerizable monomer composition (m-1). After allowing to stand in a dark place at 30 ° C. for 24 hours, the pressure was reduced and degassed (10 hectopascals, 10 minutes) while being immersed. The reduced pressure was released, and the molded product impregnated with the polymerizable monomer was taken out to obtain a translucent polymerized monomer-impregnated molded product. When this translucent polymerizable monomer-impregnated molded product was visually confirmed, no bubbles were observed inside. Next, the molded product impregnated with the polymerizable monomer was heated at 55 ° C. for 4 hours using a hot air dryer, and then heat-treated at 110 ° C. for 7 hours to obtain a mill blank.

[Example 8]
6.5 g of the surface-treated inorganic particles (c-3) obtained in the above production example was laid on a lower punch rod of a pressing die having a rectangular hole of 14.5 mm × 18 mm. The powder of the inorganic particles (c-3) was smoothed by tapping, the upper punch rod was set on the top, and a uniaxial press (press pressure 38.3 MPa, time 2 minutes) was performed using a table press machine. The upper punch rod and the lower punch rod were removed from the mold, and the press-molded product in which the powder was agglomerated was taken out. The size of the press-molded product was a rectangular parallelepiped of 14.5 mm × 18 mm × 15 mm. The press-molded product was immersed in the polymerizable monomer composition (m-1). After allowing to stand in a dark place for 24 hours at room temperature, the pressure was reduced and degassed (10 hectopascals, 10 minutes) while being immersed. The reduced pressure was released, and the molded product impregnated with the polymerizable monomer was taken out to obtain a translucent polymerized monomer-impregnated molded product. When this translucent polymerizable monomer-impregnated molded product was visually confirmed, no bubbles were observed inside. Next, the molded product impregnated with the polymerizable monomer was heated at 55 ° C. for 4 hours using a hot air dryer, and then heat-treated at 110 ° C. for 7 hours to obtain a mill blank.

[Example 9]
25 parts by weight of the polymerizable monomer composition (m-1) is mixed and kneaded with 75 parts by weight of the inorganic particles (c-3) to make it uniform, and then vacuum defoamed to obtain a paste-like dental curability. The composition was adjusted. Next, the dental curable composition was poured into a 14.5 mm × 14.5 mm × 18 mm rectangular die, oxygen was removed by press evacuation, and press molding was performed at 50 MPa to obtain a press molded body. The molded product was heated at 55 ° C. for 4 hours and then heat-treated at 110 ° C. for 7 hours to obtain a mill blank.

[Example 10]
The same operation as in Example 1 was performed except that the polymerizable monomer composition (m-7) was used instead of the polymerizable monomer composition (m-1), and the same procedure as in Example 1 was performed. A polymerizable monomer-impregnated molded product was obtained. Next, the molded product impregnated with the polymerizable monomer was heated at 60 ° C. for 7 hours using a hot air dryer, and then heat-treated at 130 ° C. for 12 hours to obtain a mill blank.

[Example 11]
The same operation as in Example 1 was performed except that the polymerizable monomer composition (m-8) was used instead of the polymerizable monomer composition (m-1), and the same procedure as in Example 1 was performed. A polymerizable monomer-impregnated molded product was obtained. Next, the molded product impregnated with the polymerizable monomer was heated at 55 ° C. for 2 hours using a hot air dryer, and then heat-treated at 90 ° C. for 3 hours to obtain a mill blank.

[Comparative Examples 1 to 4]
The same operation as in Example 1 was carried out except that the polymerizable monomer compositions (m-9) to (m-12) were used instead of the polymerizable monomer composition (m-1). A rectangular parallelepiped polymerizable monomer-impregnated molded product having no bubbles or defects similar to Example 1 was obtained. When this translucent polymerizable monomer-impregnated molded product was visually confirmed, no bubbles were observed inside. Next, the molded product impregnated with the polymerizable monomer was heated at 55 ° C. for 4 hours using a hot air dryer, and then heat-treated at 110 ° C. for 7 hours.

[Test Example 1]
The occurrence of cracks in the mill blanks obtained in each Example and Comparative Example was evaluated by the following method. The presence or absence of cracks on the surface of the manufactured mill blank was evaluated using a magnifying microscope (magnification × 10). In addition, the presence or absence of internal cracks was evaluated using ultrasonic flaw detection. The numerical value of "crack generation during polymerization" in Tables 1 and 2 below represents the number of mill blanks in which cracks have occurred among the 10 mill blanks produced.

[Test Example 2]
The flexural strength of the mill blanks obtained in each Example and Comparative Example was measured by the following method. That is, a test piece (1.2 mm × 4 mm × 14 mm) was prepared from the produced mill blank using a diamond cutter, and polished with # 1000 abrasive paper. The bending strength of the test piece was measured by a three-point bending test method using a universal testing machine (manufactured by Instron) at a crosshead speed of 1 mm / min and a distance between fulcrums of 12 mm. After that, the test piece is immersed in water at 37 ° C. for one month, and the bending strength is determined by a three-point bending test method using a universal testing machine (manufactured by Instron) in the same manner as before immersion in water. It was measured. It is preferable that the bending strength after being immersed in water at 37 ° C. for one month is 200 MPa or more.

[Test Example 3]
The color stability of the mill blanks obtained in each Example and Comparative Example was measured by the following method. A test piece (10 mm × 10 mm × 1 mm) was prepared from the produced mill blank using a diamond cutter. The clean smooth surface of the test piece was polished in the order of # 1000 abrasive paper, # 2000 abrasive paper, # 3000 abrasive paper, and wrapping film under dry conditions. The test piece was stored in water at 37 ° C., and when stored for a predetermined day, it was taken out and color tone measurement was performed using a colorimeter (spectrophotometer CM-3610d, manufactured by Konica Minolta, light source D65 / 2). The color stability (ΔE *) was determined according to the following formula. ΔE * <1.0 is preferable.
ΔE * = [(ΔL *) ² + (Δa *) ² + (Δb *) ² ] ^1/2
(In the formula, ΔL *, Δa *, Δb * are the brightness index L *, the color coordinates a *, b * before and after storage in water in the L * a * b * color system (JIS Z 8781-4: 2013). Represents the difference between

The measurement results of each test are shown in Tables 1 and 2 below.

In Examples 1 to 5, no cracks were confirmed during the heat polymerization of the dental curable composition. On the other hand, in Comparative Example 1, instead of the polyfunctional polymerization initiator (b-2), a monofunctional polymerization initiator not contained in the monofunctional polymerization initiator (b-1) is used to initiate monofunctional polymerization. The one used together with the agent (b-1) had cracks. Further, even when only the polyfunctional polymerization initiator (b-2) of Comparative Example 3 was used, the occurrence of cracks was confirmed during the heat polymerization.

From the comparison between Examples 1 to 5 and Comparative Example 2, the mill blank produced from the dental polymerizable composition of the present invention exceeds 200 MPa even after being immersed in water at 37 ° C. for one month, and has excellent mechanical strength. It became clear. Further, from the comparison between Examples 1 to 5 and Comparative Example 2, the mill blank produced from the dental polymerizable composition of the present invention had excellent color stability.

In Example 6, even when the type of the polymerizable monomer (A) was changed, no cracks were generated during the polymerization, and a mill blank having excellent mechanical strength and color tone stability could be obtained.

In Example 7, even when two different types of inorganic fillers (C) were used, no cracks were generated during polymerization, and a mill blank having excellent mechanical strength and color stability could be obtained.

The mechanical strength of the mill blank obtained in Example 8 was very excellent, and exceeded 240 MPa even after being immersed in water at 37 ° C. for one month.

From the comparison of Examples 8 and 9, by using the dental polymerizable composition of the present invention regardless of the method for producing the mill blank, no cracks were generated during polymerization, and the mechanical strength and color tone stability were excellent. It was confirmed that a mill blank could be obtained.

In Examples 10 and 11, even when the amount of the heat polymerization initiator (B) and the polymerization temperature are changed, cracks do not occur during polymerization, and a mill blank having excellent mechanical strength and color tone stability can be obtained. It was.

From the above results, by using the dental polymerizable composition of the present invention, it is possible to obtain a dental mill blank that has a low risk of cracking during polymerization, has excellent mechanical strength, and reproduces high aesthetics. It was revealed.

When the dental polymerizable composition of the present invention is used, a dental prosthesis having a low risk of cracking during polymerization and excellent mechanical strength can be obtained. Further, the dental curable composition of the present invention is suitably used as a dental mill blank. That is, it is suitably used for producing a dental prosthesis having high mechanical strength, excellent sliding durability, and color stability by cutting using a CAD / CAM system.

Claims (7)

Containing a polymerizable monomer (A), a heat polymerization initiator (B) and an inorganic filler (C),
The heat polymerization initiator (B) has a monofunctional polymerization initiator (b-1) having a 10-hour half-life temperature (τ1) of 50 to 75 ° C. and a 10-hour half-life temperature (τ2) of 80 to 120 ° C. The heat polymerization initiator (B) is 0.1 to 5 parts by weight with respect to 100 parts by weight of the polymerizable monomer (A), which contains the polyfunctional polymerization initiator (b-2) . Dental curable composition. In the thermal polymerization initiator (B), the blending amount of the monofunctional polymerization initiator (b-1) is 20 to 70% by weight, and the blending amount of the polyfunctional polymerization initiator (b-2) is 30 to 80. by weight%, the dental curable composition according to claim 1. The dental curable composition according to claim 1 or 2 , which contains 100 to 400 parts by weight of the inorganic filler (C) with respect to 100 parts by weight of the polymerizable monomer (A). A dental mill blank comprising a cured product of the dental curable composition according to any one of claims 1 to 3 . A method for producing a dental mill blank, which comprises a step of heat-polymerizing the dental curable composition according to any one of claims 1 to 3 . The step of heat polymerization includes first polymerization and second polymerization, the temperature of the first polymerization is (τ1) -25 ° C to (τ1) -15 ° C, and the temperature of the second polymerization is (τ2) −. The method for producing a dental mill blank according to claim 5 , wherein the temperature is from 10 ° C. to (τ2) + 30 ° C. The method for producing a dental mill blank according to claim 6 , wherein the first polymerization time is 1 to 30 hours and the second polymerization time is 2 to 50 hours.