Dental Polymerizable Hardening Composition

Abstract

To provide dental curable compositions containing a relatively simple inorganic filler, the compositions providing cured products with good mechanical and physical properties, having fluidity applicable to deep cavities, not only enabling aesthetic restoration but having paste properties enabling easily handling with a syringe, and further having good shape retention.SOLUTION: In a dental polymerization curable composition containing a polymerizable monomer (A), an inorganic filler (B), and a polymerization initiator (C), as at least a part of the inorganic filler (B), an inorganic particle (B1) that is treated with a surfactant and a hydrophobizing agent and has an average particle size of 0.05 μm or more and 1 μm or less is used.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a dental polymerizable and hardenable composition that can be suitably used as a dental composite resin, particularly as a dental composite resin for core construction. [Background technology]

[0002] Dental composite resins are widely used as materials for restoring teeth because they can impart a color tone equivalent to that of natural teeth and are easy to handle during tooth restoration work. Dental composite resins are primarily composed of polymerizable monomers, inorganic fillers, and polymerization initiators, with the components optimized for each application.

[0003] For example, when it comes to polymerization initiators, dental composite resins containing photopolymerization initiators are used for restoring shallow cavities that require aesthetic results because they are easy to use and cure in a short time, which reduces the burden on the patient.Photopolymerization initiators are often used that are inactive in weak light such as ambient light, but highly active in high-intensity light irradiation from a light curing device, allowing the composite resin to cure rapidly.

[0004] On the other hand, chemical polymerization initiators are primarily used to restore deep cavities where light is difficult to reach. Chemical polymerization initiators typically consist of two or more polymerization initiator components (e.g., organic peroxide and tertiary amine). Upon application, all of these components are brought into contact to generate polymerization-initiating species. Using a chemical polymerization initiator that cures at room temperature allows for curing deep areas where light cannot reach. Dental composite resins that use chemical polymerization initiators are typically packaged in two pastes to prevent the radically polymerizable monomers from polymerizing before use, so that all of the chemical polymerization initiator components (e.g., organic peroxide and tertiary amine) are not mixed together. These two pastes are then mixed together at the time of use.

[0005] Furthermore, when constructing a core on the root of a tooth after pulpectomy, so-called dual-cure composite resins, which combine the properties of both light-curing and chemical-curing, are sometimes used (see Patent Documents 1, 2, and 3). Here, core construction refers to filling and curing a deep cavity, such as the root of a tooth after pulpectomy, with a composite resin (possibly followed by post fixation), followed by building up a dental composite resin (usually of the same composition) into the shape of the core to create a core for a crown prosthesis. After the built-up paste hardens, the final core shape is usually achieved by correcting the shape using a grinding tool. When dual-cure composite resins are used for core construction, the chemical polymerization initiator allows for good curing in deep cavities, and the photopolymerization initiator allows for efficient and easy core construction.

[0006] The dual-cure dental composite resin described above uses a chemical polymerization initiator, and therefore the chemical polymerization initiator component is provided separately in two separate packages. The photopolymerization initiator is also separately packaged accordingly, and is typically provided as a first paste containing an organic peroxide (part of the chemical polymerization initiator) and an α-diketone compound, and optionally a photoacid generator (part of the photopolymerization initiator), and a second paste containing a tertiary amine (the remainder of the chemical polymerization initiator) and a reducing agent (the remainder of the photopolymerization initiator; however, the tertiary amine may also serve as a reducing agent) (see Patent Documents 1, 2, and 3).

[0007] Since abutments require high mechanical strength, dental composite resins for core construction often contain a large amount of inorganic filler, and in such cases, both of the individually packaged pastes have high viscosity. For example, the paste shown in Table 1 of Patent Document 1 contains 400 to 415 parts by mass of inorganic filler for 100 parts by mass of polymerizable monomer, and its viscosity is 970 to 1960 poise.

[0008] These two pastes need to be mixed before use, but mixing them separately and filling the resulting mixture into a syringe before use is not practical due to time constraints (i.e., polymerization hardening begins upon mixing, making it difficult to complete all of these operations within the limited operating time), and the effort required. Therefore, a dedicated tool that can simultaneously perform mixing and syringe extrusion is used. That is, as described in the examples of Patent Documents 2 and 3, the two pastes are provided by filling the cylinders of each syringe of a so-called double syringe in which two syringes are connected in parallel, and then set in a dedicated dispenser, and a nozzle tip with an automatic mixing function is attached to the tip of the double syringe. It is common to simultaneously mix and extrude the paste by pressing the pistons of both syringes simultaneously using the dispenser. The nozzle tip has a so-called inverted Y-shaped flow path (where two flow paths merge) inside, and the two flow paths before merging are connected to the outlets of each syringe at the connection part with the double syringe. A kneading section is provided in the flow path from the merging part to the outlet of the nozzle tip to knead the paste extruded from each syringe, and the structure is such that the paste kneaded in the kneading section can be extruded from the outlet.

[0009] When kneading and filling cavities with the kneaded dental composite resin using such dedicated kneading tools, various ingenious approaches have been taken with regard to the blending of fillers from the viewpoints of the mechanical and physical properties of the hardened body, the fluidity and dischargeability during filling, and the shape retention during paste build-up (ease of shaping the abutment, also known as formability). For example, Patent Document 1 proposes blending predetermined amounts of amorphous inorganic particles with an average particle size of 1 μm to 6 μm, spherical inorganic particles with an average particle size of 0.05 μm to 1 μm, and inorganic particles with a particle size of less than 0.05 μm, which are blended as needed, mainly from the viewpoints of the mechanical and physical strength of the hardened body, fluidity that allows the resin to easily reach every corner even in deep cavities, and aesthetics when restoring shallow cavities. Furthermore, Patent Document 3 proposes the combined use of inorganic particles treated with a specific silane coupling agent and having an average particle size of 1.6 to 10 μm, inorganic particles treated with a specific silane coupling agent and having an average particle size of 0.01 to 0.1 μm, and inorganic particles that have not been surface-treated and have an average particle size of 0.01 to 0.1 μm, from the viewpoints of mechanical strength, ejection properties, and formability of the cured product. [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-170813 [Patent Document 2] Patent No. 5687067 [Patent Document 3] Patent No. 5634298 Summary of the Invention [Problem to be solved by the invention]

[0010] In Patent Document 3, it is said that by using the inorganic filler of the above composition, a individually packaged dental polymerizable core material with a good balance of mechanical strength, dischargeability, and formability of the hardened body can be obtained, but the aesthetic restorative properties when shallow cavities are restored are unknown. In addition, not only is a special silane coupling agent required, but also at least three types of inorganic particles must be prepared and the composition must be adjusted.

[0011] On the other hand, in the dental hardenable composition described in Patent Document 1, the blending of inorganic particles having a particle size of less than 0.05 μm is optional, and it is said that the mechanical strength, fluidity, and aesthetics of the hardened body can be improved essentially by using only two types of inorganic particles.

[0012] However, Patent Document 1 does not specifically mention shape retention (shapeability) during paste build-up in core construction, and only explains that inorganic particles with a particle size of less than 0.05 μm can be used as a thixotropy adjuster. In other words, in paste build-up, the shape of the applied paste needs to be adjusted to match the shape of the abutment tooth, so shape retention (the property of maintaining the adjusted shape without being damaged by flow such as dripping of the paste from the time of adjustment until the paste hardens to an extent that the shape does not change) is important, but there is no direct mention of this.

[0013] Thixotropy is the property of viscosity changing over time; specifically, the viscosity gradually decreases when subjected to continuous shear stress, and conversely, the viscosity gradually increases when the material is stationary. Thixotropy is thought to correlate with the shape retention of the paste and the force required to extrude it from a syringe, but the details of the effect of adding the inorganic particles that function as a thixotropy regulator are unknown, and the shape retention is not well understood at present.

[0014] Therefore, the objective of the present invention is to provide a dental polymerizable hardening composition containing a relatively simple inorganic filler, which gives a hardened product with good mechanical and physical properties, has fluidity that makes it applicable to deep cavities, and is capable of aesthetic restoration, as well as having paste properties that can be easily handled with a syringe, and which has good shape retention. [Means for solving the problem]

[0015] In order to solve the above-mentioned problems, the present inventor first investigated the effect of adding the thixotropy adjusting agent, specifically inorganic particles with a particle size of less than 0.05 μm (hereinafter also referred to as "thixotropy adjusting microparticles") to the dental hardenable composition disclosed in Patent Document 1. As a result, it was found that while the shape retention improves as the amount of thixotropy adjusting microparticles added increases, the viscosity of the paste increases, and when the dedicated kneading tool is used, the dedicated kneading tool or dispenser may occasionally be damaged. Note that the fact that the viscosity of the paste increases with the addition of thixotropy adjusting microparticles can also be confirmed from Table 1 of Patent Document 1.

[0016] Therefore, further investigation was conducted into methods for improving the shape retention of a paste without adding thixotropy-adjusting microparticles. As a result, it was found that by using inorganic particles (B1) treated with a surfactant and a hydrophobic treatment agent and having an average particle diameter of 0.05 μm or more and 1 μm or less instead of spherical inorganic particles treated with a hydrophobic treatment agent and having an average particle diameter of 0.05 μm or more and 1 μm or less, it was possible to improve the shape retention without impairing the features of the dental polymerizable composition described in Patent Document 1, and this led to the completion of the present invention.

[0017] That is, the first invention relates to a dental polymerizable and curable composition containing a polymerizable monomer (A), an inorganic filler (B), and a polymerization initiator (C), wherein the inorganic filler (B) has an average particle size of 0.1 μm or more and 1 μm or less. Made of silica-based composite oxide An inorganic particle, having a surface of the inorganic particle: Selected from the group consisting of polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, polyethyleneimine, polyethylene oxide, and polyvinylpyrrolidone Weight average molecular weight is 2000 or more and 5 million or less Consists of at least one polymer Inorganic particles (B1) whose surfaces have been modified by bonding, adsorption, or sorption of a hydrophobic treatment agent consisting of a polymer surfactant and a silane coupling agent and / or a titanate coupling agent through a chemical reaction, and whose average particle diameter is 1 μm or more and 1000 μm or less. Inorganic particles, the surface of which has been modified by bonding, adsorbing or sorbing the hydrophobic treatment agent through a chemical reaction, but the surface of which has not been modified by bonding, adsorbing or sorbing the polymer surfactant through a chemical reaction, or the polymer surfactant. The inorganic filler (B) contains inorganic particles (B2) and has a particle diameter of less than 0.05 μm. Inorganic particles (B3) in which the surface has been modified by bonding, adsorption or sorption of the hydrophobic treatment agent through a chemical reaction, but the surface has not been modified by bonding, adsorption or sorption of the polymer surfactant through a chemical reaction. The dental polymerizable hardenable composition is characterized in that the proportion of

[0018] In the dental polymerizable hardenable composition of the present invention, the inorganic particles (B1) are preferably ball Preferably, the inorganic particles (B1') are crystalline or approximately spherical.

[0019] Also, before It is preferable that the content of the inorganic filler (B) relative to 100 parts by mass of the polymerizable monomer (A) is 100 parts by mass or more and 500 parts by mass or less, and that 10% by mass or more and 90% by mass or less of the inorganic filler (B) is the inorganic particles (B1), and the remainder is the irregular inorganic particles (B2). 。

[0020] Furthermore, from the viewpoint of obtaining the advantage of a so-called dual cure type composite resin, that is, the feature that it can be cured even in a place where the irradiated light does not reach, and can be cured in a short time in a place where the irradiated light reaches, the dental polymerizable and curable composition of the present invention is characterized in that the polymerization initiator (C) is a combination of a chemical polymerization initiator containing an organic peroxide and a tertiary amine, and a photopolymerization initiator composed of multiple components, thing is preferably divided into a first paste containing a part of the polymerizable monomer (A), a part of the inorganic filler (B), and an organic peroxide, and a second paste containing the remainder of the polymerizable monomer (A), the remainder of the inorganic filler (B), and a tertiary amine, and each of the plurality of components constituting the photopolymerization initiator is preferably blended into either the first paste or the second paste.

[0021] The second invention of the present invention is a dental core-building material comprising the above-mentioned individually packaged dental polymerizable and hardenable composition. [Effects of the Invention]

[0024] The dental polymerizable hardenable composition of the present invention not only provides a hardened product with high mechanical and physical strength, but also enables highly aesthetic restorations. Furthermore, despite its high inorganic filler content, it has excellent paste fluidity that allows it to easily reach every corner of even deep cavities and be easily discharged from a syringe. Furthermore, it has excellent shape retention, even when the paste is piled up to roughly shape an abutment.

[0025] While the mechanism by which such excellent effects are achieved is not entirely clear, the inventors believe that the following is true. Specifically, the mechanical and physical strength, aesthetics, and fluidity / dischargeability of the cured product are essentially achieved by retaining the same characteristics as the thixotropy modifier in Patent Document 1, while substantially eliminating (or minimizing the use of) thixotropy-modifying microparticles, which increase viscosity. Furthermore, with regard to shape retention, the surface of (B1), one of the main components of the inorganic filler, is thought to be a mixture of regions treated with a hydrophobic treatment agent and regions treated with a surfactant (having both hydrophilic and hydrophobic moieties), resulting in microdomains that are hydrophobic due to the presence of the hydrophilic portion of the surfactant, interspersed among the hydrophobic domains. The hydrophobic domains contribute to improved compatibility with highly hydrophobic polymerizable monomers, while the hydrophilic microdomains generate repulsive forces between the highly hydrophobic polymerizable monomers, which slightly inhibit the flow of the polymerizable monomers, resulting in improved shape retention. DETAILED DESCRIPTION OF THE INVENTION

[0026] The dental polymerizable composition of the present invention contains a polymerizable monomer (A), an inorganic filler (B), and a polymerization initiator (C), similar to conventional dental polymerizable compositions used in dental composite resins and the like. Among these components, the polymerizable monomer (A) and the polymerization initiator (C) are not particularly different from those of conventional dental polymerizable compositions. However, the inorganic filler (B) must contain specific inorganic particles in order to achieve the aforementioned effects. That is, the dental polymerizable composition of the present invention is characterized in that, in the dental polymerizable composition described above, the inorganic filler (B) contains inorganic particles (B1) that have been treated with a surfactant and a hydrophobic treatment agent and have an average particle size of 0.05 μm or more and 1 μm or less.

[0027] The components of the dental polymerizable and hardenable composition of the present invention, including the polymerizable monomer (A) and polymerization initiator (C), which are not particularly different from those of conventional dental polymerizable and hardenable compositions, will be described below.

[0028] <Polymerizable Monomer (A)> As the polymerizable monomer (hereinafter also referred to as "monomer"), any of those used in conventional dental hardenable compositions can be used without any particular limitation. Examples of polymerizable monomers that can be used in the present invention include monofunctional polymerizable monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, glycidyl (meth)acrylate, 2-cyanomethyl (meth)acrylate, benzyl methacrylate, polyethylene glycol mono(meth)acrylate, allyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and glyceryl mono(meth)acrylate; Ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, nonaethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, 2,2'-bis[4-(meth)acryloyloxyethoxyphenyl]propane, 2,2'-bis[4-(meth)acryloyloxyethoxyethoxyphenyl]propane, 2,2'-bis[4-(meth)acryloyloxyethoxyphenyl]propane, 2,2'-bis{4-[2-hydroxy-3-(meth)acryloyloxypropoxy]phenyl}propane, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-bis(methacrylethyloxycarbonyl acrylate) polyfunctional polymerizable monomers such as 1,6-bis(methacrylethyloxycarbonylamino)trimethylhexane, 1,6-bis(methacrylethyloxycarbonylamino)-2,2,4-trimethylhexane, 1,6-bis(methacrylethyloxycarbonylamino)-2,4,4-trimethylhexane, urethane (meth)acrylate, epoxy (meth)acrylate, trimethylolpropane trimethacrylate, and pentaerythritol tetramethacrylate; fumarate ester compounds such as monomethyl fumarate, diethyl fumarate, and diphenyl fumarate;Examples include styrene, divinylbenzene, α-methylstyrene, α-methylstyrene dimer, and other styrene and α-methylstyrene derivatives; and allyl compounds such as diallyl phthalate, diallyl terephthalate, diallyl carbonate, and allyl diglycol carbonate.

[0029] Among the above-mentioned monomers, polymerizable monomers compatible with organic solvents are preferred. Furthermore, (meth)acrylic polymerizable monomers are preferred because the resulting polymers have good mechanical strength and biosafety. Furthermore, bifunctional or higher functional, more preferably bifunctional to tetrafunctional, polymerizable monomers are preferred because of their high polymerizability and the particularly high mechanical properties of the cured product. These polymerizable monomers may be used alone or in combination.

[0030] <Inorganic filler (B)> The inorganic filler (B) used in the present invention must contain inorganic particles (B1) that have been treated with a surfactant and a hydrophobic treatment agent and have an average particle size of 0.05 μm or more and 1 μm or less. The inclusion of these inorganic particles (B1) makes it possible to achieve the excellent effects described above. Because of their high effectiveness in improving shape retention (shapeability) without increasing viscosity, it is preferable to use, as the inorganic particles (B1), spherical or nearly spherical inorganic particles (B1') that have been treated with a hydrophobic treatment agent consisting of a polymer surfactant with a weight-average molecular weight of 2,000 to 20,000,000 and a silane coupling agent and / or a titanate coupling agent and have an average particle size of 0.05 μm or more and 1 μm or less.

[0031] Here, "treated with a surfactant and a hydrophobic treatment agent" means that the surface of the inorganic particles (also referred to as "treated inorganic particles") to be treated is modified by the chemical or physical action of these treatment agents on the surface (including fixation by adhesion or adsorption as well as fixation by chemical bonds formed by chemical reaction). As shown in Comparative Example 2 described below, the effects of the present invention cannot be achieved by simply blending the treated inorganic particles and these treatment agents (added separately) into a curable composition without first treating the treated inorganic particles with these treatment agents. Furthermore, as shown in Comparative Example 3, when treated with only a surfactant, the shape retention is initially high due to the repulsion between the polymerizable monomer and the particles treated with only the surfactant. However, due to poor compatibility, the ejection force tends to be high and solid-liquid separation from the polymerizable monomer tends to occur, resulting in a decrease in shape retention over time. In other words, the inorganic particles (B1) are inorganic particles having an average particle diameter of 0.05 μm or more and 1 μm or less, and are surface-modified inorganic particles having a surfactant and a hydrophobic treatment agent on their surfaces (the surfactant and the hydrophobic treatment agent are bonded to the surfaces by a chemical reaction, or are adsorbed or sorbed).

[0032] The amount of inorganic filler (B) in the dental curable composition of the present invention is typically 100 to 500 parts by mass, preferably 150 to 400 parts by mass, per 100 parts by mass of polymerizable monomer (A). Particularly when the dental curable composition of the present invention is used as a core construction material, such as a composite resin for dental core construction, from the viewpoint of the mechanical strength of the cured product, it is preferably 200 to 400 parts by mass, per 100 parts by mass of polymerizable monomer (A). The proportion of inorganic particles (B1) in the inorganic filler (B) is not particularly limited, but from the viewpoint of the effects to be obtained, it is typically 10 to 90% by mass, preferably 30 to 70% by mass.

[0033] Hereinafter, the inorganic particles (B1) will be described in detail, including the surfactant and hydrophobic treatment agent as the treatment agent, the inorganic particles to be treated (also referred to as "treated inorganic particles"), the treatment method, and inorganic particles other than B1 that may be contained in the inorganic filler B (hereinafter also referred to as "other inorganic particles").

[0034] <Surfactant> The surfactant is not particularly limited as long as it has a part in the molecule that is compatible with water (hydrophilic group) and a part that is compatible with oil (lipophilic group / hydrophobic group), and nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants can be used without particular limitation, but it is preferable to use nonionic surfactants and / or anionic surfactants because they are more effective.

[0035] Suitable nonionic surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether; polyoxyethylene alkyl phenyl ethers such as polyoxyethylene lauryl phenyl ether; fatty acid polyoxyethylene lauryl esters; and polyoxyethylene sorbitan esters such as polyoxyethylene sorbitan lauryl ester, all of which have a polyoxyethylene group as a hydrophilic group.

[0036] In addition, examples of anionic surfactants that can be suitably used include alkyl sulfates such as sodium decyl sulfate and sodium lauryl sulfate; sulfonates such as sodium hexanesulfonate and sodium decylsulfonate; alkylbenzenesulfonates such as sodium decylbenzenesulfonate and sodium laurylbenzenesulfonate; aliphatic carboxylates such as sodium decanoate, sodium laurate, sodium stearate and sodium oleate; alkyl ether sulfates such as sodium lauryl ether sulfate obtained by sulfated adducts of lauryl alcohol and ethylene oxide; sulfosuccinic acid diesters such as sodium sulfosuccinate; and phosphate esters of higher alcohol ethylene oxide adducts.

[0037] Among these, it is particularly preferable to use a high-molecular-weight surfactant having a weight-average molecular weight of 2,000 to 20,000,000, particularly 6,000 to 5,000,000. Examples of suitable high-molecular-weight surfactants include polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, polyethyleneimine, polyethylene oxide, and polyvinylpyrrolidone. Among these, it is preferable to use an acrylic acid-based polymer surfactant from the viewpoint of toughness, and it is preferable to use polyacrylic acid or a partial or complete sodium salt of polyacrylic acid from the viewpoint of biological safety.

[0038] <Hydrophobic treatment agent> The hydrophobic agent is not particularly limited as long as it can react with the hydroxyl groups present on the surface of the inorganic particles to be treated to impart hydrophobicity to the surface, but from the viewpoint of high reactivity, silane coupling agents and / or titanate coupling agents are preferably used. Examples of hydrophobic agents that can be preferably used include vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, κ-methacryloyloxydodecyltrimethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, γ-glycidoxypropyl-trimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl-trimethoxysilane, γ-ureidopropyl-triethoxysilane, γ-chloropropyltrimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, methyltriethoxysilane, etc.

[0039] The preferred amount of the hydrophobic agent to be used is determined based on the total surface area (m 2 The amount may be determined appropriately depending on the amount of the inorganic particles to be treated, but is usually 1 to 30 parts by mass per 100 parts by mass of the inorganic particles to be treated.

[0040] The specific surface area of ​​the inorganic filler may be a value measured by the BET method or the like. For example, when the hydrophobic treatment agent is a silane coupling agent, the amount used: y (g) is calculated based on the specific surface area of ​​the inorganic powder: X (m 2 / g) and silane coupling agent coverage area: Y (m 2 / g) can be calculated using the following formula: y=100X / Y In addition, Y(m 2 / g) is the coverage area per molecule of the silane coupling agent, 13 × 10 -20 (m 2 ) and Avogadro's constant: AN(=6.02×10 23 / mol) and the mass of 1 mole of the silane coupling agent: SmW (g / mol), it can be calculated by the following formula. Y = (13 × 10 -20)×AN / SmW <Inorganic particles to be treated> The inorganic particles used for the treatment are inorganic particles with an average particle size of 0.05 μm or more and 1 μm or less. Here, the average particle size refers to the average particle size when the particles are individual particles, and to the average particle size of the primary particles when the particles are agglomerated particles of primary particles. This also applies to the inorganic particles (B1) obtained after treatment, and the average particle size of the treated inorganic particles and the average particle size of the inorganic particles (B1) are substantially the same (because the molecules of the treatment agent are very small compared to the particle size). Therefore, when the treated inorganic particles and the inorganic particles (B1) are agglomerated particles formed by agglomeration of primary particles, the particle size and average particle size of the agglomerated particles may exceed the above ranges.

[0041] This average particle size is determined using a scanning electron microscope. Particles are observed with a scanning electron microscope, and 30 or more particles within a unit field of view are randomly selected and the primary particle size (maximum diameter) of each is measured. The value obtained by dividing the sum of the primary particle sizes by the number of selected particles is taken as the average primary particle size.

[0042] If the average particle size is less than 0.05 μm, the viscosity of the polymerizable curable composition tends to increase, while if the average particle size exceeds 1 μm, the surface area becomes small, making it difficult to efficiently achieve the effects of adding particles. From the viewpoint of making it difficult to increase the viscosity of the polymerizable curable composition and efficiently achieving the effects of adding particles, the average particle size is preferably 0.05 μm or more and 1 μm or less, and more preferably 0.1 μm or more and 1 μm or less. Furthermore, the particle shape is not particularly limited, but is preferably spherical or approximately spherical.

[0043] The material of the inorganic particles to be treated is not particularly limited as long as it is an inorganic material whose surface can be hydrophobized with a hydrophobic treatment agent. Suitable examples of materials that can be used include metal oxides such as amorphous silica, quartz, alumina, titania, zirconia, barium oxide, yttrium oxide, lanthanum oxide, and ytterbium oxide; silica-based composite oxides such as silica-zirconia, silica-titania, silica-titania-barium oxide, and silica-titania-zirconia; and glasses such as borosilicate glass, aluminosilicate glass, and fluoroaluminosilicate glass.

[0044] The above-mentioned metal oxides and silica-based composite oxides can be densified by high-temperature calcination, and the densification effect can be enhanced by adding a small amount of an oxide of a Group I metal of the periodic table, such as sodium. Furthermore, silica-based composite oxides have the advantage that their refractive index can be easily adjusted, and because they have a large number of silanol groups on their particle surfaces, they are easily surface-modified using silane coupling agents, etc. For this reason, silica-based composite oxides are particularly suitable as the material for the treated inorganic particles. Preferred silica-based composite oxides include silica-zirconia, silica-titania, silica-titania-barium oxide, and silica-titania-zirconia because of their strong X-ray contrast properties, and silica-zirconia is most preferred because it produces a cured product with excellent wear resistance. The treated inorganic particles may also be a mixture of multiple inorganic particles with different average particle sizes, materials, and shapes, as long as the average particle sizes of each satisfy the above conditions.

[0045] <Treatment Method (Method for Producing Inorganic Particles B1)> The method for treating inorganic particles to be treated with a surfactant and a hydrophobic treatment agent, i.e., the method for producing the inorganic particles (B1), is not particularly limited as long as the treatment agent acts chemically or physically on the surface of the inorganic particles (also referred to as "treated inorganic particles") to immobilize them (including immobilization by adhesion or adsorption as well as immobilization by chemical bonds formed by chemical reaction) and leave the surface in a modified state. Because of its simple operation and high surface modification effect, it is preferable to adopt a method comprising the steps of preparing a first dispersion containing inorganic particles to be treated, a surfactant, and water (first dispersion preparation step), preparing a second dispersion containing a hydrophobic agent having a hydrolyzable group and water, in which the hydrophobic agent is dissolved or dispersed in a hydrolyzed state at least partially, and mixing the first dispersion with the second dispersion and then spray-drying the resulting mixture (mixing and spray-drying step).

[0046] In the first dispersion preparation step, a first dispersion of treated inorganic particles and a surfactant is prepared. The amount of surfactant used is not particularly limited, but is generally 0.01 to 10 parts by weight, particularly 0.05 to 5 parts by weight, and most preferably 0.1 to 3 parts by weight, per 100 parts by weight of treated inorganic particles. This is because it reduces the formation of macrovoids within the aggregated particles during the mixing and spray drying step, and improves the mechanical properties (e.g., strength) of the cured product when the dental curable composition of the present invention is prepared. If the surfactant content is less than 0.01 parts by weight per 100 parts by weight of the particles, the hydrophilic moiety becomes too small compared to the hydrophobic moiety, making it difficult to achieve the shape retention improvement effect. On the other hand, if the surfactant content is more than 10 parts by weight, the hydrophilic moiety becomes too large compared to the hydrophobic moiety, resulting in an increased ejection force and a tendency for solid-liquid separation to occur. For similar reasons, there is also a preferred range for the ratio of surfactant to hydrophobic treatment agent. The surfactant is preferably used in an amount of 0.01 to 3 parts by mass, more preferably 0.03 to 2 parts by mass, and even more preferably 0.05 to 1 part by mass per part by mass of the hydrophobic treatment agent. The method for preparing the first dispersion is not particularly limited, and it can be prepared, for example, by dispersing the inorganic particles to be treated in an aqueous medium using a mixing device such as a bead mill, and then adding the surfactant to form a slurry. Water is used as the dispersion medium, but organic solvents such as ethanol, isopropyl alcohol, chloroform, and dimethylformamide may also be added as necessary. The amount of the dispersion medium used is usually 400 to 100 parts by mass per 100 parts by mass of the inorganic particles to be treated.

[0047] In the second dispersion preparation process, a hydrophobizing agent having a hydrolyzable group is used. The hydrolyzable group is preferably an alkoxy group (-OR: R is an unsubstituted or substituted alkyl group) bonded to a Si atom or a Ti atom, and silane coupling agents or titanate coupling agents having such groups can be used without particular limitation. When these hydrophobizing agents are mixed with water (optionally, a hydrolysis catalyst such as acetic acid may be added), partial hydrolysis occurs spontaneously at the bond site of the hydrolyzable group, forming Si-OH groups or Ti-OH groups. The amount of the hydrophobizing agent used can be determined appropriately by calculating the approximate amount used using the formula for calculating Y and y described above, adjusting the amount based on that amount, performing treatment, and confirming the mechanical properties of the resulting surface-treated particles through prior experiments. Water is used, but organic solvents such as ethanol, isopropyl alcohol, chloroform, and dimethylformamide may be added as necessary. The amount of dispersion medium used is typically 400 to 100 parts by mass per 100 parts by mass of the inorganic particles to be treated in the first dispersion to be mixed.

[0048] In the mixing and spray-drying step, the first dispersion and the second dispersion are mixed until homogeneous, for example, using a stirrer, and then the resulting mixture is spray-dried. In this step, it is preferable to adjust the concentration of the inorganic particles to be treated in the first dispersion and / or the amount of the second dispersion so that the inorganic particles to be treated in the mixture are 5 to 50% by mass, preferably 20 to 45% by mass, because macrovoids are unlikely to form inside the aggregated particles formed by particle aggregation during spray-drying. If macrovoids are formed inside the aggregated particles, the macrovoids may remain in the inorganic particles B1, and when the dental curable composition of the present invention is prepared, the mechanical properties (e.g., strength) of the cured product may be reduced.

[0049] Spray drying methods that can be used include a method in which the mixed solution is formed into fine droplets using a high-speed air stream and then sprayed and dried, and a method in which the mixed solution is dropped onto a disk-shaped rotor rotating at a rotation speed of 1,000 to 50,000 rpm and then sprayed into a mist by centrifugal force for drying. Due to inevitable particle aggregation during the drying process, the resulting particles will be agglomerated particles, but it is preferable to immediately dry the atomized mixed solution using high-temperature air or an inert gas, etc., in order to obtain agglomerated particles with a uniform particle size. In this case, the temperature of the gas used for drying is preferably 60 to 300°C, particularly 80 to 250°C.

[0050] In addition, the agglomerated particles obtained by the spray drying may contain a small amount of the solvent added to the water dispersion medium. For this reason, it is preferable to further perform vacuum drying after the spray drying. Vacuum drying is generally performed under a reduced pressure of 0.01 to 100 hectopascals or less at 20 to 150°C for 1 to 48 hours.

[0051] The resulting aggregated particles are optionally pulverized to an appropriate particle size (for example, 100 μm or less, preferably 70 μm or less) before use. Pulverization may be performed using a vibrating ball mill, a bead mill, a jet mill, or the like. For particle size adjustment, a sieve, an air classifier, or a water classification may be used.

[0052] <Other inorganic particles> The inorganic filler (B) preferably contains "other inorganic particles." These "other inorganic particles" are inorganic particles other than the inorganic particles (B1) that differ from the inorganic particles (B1) in at least one of the following two respects: the average particle size (of the primary particles) and the fact that they are treated with both a surfactant and a hydrophobic treatment agent. The "other inorganic particles" are not particularly limited as long as they satisfy these conditions, but are preferably amorphous inorganic particles (B2) with an average particle size of 1 μm to 1,000 μm, preferably 1 μm to 100 μm, and more preferably 1 μm to 50 μm. The dental polymerizable curable composition of the present invention may also contain inorganic particles (B3) with a particle size of less than 0.05 μm, preferably inorganic particles (B3') with a particle size of 0.01 μm or less, in a trace amount (a proportion of the inorganic filler (B) of 1.0% by mass or less, preferably 0.8% by mass or less) that does not adversely affect the viscosity, etc., of the dental polymerizable curable composition of the present invention.

[0053] In the inorganic filler (B), the balance of the inorganic particles (B1) is accounted for by "other inorganic particles," and the irregular inorganic particles (B2) preferably account for substantially all of the balance (all of the balance, or, in the case where a trace amount of inorganic particles (B3) having a particle size of 0.05 μm or less is contained, the trace amount is subtracted from the balance). From the viewpoint of improving shape retention and the mechanical strength of the cured product, the blending ratio of the particles (B1) treated with a surfactant and a hydrophobic treatment agent to the irregular inorganic particles (B2) is preferably 10:90 to 90:10, particularly 20:80 to 80:20, and most preferably 30:70 to 70:30 by mass.

[0054] The material of the particles constituting the "other inorganic particles" can be the same as that of the inorganic particles (B1). The "other inorganic particles" may be treated with a hydrophobizing agent (in this case, no surfactant treatment is performed). Furthermore, the inorganic particles (B2) can also be compounded as a so-called organic-inorganic composite filler.

[0055] <Polymerization initiator (C)> As the polymerization initiator, any of photopolymerization initiators, chemical polymerization initiators, and thermal polymerization initiators can be used, but it is preferable to use a photopolymerization initiator and a chemical polymerization initiator in combination, because this allows obtaining the benefits of the so-called dual-cure composite resin.

[0056] As the photopolymerization initiator, any photopolymerization initiator used in conventional light-cured dental composite resins or dual-cure dental composite resins can be used without any particular restrictions. However, because of their high curing properties, it is preferable to use a photopolymerization initiator containing an α-diketone compound and a reducing agent, particularly one consisting of a combination of an α-diketone compound, a reducing agent, and a photoacid generator.

[0057] Suitable α-diketones include camphorquinone, benzil, α-naphthyl, acetonaphthene, naphthoquinone, 1,4-phenanthrenequinone, 3,4-phenanthrenequinone, and 9,10-phenanthrenequinone. Suitable reducing agents include N,N-dimethyl-p-toluidine, p-dimethylaminobenzoic acid ethyl ester, N-methyldiethanolamine, N,N-dimethylaminoethyl methacrylate, and p-tolyldiethanolamine. Suitable photoacid generators include diaryliodonium salt compounds, sulfonium salt compounds, sulfonate ester compounds, halomethyl-substituted S-triazine derivatives, and pyridinium salt compounds.

[0058] The amount of photopolymerization initiator used is not particularly different from that used in conventional light-cured dental composite resins or dual-cure dental composite resins, and is usually used in a ratio of 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass, per 100 parts by mass of polymerizable monomer (A), expressed in terms of the total mass of the photopolymerization initiator.

[0059] As the chemical polymerization initiator, any chemical polymerization initiator used in conventional chemical polymerization-curing dental composite resins or dual-cure dental composite resins can be used without particular limitation, but a chemical polymerization initiator containing an organic peroxide and an amine is preferably used because it provides high curing properties and is easy to handle. Furthermore, a chemical polymerization initiator containing an organic peroxide, an amine, and an aryl borate is particularly preferred because it provides high curing properties even when in contact with the acidic component contained in the tooth surface pretreatment agent. Suitable organic peroxides include ketone peroxides such as methyl ethyl ketone peroxide, hydroperoxides such as 2,5-dimethylhexane-2,5-dihydroperoxide, diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as di-t-butyl peroxide, peroxyketals such as 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, peroxyesters such as α-cumylperoxyneodecanoate, and peroxydicarbonates such as di-3-methoxyperoxydicarbonate. Of these, benzoyl peroxide is particularly suitable from the viewpoints of radical generation ability and stability.

[0060] Suitable amines include secondary or tertiary aromatic amines in which an amino group is bonded to an aromatic group such as an aryl group or a pyridyl group. Specifically, the amines exemplified as reducing agents for photopolymerization initiators can be similarly used.

[0061] Suitable arylborates include borate compounds having one to four boron-aryl bonds per molecule, and specific examples include metal salts, ammonium salts, pyridium salts, and quinolinium salts of monoalkyltriphenylboron, monoalkyltris(3,5-bistrifluoromethyl)phenylboron, monoalkyltris(m-octyloxyphenyl)boron, tetraphenylboron, and tetrakis(m-octyloxyphenyl)boron. Among these, triethanolammonium salt of tetraphenylboron is particularly suitable from the viewpoint of curability.

[0062] In the case of a chemical polymerization initiator comprising an organic peroxide and an amine, the amine is usually used in a ratio of 0.01 to 4 moles, preferably 0.05 to 3 moles, per mole of the organic peroxide. In the case of a chemical polymerization initiator comprising an organic peroxide, an amine, and an aryl borate, the amine is usually used in a ratio of 0.01 to 4 moles, preferably 0.05 to 3 moles, per mole of the organic peroxide, and the aryl borates are usually used in a ratio of 0.01 to 3 moles, preferably 0.05 to 2 moles, per mole of the organic peroxide.

[0063] The amount of the chemical polymerization initiator is not particularly different from that used in conventional chemical polymerization curing dental composite resins or dual cure dental composite resins, and is usually used in a ratio of 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass, per 100 parts by mass of the polymerizable monomer (A), expressed in terms of the total mass of the chemical polymerization initiator.

[0064] In addition to the above-described components A to C, the dental curable composition of the present invention may further contain a polymerization inhibitor as an optional component. Any known polymerization inhibitor may be used without limitation. When a polymerization inhibitor is used, the amount of the polymerization inhibitor is usually 0.001 to 5 parts by mass, preferably 0.01 to 3 parts by mass, per 100 parts by mass of the polymerizable monomer (A). Furthermore, various additives such as ultraviolet absorbers, dyes, antistatic agents, pigments, and fragrances may be used as optional components, as needed.

[0065] When the dental curable composition of the present invention contains a chemical polymerization initiator, particularly a chemical polymerization initiator containing an organic peroxide and a tertiary amine, it is divided into a first paste containing a portion of the polymerizable monomer (A), a portion of the inorganic filler (B), and the organic peroxide, and a second paste containing the remainder of the polymerizable monomer (A), the remainder of the inorganic filler (B), and the tertiary amine, as in conventional chemical polymerization-curable dental composite resins and dual-cure dental composite resins, so as to prevent hardening during storage. In this case, when a photopolymerization initiator is further contained, the multiple components constituting the photopolymerization initiator are blended into either the first paste or the second paste, respectively. [Example]

[0066] EXAMPLES In the following, the present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited to these examples in any way.

[0067] 1. Surface-treated inorganic particles and their manufacturing method Production Example 1 (Production of B1-01, which is inorganic particles B1) The following raw materials (inorganic particles to be treated, surfactant, and hydrophobic treatment agent) were used, and inorganic particles B1-01 were produced according to the following procedure. [Raw materials] Inorganic particles to be treated: average (primary) particle size 0.2 μm, specific surface area 15 m 2 / g spherical silica zirconia powder Surfactant: sodium polyacrylate with a weight-average molecular weight of 2000 (manufactured by Polysciences Co., Ltd.; hereinafter, sometimes abbreviated as "SA1") γ-methacryloyloxypropyltrimethoxysilane (sometimes abbreviated as "MPS") as a hydrophobic treatment agent [Operation procedure] 100 g of the treated inorganic particles and 0.5 g of SA1 were mixed with 200 ml of ion-exchanged water and dispersed using a circulation mill, an SC mill, to prepare a first dispersion. Next, 4.8 g of MPS was mixed with 80 ml of an aqueous acetic acid solution adjusted to pH 4.0 and stirred for 1 hour and 30 minutes to hydrolyze the mixture, preparing a second dispersion containing a partial hydrolyzate of MPS. The first and second dispersions were then mixed and stirred for 1 hour using a stirrer. The resulting mixture was then spray-dried by being gently stirred manually onto a rapidly rotating disk. The spray drying was carried out using a spray dryer equipped with a rotating disk and atomizing by centrifugal force (Spray Dryer "TSR-2W", product name; manufactured by Sakamoto Giken Co., Ltd.). The disk rotation speed was 10,000 rpm, and the temperature of the drying atmosphere air was 200°C. The white solid obtained by spray drying was dried under vacuum at 80°C for 18 hours to obtain inorganic particles B1, B1-01. For reference, the raw materials and the amounts of each raw material used in this production example are shown in Table 1.

[0068] Production Examples 2 to 14 and Production Comparative Examples 1 to 3 Surface-treated inorganic particles B1-02 to B1-14 corresponding to B1 and CB1-01 to CB1-03 corresponding to Comparative Example inorganic particles not satisfying the conditions of B1 were obtained in the same manner as in Production Example 1, except that the raw materials and the amounts of each raw material used were changed as shown in Table 1. In the table, the abbreviations SA2 and SA3 in the columns for surfactant and type refer to the respective surfactants. SA2: Sodium polyacrylate with a weight-average molecular weight of 6000 (manufactured by Polysciences) SA3: Sodium polyacrylate with a weight-average molecular weight of 5 million ("Aronvis-SX" manufactured by Toagosei Co., Ltd.)

[0069] [Table 1]

[0070] 2. Dental Polymerizable Hardening Compositions The abbreviations and names of various raw material compounds used in the examples and comparative examples described below are shown below in the format "abbreviation:name". [Polymerizable monomer (A)] 3G: Triethylene glycol dimethacrylate GMA: 2,2-bis[(3-methacryloyloxy-2-hydroxypropyloxy)phenyl]propane D2.6E: A compound represented by the following formula (where the average of (11 + 12) is 2.6, making it a mixture):

[0071] [ka]

[0072] [Inorganic particles B2] Amorphous silica-zirconia, average particle size: 5 μm, treated with γ-methacryloyloxypropyltrimethoxysilane (MPS) [Thixotropy adjusting particles: B3] Finely divided silica, average particle size: 0.015 μm, treated with γ-methacryloyloxypropyltrimethoxysilane (MPS) [Polymerization initiator (C)] CQ: Camphorquinone DMBE: Ethyl 4-dimethylaminobenzoate BPO: Benzoyl peroxide DMPT: N,N-dimethyl-p-toluidine DEPT: p-Tolyldiethanolamine [Other ingredients] HQME: Hydroquinone monomethyl ether Example 1 (1 paste type) A polymerizable monomer composition was prepared by blending 100 parts by weight of polymerizable monomer (A) consisting of a mixture of 10 parts by weight of GMA, 40 parts by weight of 3G, and 50 parts by weight of D2.6E with 0.15 parts by weight of HQME, 0.2 parts by weight of CQ as a polymerization initiator (C), and 0.35 parts by weight of DMBE. The resulting polymerizable monomer composition was then mixed with 30 parts by weight of B1-02 obtained in Production Example 2 and 180 parts by weight of B2 obtained in Reference Production Example as inorganic fillers (B) in a mortar and stirred until homogeneous to prepare a paste-like dental curable composition. The prepared paste (dental curable composition) was degassed and filled into a flowable syringe for one paste, and its discharge force and flowability were evaluated. The results are shown in Table 2. The ejection force and flow properties were evaluated as follows.

[0073] (1) Evaluation of ejection force (the force required to eject the paste from the syringe) The paste was filled into a syringe for flowable resin (manufactured in-house, with plunger) and a tip nozzle (Transcodent, TD-No. 6009) was attached. This was then set into a testing machine (Shimadzu, product name "Autograph AG5000D"), and the plunger was pressed at a crosshead speed of 5 mm / min to measure the force required to eject the paste from the nozzle (ejection force). Five syringes were evaluated, and the average value was taken as the ejection force.

[0074] (2) Flowability (shape retention of paste) 0.1g±0.01g of paste was piled up on a glass slide in a cylindrical or conical shape using a nozzle, and then placed in an incubator at 37°C±1°C for 2 minutes, at which point the spread (diameter) of the paste was measured. The test was performed twice, and the average was calculated to determine the flowability. The smaller the value, the lower the flowability and the better the paste's shape retention.

[0075] To evaluate the storage stability, the composition was stored at 45° C. for 7 days and the flowability was measured. Flowability of the composition not exceeding 7.0 mm was evaluated as good.

[0076] [Table 2]

[0077] Examples 2 to 24 (all one-paste type) Pastes of dental curable compositions were prepared in the same manner as in Example 1, except that the type and amount of inorganic particles blended as the inorganic filler (B) were changed as shown in Table 2, and evaluations were carried out in the same manner as in Example 1. The evaluation results are shown in Table 2.

[0078] Comparative Example 1 (1 paste type) This Comparative Example is an example in which a surfactant was not used for surface treatment of inorganic particles but was directly incorporated into the composition. That is, a dental curable composition paste was prepared in the same manner as in Example 1, except that 2 parts by mass of SA2 was added to the polymerizable monomer composition in Example 1, and the inorganic fillers shown in Table 2 were incorporated in the amounts shown in Table 2 (specifically, 120 parts by mass of CB1-01, which was not subjected to surfactant treatment, and 180 parts by mass of B2). The evaluation results are shown in Table 2.

[0079] Comparative Example 2 (1 paste type) In this comparative example, inorganic particles (CB1-01) that had been treated with a hydrophobizing agent but not with a surfactant were blended in place of inorganic particles B1. That is, a dental curable composition paste was prepared in the same manner as in Example 1, except that 120 parts by mass of CB1-01 and 180 parts by mass of B2 were blended into the polymerizable monomer composition in Example 1, and the same evaluations as in Example 1 were carried out. The evaluation results are shown in Table 2.

[0080] Comparative Example 3 (1 paste type) In this comparative example, inorganic particles (CB1-02) that had been treated with a surfactant but not with a hydrophobic treatment agent were blended in place of inorganic particles B1. That is, a dental curable composition paste was prepared in the same manner as in Example 1, except that 120 parts by mass of CB1-02 and 180 parts by mass of B2 were blended into the polymerizable monomer composition in Example 1, and the same evaluations as in Example 1 were carried out. The evaluation results are shown in Table 2.

[0081] Comparative Example 4 (1 paste type) In this comparative example, inorganic particles (CB1-03) having an average particle size exceeding 1 μm and treated with a hydrophobizing agent were blended instead of inorganic particles B1. That is, a dental curable composition paste was prepared in the same manner as in Example 1, except that 60 parts by mass of CB1-03 and 90 parts by mass of B2 were blended into the polymerizable monomer composition in Example 1, and the same evaluations as in Example 1 were carried out. The evaluation results are shown in Table 2.

[0082] Comparative Example 5 (1 paste type) This comparative example is an example in which, in addition to inorganic particles B1, inorganic particles (thixotropy-adjusting fine particles: B3) having a particle size of less than 0.05 μm that have been treated with a hydrophobizing agent were further blended. That is, a dental curable composition paste was prepared in the same manner as in Example 1, except that 114 parts by mass of B1-02, 6 parts by mass of thixotropy-adjusting fine particles B3, and 180 parts by mass of B2 were blended into the polymerizable monomer composition in Example 1, and the same evaluations as in Example 1 were carried out. The evaluation results are shown in Table 2.

[0083] Example 20 (2-paste type) A first paste (PA-1) was prepared in the same manner as in Example 1, except that 3 parts by mass of BPO was added as part of the polymerization initiator (C) and 30 parts by mass of B1-02 and 180 parts by mass of B2 were added as the inorganic filler (B) when preparing the polymerizable monomer composition. Separately, a second paste (PB-1) was prepared in the same manner as in Example 1, except that 2 parts by mass of DMPT was added as part of the polymerization initiator (C) and 30 parts by mass of B1-02 and 180 parts by mass of B2 were added as the inorganic filler (B). PA-1 and PB-1 were then filled into separate syringes (different syringes) of a double syringe set, and the discharge force and flowability were evaluated. The results are shown in Table 3. The flowability evaluation using a double syringe was performed as follows. Specifically, a double syringe (Mixpack SDL X05-01-78) was filled with pastes PA-1 and PA-2, a plunger (Mixpack PLH X05-01-46) was attached, and a mixing tip (Mixpack ML 2.5-08-D) and a tip nozzle (Mixpack IOR 209-20) were attached to the tip of the double syringe. This was then set in a testing machine (Shimadzu Autograph AG5000D), and the plunger was pressed at a crosshead speed of 5 mm / min to measure the force (discharge force) required to discharge the paste from the nozzle. Five syringes were evaluated, and the average value was taken as the discharge force.

[0084] Examples 20 to 37 and Comparative Examples 6 to 9 A first paste and a second paste were prepared in the same manner as in Example 1, except that the first paste composition and the second paste composition were changed to those shown in Table 3, and evaluations were carried out in the same manner as in Example 1. The results are shown in Tables 3 to 5.

[0085] [Table 3]

[0086] [Table 4]

[0087] [Table 5]

[0088] A paste made from the dental curable composition of the present invention using inorganic particles B1 exhibits good shape retention and ejection force. In contrast, when a surfactant is directly incorporated into the polymerizable monomer composition rather than as a surface treatment agent for the inorganic particles, flowability increases, resulting in poor shape retention (see Comparative Examples 1 and 6). Furthermore, when similar treated inorganic particles were used, CB1-01, which was treated only with a hydrophobic treatment agent but not with a surfactant, exhibited poor shape retention (see Comparative Examples 2 and 7). On the other hand, when CB1-02, which was treated only with a surfactant but not with a hydrophobic treatment agent, was used, both shape retention and ejection force were good immediately after paste production, but the storage stability of shape retention was poor, resulting in poor shape retention (see Comparative Examples 3 and 8). Furthermore, when CB1-03, which was treated with a hydrophobic treatment agent and a surfactant and had an inorganic particle size that was too large, was used, shape retention was poor (see Comparative Examples 4 and 9).

[0089] When B3, which is an ultrafine particle having an average particle size of less than 0.05 μm, is used instead of B1 in order to improve shape retention, the ejection force becomes high (see Comparative Example 5).

Claims

1. A dental polymerizable and hardenable composition containing a polymerizable monomer (A), an inorganic filler (B), and a polymerization initiator (C), The inorganic filler (B) is Inorganic particles (B1) made of a silica-based composite oxide and having an average particle size of 0.1 μm or more and 1 μm or less, the surfaces of which are modified by bonding by chemical reaction or by adsorption or sorption with a hydrophobic treatment agent comprising a polymer surfactant comprising at least one polymer selected from the group consisting of polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, polyethyleneimine, polyethylene oxide, and polyvinylpyrrolidone and having a weight-average molecular weight of 2,000 to 5,000,000, and a silane coupling agent and / or a titanate coupling agent; The inorganic particles (B2) have an average particle diameter of 1 μm or more and 1000 μm or less, and the surface thereof has been modified by bonding, adsorption or sorption of the hydrophobic treatment agent by chemical reaction, but has not been surface modified by bonding, adsorption or sorption of the polymer surfactant by chemical reaction, and the inorganic filler (B) contains inorganic particles (B3) having a particle diameter of less than 0.05 μm, which have been surface-modified by bonding, adsorption, or sorption of the hydrophobic treatment agent through a chemical reaction, but have not been surface-modified by bonding, adsorption, or sorption of the polymer surfactant through a chemical reaction, and the inorganic filler (B) contains inorganic particles having a particle diameter of less than 0.05 μm, and the inorganic filler (B) contains inorganic particles having a particle diameter of less than 0.05 μm, which have been surface-modified by bonding, adsorption, or sorption of the polymer surfactant through a chemical reaction, but have not been surface-modified by bonding, adsorption, or sorption of the polymer surfactant through a chemical reaction, and the inorganic filler (B3) contains inorganic particles having a particle diameter of less than 0.05 μm, and the inorganic filler (B) contains inorganic particles having a particle diameter of less than 0.05 μm, which are surface-modified by bonding, adsorption, or sorption of the polymer surfactant through a chemical reaction, but have not been ... The dental polymerizable hardenable composition characterized by the above.

2. 2. The dental polymerizable hardenable composition according to claim 1, wherein the content of the inorganic filler (B) relative to 100 parts by mass of the polymerizable monomer (A) is 100 parts by mass or more and 500 parts by mass or less, and 10% by mass or more and 90% by mass or less of the inorganic filler (B) is the inorganic particles (B1), and the remainder is the inorganic particles (B2).

3. 3. The dental polymerizable and hardenable composition according to claim 1, wherein the polymerization initiator (C) is a combination of a chemical polymerization initiator containing an organic peroxide and a tertiary amine, and a photopolymerization initiator composed of multiple components, the dental polymerizable curable composition is divided into a first paste containing a part of the polymerizable monomer (A), a part of the inorganic filler (B), and an organic peroxide, and a second paste containing the remainder of the polymerizable monomer (A), the remainder of the inorganic filler (B), and a tertiary amine, and packaged; The dental polymerizable hardenable composition, characterized in that the plurality of components constituting the photopolymerization initiator are each blended into either the first paste or the second paste.

4. A dental core construction material comprising the dental polymerizable and hardenable composition according to claim 3.

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