Method for producing dental composition

Abstract

To provide a method for producing a dental composition which can achieve both a thin film of a cured material and high mechanical strength of the cured material.SOLUTION: There is provided a method for producing a dental composition, wherein the dental composition comprises a polymerizable monomer (A) and a filler (B) having an average primary particle diameter of 0.001 μm or more and less than 1 μm, the content of the filler (B) is 3 to 25 mass% based on 100 mass% of the total of the polymerizable monomer (A), the method comprising: a step (1) of mixing a polymerizable monomer-containing polymer (P0) containing a polymerizable monomer (A) and a filler (B) to obtain a polymerizable monomer-containing polymer (P0); and a step (2) of mixing the polymerizable monomer-containing polymer (P0) and a polymerizable monomer-containing polymer (P2) containing the polymerizable monomer (A), wherein the viscosity P0n[cP] of the polymerizable monomer-containing polymer (P0) and the viscosity P2n[cP] of the polymerizable monomer-containing polymer (P2) satisfy the following relation, P0n>P2n.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for making a dental composition. [Background technology]

[0002] Compositions containing a polymerizable monomer, a filler and a volatile organic solvent are used in dental applications, primarily as dental materials such as dental primers, dental bonding materials and dental coating materials.

[0003] The above dental materials are applied to the surface of tooth structure or dental restorative material with a brush or pen, and after most of the volatile organic solvent is removed with an air blower, the materials are cured by polymerization reaction caused by polymerization initiators contained in the dental materials or other dental materials used in combination, and finally formed into a thin film of 1 mm or less. Therefore, it is desirable that the composition used in the dental material has a low viscosity so that it can be easily applied with a writing brush and the volatile organic solvent can be easily removed by air blowing.

[0004] As manufacturing methods for reducing the viscosity of a dental composition, for example, Patent Documents 1 to 3 have been proposed. Patent Document 1 discloses a production method in which the entire amount of polymerizable monomers and a filler are dispersed first, and then a solvent is added. Patent Document 2 discloses a production method in which the entire amount of polymerizable monomer is stirred and then divided, and the divided polymerizable monomer-containing composition and filler are first dispersed, and then the remaining polymerizable monomer is added. Patent Document 3 discloses a production method for controlling the viscosity of a polymerizable composition, in which the entire amount of polymerizable monomers and a filler are dispersed using a stirring blade, and then the stirring vessel is rotated and revolved to disperse the mixture.

[0005] In recent years, the versatility of dental compositions has increased, and one-liquid dental bonding materials that can be used for coating applications are in demand. For example, in coating applications for exposed root surfaces, the cured product of the bonding material layer is exposed on the outermost surface, so the cured product must have high strength. On the other hand, when used for cavity coating before taking an impression for indirect restoration, the hardened bonding material layer must have high strength so that it can withstand the physical stimuli that occur during the subsequent impression taking and removal of the temporary adhesive. In addition, if the bonding material layer is thick at the margin after the indirect restoration is completed, there is a concern that the prosthesis may be adhered to the tooth in a state where it floats up against the tooth substance. Therefore, it is necessary for the bonding material to be able to be made into a thin film, i.e., for the viscosity of the bonding material to be low from the start to the end of air blowing. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2012-012314 A [Patent Document 2] International Publication No. 2021 / 132707 [Patent Document 3] JP 2013-014690 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, although the compositions described in the above-mentioned Patent Documents 1, 2, and 3 have achieved a certain degree of low viscosity, they are not intended for use in cavity coating applications. Therefore, in order to use them as thin films in cavity coating applications, there is room for further improvement in terms of the high strength and low viscosity. Possible methods for lowering the viscosity of a dental composition include reducing the filler, increasing the amount of solvent, or increasing the amount of low-viscosity polymerizable monomer, but such compositional changes have the problem of significantly reducing the strength of the cured product.

[0008] As described above, conventional techniques have not been able to achieve both low viscosity sufficient to achieve thin films for coating applications (particularly cavity coating applications) and high mechanical strength of the cured product. In the case of a dental composition using a filler having an average particle size of less than 1 μm (particularly an average particle size of 0.2 μm or less), the filler tends to easily aggregate in the composition. Therefore, although this may not be a problem depending on the application of the dental composition, there was a problem, particularly in cavity coating applications, when the inside of a cavity was coated with the composition, and then air was blown to volatilize the volatile components while thinning the coating layer so as not to cause the prosthesis to lift off. That is, even in Patent Documents 1 to 3, which aim to reduce the viscosity, there was room for improvement in thinning the coating sufficiently for cavity coating applications. As described above, even in Patent Documents 1 to 3, which aim to reduce viscosity, it has not been possible to achieve both low viscosity for coating applications and high mechanical strength of the cured product. In addition, when the composition is changed as described above simply for the purpose of lowering the viscosity, there is a difficulty in that it is not possible to achieve both a low viscosity for the composition and high mechanical strength for the cured product.

[0009] Therefore, an object of the present invention is to provide a method for producing a dental composition which can achieve both thinning of the cured product and high mechanical strength of the cured product. [Means for solving the problem]

[0010] As a result of extensive research to solve the above problems, the inventors discovered that by first dispersing a high-viscosity polymerizable monomer-containing composition and a filler, and then adding a low-viscosity polymerizable monomer-containing composition, a dental composition having a lower viscosity while maintaining the strength of the cured product can be obtained. Based on this finding, the inventors conducted further research and completed the present invention.

[0011] The present invention includes the following inventions. [1] A method for producing a dental composition, comprising the steps of: The dental composition comprises a polymerizable monomer (A) and a filler (B) having an average primary particle size of 0.001 μm or more and less than 1 μm, The content of the filler (B) is 3 to 25% by mass relative to 100% by mass of the total amount of the polymerizable monomer (A); A step [1] of mixing a polymerizable monomer-containing composition (P0) containing a polymerizable monomer (A) with a filler (B) to obtain a polymerizable monomer-containing composition (P1); The method includes a step [2] of mixing the polymerizable monomer-containing composition (P1) with a polymerizable monomer-containing composition (P2) containing a polymerizable monomer (A), A method for producing a dental composition, wherein a viscosity P0n [cP] of a polymerizable monomer-containing composition (P0) and a viscosity P2n [cP] of a polymerizable monomer-containing composition (P2) satisfy the relationship P0n>P2n. [2] The method for producing the dental composition according to [1], wherein P0n / P2n=3 to 2000. [3] The method for producing a dental composition according to [1] or [2], wherein the concentration of the filler (B) in the polymerizable monomer-containing composition (P1) is 5% by mass or more and less than 50% by mass, relative to 100% by mass of the total of the polymerizable monomer (A) and the filler (B) in step [1]. [4] The method for producing a dental composition according to any one of [1] to [3], wherein the viscosity P0n of the polymerizable monomer-containing composition (P0) is 230 to 5000 cP. [5] The method for producing a dental composition according to any one of [1] to [4], wherein the viscosity P2n of the polymerizable monomer-containing composition (P2) is 0.5 to 150 cP. [6] The method for producing a dental composition according to any one of [1] to [5], wherein the polymerizable monomer-containing composition (P0) contains two or more types of polymerizable monomers as the polymerizable monomer (A). [7] The method for producing a dental composition according to any one of [1] to [6], wherein the filler (B) is an inorganic filler. [8] The method for producing a dental composition according to any one of [1] to [7], wherein the dental composition further contains a polymerization initiator (C). [9] The method for producing a dental composition according to [8], wherein the polymerization initiator (C) is a photopolymerization initiator.

[10] A method for producing a dental composition according to any one of [1] to [9], further comprising the step of mixing water (E) and / or an organic solvent (F) after the step [2].

[11] The method for producing a dental composition according to any one of [1] to

[10] , wherein the dental composition is a dental adhesive composition.

[12] The method for producing a dental composition according to

[11] , wherein the dental adhesive composition is a one-component dental adhesive composition.

[13] A dental composition comprising a polymerizable monomer (A), a filler (B) having an average primary particle size of 0.001 to 1 μm, a polymerization initiator (C), and an organic solvent (F), The polymerizable monomer (A) contains two or more types of polymerizable monomers, the organic solvent (F) comprises a volatile organic solvent; The content of the filler (B) is 3 to 25% by mass relative to 100% by mass of the total amount of the polymerizable monomer (A); The viscosity is 100 cP or less, A dental composition, wherein the volatile organic solvent is volatilized from the dental composition, and the resulting hardened product having a size of 2 mm x 2 mm x 25 mm has a bending strength of 110 MPa or more after being immersed in distilled water at 37°C for 24 hours.

[14] The dental composition according to

[13] , wherein the polymerizable monomer (A) comprises a polymerizable monomer (A-1) having an acidic group. Effect of the Invention

[0012] According to the present invention, there is provided a method for producing a dental composition which can achieve both thinning of the cured product and high mechanical strength of the cured product. Furthermore, according to the present invention, a method for producing a dental composition can be provided in which the obtained dental composition can be sufficiently thinned even when used for coating purposes (particularly for cavity coating purposes), and the thin, cured product has high mechanical strength. Furthermore, in the manufacturing method of the present invention, the viscosity of the dental composition can be reduced, making it unnecessary to carry out the complicated kneading process of rotating and revolving a stirring vessel as in Patent Document 3. This makes it possible to easily provide a dental composition that can provide a thin cured product that has both high mechanical strength and is industrially advantageous. Furthermore, the dental composition of the present invention can be made particularly thin, and therefore can prevent the dental prosthesis from lifting off even when a coating layer is formed on a corner where a thick coating would cause the dental prosthesis placed on the coating layer to be prone to lifting off. Furthermore, the dental composition of the present invention, when used for cavity coating, can withstand physical stimuli that occur when taking an impression or removing a temporary adhesive. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present invention will be described in detail below. In this specification, the upper and lower limits of numerical ranges (contents of each component, values ​​calculated from each component, and each physical property, etc.) can be appropriately combined. Furthermore, the embodiments can be combined as appropriate as long as the effects of the present invention are not impaired.

[0014] The method for producing a dental composition according to the present invention includes a step [1] of mixing a polymerizable monomer-containing composition (P0) and a filler (B) to obtain a polymerizable monomer-containing composition (P1), and a step [2] of mixing the polymerizable monomer-containing composition (P1) and a polymerizable monomer-containing composition (P2), wherein the viscosity P0n [cP] of the polymerizable monomer-containing composition (P0) and the viscosity P2n [cP] of the polymerizable monomer-containing composition (P2) satisfy the relationship P0n>P2n.

[0015] In the method for producing a dental composition of the present invention, a filler (B) (hereinafter also simply referred to as "filler (B)") having an average primary particle diameter of 0.001 μm or more and less than 1 μm is first dispersed in a high-viscosity polymerizable monomer-containing composition (P0) to obtain a polymerizable monomer-containing composition (P1), and then a polymerizable monomer-containing composition (P2) having a lower viscosity than the polymerizable monomer-containing composition (P0) is mixed with the polymerizable monomer-containing composition (P1). As a result, a dental composition having a lower viscosity overall than that of conventional techniques can be obtained while maintaining the high mechanical strength of the cured product.

[0016] The reason why the production method of the present invention exhibits the above-mentioned excellent effects is not necessarily clear, but is presumed to be as follows. By first mixing the high-viscosity polymerizable monomer-containing composition with the fine particle filler (B), the filler (B) is stirred in the composition in a high-viscosity state, and as a result, a polymerizable monomer-containing composition (P1) in which the filler (B) is sufficiently dispersed can be obtained. When the filler (B) is dispersed in a high viscosity composition, the filler, which is originally in an aggregated state, is subjected to a strong shear force in the high viscosity of the composition and is thoroughly dispersed, so that a polymerizable monomer-containing composition (P1) can be obtained that has less aggregation than when the filler (B) is dispersed in the entire amount of the polymerizable monomer. Furthermore, when the prepared polymerizable monomer-containing composition (P1) is mixed with a polymerizable monomer-containing composition (P2) having a lower viscosity than the polymerizable monomer-containing composition (P0), which is the raw material of the polymerizable monomer-containing composition (P1), the viscosity of the dental composition as a whole can be reduced to a level that allows a thin coating layer to be formed when coated. However, since the filler (B) is already in a sufficiently dispersed state, the filler does not move sufficiently within the composition to form aggregates after mixing the two, and it is considered that the filler (B) can be maintained in a sufficiently dispersed state. In Patent Document 1, which uses a volatile organic solvent instead of a low-viscosity polymerizable monomer-containing composition (P2), the volatile organic solvent is evaporated by blowing air during clinical use to evaporate the water and volatile organic solvent contained in the dental composition during use. Therefore, the viscosity of the dental composition in a state in which the volatile organic solvent is no longer present is not reduced, and the low viscosity required for coating applications (particularly cavity coating applications) has not been achieved. As described above, the polymerizable monomer used to disperse the filler (B) is separately prepared as at least a high-viscosity polymerizable monomer-containing composition (P0) and a low-viscosity polymerizable monomer-containing composition (P2). The high-viscosity polymerizable monomer-containing composition (P0) is then used to first prepare a polymerizable monomer-containing composition (P1) in which the filler (B) is sufficiently dispersed and has a low degree of aggregation. This makes it possible to maintain the filler (B) in a sufficiently dispersed state even when the filler is later mixed with the lower-viscosity polymerizable monomer-containing composition (P2). Therefore, compared to when the particulate filler is dispersed in the entire amount of polymerizable monomer, the viscosity of the dental composition as a whole can be made lower, and since the mechanical strength of the cured product depends greatly on the filler content, it is believed that by keeping the filler content at the same level as in the prior art, it is possible to achieve both a lower viscosity of the composition and high mechanical strength of the cured product.

[0017] In contrast, in conventional technology, there was no technical idea of ​​dividing the polymerizable monomer used to disperse the particulate filler into a high-viscosity polymerizable monomer-containing composition and a low-viscosity polymerizable monomer-containing composition, and it was not possible to achieve both low viscosity as a composition and high mechanical strength of the cured product.

[0018] In the production method of the present invention, the polymerizable monomer-containing composition (P0) contains a polymerizable monomer (A). It is preferable that the polymerizable monomer-containing composition (P0) does not contain a filler (B). The polymerizable monomer-containing composition (P0) may contain only one type of polymerizable monomer, but a polymerizable monomer mixture (M0) containing two or more types of polymerizable monomers may also be used. By including two or more types of polymerizable monomers, it becomes easy to adjust the viscosity. The polymerizable monomer-containing composition (P0) preferably contains at least one type of polymerizable monomer (A-1) having an acidic group, which will be described later, and / or at least one type of polymerizable monomer (A-2) not having an acidic group, which will be described later, thereby containing two or more types of polymerizable monomers. The polymerizable monomer-containing composition (P0) may also contain a polymerization initiator (C) and / or a polymerization accelerator (D). In an embodiment, for example, when the polymerization initiator (C) and the polymerization accelerator (D) are not contained, the polymerizable monomer mixture (M0) consisting of only polymerizable monomers may be used as it is as the polymerizable monomer-containing composition (P0). The polymerizable monomer-containing composition (P0) preferably does not contain water (E) and an organic solvent (F) in that the viscosity can be easily adjusted to a high level.

[0019] The total content of the polymerizable monomers contained in the polymerizable monomer-containing composition (P0) is preferably 20 mass% or more, more preferably 25 mass% or more, and even more preferably 30 mass% or more, based on the total amount (100 mass%) of the polymerizable monomers (A) contained in the final dental composition. In addition, the total content of the polymerizable monomers contained in the polymerizable monomer-containing composition (P0) is preferably 95 mass% or less, more preferably 93 mass% or less, and even more preferably 90 mass% or less, of the total amount (100 mass%) of the polymerizable monomers (A) contained in the final dental composition. In this specification, "100% by mass of the total amount of polymerizable monomer (A)" means 100% by mass of the total amount of polymerizable monomer (A) contained in the dental composition finally obtained by mixing all components.

[0020] The total content of the polymerizable monomers contained in the polymerizable monomer-containing composition (P2) is preferably 5 mass% or more, more preferably 7 mass% or more, and even more preferably 10 mass% or more, based on 100 mass% of the total amount of polymerizable monomers (A), from the viewpoints of being able to maintain a state in which the filler (B) is sufficiently dispersed while reducing the viscosity of the composition and maintaining high mechanical strength of the cured product. In addition, the total content of the polymerizable monomers contained in the polymerizable monomer-containing composition (P2) is preferably 80 mass% or less, more preferably 75 mass% or less, and even more preferably 70 mass% or less, based on 100 mass% of the total amount of the polymerizable monomers (A).

[0021] One preferred embodiment is a method for producing a dental composition, in which the ratio P0 / P2 of the total content of polymerizable monomers contained in the polymerizable monomer-containing composition (P0) to the total content of polymerizable monomers contained in the polymerizable monomer-containing composition (P2) is P0 / P2>1. Regarding the total content of the polymerizable monomers, when P0 / P2 is 1 or more, the polymerizable monomer-containing composition (P1) and the polymerizable monomer-containing composition (P2) become more compatible with each other, and the state in which the filler (B) is already sufficiently dispersed can be easily maintained until the final composition. Furthermore, the ratio P0 / P2 of the total contents of polymerizable monomers is more preferably 1.2 or more, and further preferably 1.5 or more.

[0022] In step [1] of mixing the polymerizable monomer-containing composition (P0) and the filler (B) to obtain the polymerizable monomer-containing composition (P1), the amount of the filler (B) is preferably 80 mass% or more, more preferably 90 mass% or more, and even more preferably 100 mass%, relative to the total amount of the filler (B) contained in the final dental composition (100 mass%). In this specification, "the total amount of the filler (B) is 100% by mass" means that the total amount of the filler (B) contained in the dental composition finally obtained by mixing all the components is 100% by mass.

[0023] The mixing of the polymerizable monomer-containing composition (P0) and the filler (B) is not particularly limited, and a known mixing and stirring method can be used. For example, a commercially available kneader (e.g., a motor equipped with stirring blades (manufactured by SMT Corporation, product name "HIGH-FLEX DISPENSER HG-92")) can be used. The stirring speed during mixing and stirring is not limited as long as the filler (B) can be kept sufficiently dispersed, and may be 1,000 to 18,000 rpm. The stirring time during mixing and stirring is not limited as long as the filler (B) can be kept sufficiently dispersed, and may be from 10 minutes to 10 hours.

[0024] The viscosity P0n [cP] of the polymerizable monomer-containing composition (P0) is preferably 5000 cP or less, more preferably 4000 cP or less, and even more preferably 3000 cP or less, from the viewpoint of deterioration of the composition due to load on the stirring device and heat generation, and from the viewpoint of reducing the viscosity of the composition in combination with step [2] while maintaining a state in which the filler (B) is sufficiently dispersed. Furthermore, in order to maintain the filler (B) in a sufficiently dispersed state, from the viewpoint of dispersion efficiency of the filler (B), the viscosity P0n is preferably 230 cP or more, more preferably 500 cP or more, and even more preferably 1000 cP or more. In this specification, viscosity can be measured by a method in accordance with JIS K 5600-2-3:2014 (cone-plate viscosity method). A specific example of the method for measuring the viscosity is as described in the Examples section below.

[0025] In the production method of the present invention, the polymerizable monomer-containing composition (P2) contains a polymerizable monomer (A). The polymerizable monomer-containing composition (P2) may contain only one type of polymerizable monomer, but may contain two or more types of polymerizable monomers. By containing two or more types of polymerizable monomers, it becomes easy to adjust the viscosity. The polymerizable monomer-containing composition (P2) preferably contains two or more polymerizable monomers by including at least one polymerizable monomer (A-1) having an acidic group described below and / or at least one polymerizable monomer (A-2) not having an acidic group described below. The content of the polymerizable monomer (A-1) having an acidic group, which will be described later, in the polymerizable monomer-containing composition (P2) may be 10 mass % or less, or may be 0 mass %. The polymerizable monomer-containing composition (P2) may also contain a polymerization initiator (C) and / or a polymerization accelerator (D). The polymerizable monomer-containing composition (P2) may contain water (E) and / or an organic solvent (F). However, since water (E) and / or organic solvent (F) may volatilize during the preparation, it is preferable not to mix them with the polymerizable monomer-containing composition (P1) before mixing the polymerizable monomer-containing composition (P1) with the polymerizable monomer-containing composition (P2).

[0026] The polymerization initiator (C) and / or the polymerization accelerator (D) may be added to the polymerizable monomer-containing composition (P1) after obtaining the polymerizable monomer-containing composition (P1) and before mixing the polymerizable monomer-containing composition (P1) with the polymerizable monomer-containing composition (P2).

[0027] The viscosity P2n of the polymerizable monomer-containing composition (P2) is preferably 0.5 cP or more, more preferably 1 cP or more, and even more preferably 2 cP or more, in order to reduce the viscosity of the composition while maintaining the filler (B) in a sufficiently dispersed state. In addition, P2n is preferably 200 cP or less, more preferably 120 cP or less, and even more preferably 70 cP or less, in order to provide a sufficient difference in viscosity from the viscosity P0n of the polymerizable monomer-containing composition (P0) and to lower the viscosity of the entire dental composition while maintaining a state in which the filler (B) is sufficiently dispersed in the polymerizable monomer-containing composition (P1).

[0028] As described above, in the method for producing a dental composition of the present invention, the viscosity P0n [cP] of the polymerizable monomer-containing composition (P0) and the viscosity P2n [cP] of the polymerizable monomer-containing composition (P2) satisfy the relationship P0n>P2n, and by mixing the filler (B) in step [1], it is possible to reduce the viscosity of the composition while maintaining the high mechanical strength of the cured product. Furthermore, in order to reduce the viscosity of the composition while maintaining the filler (B) in a sufficiently dispersed state, the ratio P0n / P2n of the viscosity P0n [cP] of the polymerizable monomer-containing composition (P0) to the viscosity P2n [cP] of the polymerizable monomer-containing composition (P2) is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. Furthermore, P0n / P2n is preferably 2000 or less, more preferably 1500 or less, and even more preferably 1000 or less, from the viewpoint of achieving a lower viscosity of the composition while maintaining the filler (B) in a sufficiently dispersed state.

[0029] In addition, in a preferred embodiment, the difference P0n-P2n between the viscosity P0n [cP] of the polymerizable monomer-containing composition (P0) and the viscosity P2n [cP] of the polymerizable monomer-containing composition (P2) is preferably 150 cP or more, more preferably 200 cP or more, and even more preferably 220 cP or more, in order to easily reduce the viscosity of the composition while maintaining the filler (B) in a sufficiently dispersed state.

[0030] The mixing of the polymerizable monomer-containing composition (P1) and the polymerizable monomer-containing composition (P2) is not particularly limited and can be carried out by a known method. For example, a commercially available kneader can be used.

[0031] The polymerizable monomer-containing composition (P1) obtained in the step [1] and the polymerizable monomer-containing composition (P2) are mixed to obtain a mixture (PC 〔1+2〕 ) viscosity (PC 〔1+2〕 n) [cP] is preferably 800 cP or less, more preferably 750 cP or less, and even more preferably 700 cP or less.

[0032] From the viewpoint of dispersion efficiency that enables the filler (B) to be maintained in a sufficiently dispersed state, the concentration of the filler (B) in the polymerizable monomer-containing composition (P1) obtained in step [1] is preferably 5% by mass or more and less than 50% by mass, more preferably 5% by mass or more and 40% by mass or less, and even more preferably 5% by mass or more and 30% by mass or less, relative to 100% by mass of the total of the polymerizable monomer (A) and the filler (B) in step [1]. By making the concentration of the filler (B) in the polymerizable monomer-containing composition (P1) less than 50 mass %, in the high-viscosity polymerizable monomer-containing composition (P0), deterioration of the composition can be prevented, excessive load is not placed on the device, and the filler (B) can be sufficiently dispersed.

[0033] The content of the filler (B) in the dental composition obtained in step [2] is preferably 3 to 25 mass%, more preferably 4 to 20 mass%, even more preferably 4 to 18 mass%, and particularly preferably 5 to 15 mass%, relative to the total amount of the polymerizable monomer (A) (100 mass%), in order to achieve both a thin film of the cured product and high mechanical strength of the cured product.

[0034] In the method for producing a dental composition of the present invention, after the step [2], an arbitrary polymerizable monomer-containing composition (P3) may be further mixed, if necessary (step [3]). When mixing the polymerizable monomer-containing composition (P3), it is preferable that the viscosity of the final dental composition obtained after mixing the mixture obtained by step [2] with the polymerizable monomer-containing composition (P3) is 100 cP or less. In the polymerizable monomer-containing composition (P3), the polymerizable monomer may be used alone or in combination of two or more kinds. The polymerizable monomer-containing composition (P3) may also contain a polymerization initiator (C) and / or a polymerization accelerator (D). The polymerizable monomer-containing composition (P3) may contain water (E) and / or an organic solvent (F). In order to prevent the water (E) and / or the organic solvent (F) from volatilizing during the preparation, the polymerizable monomer-containing composition (P3) may be mixed, and then the resulting composition may be mixed with water (E) and / or the organic solvent (F).

[0035] The viscosity P3n of the polymerizable monomer-containing composition (P3) is preferably 4000 cP or less, more preferably 3000 cP or less, and even more preferably 2000 cP or less, in order to reduce the viscosity of the composition while maintaining the filler (B) in a sufficiently dispersed state. In addition, in order to maintain the filler (B) in a sufficiently dispersed state, from the viewpoint of dispersion efficiency of the filler (B), the viscosity P3n is preferably 2 cP or more, more preferably 5 cP or more, and even more preferably 10 cP or more.

[0036] In an embodiment in which the polymerizable monomer-containing composition (P3) is mixed, the total content of the polymerizable monomers contained in the polymerizable monomer-containing composition (P0) is preferably 10 mass% or more, more preferably 20 mass% or more, and even more preferably 25 mass% or more, based on the total amount (100 mass%) of the polymerizable monomers (A) contained in the final dental composition. In addition, the total content of the polymerizable monomers contained in the polymerizable monomer-containing composition (P0) is preferably 65 mass% or less, more preferably 60 mass% or less, and even more preferably 55 mass% or less, based on the total amount (100 mass%) of the polymerizable monomers (A) contained in the dental composition.

[0037] In an embodiment in which the polymerizable monomer-containing composition (P3) is mixed, the total content of the polymerizable monomers contained in the polymerizable monomer-containing composition (P2) is preferably 1 mass % or more, more preferably 5 mass % or more, and even more preferably 8 mass % or more, based on 100 mass % of the total amount of the polymerizable monomers (A), from the viewpoints of being able to maintain a state in which the filler (B) is sufficiently dispersed while reducing the viscosity of the composition and maintaining high mechanical strength of the cured product. In addition, the total content of the polymerizable monomers contained in the polymerizable monomer-containing composition (P2) is preferably 40 mass% or less, more preferably 35 mass% or less, and even more preferably 30 mass% or less, based on 100 mass% of the total amount of the polymerizable monomers (A).

[0038] In an embodiment in which the polymerizable monomer-containing composition (P3) is mixed, the total content of the polymerizable monomers contained in the polymerizable monomer-containing composition (P3) is preferably 10 mass% or more, more preferably 20 mass% or more, and even more preferably 25 mass% or more, based on 100 mass% of the total amount of polymerizable monomers (A), from the viewpoints of being able to maintain a state in which the filler (B) is sufficiently dispersed while reducing the viscosity of the composition and maintaining high mechanical strength of the cured product. In addition, the total content of the polymerizable monomers contained in the polymerizable monomer-containing composition (P3) is preferably 65 mass% or less, more preferably 60 mass% or less, and even more preferably 55 mass% or less, based on the total amount (100 mass%) of the polymerizable monomers (A) contained in the dental composition.

[0039] In an embodiment in which the polymerizable monomer-containing composition (P3) is mixed, the ratio P0 / P2 of the total content of the polymerizable monomers contained in the polymerizable monomer-containing composition (P0) to the total content of the polymerizable monomers contained in the polymerizable monomer-containing composition (P2) is preferably 1 or more, more preferably 1.2 or more, and even more preferably 1.5 or more. Regarding the total content of the polymerizable monomers, when P0 / P2 is 1 or more, the compatibility with the polymerizable monomer-containing composition (P2) is improved, and the state in which the filler (B) is already sufficiently dispersed is easily maintained until the final composition. In addition, in an embodiment in which the polymerizable monomer-containing composition (P3) is mixed, the ratio P3 / P2 of the total content of polymerizable monomers contained in the polymerizable monomer-containing composition (P3) to the total content of polymerizable monomers contained in the polymerizable monomer-containing composition (P2) is preferably 1 or more, more preferably 1.2 or more, and even more preferably 1.5 or more. With regard to the total content of polymerizable monomers, when P3 / P2 is 1 or more, the dental composition as a whole is more likely to have a lower viscosity, the filler (B) is more likely to be maintained in a state in which it is already sufficiently dispersed, and the cured product is more likely to have high mechanical strength.

[0040] The method for mixing the mixture obtained in the step [2] with the polymerizable monomer-containing composition (P3) is not particularly limited and can be carried out by a known method. For example, a commercially available kneader can be used. In the method for producing a dental composition of the present invention, after the step [3], any polymerizable monomer or other materials may be further mixed, if necessary.

[0041] The method for producing a dental composition of the present invention preferably further comprises a step of mixing water (E) and / or an organic solvent (F) after the step [2]. When the step [3] is performed, this step is preferably performed after the step [3]. A preferred embodiment of the method for producing the dental composition of the present invention will be described below. In the step [1], a polymerizable monomer-containing composition (P0) containing a polymerizable monomer (A), a polymerization initiator (C), and a polymerization accelerator (D) is mixed with a filler (B) to obtain a polymerizable monomer-containing composition (P1). In this case, the content of the polymerizable monomer (A) in the total amount of the polymerizable monomer-containing composition (P0) is preferably 90% by mass or more, more preferably 95% by mass or more. Next, in the step [2], the polymerizable monomer-containing composition (P1) is mixed with a polymerizable monomer-containing composition (P2) containing a polymerizable monomer (A). At this time, the content of the polymerizable monomer (A) in the total amount of the polymerizable monomer-containing composition (P2) is preferably 90 mass% or more, more preferably 95 mass% or more. The amount of the polymerizable monomer-containing composition (P2) used is preferably 5 to 200 parts by mass, more preferably 10 to 100 parts by mass, and even more preferably 15 to 50 parts by mass, per 100 parts by mass of the polymerizable monomer-containing composition (P1). Next, in the step of mixing water (E) and / or organic solvent (F), water (E) and / or organic solvent (F) are mixed with the composition obtained in the step [2]. At this time, the total amount of water (E) and organic solvent (F) added is preferably 10 to 100 parts by mass, more preferably 200 to 80 parts by mass, and even more preferably 30 to 60 parts by mass, per 100 parts by mass of the total of the polymerizable monomer-containing composition (P1) and the polymerizable monomer-containing composition (P2).

[0042] Certain preferred embodiments include a method for making a dental composition, wherein the dental composition is a dental adhesive composition. The dental adhesive composition preferably contains a polymerizable monomer (A-1) having an acidic group, which will be described later. The dental adhesive composition is preferably a one-liquid dental adhesive composition.

[0043] Each component used in the method for producing the dental composition of the present invention will be described below.

[0044] Polymerizable monomer (A) The dental composition of the present invention preferably contains a polymerizable monomer (A-1) having an acidic group as the polymerizable monomer (A). The polymerizable monomer (A-1) having an acidic group penetrates the tooth tissue while demineralizing the tooth tissue, and bonds to the tooth tissue, thereby improving the adhesion to the tooth tissue. The polymerizable monomer (A-1) having an acidic group may be a monomer having at least one acidic group such as a phosphoric acid group, a phosphonic acid group, a pyrophosphoric acid group, a carboxylic acid group, or a sulfonic acid group, and at least one polymerizable group such as an acryloyl group, a methacryloyl group, an acrylamide group, or a methacrylamide group. From the viewpoint of adhesion to enamel, the polymerizable monomer (A-1) having an acidic group is preferably a monofunctional monomer having any one of an acryloyl group, a methacryloyl group, an acrylamide group, and a methacrylamide group. Specific examples include the following.

[0045] Examples of the monomer having a phosphoric acid group include 2-(meth)acryloyloxyethyl dihydrogen phosphate, 3-(meth)acryloyloxypropyl dihydrogen phosphate, 4-(meth)acryloyloxybutyl dihydrogen phosphate, 5-(meth)acryloyloxypentyl dihydrogen phosphate, 6-(meth)acryloyloxyhexyl dihydrogen phosphate, 7-(meth)acryloyloxyheptyl dihydrogen phosphate, 8-(meth)acryloyloxyoctyl dihydrogen phosphate, 9-(meth)acryloyloxynonyl dihydrogen phosphate, 10-(meth)acryloyloxydecyl dihydrogen phosphate, and 11-(meth)acryloyloxyundecyl dihydrogen phosphate. monofunctional (meth)acrylate compounds containing a phosphate group, such as 1-(meth)acryloyloxydodecyl dihydrogen phosphate, 16-(meth)acryloyloxyhexadecyl dihydrogen phosphate, 20-(meth)acryloyloxyeicosyl dihydrogen phosphate, 2-(meth)acryloyloxyethylphenyl hydrogen phosphate, 2-(meth)acryloyloxyethyl-2-bromoethyl hydrogen phosphate, 2-(meth)acryloyloxyethyl-(4-methoxyphenyl)hydrogen phosphate, and 2-(meth)acryloyloxypropyl-(4-methoxyphenyl)hydrogen phosphate, and acid chlorides, alkali metal salts, and ammonium salts thereof;Examples of such compounds include phosphate group-containing bifunctional (meth)acrylate compounds such as bis[2-(meth)acryloyloxyethyl]hydrogen phosphate, bis[4-(meth)acryloyloxybutyl]hydrogen phosphate, bis[6-(meth)acryloyloxyhexyl]hydrogen phosphate, bis[8-(meth)acryloyloxyoctyl]hydrogen phosphate, bis[9-(meth)acryloyloxynonyl]hydrogen phosphate, bis[10-(meth)acryloyloxydecyl]hydrogen phosphate, and 1,3-di(meth)acryloyloxypropyl dihydrogen phosphate, as well as their acid chlorides, alkali metal salts, and ammonium salts.

[0046] Examples of the monomer having a phosphonic acid group include 2-(meth)acryloyloxyethyl phenyl phosphonate, 5-(meth)acryloyloxypentyl-3-phosphonopropionate, 6-(meth)acryloyloxyhexyl-3-phosphonopropionate, 10-(meth)acryloyloxydecyl-3-phosphonopropionate, 6-(meth)acryloyloxyhexyl phosphonoacetate, 10-(meth)acryloyloxydecyl phosphonoacetate, and acid chlorides, alkali metal salts, and ammonium salts thereof.

[0047] Examples of monomers having a pyrophosphate group include bis[2-(meth)acryloyloxyethyl]pyrophosphate, bis[4-(meth)acryloyloxybutyl]pyrophosphate, bis[6-(meth)acryloyloxyhexyl]pyrophosphate, bis[8-(meth)acryloyloxyoctyl]pyrophosphate, bis[10-(meth)acryloyloxydecyl]pyrophosphate, and acid chlorides, alkali metal salts, and ammonium salts thereof.

[0048] Examples of monomers having a carboxylic acid group include (meth)acrylic acid, 4-(meth)acryloyloxyethoxycarbonylphthalic acid, 4-(meth)acryloyloxyethyltrimellitic acid, 4-(meth)acryloyloxybutyloxycarbonylphthalic acid, 4-(meth)acryloyloxyhexyloxycarbonylphthalic acid, 4-(meth)acryloyloxyoctyloxycarbonylphthalic acid, 4-(meth)acryloyloxydecyloxycarbonylphthalic acid, 5-(meth)acryloylaminopentylcarboxylic acid, and acid anhydrides, acid chlorides, alkali metal salts, and ammonium salts thereof.

[0049] Examples of the monomer having a sulfonic acid group include 2-(meth)acrylamide-2-methylpropanesulfonic acid, 2-sulfoethyl (meth)acrylate, and acid chlorides, alkali metal salts, and ammonium salts thereof.

[0050] As the polymerizable monomer (A-1) having an acidic group, from the viewpoint of being able to exhibit superior adhesiveness to tooth structure, a monomer having a phosphate group or a monomer having a pyrophosphate group is preferred, a monomer having a phosphate group is more preferred, and a monofunctional monomer having a phosphate group is even more preferred. Among them, a (meth)acrylate-based monofunctional monomer having a phosphate group and an alkyl or alkylene group having 6 to 20 carbon atoms as a main chain in the molecule is particularly preferred, and a (meth)acrylate-based monofunctional monomer having a phosphate group and an alkylene group having 8 to 12 carbon atoms as a main chain in the molecule, such as 10-methacryloyloxydecyl dihydrogen phosphate, is most preferred. The polymerizable monomer (A-1) having an acidic group may be used alone or in combination of two or more kinds.

[0051] The content of the polymerizable monomer (A-1) having an acidic group in the dental composition of the present invention is preferably 1 mass % or more, more preferably 2 mass % or more, and even more preferably 3 mass % or more, of the total mass of the monomer components contained in the dental composition, in order to further improve adhesion to both dental restorative materials and tooth structure. Furthermore, the content of the polymerizable monomer (A-1) having an acidic group is preferably 50 mass % or less, more preferably 30 mass % or less, and even more preferably 20 mass % or less, of the total mass of the monomer components.

[0052] From the viewpoint of adhesion, it is preferable that the polymerizable monomer (A) of the dental composition of the present invention further contains a polymerizable monomer (A-2) that does not have an acidic group. As the polymerizable monomer (A-2) having no acidic group, a known monomer having no acidic group can be used, for example, a hydrophobic monomer (A-2x) having no acidic group, a hydrophilic monomer (A-2y) having no acidic group, etc. The polymerizable monomer (A-2) having no acidic group may be used alone or in combination of two or more. For example, the polymerizable monomer (A-2) having no acidic group may be used in combination with a hydrophobic monomer (A-2x) having no acidic group and a hydrophilic monomer (A-2y) having no acidic group.

[0053] (i) Hydrophobic monomer having no acidic group (A-2x) When the dental composition of the present invention contains a hydrophobic monomer (A-2x) that does not have an acidic group, the mechanical strength, handleability, etc. of the cured product (the hardened product obtained by hardening the dental composition) can be improved. The hydrophobic monomer (A-2x) having no acidic group is preferably a radical polymerizable monomer having no acidic group and a polymerizable group. As the polymerizable group, a (meth)acryloyl group or a (meth)acrylamide group is preferred because radical polymerization is easy. As the hydrophobic monomer (A-2x) having no acidic group, one having a solubility in water at 25° C. of less than 10% by mass can be used. Examples of the hydrophobic monomer (A-2x) having no acidic group include crosslinkable monomers such as monofunctional monomers, aromatic bifunctional monomers, aliphatic bifunctional monomers, and trifunctional or higher monomers.

[0054] Examples of monofunctional monomers include 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, octafluoropentyl (meth)acrylate, m-phenoxybenzyl (meth)acrylate, biphenylmethyl (meth)acrylate, O-phenylphenolethyl (meth)acrylate, and O-phenyl(EO)2 (meth)acrylate.

[0055] Examples of aromatic bifunctional monomers include 2,2-bis((meth)acryloyloxyphenyl)propane, 2,2-bis[4-(2-hydroxy-3-(meth)acryloyloxypropoxy)phenyl]propane, 2,2-bis(4-(meth)acryloyloxyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxypolyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxydiethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytriethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytetraethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxypentaethoxyphenyl)propane, and 2,2-bis(4-(meth)acryloyloxypentaethoxyphenyl). phenyl)propane, 2,2-bis(4-(meth)acryloyloxydipropoxyphenyl)propane, 2-(4-(meth)acryloyloxydiethoxyphenyl)-2-(4-(meth)acryloyloxyethoxyphenyl)propane, 2-(4-(meth)acryloyloxydiethoxyphenyl)-2-(4-(meth)acryloyloxytriethoxyphenyl)propane, 2-(4-(meth)acryloyloxydipropoxyphenyl)-2-(4-(meth)acryloyloxytriethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxypropoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxyisopropoxyphenyl)propane, and the like. Among these, 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane (commonly known as "Bis-GMA"), 2,2-bis(4-(meth)acryloyloxyethoxyphenyl)propane, 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane (average number of moles added of ethoxy groups: 2.6, commonly known as "D-2.6E"), 2,2-bis(4-(meth)acryloyloxydiethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytriethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytetraethoxyphenyl)propane, and 2,2-bis(4-(meth)acryloyloxypentaethoxyphenyl)propane are preferred, and Bis-GMA and D-2.6E are more preferred.

[0056] Examples of the aliphatic difunctional monomers include glycerol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,10-deca(meth)acrylate, 1,2-dimethylphenyl di(meth)acrylate, 1,3-dimethylphenyl di(meth)acrylate, 1,5-dimethylphenyl di(meth)acrylate, 1,6-dimethylphenyl di(meth)acrylate, 1,2-dimethylphenyl di(meth)acrylate, 1,3-dimethylphenyl di(meth)acrylate, 1,5-dimethylphenyl di(meth)acrylate, 1,6-dimethylphenyl di(meth)acrylate, 1,10 ...3-dimethylphenyl di(meth)acrylate, 1,5-dimethylphenyl di(meth)acrylate, 1,6-dimethylphenyl di(meth)acrylate, 1,10-dimethylphenyl di(meth)acrylate, 1,3-dimethylphenyl di(meth)acrylate, 1,5-dimethylphenyl di( Examples of suitable acrylamide include dimethyl ether, ... Among these, glycerol di(meth)acrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate (commonly known as "3G"), neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,2-bis(3-methacryloyloxy-2-hydroxypropoxy)ethane, 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate (commonly known as "UDMA"), N-methacryloyloxyethyl acrylamide (commonly known as "MAEA"), and N-methacryloyloxypropyl acrylamide are preferred.

[0057] Examples of trifunctional or higher monomers include trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolmethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, N,N-(2,2,4-trimethylhexamethylene)bis[2-(aminocarboxy)propane-1,3-diol]tetra(meth)acrylate, 1,7-diacryloyloxy-2,2,6,6-tetra(meth)acryloyloxymethyl-4-oxaheptane, and N,N'-(trimethylhexamethylene)bis[2-(aminocarboxy)propane-1,3-diol]tetramethacrylate (commonly known as "U4TH"). Among these, N,N-(2,2,4-trimethylhexamethylene)bis[2-(aminocarboxy)propane-1,3-diol]tetramethacrylate and N,N'-(trimethylhexamethylene)bis[2-(aminocarboxy)propane-1,3-diol]tetramethacrylate are preferred.

[0058] Among the above-mentioned hydrophobic monomers (A-2x) not having an acidic group, from the viewpoints of the mechanical strength and handleability of the cured product, aromatic bifunctional monomers and aliphatic bifunctional monomers are preferred, and from the viewpoints of adhesive strength and the mechanical strength of the cured product, Bis-GMA, D-2.6E, 3G, UDMA, MAEA, and U4TH are more preferred, and Bis-GMA, 3G, UDMA, MAEA, and U4TH are even more preferred. The hydrophobic monomer (A-2x) having no acidic group may be used alone or in combination of two or more kinds.

[0059] The content of the hydrophobic monomer (A-2x) not having an acidic group in the dental composition of the present invention is, from the viewpoints of the mechanical strength and handleability of the cured product (a cured product obtained by curing the dental composition), preferably 9 mass % or more, more preferably 15 mass % or more, even more preferably 20 mass % or more, and particularly preferably 25 mass % or more, of the total mass of the monomer components contained in the dental composition. In addition, the content of the hydrophobic monomer (A-2x) not having an acidic group is preferably 90 mass% or less, more preferably 80 mass% or less, even more preferably 75 mass% or less, and particularly preferably 70 mass% or less, of the total mass of the monomer components.

[0060] (ii) Hydrophilic monomer having no acidic group (A-2y) The dental composition of the present invention contains a hydrophilic monomer (A-2y) that does not have an acidic group, and thus the adhesiveness to the tooth structure can be improved. The hydrophilic monomer (A-2y) that does not have an acidic group is preferably a radical polymerizable monomer that does not have an acidic group and has a polymerizable group. As the polymerizable group, a (meth)acryloyl group or a (meth)acrylamide group is preferable because it is easy to radically polymerize. As the hydrophilic monomer (A-2y) that does not have an acidic group, one having a solubility in water of 10% by mass or more at 25°C can be used, preferably one having a solubility of 30% by mass or more, and more preferably one that can be dissolved in water at any ratio at 25°C.

[0061] As the hydrophilic monomer (A-2y) having no acidic group, those having a hydrophilic group such as a hydroxyl group, an oxymethylene group, an oxyethylene group, an oxypropylene group, or an amide group are preferable. Examples of the hydrophilic monomer (A-2y) having no acidic group include (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 1,3-dihydroxypropyl (meth)acrylate, 2,3-dihydroxypropyl (meth)acrylate, 2-trimethylammoniumethyl (meth)acryl chloride, and polyethylene glycol di(meth)acrylate (average number of moles of oxyethylene groups added: 9 or more); N-methylol (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, diacetone (meth)acrylamide, 4-(meth)acryloylmorpholine, and monofunctional (meth)acrylamides such as disubstituted (meth)acrylamides represented by the following general formula (1).

[0062] [ka]

[0063] In the general formula (1), R 3 and R 4 each independently represents a linear or branched alkyl group having 1 to 3 carbon atoms which may have a substituent; R 5 is a hydrogen atom or a methyl group.

[0064] R 3 and R 4 Examples of the alkyl group having 1 to 3 carbon atoms represented by the following formula include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group, and examples of the substituents which these groups may have include a hydroxyl group.

[0065] Examples of the disubstituted (meth)acrylamide represented by the general formula (1) include N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, and N,N-di(hydroxyethyl)(meth)acrylamide. From the viewpoint of storage stability, N,N-dimethylacrylamide and N,N-diethylacrylamide are preferred, and N,N-diethylacrylamide is more preferred.

[0066] Among the hydrophilic monomers (A-2y) not having an acidic group, from the viewpoint of adhesion to tooth structure, 2-hydroxyethyl (meth)acrylate, 2,3-dihydroxypropyl (meth)acrylate, and monofunctional (meth)acrylamide are preferred, 2-hydroxyethyl (meth)acrylate, 2,3-dihydroxypropyl (meth)acrylate, diacetone (meth)acrylamide, and disubstituted (meth)acrylamide represented by the general formula (1) are more preferred, 2-hydroxyethyl (meth)acrylate and disubstituted (meth)acrylamide represented by the general formula (1) are even more preferred, and 2-hydroxyethyl methacrylate and N,N-diethylacrylamide are particularly preferred. The hydrophilic monomer (A-2y) having no acidic group may be used alone or in combination of two or more kinds.

[0067] From the viewpoints of adhesion to tooth structure and minimizing changes in properties during storage, the content of the hydrophilic monomer (A-2y) not having an acidic group in the dental composition of the present invention is preferably 8 mass% or more, more preferably 10 mass% or more, and even more preferably 12 mass% or more, of the total mass of the monomer components contained in the dental composition. In addition, the content of the hydrophilic monomer (A-2y) not having an acidic group is preferably 90 mass% or less, more preferably 80 mass% or less, even more preferably 70 mass% or less, and particularly preferably 60 mass% or less, of the total mass of the monomer components.

[0068] The total content of all monomers contained in the dental composition of the present invention, including the polymerizable monomer (A-1) having an acidic group and the polymerizable monomer (A-2) not having an acidic group, is preferably 20 mass% or more, and more preferably 35 mass% or more, from the viewpoint of the mechanical strength of the cured product. The total content of all monomers is preferably 90% by mass or less, and more preferably 80% by mass or less.

[0069] Filler (B) The dental composition of the present invention contains a filler (B) having an average primary particle size of 0.001 μm or more and less than 1 μm. The inclusion of the filler (B) improves the ease of handling of the dental composition and the mechanical strength of the cured product, and therefore the dental composition of the present invention can be suitably used as a one-liquid dental bonding material and for coating exposed root surfaces.

[0070] The filler (B) can be roughly classified into organic fillers, inorganic fillers, and organic-inorganic composite fillers. The filler (B) may be used alone or in combination of two or more. When two or more types are used in combination, for example, fillers with different materials, particle size distributions, shapes, etc. may be used in combination. As the filler (B), a commercially available product can be used.

[0071] Examples of the organic filler material include polymethyl methacrylate, polyethyl methacrylate, methyl methacrylate-ethyl methacrylate copolymer, cross-linked polymethyl methacrylate, cross-linked polyethyl methacrylate, polyamide, polyvinyl chloride, polystyrene, chloroprene rubber, nitrile rubber, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, acrylonitrile-styrene copolymer, acrylonitrile-styrene-butadiene copolymer, etc. The organic filler may be used alone or in combination of two or more kinds. The shape of the organic filler is not particularly limited.

[0072] Examples of inorganic filler materials include quartz, silica, alumina, silica-titania, silica-titania-barium oxide, silica-zirconia, silica-alumina, lanthanum glass, borosilicate glass, soda glass, barium glass, strontium glass, glass ceramic, aluminosilicate glass, barium boroaluminosilicate glass, strontium boroaluminosilicate glass, fluoroaluminosilicate glass, calcium fluoroaluminosilicate glass, strontium fluoroaluminosilicate glass, barium fluoroaluminosilicate glass, strontium calcium fluoroaluminosilicate glass, etc. The inorganic fillers may be used alone or in combination of two or more.

[0073] The shape of the inorganic filler is not particularly limited, and examples of the inorganic filler include irregular fillers, spherical fillers, etc. From the viewpoint of improving the mechanical strength of the cured product, it is preferable to use a spherical filler as the inorganic filler. Here, a spherical filler can be defined as a filler in which, when a photograph of the filler is taken with a scanning electron microscope (hereinafter abbreviated as SEM), the particles observed within a unit field of view are rounded, and the average uniformity obtained by dividing the particle diameter in a direction perpendicular to the maximum diameter by the maximum diameter is 0.6 or more. When a spherical filler is used as the inorganic filler, the average particle size is preferably 0.1 μm or more in order to prevent a decrease in the filling rate of the spherical filler in the dental composition and to maintain the mechanical strength of the cured product, and is preferably 5 μm or less in order to provide a sufficient surface area for maintaining the mechanical strength of the cured product.

[0074] In order to adjust the fluidity of the dental composition, the inorganic filler may be surface-treated with a known surface treatment agent such as a silane coupling agent before use, if necessary. Examples of such surface treatment agents include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, vinyltri(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, 11-methacryloyloxyundecyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane.

[0075] As the organic-inorganic composite filler, a filler obtained by adding a monomer compound to the inorganic filler described above in advance, forming a paste, polymerizing it, and pulverizing it can be used. As the organic-inorganic composite filler, for example, a TMPT filler (a mixture of trimethylolpropane methacrylate and a silica filler, polymerizing it, and pulverizing it) can be used. The shape of the organic-inorganic composite filler is not particularly limited.

[0076] The average particle size of the filler (B) is from 0.001 μm to less than 1 μm from the viewpoints of the handleability of the resulting dental composition and the mechanical strength of the cured product. Furthermore, from the viewpoint of the mechanical strength of the cured product as a thin coating layer, the average particle size of the filler (B) is preferably 0.001 μm or more and 0.9 μm or less, more preferably 0.001 μm or more and 0.5 μm or less, and even more preferably 0.001 μm or more and 0.1 μm or less. In this specification, the average particle size of the filler (B) means the average particle size of the primary particles of the filler (B) (average primary particle size).

[0077] The average particle size of the filler (B) can be determined by a laser diffraction scattering method or by observing the particles with an electron microscope. Specifically, the laser diffraction scattering method is convenient for measuring particle sizes of 0.1 μm or more, and electron microscope observation is convenient for measuring the particle sizes of ultrafine particles less than 0.1 μm. The laser diffraction scattering method can be used to determine whether the particle size is 0.1 μm or more.

[0078] In the laser diffraction scattering method, for example, the average particle size can be determined by volumetric measurement using a laser diffraction particle size distribution measuring device (e.g., the "SALD-2300" manufactured by Shimadzu Corporation) using a 0.2% aqueous solution of sodium hexametaphosphate as a dispersion medium.

[0079] In electron microscope observation, for example, a photograph of the particles is taken with a scanning electron microscope (e.g., Hitachi's "S-4000" model, etc.), and the particle diameters of the particles (200 or more) observed within a unit field of view of the photograph are measured using image analysis type particle size distribution measurement software (Mountec's "Mac-View" etc.), to obtain the average particle diameter. In this case, the particle diameter of the particles is obtained as the arithmetic mean value of the longest and shortest lengths of the particles, and the average particle diameter is calculated from the number of particles and their particle diameters.

[0080] From the viewpoints of the handleability of the resulting dental composition and the mechanical strength of the cured product, the content of the filler (B) in the dental composition of the present invention is preferably 3 mass% or more, more preferably 4 mass% or more, and even more preferably 5 mass% or more, relative to 100 mass% of the total amount of the polymerizable monomer (A). The content of the filler (B) is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on 100% by mass of the total amount of the polymerizable monomer (A).

[0081] One preferred embodiment is a method for producing a dental composition, in which the filler (B) is an inorganic filler, from the viewpoint of the mechanical strength of the cured product as a thin coating layer.

[0082] The dental composition and its manufacturing method of the present invention may contain a filler having an average particle size other than filler (B) (hereinafter, also simply referred to as "filler other than filler (B)"). The average particle size of the filler other than the filler (B) is preferably from 1 μm to 50 μm, more preferably from 1 μm to 30 μm, and even more preferably from 1 μm to 20 μm. As the filler other than the filler (B), an organic filler, an inorganic filler, or an organic-inorganic composite filler can be used, similarly to the filler (B). The materials for these fillers can be the same as those for the filler (B). When a filler other than the filler (B) is contained, the total content of the filler (B) and the filler other than the filler (B) in the dental composition is preferably 3 mass% or more, more preferably 4 mass% or more, and even more preferably 5 mass% or more, relative to 100 mass% of the total amount of the polymerizable monomer (A), from the viewpoints of the handleability of the resulting dental composition and the mechanical strength of the cured product. Furthermore, the total content of the filler (B) and fillers other than the filler (B) is preferably 25 mass% or less, more preferably 20 mass% or less, and even more preferably 15 mass% or less, relative to 100 mass% of the total amount of the polymerizable monomer (A).

[0083] Polymerization initiator (C) From the viewpoint of adhesiveness, the dental composition of the present invention preferably further contains a polymerization initiator (C). As the polymerization initiator (C), a known polymerization initiator can be used, for example, a photopolymerization initiator (C-1), a chemical polymerization initiator (C-2), etc. can be used. The polymerization initiator (C) may be used alone or in combination of two or more kinds, for example, a photopolymerization initiator (C-1) and a chemical polymerization initiator (C-2) may be used in combination.

[0084] (i) Photopolymerization initiator (C-1) Examples of the photopolymerization initiator (C-1) include (bis)acylphosphine oxides (including salts), thioxanthones (including salts such as quaternary ammonium salts), ketals, α-diketones, coumarins, anthraquinones, benzoin alkyl ether compounds, and α-aminoketone compounds.

[0085] Among the (bis)acylphosphine oxides, examples of the acylphosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylmethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, 2,3,5,6-tetramethylbenzoyldiphenylphosphine oxide, and benzoyldi(2,6-dimethylphenyl)phosphonate.

[0086] Of the (bis)acylphosphine oxides, examples of the bisacylphosphine oxides include bis(2,6-dichlorobenzoyl)phenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and bis(2,3,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide.

[0087] The acylphosphine oxide may be a water-soluble acylphosphine oxide. Examples of the water-soluble acylphosphine oxide include those having an ion such as an alkali metal ion, an alkaline earth metal ion, a pyridinium ion, or an ammonium ion in the acylphosphine oxide molecule. The water-soluble acylphosphine oxide can be synthesized by the method disclosed in, for example, European Patent No. 0009348 and Japanese Patent Laid-Open No. 57-197289.

[0088] Specific examples of the water-soluble acylphosphine oxides include monomethyl acetylphosphonate sodium salt, monomethyl (1-oxopropyl)phosphonate sodium salt, monomethyl benzoylphosphonate sodium salt, monomethyl (1-oxobutyl)phosphonate sodium salt, monomethyl (2-methyl-1-oxopropyl)phosphonate sodium salt, acetylphosphonate sodium salt, methyl 4-(hydroxymethoxyphosphinyl)-4-oxobutanoate sodium salt, methyl 4-oxo-4-phosphonobutanoate monosodium salt, acetylphenylphosphinate sodium salt, (1-oxopropyl)pentylphosphinate sodium salt, methyl 4-(hydroxypentylphosphinyl)-4-oxobutanoate sodium salt, acetylpentylphosphinate sodium salt, acetylethylphosphine methyl 4-(hydroxymethylphosphinyl)-4-oxobutanoate sodium salt, methyl 4-(hydroxymethylphosphinyl)-4-oxobutanoate lithium salt, 4-(hydroxymethylphosphinyl)-4-oxobutanoic acid dilithium salt, acetyl phosphinate sodium salt, acetyl methyl phosphinate oxime sodium salt, acetyl methyl phosphinate-O-benzyl oxime sodium salt, acetyl methyl phosphinate semicarbazone sodium salt, formyl methyl phosphinate sodium salt, methyl (1-oxopropyl) phosphinate sodium salt, acetyl methyl phosphinate thiosemicarbazone sodium salt, 2,4,6-trimethylbenzoylphenylphosphine oxide sodium salt, 2,4,6-trimethylbenzoylphenylphosphine oxide potassium salt, 2,4,6-trimethylbenzoylphenylphosphine oxide ammonium salt.

[0089] Among these (bis)acylphosphine oxides, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylmethoxyphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and the sodium salt of 2,4,6-trimethylbenzoylphenylphosphine oxide are particularly preferred.

[0090] Examples of the thioxanthones include thioxanthone, 2-chlorothioxanthene-9-one, 2-hydroxy-3-(9-oxy-9H-thioxanthen-4-yloxy)-N,N,N-trimethylpropaneaminium chloride, 2-hydroxy-3-(1-methyl-9-oxo-9H-thioxanthen-4-yloxy)-N,N,N-trimethyl-1-propaneaminium chloride, and 2-hydroxy-3-(9-oxo-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-propaneaminium chloride. ammonium chloride, 2-hydroxy-3-(3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-propaneaminium chloride, 2-hydroxy-3-(3,4-dimethyl-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-propaneaminium chloride, 2-hydroxy-3-(1,3,4-trimethyl-9-oxo-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-propaneaminium chloride, and the like.

[0091] Among these thioxanthones, 2-chlorothioxanthene-9-one and 2-hydroxy-3-(3,4-dimethyl-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-propanaminium chloride are preferred.

[0092] Examples of the ketals include benzyl dimethyl ketal and benzyl diethyl ketal.

[0093] Examples of the α-diketones include diacetyl, benzil, camphorquinone, 2,3-pentadione, 2,3-octadione, 9,10-phenanthrenequinone, 4,4′-oxybenzil, acenaphthenequinone, etc. Among these, camphorquinone is particularly preferred from the viewpoint of having a maximum absorption wavelength in the visible light region.

[0094] Examples of the coumarins include 3,3'-carbonylbis(7-diethylaminocoumarin), 3-(4-methoxybenzoyl)coumarin, 3-thienylcoumarin, 3-benzoyl-5,7-dimethoxycoumarin, 3-benzoyl-7-methoxycoumarin, 3-benzoyl-6-methoxycoumarin, 3-benzoyl-8-methoxycoumarin, 3-benzoylcoumarin, 7-methoxy-3-(p-nitrobenzoyl)coumarin, 3-(p-nitrobenzoyl)coumarin, 3,5-carbonylbis(7-methoxycoumarin), 3-benzoyl-6-bromobenzoyl coumarin, 3,3'-carbonylbiscoumarin, 3-benzoyl-7-dimethylaminocoumarin, 3-benzoylbenzo[f]coumarin, 3-carboxycoumarin, 3-carboxy-7-methoxycoumarin, 3-ethoxycarbonyl-6-methoxycoumarin, 3-ethoxycarbonyl-8-methoxycoumarin, 3-acetylbenzo[f]coumarin, 3-benzoyl-6-nitrocoumarin, 3-benzoyl-7-diethylaminocoumarin, 7-dimethylamino-3-(4-methoxybenzoyl)coumarin, 7-diethylamino-3-(4-methoxybenzoyl)coumarin )coumarin, 7-diethylamino-3-(4-diethylamino)coumarin, 7-methoxy-3-(4-methoxybenzoyl)coumarin, 3-(4-nitrobenzoyl)benzo[f]coumarin, 3-(4-ethoxycinnamoyl)-7-methoxycoumarin, 3-(4-dimethylaminocinnamoyl)coumarin, 3-(4-diphenylaminocinnamoyl)coumarin, 3-[(3-dimethylbenzothiazol-2-ylidene)acetyl]coumarin, 3-[(1-methylnaphtho[1,2-d]thiazol-2-ylidene)acetyl]coumarin, 3,3'-carbo nylbis(6-methoxycoumarin), 3,3'-carbonylbis(7-acetoxycoumarin), 3,3'-carbonylbis(7-dimethylaminocoumarin), 3-(2-benzothiazolyl)-7-(diethylamino)coumarin, 3-(2-benzothiazolyl)-7-(dibutylamino)coumarin, 3-(2-benzimidazolyl)-7-(diethylamino)coumarin, 3-(2-benzothiazolyl)-7-(dioctylamino)coumarin, 3-acetyl-7-(dimethylamino)coumarin, 3,3'-carbonylbis(7-dibutylamino)coumarin, 3,Examples of the 3'-carbonyl-7-diethylaminocoumarin-7'-bis(butoxyethyl)aminocoumarin include 10-[3-[4-(dimethylamino)phenyl]-1-oxo-2-propenyl]-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-11-one and 10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-11-one.

[0095] Among these coumarins, 3,3'-carbonylbis(7-diethylaminocoumarin) and 3,3'-carbonylbis(7-dibutylaminocoumarin) are preferred.

[0096] Examples of the anthraquinones include anthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone, 1-bromoanthraquinone, 1,2-benzanthraquinone, 1-methylanthraquinone, 2-ethylanthraquinone, and 1-hydroxyanthraquinone.

[0097] Examples of the benzoin alkyl ether compounds include benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

[0098] Examples of the α-aminoketone compounds include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one.

[0099] Among these photopolymerization initiators (C-1), at least one selected from the group consisting of (bis)acylphosphine oxides, α-diketones, and coumarins is preferred. This makes it possible to obtain a dental composition that is excellent in photocurability in the visible light region and near ultraviolet light region and exhibits sufficient photocurability even when using any of the light sources, such as a halogen lamp, a light-emitting diode (LED), and a xenon lamp.

[0100] (ii) Chemical polymerization initiator (C-2) As the chemical polymerization initiator (C-2), any of the conventionally known initiators can be used, and organic peroxides are particularly preferred. Examples of the organic peroxide include ketone peroxides, hydroperoxides, diacyl peroxides, dialkyl peroxides, peroxyketals, peroxyesters, and peroxydicarbonates.

[0101] Examples of the ketone peroxide include methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, methylcyclohexanone peroxide, and cyclohexanone peroxide.

[0102] Examples of the hydroperoxide include 2,5-dimethylhexane-2,5-dihydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide.

[0103] Examples of the diacyl peroxide include acetyl peroxide, isobutyryl peroxide, benzoyl peroxide, decanoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, 2,4-dichlorobenzoyl peroxide, and lauroyl peroxide.

[0104] Examples of the dialkyl peroxide include di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 1,3-bis(t-butylperoxyisopropyl)benzene, and 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne.

[0105] Examples of the peroxyketals include 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, and 4,4-bis(t-butylperoxy)valeric acid n-butyl ester.

[0106] Examples of the peroxy ester include α-cumyl peroxy neodecanoate, t-butyl peroxy neodecanoate, t-butyl peroxy pivalate, 2,2,4-trimethylpentyl peroxy-2-ethylhexanoate, t-amyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexanoate, di-t-butyl peroxy isophthalate, di-t-butyl peroxy hexahydroterephthalate, t-butyl peroxy-3,3,5-trimethylhexanoate, t-butyl peroxy acetate, t-butyl peroxy benzoate, and t-butyl peroxy valeric acid.

[0107] Examples of the peroxydicarbonate include di-3-methoxybutyl peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, bis(4-t-butylcyclohexyl) peroxydicarbonate, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl) peroxydicarbonate, and diallyl peroxydicarbonate.

[0108] Among these organic peroxides, diacyl peroxides are preferred, and benzoyl peroxide is particularly preferred, in view of the overall balance of safety, storage stability, and radical generating ability.

[0109] The polymerization initiator (C) preferably contains a photopolymerization initiator (C-1).

[0110] The content of the polymerization initiator (C) in the dental composition of the present invention is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, even more preferably 0.1 mass% or more, and particularly preferably 0.3 mass% or more, from the viewpoint of the adhesiveness of the resulting dental composition. The content of the polymerization initiator (C) is preferably 10% by mass or less.

[0111] Polymerization accelerator (D) The dental composition of the present invention may further contain a polymerization accelerator (D). The polymerization accelerator (D) is preferably used together with the polymerization initiator (C). As the polymerization accelerator (D), known polymerization accelerators can be used, and examples thereof include amines, sulfinic acids (including salts), borate compounds, barbituric acid compounds, triazine compounds, copper compounds, tin compounds, vanadium compounds, halogen compounds, aldehydes, thiol compounds, sulfites, hydrogen sulfites, and thiourea compounds. The polymerization accelerator (D) may be used alone or in combination of two or more kinds.

[0112] The amines are divided into aliphatic amines and aromatic amines. Examples of the aliphatic amine include primary aliphatic amines such as n-butylamine, n-hexylamine, and n-octylamine; secondary aliphatic amines such as diisopropylamine, dibutylamine, and N-methylethanolamine; and tertiary aliphatic amines such as N-methyldiethanolamine, N-ethyldiethanolamine, Nn-butyldiethanolamine, N-lauryldiethanolamine, 2-(dimethylamino)ethyl methacrylate, N-methyldiethanolamine dimethacrylate, N-ethyldiethanolamine dimethacrylate, triethanolamine monomethacrylate, triethanolamine dimethacrylate, triethanolamine trimethacrylate, triethanolamine, trimethylamine, triethylamine, and tributylamine. Among these, from the viewpoints of adhesion and storage stability of the dental composition, tertiary aliphatic amines are preferred, and N-methyldiethanolamine and triethanolamine are more preferred.

[0113] Examples of the aromatic amine include N,N-bis(2-hydroxyethyl)-3,5-dimethylaniline, N,N-di(2-hydroxyethyl)-p-toluidine, N,N-bis(2-hydroxyethyl)-3,4-dimethylaniline, N,N-bis(2-hydroxyethyl)-4-ethylaniline, N,N-bis(2-hydroxyethyl)-4-isopropylaniline, N,N-bis(2-hydroxyethyl)-4-t-butylaniline, N,N-bis(2-hydroxyethyl)-3,5-diisopropylaniline, N,N-bis(2-hydroxyethyl)-3,5-di-t-butylaniline, N,N-dimethylaniline, N,N-dimethyl-p-toluidine, N,N-dimethyl-m-toluidine, N,N-diethyl-p-toluidine, N, N-dimethyl-3,5-dimethylaniline, N,N-dimethyl-3,4-dimethylaniline, N,N-dimethyl-4-ethylaniline, N,N-dimethyl-4-isopropylaniline, N,N-dimethyl-4-t-butylaniline, N,N-dimethyl-3,5-di-t-butylaniline, 4-(N,N-dimethylamino)ethyl benzoate, 4-(N,N-dimethylamino)methyl benzoate, 4-(N,N-dimethylamino)propyl benzoate, 4-(N,N-dimethylamino)n-butoxyethyl benzoate, 4-(N,N-dimethylamino)2-[(meth)acryloyloxy]ethyl benzoate, 4-(N,N-dimethylamino)benzophenone, 4-dimethylaminobutyl benzoate, and 4-(dimethylamino)benzonitrile are listed. Among these, from the viewpoint of imparting excellent adhesive properties to the dental composition, N,N-di(2-hydroxyethyl)-p-toluidine, ethyl 4-(N,N-dimethylamino)benzoate, n-butoxyethyl 4-(N,N-dimethylamino)benzoate, and 4-(N,N-dimethylamino)benzophenone are preferred.

[0114] Examples of the sulfinic acids include p-toluenesulfinic acid, sodium p-toluenesulfinate, potassium p-toluenesulfinate, lithium p-toluenesulfinate, calcium p-toluenesulfinate, benzenesulfinic acid, sodium benzenesulfinate, potassium benzenesulfinate, lithium benzenesulfinate, calcium benzenesulfinate, 2,4,6-trimethylbenzenesulfinic acid, sodium 2,4,6-trimethylbenzenesulfinate, potassium 2,4,6-trimethylbenzenesulfinate, lithium 2,4,6-trimethylbenzenesulfinate, and 2,4,6-trimethylbenzenesulfinate. Examples of sulfinate include calcium sulfinate, 2,4,6-triethylbenzenesulfinic acid, sodium 2,4,6-triethylbenzenesulfinate, potassium 2,4,6-triethylbenzenesulfinate, lithium 2,4,6-triethylbenzenesulfinate, calcium 2,4,6-triethylbenzenesulfinate, 2,4,6-triisopropylbenzenesulfinic acid, sodium 2,4,6-triisopropylbenzenesulfinate, potassium 2,4,6-triisopropylbenzenesulfinate, lithium 2,4,6-triisopropylbenzenesulfinate, and calcium 2,4,6-triisopropylbenzenesulfinate. Among these, sodium benzenesulfinate, sodium p-toluenesulfinate, and sodium 2,4,6-triisopropylbenzenesulfinate are particularly preferable.

[0115] The borate compound is preferably an aryl borate compound, such as a borate compound having 1 to 4 aryl groups in one molecule.

[0116] Examples of the borate compound having one aryl group per molecule include trialkylphenyl boron, trialkyl(p-chlorophenyl) boron, trialkyl(p-fluorophenyl) boron, trialkyl[3,5-bis(trifluoromethyl)phenyl] boron, trialkyl[3,5-bis(1,1,1,3,3,3-hexafluoro-2-methoxy-2-propyl)phenyl] boron, trialkyl(p-nitrophenyl) boron, trialkyl(m-nitrophenyl) boron, trialkyl(p-butylphenyl) boron, trialkyl(m-butylphenyl) boron, trialkyl(p-butyloxo) boron, Examples of such borane include trialkyl(m-butyloxyphenyl)borane, trialkyl(p-octyloxyphenyl)borane, trialkyl(m-octyloxyphenyl)borane (the alkyl group in each of the above examples is an n-butyl group, an n-octyl group, an n-dodecyl group, etc.), and salts thereof (sodium salt, lithium salt, potassium salt, magnesium salt, tetrabutylammonium salt, tetramethylammonium salt, tetraethylammonium salt, methylpyridinium salt, ethylpyridinium salt, butylpyridinium salt, methylquinolinium salt, ethylquinolinium salt, butylquinolinium salt, etc.).

[0117] Examples of the borate compound having two aryl groups in one molecule include dialkyldiphenylboron, dialkyldi(p-chlorophenyl)boron, dialkyldi(p-fluorophenyl)boron, dialkyldi[3,5-bis(trifluoromethyl)phenyl]boron, dialkyldi[3,5-bis(1,1,1,3,3,3-hexafluoro-2-methoxy-2-propyl)phenyl]boron, dialkyldi(p-nitrophenyl)boron, dialkyldi(m-nitrophenyl)boron, dialkyldi(p-butylphenyl)boron, and dialkyldi(m-butylphenyl)boron. dialkyldi(p-butyloxyphenyl)boron, dialkyldi(m-butyloxyphenyl)boron, dialkyldi(p-octyloxyphenyl)boron, dialkyldi(m-octyloxyphenyl)boron, and salts thereof (sodium salts, lithium salts, potassium salts, magnesium salts, tetrabutylammonium salts, tetramethylammonium salts, tetraethylammonium salts, methylpyridinium salts, ethylpyridinium salts, butylpyridinium salts, methylquinolinium salts, ethylquinolinium salts, butylquinolinium salts, etc.). Examples of the alkyl group in each of the examples of the borate compound include an n-butyl group, an n-octyl group, and an n-dodecyl group.

[0118] Examples of borate compounds having three aryl groups in one molecule include monoalkyltriphenylboron, monoalkyltri(p-chlorophenyl)boron, monoalkyltri(p-fluorophenyl)boron, monoalkyltri[3,5-bis(trifluoromethyl)phenyl]boron, monoalkyltri[3,5-bis(1,1,1,3,3,3-hexafluoro-2-methoxy-2-propyl)phenyl]boron, monoalkyltri(p-nitrophenyl)boron, monoalkyltri(m-nitrophenyl)boron, monoalkyltri(p-butylphenyl)boron, monoalkyltri(m

[0043] Examples of the alkyl group include monoalkyltri(p-butyloxyphenyl)boron, monoalkyltri(m-butyloxyphenyl)boron, monoalkyltri(p-octyloxyphenyl)boron, monoalkyltri(m-octyloxyphenyl)boron, and salts thereof (sodium salts, lithium salts, potassium salts, magnesium salts, tetrabutylammonium salts, tetramethylammonium salts, tetraethylammonium salts, methylpyridinium salts, ethylpyridinium salts, butylpyridinium salts, methylquinolinium salts, ethylquinolinium salts, butylquinolinium salts, etc.). Examples of the alkyl group in each of the examples of the borate compound include an n-butyl group, an n-octyl group, and an n-dodecyl group.

[0119] Examples of borate compounds having four aryl groups in one molecule include tetraphenylboron, tetrakis(p-chlorophenyl)boron, tetrakis(p-fluorophenyl)boron, tetrakis[3,5-bis(trifluoromethyl)phenyl]boron, tetrakis[3,5-bis(1,1,1,3,3,3-hexafluoro-2-methoxy-2-propyl)phenyl]boron, tetrakis(p-nitrophenyl)boron, tetrakis(m-nitrophenyl)boron, tetrakis(p-butylphenyl)boron, tetrakis(m-butylphenyl)boron, tetrakis(p-butyloxyphenyl)boron, tetrakis(m-butyloxyphenyl)boron, tetrakis(p-octyloxyphenyl)boron, and tetrakis(m-octyloxyphenyl)boron.

[0046] Examples of suitable aryloxyphenyls include (p-nitrophenyl)triphenylboron, (m-butyloxyphenyl)triphenylboron, (p-butyloxyphenyl)triphenylboron, (m-octyloxyphenyl)triphenylboron, (p-octyloxyphenyl)triphenylboron, and salts thereof (sodium salts, lithium salts, potassium salts, magnesium salts, tetrabutylammonium salts, tetramethylammonium salts, tetraethylammonium salts, methylpyridinium salts, ethylpyridinium salts, butylpyridinium salts, methylquinolinium salts, ethylquinolinium salts, butylquinolinium salts, etc.).

[0120] Among these aryl borate compounds, from the viewpoint of storage stability, borate compounds having three or four aryl groups in one molecule are preferred. The aryl borate compounds may be used alone or in combination of two or more kinds.

[0121] Examples of the barbituric acid compound include barbituric acid, 1,3-dimethylbarbituric acid, 1,3-diphenylbarbituric acid, 1,5-dimethylbarbituric acid, 5-butylbarbituric acid, 5-ethylbarbituric acid, 5-isopropylbarbituric acid, 5-cyclohexylbarbituric acid, 1,3,5-trimethylbarbituric acid, 1,3-dimethyl-5-ethylbarbituric acid, 1,3-dimethyl-5-n-butylbarbituric acid, 1,3-dimethyl-5-isobutylbarbituric acid, 1,3-dimethyl-5-cyclopentylbarbituric acid, 1,3-dimethyl-5-cyclohexylbarbituric acid, 1,3-dimethyl-5-phenylbarbituric acid, 1-cyclo Examples of the barbituric acid include hexyl-1-ethylbarbituric acid, 1-benzyl-5-phenylbarbituric acid, 5-methylbarbituric acid, 5-propylbarbituric acid, 1,5-diethylbarbituric acid, 1-ethyl-5-methylbarbituric acid, 1-ethyl-5-isobutylbarbituric acid, 1,3-diethyl-5-butylbarbituric acid, 1-cyclohexyl-5-methylbarbituric acid, 1-cyclohexyl-5-ethylbarbituric acid, 1-cyclohexyl-5-octylbarbituric acid, 1-cyclohexyl-5-hexylbarbituric acid, 5-butyl-1-cyclohexylbarbituric acid, 1-benzyl-5-phenylbarbituric acid, thiobarbituric acids, and salts thereof. Salts of these barbituric acid compounds include, for example, alkali metal salts and alkaline earth metal salts, and more specifically, include sodium 5-butylbarbiturate, sodium 1,3,5-trimethylbarbiturate, sodium 1-cyclohexyl-5-ethylbarbiturate, etc.

[0122] Particularly preferred barbituric acid compounds are 5-butylbarbituric acid, 1,3,5-trimethylbarbituric acid, 1-cyclohexyl-5-ethylbarbituric acid, 1-benzyl-5-phenylbarbituric acid, and the sodium salts thereof.

[0123] Examples of the triazine compound include 2,4,6-tris(trichloromethyl)-s-triazine, 2,4,6-tris(tribromomethyl)-s-triazine, 2-methyl-4,6-bis(trichloromethyl)-s-triazine, 2-methyl-4,6-bis(tribromomethyl)-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methylthiophenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-chlorophenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(2,4-dichlorophenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-bromophenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine, 2-n-propyl-4,6-bis(trichloromethyl)-s-triazine, 2-(α,α,β-trichloroethyl)-4,6-bis(trichloromethyl)-s-triazine, 2-styryl-4,6- Bis(trichloromethyl)-s-triazine, 2-[2-(p-methoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(o-methoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(p-butoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(3,4-dimethoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(3,4,5-trimethoxyphenyl)ethenyl]-4, 6-bis(trichloromethyl)-s-triazine, 2-(1-naphthyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-biphenylyl)-4,6-bis(trichloromethyl)-s-triazine, 2-[2-{N,N-bis(2-hydroxyethyl)amino}ethoxy]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-{N-hydroxyethyl-N-ethylamino}ethoxy]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-{N-hydroxyethyl-N-methylamino}ethoxy]-4,Examples include 6-bis(trichloromethyl)-s-triazine and 2-[2-{N,N-diallylamino}ethoxy]-4,6-bis(trichloromethyl)-s-triazine.

[0124] Among these triazine compounds, 2,4,6-tris(trichloromethyl)-s-triazine is preferred in terms of polymerization activity, and 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(p-chlorophenyl)-4,6-bis(trichloromethyl)-s-triazine, and 2-(4-biphenylyl)-4,6-bis(trichloromethyl)-s-triazine are preferred in terms of storage stability. The triazine compounds may be used alone or in combination of two or more kinds.

[0125] Examples of the copper compound include copper acetylacetonate, copper (II) acetate, copper oleate, copper (II) chloride, and copper (II) bromide.

[0126] Examples of the tin compound include di-n-butyltin dimaleate, di-n-octyltin dimaleate, di-n-octyltin dilaurate, di-n-butyltin dilaurate, etc. Among these, di-n-octyltin dilaurate and di-n-butyltin dilaurate are preferred.

[0127] The vanadium compound is preferably a trivalent or pentavalent vanadium compound. Examples of the trivalent or pentavalent vanadium compound include divanadium(IV) tetroxide, vanadium oxide acetylacetonate(IV), vanadyl oxalate(IV), vanadyl sulfate(IV), oxo-bis(1-phenyl-1,3-butanedionato)vanadium(IV), bis(maltolato)oxo-vanadium(IV), vanadium pentoxide(V), sodium metavanadate(V), and ammonium metavanadate(V).

[0128] Examples of the halogen compounds include dilauryl dimethyl ammonium chloride, lauryl dimethyl benzyl ammonium chloride, benzyl trimethyl ammonium chloride, tetramethyl ammonium chloride, benzyl dimethyl cetyl ammonium chloride, and dilauryl dimethyl ammonium bromide.

[0129] Examples of the aldehydes include terephthalaldehyde and benzaldehyde derivatives. Examples of the benzaldehyde derivatives include dimethylaminobenzaldehyde, p-methoxybenzaldehyde, p-ethoxybenzaldehyde, and pn-octyloxybenzaldehyde. Among these, pn-octyloxybenzaldehyde is preferred from the viewpoint of adhesiveness.

[0130] Examples of the thiol compound include 3-mercaptopropyltrimethoxysilane, 2-mercaptobenzoxazole, decanethiol, and thiobenzoic acid.

[0131] Examples of the sulfite include sodium sulfite, potassium sulfite, calcium sulfite, and ammonium sulfite.

[0132] Examples of the hydrogen sulfite include sodium hydrogen sulfite and potassium hydrogen sulfite.

[0133] Examples of the thiourea compound include 1-(2-pyridyl)-2-thiourea, thiourea, methylthiourea, ethylthiourea, N,N'-dimethylthiourea, N,N'-diethylthiourea, N,N'-di-n-propylthiourea, N,N'-dicyclohexylthiourea, trimethylthiourea, triethylthiourea, tri-n-propylthiourea, tricyclohexylthiourea, tetramethylthiourea, tetraethylthiourea, tetra-n-propylthiourea, and tetracyclohexylthiourea.

[0134] The content of the polymerization accelerator (D) in the dental composition of the present invention is preferably 0.01 mass % or more, more preferably 0.05 mass % or more, and even more preferably 0.1 mass % or more, from the viewpoint of the adhesiveness of the resulting dental composition. The content of the polymerization accelerator (D) is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less.

[0135] ·Water (E) The dental composition of the present invention preferably further contains water (E). When the dental composition contains a polymerizable monomer (A-1) having an acidic group, the demineralizing action of the polymerizable monomer (A-1) having an acidic group can be promoted by containing water (E). As the water (E) used for preparing the dental composition of the present invention, distilled water or ion-exchanged water is preferable from the viewpoint of not introducing impurities that adversely affect adhesion.

[0136] The content of water (E) in the dental composition of the present invention is preferably 1.0% by mass or more, more preferably 5.0% by mass or more, and even more preferably 8.0% by mass or more, since the dental composition exhibits high adhesiveness to both dental restorative materials such as porcelain and tooth structure. Moreover, since the adhesiveness decreases when the content of water (E) is too high, the content of water (E) is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.

[0137] Organic solvents (F) It is preferable that the dental composition of the present invention further contains an organic solvent (F), since this can further improve adhesion, application properties, and penetration into tooth structure, and can further prevent separation of the components in the dental composition.

[0138] Examples of the organic solvent (F) include alcohol solvents such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-methyl-2-propanol; ketone solvents such as acetone and methyl ethyl ketone; ether solvents such as tetrahydrofuran, diethyl ether, and diisopropyl ether; non-aromatic hydrocarbon solvents such as hexane and cyclohexane; aromatic hydrocarbon solvents such as toluene; chlorine-based solvents such as chloroform; and ester solvents such as ethyl acetate and butyl acetate. Among these, taking into consideration both safety to the living body and ease of removal based on volatility, volatile organic solvents are preferred, water-soluble organic solvents are more preferred, and alcohol solvents, ketone solvents, and ether solvents are even more preferred. Specifically, the water-soluble organic solvent is preferably ethanol, 2-propanol, 2-methyl-2-propanol, acetone, or tetrahydrofuran, and more preferably ethanol, 2-propanol, 2-methyl-2-propanol, or tetrahydrofuran.

[0139] The content of the organic solvent (F) in the dental composition of the present invention is preferably 1 mass % or more, more preferably 5 mass % or more, and even more preferably 8 mass % or more. Furthermore, if the amount of organic solvent (F) is too large, it may not be possible to completely remove it by air blowing, which may result in impaired adhesion or reduced strength. Therefore, the content of organic solvent (F) is preferably 70 mass % or less, more preferably 50 mass % or less, and even more preferably 30 mass % or less. In some embodiments, the organic solvent (F) may not be contained.

[0140] Other ingredients The dental composition of the present invention may contain known additives within the range that does not impair the effects of the present invention. Such additives include pH adjusters, polymerization inhibitors, fluoride ion releasing components, ultraviolet absorbers, thickeners, colorants, fluorescent agents, fragrances, antibacterial substances, etc. The additives may be used alone or in combination of two or more kinds.

[0141] Examples of the antibacterial substance include cetylpyridinium chloride, benzalkonium chloride, (meth)acryloyloxydodecylpyridinium bromide, (meth)acryloyloxyhexadecylpyridinium chloride, (meth)acryloyloxydecylammonium chloride, and triclosan.

[0142] Examples of the polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, dibutylhydroquinone, dibutylhydroquinone monomethyl ether, t-butylcatechol, 2-t-butyl-4,6-dimethylphenol, 2,6-di-t-butylphenol, and 3,5-di-t-butyl-4-hydroxytoluene. The content of the polymerization inhibitor in the dental composition of the present invention is preferably 0.001 to 3.0% by mass.

[0143] A preferred embodiment of the present invention is a dental composition comprising a polymerizable monomer (A), a filler (B) having an average primary particle size of 0.001 to 1 μm, a polymerization initiator (C), and an organic solvent (F), The polymerizable monomer (A) contains two or more types of polymerizable monomers, the organic solvent (F) comprises a volatile organic solvent; The content of the filler (B) is 3 to 25% by mass relative to 100% by mass of the total amount of the polymerizable monomer (A); The viscosity is 100 cP or less, The dental composition is exemplified by a dental composition in which the volatile organic solvent is evaporated from the dental composition, followed by polymerization and hardening to obtain a hardened product measuring 2 mm x 2 mm x 25 mm, which has a bending strength of 110 MPa or more after being immersed in 37°C water for 24 hours. The bending strength after immersion in water at 37° C. for 24 hours was measured by a method as described in the Examples section below. The bending strength after immersion in water at 37° C. for 24 hours is preferably 105 MPa or more, more preferably 108 MPa or more, and even more preferably 110 MPa or more.

[0144] The viscosity of the dental composition of the present invention is preferably 100 cP or less, more preferably 50 cP or less, and even more preferably 35 cP or less, from the viewpoint of forming a thin film of the cured product. Within the viscosity range of the dental composition, the filler (B) is already in a sufficiently dispersed state. Therefore, even when a coating layer is formed on a corner portion where a dental prosthesis placed on the coating layer is likely to lift off, the dental prosthesis can be effectively prevented from lifting off, the dental composition can withstand physical stimuli when taking an impression or removing the temporary adhesive, and the dental composition can also have the bending strength.

[0145] In the dental composition according to the preferred embodiment described above, each component can be appropriately changed based on the description in this specification. For example, when the dental composition is to be a dental adhesive composition, the polymerizable monomer (A) preferably contains a polymerizable monomer (A-1) having an acidic group. EXAMPLES

[0146] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The abbreviations used below are as follows.

[0147] [Polymerizable monomer (A-1) having an acidic group] MDP: 10-methacryloyloxydecyl dihydrogen phosphate

[0148] [Hydrophobic monomer (A-2x) having no acidic group] Bis-GMA: 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane MAEA: N-methacryloyloxyethyl acrylamide U4TH: N,N'-(trimethylhexamethylene)bis[2-(aminocarboxy)propane-1,3-diol]tetramethacrylate

[0149] [Hydrophilic monomer having no acidic group (A-2y)] HEMA: 2-hydroxyethyl methacrylate DEAA: N,N-diethylacrylamide

[0150] [Filler (B)] R972: Aerosil (registered trademark) R 972, fine silica particles manufactured by Nippon Aerosil Co., Ltd., average particle size: 16 nm

[0151] [Photopolymerization initiator (C-1)] CQ: Camphorquinone BAPO: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide

[0152] [Polymerization accelerator (D)] DABE: Ethyl 4-(N,N-dimethylamino)benzoate DEPT: N,N-di(2-hydroxyethyl)-p-toluidine

[0153] [Organic solvent (F)] EtOH: Ethanol

[0154] [Other ingredients] BHT: 3,5-di-t-butyl-4-hydroxytoluene (polymerization inhibitor)

[0155] [Polymerizable monomer mixture (M0)] Various polymerizable monomers (A) were mixed in the mixing ratios shown in Table 1 to prepare polymerizable monomer mixtures (M0) a to q.

[0156] [Examples 1 to 9 and Comparative Examples 3 to 5] In Example 1, 47.0 parts by mass of "a" listed in Table 1 as the polymerizable monomer mixture (M0), 1.57 parts by mass of CQ, 0.59 parts by mass of BAPO, 1.57 parts by mass of DABE, 0.59 parts by mass of DEPT, and 0.04 parts by mass of BHT were stirred using a mechanical stirrer until a homogeneous solution was formed with the naked eye free of insoluble matter, thereby obtaining a polymerizable monomer-containing composition (P0). For Examples 2 to 9 and Comparative Examples 3 to 5, similarly to Example 1, the polymerizable monomer mixture (M0) shown in Table 1 was used based on the description in Table 2, and the polymerization initiator (C), polymerization accelerator (D) and BHT as another component were stirred with a mechanical stirrer in the ratios shown in each Example and Comparative Example in Table 2 until a uniform solution was obtained with the naked eye free of insoluble matter, thereby obtaining a polymerizable monomer-containing composition (P0). In Table 2, for example, "P0-a" means that "a" of the polymerizable monomer mixture (M0) shown in Table 1 was used as a raw material for the polymerizable monomer-containing composition (P0) obtained by mixing it with the polymerization initiator (C), the polymerization accelerator (D), and BHT, which is another component. The same applies to the polymerizable monomer-containing compositions (P2), (P3), and (P).

[0157] The polymerizable monomer-containing composition (P0) and the filler (B) were mixed at the ratios shown in each of the Examples and Comparative Examples in Table 2 using a mixing blade (manufactured by SMT Co., Ltd., product name "HIGH-FLEX DISPENSER HG-92") of a motor equipped with a mixing blade (manufactured by SMT Co., Ltd., product name "round blade type KO-01") at 4000 rpm for 2 hours (the above is step [1]). As a result, a polymerizable monomer-containing composition (P1) was obtained.

[0158] The polymerizable monomer-containing composition (P1) obtained in step [1] was mixed with the polymerizable monomer-containing composition (P2) in the ratio shown in each Example and Comparative Example in Table 2 using a mechanical stirrer until a homogeneous solution was obtained that was free of insoluble matter when observed with the naked eye (this is step [2]).

[0159] To the mixture of polymerizable monomer-containing compositions (P1) and (P2) obtained in step [2], water (E) and organic solvent (F) were stirred in the ratios shown in each Example and Comparative Example in Table 2 using a mechanical stirrer until a homogeneous solution was obtained that was visually free of insoluble matter, thereby obtaining a dental composition.

[0160] [Examples 10 and 11] The polymerization initiator (C), the polymerization accelerator (D) and BHT, which is another component, were stirred with a mechanical stirrer into the polymerizable monomer mixture (M0) until a homogeneous solution was formed with no visible insoluble matter, thereby obtaining a polymerizable monomer-containing composition (P0).

[0161] The polymerizable monomer-containing composition (P0) and the filler (B) were mixed in the ratios shown in Examples 10 and 11 of Table 2 using a mixing blade (manufactured by SMT Co., Ltd., product name "HIGH-FLEX DISPENSER HG-92") of a motor equipped with a mixing blade (manufactured by SMT Co., Ltd., product name "round blade type KO-01") at 4000 rpm for 2 hours (the above is step [1]). As a result, a polymerizable monomer-containing composition (P1) was obtained.

[0162] The polymerizable monomer-containing composition (P1) obtained in step [1] was mixed with the polymerizable monomer-containing composition (P2) in the ratios shown in Examples 10 and 11 in Table 2 using a mechanical stirrer until a homogeneous solution was obtained that was visually free of insoluble matter (this is step [2]).

[0163] The mixture of the polymerizable monomer-containing compositions (P1) and (P2) was stirred with the polymerizable monomer-containing composition (P3) in the ratios shown in Examples 10 and 11 of Table 2 using a mechanical stirrer until a homogeneous solution was formed with no visible insoluble matter (this is step [3]).

[0164] The mixture of polymerizable monomer-containing compositions (P1), (P2), and (P3) obtained in step [3] was stirred with water (E) and organic solvent (F) in the ratios shown in Examples 10 and 11 of Table 2 using a mechanical stirrer until a homogeneous solution was obtained that was free of visually insoluble matter, thereby obtaining a dental composition.

[0165] [Comparative Examples 1 and 2] The polymerizable monomer-containing composition (P) shown in Table 2 was mixed with the polymerization initiator (C), the polymerization accelerator (D) and BHT as another component in the ratios shown in Comparative Examples 1 and 2 in Table 2 using a mechanical stirrer until a homogeneous solution was obtained that was visually free of insoluble matter.

[0166] The polymerizable monomer-containing composition (P) and the filler (B) were mixed in the ratios shown in Comparative Examples 1 and 2 in Table 2 at 4000 rpm for 2 hours using a mixing blade (manufactured by SMT Corporation, product name "HIGH-FLEX DISPENSER HG-92") of a motor equipped with a mixing blade (manufactured by SMT Corporation, product name "round blade type KO-01").

[0167] The obtained mixture of polymerizable monomer-containing composition (P) and filler (B) was stirred with water (E) and organic solvent (F) in the ratios shown in Comparative Examples 1 and 2 in Table 2 using a mechanical stirrer until a homogeneous solution was obtained that was visually free of insoluble matter, thereby obtaining a dental composition.

[0168] ·Viscosity measurement A viscometer (Toki Sangyo Co., Ltd., TV-100EH type viscometer, compliant with JIS K 5600-2-3:2014 (cone-plate viscosity method), cone-plate type) was used, with a cone rotor of 0.8° × R24, sample volume: 0.6 mL, shear rate: 7.5 N (s -1 ) and measured at 30°C. After preheating for 3 minutes (30° C.), the measurement was started, and the measured value after 3 minutes was recorded as the viscosity (n=2). Using the above method, the viscosity of the polymerizable monomer mixtures (M0: a to q) obtained in Table 1 was measured. The results are shown in Table 1. In addition, in Table 3, values ​​were transcribed based on the results of Table 1 in the columns M0n, P2n, and Pn according to the polymerizable monomer mixture (M0) used. In addition, the viscosity (P0n) of the polymerizable monomer-containing composition (P0), the viscosity (P0n) of the mixture (PC 〔1+2〕 ) (However, in Examples 10 and 11, the viscosity (PC 〔1+2〕The viscosity (PCn) of the polymerizable monomer-containing composition (PC) finally obtained by mixing the entire amount of the polymerizable monomer-containing composition (P) at once was measured for each of the examples and comparative examples. The results are shown in Table 3.

[0169] -Bending strength measurement Compressed air was sprayed onto the prepared dental compositions of Examples and Comparative Examples to volatilize the volatile organic solvent. After vacuum degassing, the compositions were filled into a stainless steel mold (dimensions 2 mm x 2 mm x 25 mm), pressed against glass slides from above and below, and irradiated with light from a dental LED photopolymerizer (manufactured by Morita Corporation, product name "Pencure 2000") for 10 seconds at each point, 5 points on each side, to obtain a cured product. Five cured products were prepared for each of the Examples and Comparative Examples, and the cured products were removed from the molds and then left to stand in distilled water at 37° C. for 24 hours. The cured products after storage were used as test samples and their bending strength was measured using a universal testing machine (manufactured by Shimadzu Corporation, product name "AG-I 100N") under conditions of a support distance of 20 mm and a crosshead speed of 1 mm / min, and the average value of the measured values ​​for each sample was calculated as the bending strength. The results are shown in Table 3. The bending strength is preferably 105 MPa or more, more preferably 108 MPa or more, and even more preferably 110 MPa or more.

[0170] - Determination of the thickness of the coating around the cornea A first-class cavity of φ3 mm×2 mm with a pronounced corner angle was formed on the labial surface of a bovine mandibular anterior tooth. The dental composition prepared in each Example or Comparative Example was applied to the first-class cavity with a brush, left for 3 seconds, and then air-dried the surface until the fluidity of the applied dental composition was lost. Next, the applied dental composition was cured by irradiating it with light for 10 seconds using a dental LED photopolymerizer (manufactured by Morita Corporation, product name "PenCure 2000"). A dental filling composite resin (manufactured by Kuraray Noritake Dental Co., Ltd., product name "Clearfil (registered trademark) AP-X") was filled into the first-class cavity in which the dental composition had hardened, and the dental filling composite resin was hardened by irradiating it with light for 20 seconds using a dental LED light polymerization device to produce a sample for measuring coating thickness. The coating thickness measurement sample was allowed to stand in distilled water at 37° C. for 24 hours, and then cut using a diamond cutter so as to pass through the center of the first-class cavity. The cut surface was polished with #1500 polishing paper and finally mirror-polished with diamond paste. The coating thickness of the corner of the obtained sample was observed with a 3D laser microscope (manufactured by Keyence Corporation, product name "VK-9710"). The thickness of the coating at the corner of the tooth was measured at 10 points on each sample, and an average value of less than 15 μm was evaluated as good (◯), and an average value of 15 μm or more was evaluated as poor (×). The results are shown in Table 3.

[0171] [Table 1]

[0172] [Table 2]

[0173] [Table 3]

[0174] As shown in Table 3, the dental compositions according to the present invention (Examples 1 to 11) had a viscosity of 35 cP or less, a good coating thickness at the corner, and further exhibited a bending strength of 110 MPa or more. In contrast, dental compositions prepared by a manufacturing method in which the polymerizable monomer-containing composition (P) and the filler (B) are dispersed in a single step (Comparative Examples 1 and 2) and dental compositions in which the viscosity P0n [cP] of the polymerizable monomer-containing composition (P0) and the viscosity P2n [cP] of the polymerizable monomer-containing composition (P2) do not satisfy the relationship P0n > P2n (Comparative Examples 4 and 5) had poor coating thickness at the corners, and it was confirmed that the filler was not sufficiently dispersed. A dental composition (Comparative Example 3) containing less than 3 mass% of filler (B) relative to 100 mass% of the total amount of polymerizable monomer (A) had a good coating thickness at the corner, but the bending strength was 99 MPa, indicating a decrease in bending strength due to the reduced filler content.

Claims

1. A method for producing a dental composition, wherein the dental composition contains a polymerizable monomer (A) and a filler (B) having an average primary particle diameter of 0.001 μm or more and less than 1 μm, the content of the filler (B) is 3 to 25% by mass based on 100% by mass of the total amount of the polymerizable monomer (A), Step [1] of mixing a polymerizable monomer-containing composition (P0) containing a polymerizable monomer (A) and a filler (B) to obtain a polymerizable monomer-containing composition (P1); and Step [2] of mixing the polymerizable monomer-containing composition (P1) and a polymerizable monomer-containing composition (P2) containing a polymerizable monomer (A), A method for producing a dental composition, wherein the viscosity P0n [cP] of the polymerizable monomer-containing composition (P0) and the viscosity P2n [cP] of the polymerizable monomer-containing composition (P2) satisfy the relationship P0n > P2n.

2. The method for producing a dental composition according to claim 1, wherein P0n / P2n = 3 to 2000.

3. The method for producing a dental composition according to claim 1 or 2, wherein the concentration of the filler (B) in the polymerizable monomer-containing composition (P1) is 5% by mass or more and less than 50% by mass based on 100% by mass of the total of the polymerizable monomer (A) and the filler (B) in Step [1].

4. The method for producing a dental composition according to claim 1 or 2, wherein the viscosity P0n of the polymerizable monomer-containing composition (P0) is 230 to 5000 cP.

5. The method for producing a dental composition according to claim 1 or 2, wherein the viscosity P2n of the polymerizable monomer-containing composition (P2) is 0.5 to 150 cP.

6. The method for producing a dental composition according to claim 1 or 2, wherein the polymerizable monomer-containing composition (P0) contains two or more polymerizable monomers as the polymerizable monomer (A).

7. The method for producing a dental composition according to claim 1 or 2, wherein the filler (B) is an inorganic filler.

8. The method for producing a dental composition according to claim 1 or 2, wherein the dental composition further comprises a polymerization initiator (C).

9. The method for producing a dental composition according to claim 8, wherein the polymerization initiator (C) is a photoinitiator.

10. The method for producing a dental composition according to claim 1 or 2, further comprising a step of mixing water (E) and / or an organic solvent (F) after the step [2].

11. The method for producing a dental composition according to claim 1 or 2, wherein the dental composition is a dental adhesive composition.

12. The method for producing a dental composition according to claim 11, wherein the dental adhesive composition is a one-component dental adhesive composition.

13. A dental composition comprising a polymerizable monomer (A), a filler (B) having an average primary particle diameter of 0.001 to 1 μm, a polymerization initiator (C), and an organic solvent (F), wherein the polymerizable monomer (A) comprises two or more polymerizable monomers, the organic solvent (F) comprises a volatile organic solvent, the content of the filler (B) is 3 to 25% by mass based on 100% by mass of the total amount of the polymerizable monomer (A), the viscosity is 100 cP or less, a dental composition, wherein the flexural strength after immersing a cured product of 2 mm × 2 mm × 25 mm obtained by volatilizing the volatile organic solvent from the dental composition and subjecting it to polymerization curing in distilled water at 37°C for 24 hours is 110 MPa or more.

14. The dental composition according to claim 13, wherein the polymerizable monomer (A) comprises a polymerizable monomer (A-1) having an acidic group.