Single-component-type dental adhesive composition and method for producing same

Abstract

The present invention achieves exceptional adhesive strength, and inhibits any decrease in adhesive strength even when a filling material is packed to a greater thickness. Provided is a single-component-type dental adhesive composition that is used in order to bond a photocurable filling material to dentin, the composition containing a polymerizable monomer (A) including an acid monomer (A1), a photopolymerization initiator (B), water (C), a water-soluble organic solvent (D), and a monovalent to tetravalent metal compound (E). The acid monomer (A1) includes a strong acid monomer (a1) and a carboxylic-acid-polymer-based polymerizable monomer (a2). The amount of the monovalent to tetravalent metal compound (E) contained per 1 mol of the strong acid monomer (a1) is 0.02-1 mol in terms of the number of moles of metal ions constituting the monovalent to tetravalent metal compound (E). The amount of the monovalent to tetravalent metal compound (E) contained per 1 g of the carboxylic-acid-polymer-based polymerizable monomer (a2) is 0.0002-0.005 mol. The metal ions constituting component (E) form an aggregate with at least some of the strong acid monomer (a1).　

Description

One-component dental adhesive composition and method for producing same

[0001] The present invention relates to a one-component dental adhesive composition and a method for producing the same.

[0002] Hardening filling materials called composite resins are used to repair teeth damaged by caries and other conditions. Dental filling materials (hereinafter simply referred to as "filling materials") used to fill damaged areas of teeth have little adhesiveness to the tooth structure that constitutes the tooth. For this reason, filling materials are typically bonded to the tooth structure via an adhesive (dental adhesive composition). Conventional adhesives must be pre-cured to achieve high adhesive strength. Here, adhesives used in combination with photocurable filling materials that cure only by light irradiation are known to have three types: (i) a photocurable type that cures only by light irradiation, a chemically curable type that cures only by chemical polymerization, and a dual-curable type that cures by light curing and / or chemical curing; and (ii) two types, a single-light-irradiation type and a double-light-irradiation type, based on the number of light irradiations required during dental treatment (see, for example, Patent Documents 1 to 4).

[0003] In dental treatment using the adhesive (a light-curing, two-time light-irradiation adhesive) described in Patent Document 1, the following Steps 1(2) to 4(2) are carried out in order, with further post-processing (such as cutting and removing excess hardened filling material) being carried out as necessary. (Step 1(2)) The adhesive is applied to the damaged area of ​​the tooth and allowed to dry. (Step 2(2)) The dried adhesive is irradiated with light (first light irradiation) to harden the adhesive. (Step 3(2)) The damaged area of ​​the tooth covered with the hardened adhesive is filled with a light-curing filling material. (Step 4(2)) The filled filling material is irradiated with light (second light irradiation) to harden the filling material.

[0004] The two-light-irradiation adhesive described in Patent Document 1 requires two light irradiations in the oral cavity during dental treatment. Furthermore, in order to harden the two-light-irradiation adhesive described in Patent Document 1, light irradiation for several seconds to several tens of seconds is required in Step 2(2). Therefore, dental treatment using the two-light-irradiation adhesive described in Patent Document 1 increases the treatment time and increases the burden on the patient due to heat generation associated with light irradiation. Furthermore, since the two-light-irradiation adhesive described in Patent Document 1 is exposed to the oral cavity during the first light irradiation, it may be contaminated by the patient's saliva, blood, or the like. Therefore, an adhesive that does not require light irradiation before filling with a filling material is desired. Examples of adhesives (single-light-irradiation adhesives) that do not require light irradiation before filling with a filling material (a process corresponding to Step 2(2) in the two-light-irradiation adhesive described above) include adhesives exemplified in Patent Documents 2 to 4.

[0005] The single-light-irradiation adhesive described in Patent Document 2 is a two-component adhesive (chemically curable adhesive) that is configured to undergo chemical polymerization curing by mixing a first agent and a second agent. However, with this adhesive, it takes time and effort to mix the first agent and the second agent during treatment.

[0006] The single-light-irradiation adhesive described in Patent Document 3 is a dual-cure adhesive in which, after filling with a filler material, photopolymerization occurs due to the light irradiated during curing of the filler material, and chemical polymerization occurs due to the supply of aromatic amine from the filler material. Therefore, there is no need to spend time or effort curing the adhesive separately from the curing of the filler material. However, the single-light-irradiation adhesive described in Patent Document 3 cannot be used with filler materials other than those containing aromatic amines.

[0007] The single-light-irradiation adhesive described in Patent Document 4 is a light-curing adhesive that cures only by light irradiation, similar to the two-light-irradiation adhesive, but is characterized by the inclusion of a highly active photopolymerization initiator. Therefore, with the adhesive described in Patent Document 4, Step 2(2) of the two-light-irradiation adhesive is omitted, and the adhesive can be cured simultaneously with the curing of the filling material by only the light irradiation in Step 4(2) (i.e., a single light irradiation). That is, in dental treatment using the single-light-irradiation adhesive described in Patent Document 4, the following Steps 1(1) to 3(1) are performed sequentially, with further post-treatment performed as necessary. (Step 1(1)) The adhesive is applied to the damaged area of ​​the tooth and allowed to dry. (Step 2(1)) The damaged area of ​​the tooth covered with the dried adhesive is filled with a light-curing filling material. (Step 3(1)) The filled filling material and the adhesive material covered with the filling material are irradiated with light to harden the filling material and the adhesive material.

[0008] The single-light-irradiation adhesive (photo-curing adhesive) described in Patent Document 4 has the advantage of being able to treat more quickly and therefore placing less strain on the patient than the single-light-irradiation adhesive (chemically polymerized adhesive) described in Patent Document 2. Furthermore, the single-light-irradiation adhesive described in Patent Document 4 has the advantage of being highly versatile in that there are no restrictions on the composition of the photo-curing filling material used in combination with the adhesive, and it can be used in combination with photo-curing filling materials of various compositions, compared to the single-light-irradiation adhesive (dual-cure adhesive) described in Patent Document 3.

[0009] JP 2009-137960 A JP 2018-027913 A JP 2020-138911 A JP 2022-132064 A

[0010] However, the single-light-irradiation / light-curing adhesive described in Patent Document 4 requires that the adhesive be cured by irradiating light that reaches the adhesive layer through the filler material layer. Therefore, the adhesive strength decreases when the thickness of the filler material layer covering the adhesive layer increases. Therefore, the adhesive described in Patent Document 4 tends to be difficult to use in cases where a thicker filler material is required, such as the treatment of deep cavities.

[0011] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a one-component dental adhesive composition that is photocurable with single light irradiation and is used in combination with a photocurable filling material, which has excellent adhesive strength and is less likely to decrease even when a thicker filling material is used, and a method for producing the same.

[0012] The above object is achieved by the present invention as follows: The one-component dental adhesive composition of the present invention is used for adhering a photocurable filling material to a tooth structure, and comprises a polymerizable monomer (A) containing an acidic group-containing polymerizable monomer (A1), a photopolymerization initiator (B), water (C), a water-soluble organic solvent (D), and a monovalent to tetravalent metal compound (E), wherein the acidic group-containing polymerizable monomer (A1) contains, in its molecule, at least one radically polymerizable group and a phosphono group {-P(=O)(OH)} ２}, dihydrogen phosphate monoester group {—O—P(═O)(OH) ２}, a hydrogen phosphate diester group {(—O—) ２ P(=O)OH} and sulfo group (-SO ３ and a carboxylic acid polymer-based polymerizable monomer (a2) having at least one radically polymerizable group and at least one carboxyl group in the molecule, not having the strongly acidic group, and having a weight average molecular weight (Mw) of 2,000 to 120,000, wherein the ratio of the strongly acidic group-containing polymerizable monomer (a1) to the monovalent to tetravalent metal(s) per 1 mol of the strongly acidic group-containing polymerizable monomer (a1) is The content of the compound (E) is 0.02 mol to 1 mol in terms of the molar amount of the metal ions constituting the monovalent to tetravalent metal compound (E), the content of the monovalent to tetravalent metal compound (E) per 1 g of the carboxylic acid polymer-based polymerizable monomer (a2) is 0.0002 mol to 0.005 mol, and the metal ions constituting the monovalent to tetravalent metal compound (E) form aggregates with at least a part of the strongly acidic group-containing polymerizable monomer (a1).

[0013] One embodiment of the one-component dental adhesive composition of the present invention preferably contains 6 to 60 parts by mass of the strongly acidic group-containing polymerizable monomer (a1) per 100 parts by mass of the polymerizable monomer (A).

[0014] In another embodiment of the one-component dental adhesive composition of the present invention, it is preferable that the one-component dental adhesive composition contains 6 to 40 parts by mass of the carboxylic acid polymer-based polymerizable monomer (a2) per 100 parts by mass of the polymerizable monomer (A).

[0015] In another embodiment of the one-component dental adhesive composition of the present invention, the weight average molecular weight of the aggregate, measured by gel permeation chromatography analysis and converted into standard polystyrene, is preferably 1,000 to 6,000.

[0016] In another embodiment of the one-component dental adhesive composition of the present invention, the carboxylic acid polymer-based polymerizable monomer (a2) preferably has an acid value of 50 mg·KOH / g to 750 mg·KOH / g.

[0017] Another embodiment of the one-component dental adhesive composition of the present invention preferably contains 10 to 500 parts by mass of the water-soluble organic solvent (D) relative to 100 parts by mass of the polymerizable monomer (A).

[0018] Another embodiment of the one-component dental adhesive composition of the present invention preferably further contains 5 to 30 parts by mass of a filler (F) per 100 parts by mass of the polymerizable monomer (A).

[0019] In another embodiment of the one-component dental adhesive composition of the present invention, the monovalent to tetravalent metal compound (E) preferably contains at least one metal selected from the group consisting of Na(I), Mg(II), Ti(IV), Zr(IV), Zn(II), Ga(III), and Al(III).

[0020] The method for producing the one-component dental adhesive composition of the present invention includes at least the following steps: a raw material component preparation step of preparing at least the strongly acidic group-containing polymerizable monomer (a1), the carboxylic acid polymer-based polymerizable monomer (a2), the photopolymerization initiator (B), water (C), the water-soluble organic solvent (D), and the mono- to tetravalent metal compound (E) as raw material components; a first composition preparation step of selecting at least the strongly acidic group-containing polymerizable monomer (a1) and the mono- to tetravalent metal compound (E) from the raw material components prepared in the raw material component preparation step, excluding the carboxylic acid polymer-based polymerizable monomer (a2) from options for mixing the raw material components together, and mixing the selected raw material components to prepare a first composition; and a second composition preparation step of selecting at least the carboxylic acid polymer-based polymerizable monomer (a2) from the raw material components not selected in the first composition preparation step, and mixing the selected raw material components with the first composition to prepare a second composition. Here, in the first composition preparation step, the mixing ratio of the strongly acidic group-containing polymerizable monomer (a1) to the metal ions constituting the monovalent to tetravalent metal compound (E) is set to 1 mol:0.02 mol to 1 mol, and in the second composition preparation step, the mixing ratio of the carboxylic acid polymer-based polymerizable monomer (a2) to the monovalent to tetravalent metal compound (E) is set to 1 g:0.0002 mol to 0.005 mol.

[0021] According to the present invention, it is possible to provide a one-component dental adhesive composition that is photocurable after one-time light irradiation and is used in combination with a photocurable filling material, which has excellent adhesive strength and is less likely to decrease in adhesive strength even when a thicker filling material is used, and a method for producing the same.

[0022] The one-component dental adhesive composition of this embodiment and its manufacturing method will be described in detail below. In the following description, the numerical range "x to y" includes x and y, that is, "x to y" means "x or more and y or less." Furthermore, in this specification, the term "(meth)acrylic" means both "acrylic" and "methacrylic." Similarly, the term "(meth)acrylate" means both "acrylate" and "methacrylate," and the term "(meth)acryloyl" means both "acryloyl" and "methacryloyl."

[0023] 1. One-Part Dental Adhesive Composition The one-part dental adhesive composition of this embodiment is used to bond a light-curing filling material to tooth structure, and from the standpoint of the number of light irradiations required during dental treatment and the curing mechanism, it is classified as a one-time light-irradiation / light-curing adhesive composition. The one-part dental adhesive composition of this embodiment has a composition that satisfies at least the following (i) to (v): (i) It contains a polymerizable monomer (A) including an acidic group-containing polymerizable monomer (A1), a photopolymerization initiator (B), water (C), and a water-soluble organic solvent (D). (ii) It further contains a monovalent to tetravalent metal compound (E). (iii) The acidic group-containing polymerizable monomer (A1) contains a strongly acidic group-containing polymerizable monomer (a1) and a carboxylic acid polymer-based polymerizable monomer (a2). (iv) The content of the monovalent to tetravalent metal compound (E) per mol of the strongly acidic group-containing polymerizable monomer (a1) is 0.02 mol to 1 mol in terms of the molar amount of the metal ions constituting the monovalent to tetravalent metal compound (E), and the content of the monovalent to tetravalent metal compound (E) per gram of the carboxylic acid polymer-based polymerizable monomer (a2) is 0.0002 mol to 0.005 mol. (v) The metal ions constituting the monovalent to tetravalent metal compound (E) form aggregates with at least a portion of the strongly acidic group-containing polymerizable monomer (a1).

[0024] Here, the strongly acidic group-containing polymerizable monomer (a1) has at least one radically polymerizable group and a phosphono group {—P(═O)(OH) ２}, dihydrogen phosphate monoester group {—O—P(═O)(OH) ２}, a hydrogen phosphate diester group {(—O—) ２ P(=O)OH} and sulfo group (-SO ３ and at least one strongly acidic group selected from the group consisting of (a) and (b). The carboxylic acid polymer-based polymerizable monomer (a2) (also referred to as a "carboxyl group-containing high-molecular-weight polymerizable monomer") is a compound having at least one radically polymerizable group and at least one carboxyl group in the molecule, not having any strongly acidic group, and having a weight-average molecular weight (Mw) of 2,000 to 120,000.

[0025] The one-part dental adhesive composition of the present embodiment, which is photocurable and irradiated with light once and is used in combination with a photocurable filling material during dental treatment, has the compositions shown in (i) to (v) above, and thereby has the effect of having excellent adhesive strength and being less likely to decrease in adhesive strength even when a thicker filling material is filled. Note that, in discovering the one-part dental adhesive composition of the present embodiment which exhibits such effects, the inventors first investigated the problem of a decrease in adhesive strength as the filling material layer becomes thicker with respect to the conventional one-part dental adhesive composition of the photocurable and irradiated with light once, as exemplified in Patent Document 4.

[0026] First, in the conventional one-component dental adhesive composition of a single-time photoirradiation / photocuring type having the composition shown in (i) above, as exemplified by Patent Document 4, in order to obtain high adhesive strength, it is necessary to generate a sufficient amount of radicals upon light irradiation in the uncured adhesive layer formed by applying the adhesive composition and drying (solvent removal). This allows the polymerizable monomer to be sufficiently cured to form a high-strength adhesive layer. However, when photopolymerization is carried out in the uncured adhesive layer using irradiation light transmitted through the filler material layer in Step 3(1), the thicker the filler material layer, the less radicals are generated by the photopolymerization initiator in the inner part (i.e., the uncured adhesive layer) where the irradiation light is difficult to reach. Therefore, if the filler material layer is thick, the strength of the cured adhesive layer decreases, and the stress associated with polymerization shrinkage of the filler material layer damages the low-strength cured adhesive layer, resulting in reduced adhesive strength.

[0027] To solve these problems, the present inventors investigated the incorporation of components capable of forming an ionomer structure (a carboxylic acid polymer and a metal ion) into a one-component dental adhesive composition. This is because, if an adhesive layer having an ionomer structure with high strength can be formed by the reaction of a carboxylic acid polymer and a metal ion contained in the one-component dental adhesive composition upon drying (removal of the solvent) in Step 1(1), it is believed that a relatively high adhesive strength can be easily ensured at the end of Step 3(1) even when the filler material layer is thick. However, when a carboxylic acid polymer and a metal ion coexist in a solution, the ionomer-forming reaction usually proceeds rapidly, resulting in the precipitation of a reaction product formed by this reaction. Therefore, the present inventors considered it necessary to design the composition of a one-component dental adhesive composition containing a carboxylic acid polymer and a metal ion so that the ionomer-forming reaction is suppressed as much as possible in the one-component dental adhesive composition, while the ionomer-forming reaction proceeds significantly when the solvent is removed from the one-component dental adhesive composition, and conducted further investigations.

[0028] As a result, the present inventors discovered a one-component dental adhesive composition of this embodiment having the composition shown in (i) to (v) above. The one-component dental adhesive composition of this embodiment has the following characteristics (1) to (3). (1) In the one-component dental adhesive composition, metal ions present in the form of monovalent to tetravalent metal compounds (E) associate with the strongly acidic group-containing polymerizable monomer (a1) to form aggregates soluble in the water-soluble organic solvent (D). (2) In the one-component dental adhesive composition in a state before the solvent components (water (C) and organic solvent (D)) are volatilized, in other words, in a state in which the solvent components are sufficiently contained, the aggregates and the carboxylic acid polymer can coexist stably without reacting with each other (as a result, the one-component dental adhesive composition has excellent storage stability). (3) When a carboxylic acid polymer-based polymerizable monomer (a2) is used as the carboxylic acid polymer, when the solvent component is volatilized and removed from the one-component dental adhesive composition in Step 1(1), an adhesive layer containing a strong ionomer structure with relatively high strength is formed.

[0029] When dental treatment is performed using the one-component dental adhesive composition of this embodiment having the characteristics described in (1) to (3) above, the following Steps 1(1) to 3(1) are performed sequentially, as with the single-time light-irradiation adhesive (light-curing adhesive) described in Patent Document 4, with further post-treatment being performed as necessary. (Step 1(1)) An adhesive is applied to the damaged area of ​​the tooth and allowed to dry. (Step 2(1)) A light-curing filling material is filled into the damaged area of ​​the tooth covered with the dried adhesive. (Step 3(1)) The filled filling material and the adhesive covered by the filling material are irradiated with light to cure the filling material and adhesive.

[0030] In Step 3(1), light irradiation is performed to photocure the uncured filling material formed in Step 2(1), and simultaneously photocure the uncured adhesive layer formed in Step 1(1). Here, the degree of photocuring of the uncured adhesive layer formed in Step 1(1) decreases as the thickness of the uncured filling material layer increases. This is because the intensity of the irradiated light reaching the uncured adhesive layer through the uncured filling material layer during light irradiation decreases in proportion to the thickness of the uncured filling material layer. This is a phenomenon common to the single-light-irradiation adhesive (photocurable adhesive) described in Patent Document 4 and the one-component dental adhesive composition of this embodiment.

[0031] However, unlike the single-light-irradiation adhesive (photocurable adhesive) described in Patent Document 4, in the one-component dental adhesive composition of this embodiment, an ionomer structure is further formed in the uncured adhesive layer upon completion of Step 1(1). Therefore, even when the thickness of the uncured filling material layer increases (in other words, when the intensity of the irradiated light reaching the uncured adhesive layer decreases, resulting in insufficient photocuring of the adhesive layer, and <ii> the amount of polymerization shrinkage of the filling material layer during photocuring increases, resulting in increased peel stress between the photocured adhesive layer and the damaged area of ​​the tooth), the presence of the ionomer structure ensures that the adhesive layer after photocuring has the strength necessary to prevent peeling from the damaged area of ​​the tooth. Consequently, as a result, even when the filling material layer is thick, a decrease in adhesive strength can be significantly suppressed compared to when the filling material layer is thin.

[0032] Next, each component constituting the one-component dental adhesive composition of this embodiment will be described in detail.

[0033] 1-1. Polymerizable Monomer (A) The polymerizable monomer (A) used in the one-component dental adhesive composition of this embodiment contains at least an acidic group-containing polymerizable monomer (A1). The acidic group-containing polymerizable monomer (A1) includes at least a strongly acidic group-containing polymerizable monomer (a1) and a carboxylic acid polymer-based polymerizable monomer (a2). If necessary, another acidic group-containing polymerizable monomer (a3) ​​may be used as the acidic group-containing polymerizable monomer (A1). If necessary, a non-acidic group-containing polymerizable monomer (A2) may be used as the polymerizable monomer (A).

[0034] 1-1-1. Acidic Group-Containing Polymerizable Monomer (A1) <<Strongly Acidic Group-Containing Polymerizable Monomer (Strong Acid Monomer) (a1)>> The strongly acidic group-containing polymerizable monomer (strong acid monomer) (a1) is a polymerizable monomer containing at least one radically polymerizable group and at least one strongly acidic group in the molecule. The strong acid monomer (a1) mainly improves adhesion to tooth structure (dentin, enamel), base metals (iron, nickel, chromium, cobalt, tin, aluminum, copper, titanium, etc., or alloys containing these as the main components), and metal oxides containing metals such as zirconium and oxygen as the main components (zirconia ceramics, alumina, titania, etc.). In addition, the strong acid monomer (a1) has a demineralizing effect on tooth structure and a high penetration-improving effect on tooth structure, thereby improving the adhesion of filling materials to tooth structure. Therefore, in the one-component dental adhesive composition of this embodiment, by using the strong acid monomer (a1), excellent adhesive strength can be ensured.

[0035] In the one-component dental adhesive composition of this embodiment, the strong acid monomer (a1) forms aggregates by association with metal ions generated by dissociation of the monovalent to tetravalent metal compound (E). The formation of aggregates in the one-component dental adhesive composition makes it possible to prevent insolubilization due to the formation of an ionomer, even when the one-component dental adhesive composition is stored in a state in which the metal ions generated by dissociation from the monovalent to tetravalent metal compound (E) and the carboxylic acid polymer-based polymerizable monomer (a2) coexist in a single liquid.

[0036] The strong acid monomer (a1) has, as a radical polymerizable group, an acryloyl group, a methacryloyl group, an acrylamide group, a methacrylamide group, a styryl group, etc. Among these, from the viewpoint of adhesion to a filler material, etc., the radical polymerizable group is preferably an acryloyl group and / or a methacryloyl group.

[0037] Furthermore, the strong acid monomer (a1) must have a strong acidic group with a lower pKa than the carboxylic acid polymer-based polymerizable monomer (a2). When a monomer having an acidic group such as a carboxyl group with a high pKa is used instead of the strong acid monomer (a1), the difference in acidity between this monomer and the carboxylic acid polymer-based polymerizable monomer (a2) becomes smaller. As a result, during storage in a one-liquid solution, the carboxylic acid polymer-based polymerizable monomer (a2) aggregates via metal ions to form an insoluble ionomer, and therefore, when the adhesive composition is applied and dried, an ionomer structure cannot be formed in the adhesive layer. Therefore, the strong acid monomer (a1) must have a phosphono group {-P(=O)(OH) ２}, dihydrogen phosphate monoester group {—O—P(═O)(OH) ２}, a hydrogen phosphate diester group {(—O—) ２ P(=O)OH} and sulfo group (-SO ３ The strong acid monomer (a1) preferably contains at least one strongly acidic group selected from a dihydrogen phosphate monoester group and a hydrogen phosphate diester group, because these groups have high stability to water and can slowly dissolve the smear layer on the tooth surface and slowly demineralize the teeth.

[0038] Examples of the strong acid monomer (a1) that can be suitably used include the following: That is, examples of the strong acid monomer (a1) having a sulfo group include 2-methacrylamido-2-methylpropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, p-vinylbenzenesulfonic acid, and vinylsulfonic acid.

[0039] Examples of the strong acid monomer (a1) having a dihydrogen phosphate monoester group or a hydrogen phosphate diester group include 2-(meth)acryloyloxyethyl dihydrogen phosphate, bis[2-(meth)acryloyloxyethyl]hydrogen phosphate, 2-(meth)acryloyloxyethylphenyl hydrogen phosphate, 6-(meth)acryloyloxyhexyl dihydrogen phosphate, 6-(meth)acryloyloxyhexylphenyl hydrogen phosphate, 10-(meth)acryloyloxydecyl Examples of suitable hydroxypropyl acrylates include 1,3-di(meth)acryloylpropane-2-dihydrogen phosphate, 1,3-di(meth)acryloylpropane-2-phenylhydrogen phosphate, bis[5-{2-(meth)acryloyloxyethoxycarbonyl}heptyl]hydrogen phosphate, 11-(meth)acryloyloxytetrapropylene glycol hydrogen phosphate, and 14-(meth)acryloyloxypentapropylene glycol hydrogen phosphate.

[0040] Examples of the strong acid monomer (a1) having a phosphono group include vinylphosphonic acid and p-vinylbenzenephosphonic acid.

[0041] In particular, from the viewpoint of adhesion to tooth structure and oxide ceramics (zirconia), the strong acid monomer (a1) is preferably 10-(meth)acryloyloxydecyl dihydrogen phosphate. The strong acid monomer (a1) may be used alone or in combination of two or more.

[0042] Furthermore, from the viewpoint of achieving both adhesion to tooth structure and strength of the adhesive layer after curing, the amount of the strong acid monomer (a1) to be blended is preferably 3 to 60 parts by mass, more preferably 6 to 60 parts by mass, and even more preferably 8.5 to 50 parts by mass, relative to 100 parts by mass of the polymerizable monomer (A) contained in the one-component dental adhesive composition of this embodiment.

[0043] <<Carboxylic Acid Polymer Polymerizable Monomer (a2)>> The carboxylic acid polymer polymerizable monomer (a2) is a polymerizable monomer containing at least one radically polymerizable group and at least one carboxyl group in the molecule, not containing a strongly acidic group, and having a weight-average molecular weight of 2,000 to 120,000. Here, the term "strongly acidic group" refers to a strongly acidic group constituting the molecule of the strong acid monomer (a1). When the solvent component is removed by evaporation from the one-component dental adhesive composition of this embodiment, the carboxylic acid polymer polymerizable monomer (a2) forms an ionomer with the metal ion constituting the monovalent to tetravalent metal compound (E), thereby contributing to improving the strength of the adhesive layer. Furthermore, the carboxylic acid polymer polymerizable monomer (a2) improves adhesion to tooth structures (dentin, enamel) and base metals (iron, nickel, chromium, cobalt, tin, aluminum, copper, titanium, etc., or alloys containing these as the main component).

[0044] The carboxylic acid polymer-based polymerizable monomer (a2) has a radical polymerizable group such as an acryloyl group, a methacryloyl group, an acrylamide group, a methacrylamide group, or a styryl group. Among these, the radical polymerizable group is preferably an acryloyl group and / or a methacryloyl group from the viewpoint of adhesion to filler materials, etc. If the carboxylic acid polymer-based polymerizable monomer (a2) does not contain a radical polymerizable group, it cannot copolymerize with other polymerizable monomers present in the uncured adhesive layer other than the carboxylic acid polymer-based polymerizable monomer (a2), resulting in reduced adhesive strength. As the main chain constituting the carboxylic acid polymer-based polymerizable monomer (a2) molecule, a polyacrylic chain or a polymethacrylic chain is preferred from the viewpoint of stability and biocompatibility.

[0045] The carboxylic acid polymer-based polymerizable monomer (a2) preferably includes a first repeating unit shown in (i) below and a second repeating unit shown in (ii) below. (i) A first repeating unit in which the functional group bonded to a carbon atom constituting the main chain selected from the group consisting of an ethylene chain and a propylene chain is a carboxyl group. (ii) A second repeating unit in which the functional group bonded to a carbon atom constituting the main chain selected from the group consisting of an ethylene chain and a propylene chain is a linking group having an acryloyl group, a methacryloyl group, an acrylamide group, or a methacrylamide group at its terminal. Here, the number of atoms constituting the main chain of the linking group (however, when the main chain includes a cyclic structure in addition to a linear structure, the number of atoms included in the path with the fewer atoms constituting the path is counted as the number of atoms) is preferably 3 to 30. Furthermore, when the main chain is an ethylene chain, a carboxyl group bonded to a carbon atom of the ethylene main chain may be included.

[0046] The carboxylic acid polymer-based polymerizable monomer (a2) is preferably a compound represented by the following general formula (1), (2) or (3).

[0047]

[0048] In the above general formula (1), R １ , R ２ represents a hydrogen atom, a methyl group, or a carboxyl group, and R ３ is an alkylene group having 1 to 15 carbon atoms or a polyethylene oxide segment having 2 to 7 repeating units, and R ４ represents a hydrogen atom or a methyl group. １ , X ２ represents -O- or -NH-. In general formula (1), the repeat number a of the repeating unit on the left side and the repeat number b of the repeating unit on the right side may be the same or different. The ratio of the two (a:b) is preferably 95:5 to 5:95, and more preferably 80:20 to 20:80.

[0049]

[0050] In the above general formula (2), R ５ , R ６ represents a hydrogen atom, a methyl group, or a carboxyl group, and R ７ is an alkylene group having 1 to 15 carbon atoms or a polyethylene oxide segment having 2 to 7 repeating units, and R ８ represents a hydrogen atom or a methyl group. ３ , X ４ represents -O- or -NH-. Note that in general formula (2), the repeat number a of the repeating unit on the left side and the repeat number b of the repeating unit on the right side may be the same or different. The ratio of the two (a:b) is preferably 95:5 to 5:95, more preferably 95:5 to 50:50, and even more preferably 90:10 to 70:30.

[0051]

[0052] In the above general formula (2), R ９ , R １０ , R １１ represents a hydrogen atom or a methyl group. In general formula (3), the repeat number a of the left repeating unit and the repeat number b of the right repeating unit may be the same or different. The ratio of the two (a:b) is preferably 95:5 to 5:95, and more preferably 80:20 to 20:80.

[0053] The weight-average molecular weight (Mw) of the carboxylic acid polymer-based polymerizable monomer (a2) is 2,000 to 120,000, preferably 5,000 to 100,000, from the viewpoint of achieving both the effect of improving the strength of the adhesive layer and the permeability of the carboxylic acid polymer-based polymerizable monomer (a2) into tooth structure. The weight-average molecular weight of the carboxylic acid polymer-based polymerizable monomer (a2) refers to a value measured by gel permeation chromatography (GPC) using polystyrene as a standard.

[0054] From the viewpoint of achieving both an effect of improving the strength of the adhesive layer and the storage stability of the one-component dental adhesive composition, the acid value of the carboxylic acid polymer-based polymerizable monomer (a2) is preferably 50 to 750 mg KOH / g, more preferably 100 to 600 mg KOH / g, where the acid value means the number of mg of potassium hydroxide (KOH) required to neutralize 1 g of sample.

[0055] Examples of the carboxylic acid polymer-based polymerizable monomer (a2) that can be suitably used include a polymer in which pendant methacrylate groups have been introduced into the side chain of a copolymer of acrylic acid and itaconic acid, which is prepared by reacting a copolymer of acrylic acid and itaconic acid with a sufficient amount of 2-isocyanatoethyl methacrylate to convert some of the acid groups of the copolymer into pendant methacrylate groups (for example, the compound VBC described in Example 11 of U.S. Pat. No. 5,130,347 (Mitra)); a polymer (PAH20) prepared by reacting commercially available polyacrylic acid with a sufficient amount of 2-isocyanatoethyl methacrylate to convert some of the acid groups of the polyacrylic acid into pendant methacrylate groups; and Z230AA, Z250, Z254F, Z300, and Z320 of the Cyclomer-P (ACA) series (manufactured by Daicel Allnex Corporation). An example of a compound corresponding to the general formula (1) is PAH20, an example of a compound corresponding to the general formula (2) is VBC, and an example of a compound corresponding to the general formula (3) is various compounds of the Cyclomer-P (ACA) series.

[0056] Furthermore, from the viewpoint of improving the strength of the adhesive layer, the amount of the carboxylic acid polymer-based polymerizable monomer (a2) blended is preferably 2 parts by mass to 40 parts by mass, more preferably 6 parts by mass to 40 parts by mass, and even more preferably 8 parts by mass to 40 parts by mass, relative to 100 parts by mass of the polymerizable monomer (A) contained in the one-component dental adhesive composition of this embodiment.

[0057] <<Other Acidic Group-Containing Polymerizable Monomers (Other Acid Monomers) (a3)>> The polymerizable monomer (A) may further contain, if necessary, other acidic group-containing polymerizable monomers (other acid monomers) (a3) ​​other than the strongly acidic group-containing polymerizable monomer (a1) and the carboxylic acid polymer-based polymerizable monomer (a2).

[0058] The other acidic group-containing polymerizable monomer (other acid monomer) (a3) ​​is a polymerizable monomer having an acidic group other than the strong acid monomer (a1) and the carboxylic acid polymer-based polymerizable monomer (a2), specifically a polymerizable monomer having at least one radically polymerizable group and at least one acidic group (excluding strong acidic groups) in the molecule and having a weight-average molecular weight of less than 2000. Here, the "strong acidic group" refers to the strong acidic group constituting the strong acid monomer (a1) molecule, and the "weight-average molecular weight" refers to a value measured by gel permeation chromatography (GPC) using polystyrene as a standard.

[0059] The radical polymerizable group may be the same as that of the strong acid monomer (a1) or the carboxylic acid polymer-based polymerizable monomer (a2), and among these, an acryloyl group and / or a methacryloyl group is preferred. Furthermore, the acidic group may be a carboxyl group. The other acid monomer (a3) ​​is preferably a low-molecular-weight polymerizable monomer that does not contain a repeating unit structure in the molecule like a polymer, and in this case, the molecular weight is generally within the range of about 50 to 800.

[0060] Examples of other acid monomers (a3) ​​having a carboxyl group as the acidic group include acrylic acid, methacrylic acid, 4-(meth)acryloxyethyltrimellitic acid, 11-(meth)acryloyloxy-1,1-undecanedicarboxylic acid, 1,4-di(meth)acryloyloxypyromellitic acid, 2-(meth)acryloyloxyethyl maleic acid, 2-(meth)acryloyloxyethyl phthalic acid, and 2-(meth)acryloyloxyethylhexahydrophthalic acid.

[0061] Furthermore, from the viewpoint of improving the strength of the adhesive layer, the amount of the other acid monomer (a3) ​​to be blended is preferably 0 parts by mass to 30 parts by mass, more preferably 0 parts by mass to 15 parts by mass, relative to 100 parts by mass of the polymerizable monomer (A) contained in the one-component dental adhesive composition of this embodiment.

[0062] 1-1-2. Acidic Group-Free Polymerizable Monomer (Non-Acid Monomer) (A2) The polymerizable monomer (A) may further contain an acidic group-free polymerizable monomer (non-acid monomer) (A2) as needed. The acidic group-free polymerizable monomer (non-acid monomer) (A2) is a polymerizable monomer that contains at least one radically polymerizable group in the molecule, and does not contain an acidic group. Examples of the radically polymerizable group include the same radically polymerizable groups as those in the strong acid monomer (a1) and the carboxylic acid polymer-based polymerizable monomer (a2). Among these, an acryloyl group and / or a methacryloyl group is preferred.

[0063] Examples of monomers that can be suitably used as the non-acid monomer (A2) include the following: That is, examples of monofunctional non-acid monomers (A2) include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, glycidyl (meth)acrylate, 2-cyanomethyl (meth)acrylate, benzyl methacrylate, polyethylene glycol mono(meth)acrylate, allyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and glyceryl mono(meth)acrylate.

[0064] Examples of the polyfunctional non-acid monomer (A2) include 2,2'-bis{4-[2-hydroxy-3-(meth)acryloyloxypropoxy]phenyl}propane, triethylene glycol methacrylate, 2,2-bis[(4-(meth)acryloyloxypolyethoxyphenyl)propane], 1,6-bis(methacrylethyloxycarbonylamino)-2,2,4-trimethylhexane, 1,6-bis(methacrylethyloxycarbonylamino)-2,4,4-trimethylhexane, trimethylolpropane trimethacrylate, etc. The non-acid monomer (A2) may be used alone or in combination of two or more.

[0065] When a non-acid monomer (A2) is used as the polymerizable monomer (A), the content of the acid monomer (A1) in the polymerizable monomer (A) is preferably 20% to 75% by mass, and more preferably 30% to 60% by mass. In this case, the content of the non-acid monomer (A2) in the polymerizable monomer (A) corresponds to the remainder obtained by subtracting the acid monomer (A1) from the polymerizable monomer (A), and specifically, is preferably 25% to 80% by mass, and more preferably 40% to 70% by mass.

[0066] Furthermore, when other acid monomers (a3) ​​and non-acid monomers (A2) are used as the polymerizable monomers (A) together with the strong acid monomer (a1) and the carboxylic acid polymer-based polymerizable monomer (a2), as needed, the amount of the strong acid monomer (a1) blended is preferably 3 to 60 parts by mass, the amount of the carboxylic acid polymer-based polymerizable monomer (a2) blended is preferably 6 to 40 parts by mass, the amount of the other acid monomers (a3) ​​blended is preferably 0 to 30 parts by mass, and the amount of the non-acid monomer (A2) blended is preferably 25 to 80 parts by mass, relative to 100 parts by mass of the polymerizable monomers (A). However, in this case, the blending amounts of the above-mentioned strong acid monomer (a1), carboxylic acid polymer-based polymerizable monomer (a2), and other acid monomer (a3) ​​are selected so that the total amount of these three components is within the range of 20 to 75 parts by mass, and at the same time, the blending amounts of the above-mentioned strong acid monomer (a1), carboxylic acid polymer-based polymerizable monomer (a2), other acid monomer (a3), and non-acid monomer (A2) are selected so that the total amount of these four components is 100 parts by mass.

[0067] 1-2. Photopolymerization initiator (B) The photopolymerization initiator (B) is a compound that initiates radical polymerization of the polymerizable monomer (A) by irradiation with light. This allows the one-component dental adhesive composition of this embodiment to proceed with photopolymerization curing. As the photopolymerization initiator (B), any known photopolymerization initiator can be used without any particular limitation. For example, α-diketones such as camphorquinone, acylphosphine oxides, etc. can be used, and it is particularly preferable to use bisacylphosphine oxide (b1).

[0068] <Bisacylphosphine oxide (b1)> Bisacylphosphine oxide (b1) is a highly active photopolymerization initiator of the monomolecular cleavage type. Therefore, bisacylphosphine oxide (b1) can promote photopolymerization curing of the polymerizable monomer (A) even with a small amount of light. Bisacylphosphine oxide (b1) is a compound represented by the following formula:

[0069]

[0070] In the above formula, R １２ represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an acyl group, or an acyloxy group. １３ ~R ２２ each independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an acyl group, or an acyloxy group.

[0071] Examples of the bisacylphosphine oxide (b1) 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 (2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide. It is also preferable to use a derivative of bisacylphosphine oxide (b1) as the photopolymerization initiator (B).

[0072] Furthermore, from the viewpoint of obtaining high polymerization activity and adhesive strength, the amount of the photopolymerization initiator (B) to be blended is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the polymerizable monomer (A) contained in the one-component dental adhesive composition of this embodiment.

[0073] 1-3. Water (C) From the viewpoint of the storage stability, biocompatibility, and adhesiveness of the one-component dental adhesive composition of this embodiment, it is preferable to use water that is substantially free of harmful impurities as water (C), and for example, deionized water, distilled water, etc. can be used. The blending ratio of water is preferably 1 to 70 parts by mass, more preferably 3 to 60 parts by mass, and even more preferably 5 to 50 parts by mass, per 100 parts by mass of the polymerizable monomer (A) contained in the one-component dental adhesive composition of this embodiment.

[0074] 1-4. Water-Soluble Organic Solvent (D) Any known water-soluble organic solvent can be used as the water-soluble organic solvent (D) without any restrictions, but it is usually preferable to use a highly volatile organic solvent having a boiling point of less than 100°C. The amount of water-soluble organic solvent (D) is preferably 10 parts by mass to 500 parts by mass, and more preferably 30 parts by mass to 450 parts by mass, relative to 100 parts by mass of the polymerizable monomer (A) contained in the one-component dental adhesive composition of this embodiment. By setting the amount of water-soluble organic solvent (D) to 10 parts by mass or more, the storage stability of the one-component dental adhesive composition can be further improved, and by setting the amount to 500 parts by mass or less, it becomes easy to increase the thickness of the adhesive layer formed on the damaged part of the tooth in Step 1(1) and also to shorten the drying time.

[0075] Specific examples of the water-soluble organic solvent (D) include alcohols such as methanol, ethanol, isopropyl alcohol, t-butyl alcohol, and butanol; ketones such as acetone and methyl ethyl ketone; ethers such as ethyl ether, 1,4-dioxane, and tetrahydrofuran; and esters such as ethyl acetate and ethyl formate. Among these, acetone, ethanol, and isopropyl alcohol are particularly preferred as the water-soluble organic solvent (D) for reasons of biological safety, solubility, and storage stability. As the water-soluble organic solvent (D), one or a combination of two or more water-soluble organic solvents can also be used.

[0076] 1-5. Monovalent to Tetravalent Metal Compound (E) Examples of the monovalent to tetravalent metal compound (E) include salts of monovalent to tetravalent metals (e1) and / or alkoxide compounds of monovalent to tetravalent metals (e2). In the one-component dental adhesive composition after preparation and during storage, metal ions generated by dissociation from the monovalent to tetravalent metal compound (E) form aggregates with at least a portion of the strong acid monomer (a1) contained in the one-component dental adhesive composition. The metal ions forming the aggregates in the one-component dental adhesive composition then form an ionomer with the carboxylic acid polymer-based polymerizable monomer (a2) during the drying treatment (solvent removal from the one-component dental adhesive composition) when Step 1(1) is performed, thereby forming an adhesive layer having a strong ionomer structure.

[0077] Examples of the monovalent to tetravalent metal compound (E) that can be used include metal salts (e1) such as hydroxy salts, carboxylates such as acetate, and halide salts such as fluorides, as well as metal alkoxide compounds (e2) such as isopropoxide. Specific examples of suitable monovalent to tetravalent metal compounds (E) that generate monovalent metal ions such as Li(I), Na(I), K(I), and Rb(I) include lithium hydroxide, sodium hydroxide, sodium ethoxide, sodium fluoride, and potassium hydroxide. Specific examples of suitable monovalent to tetravalent metal compounds (E) that generate divalent metal ions such as Mg(II), Ca(II), Sr(II), Ba(II), Zn(II), and Cd(II) include magnesium acetate tetrahydrate, calcium acetate monohydrate, strontium acetate 0.5hydrate, barium acetate, and zinc acetate dihydrate. Specific preferred examples of the monovalent to tetravalent metal compound (E) that generates trivalent metal ions such as Sc(III), Y(III), La(III), Ce(III), Al(III), Ga(III), and In(III) include scandium acetate hydrate, ytterbium acetate tetrahydrate, lanthanum acetate n-hydrate, cerium acetate monohydrate, aluminum triethoxide, aluminum trisec-butoxide, aluminum acetylacetonate, tris(ethylacetoacetato)aluminum, and gallium acetylacetonate. Specific preferred examples of the monovalent to tetravalent metal compound (E) that generates tetravalent metal ions such as Ti(IV), Zr(IV), and Hf(IV) include titanium tetraisopropoxide, zirconium tetrapropoxide, and zirconium tetrabutoxide.

[0078] The storage stability and ionomer-forming ability of a one-component dental adhesive composition differ depending on the type of metal constituting the monovalent to tetravalent metal compound (E). For example, if a metal compound containing a metal with catalytic function, such as Cu(II) or V(IV), is incorporated into a one-component dental adhesive composition in an amount sufficient to exhibit sufficient ionomer-forming ability, the storage stability may be impaired. For this reason, the metal constituting the monovalent to tetravalent metal compound (E) is preferably Na(I), Mg(II), Ti(IV), Zr(IV), Zn(II), Ga(III), or Al(III), and from the viewpoint of adhesiveness, Ti(IV), Ga(III), or Al(III) is more preferred. Furthermore, the monovalent to tetravalent metal compound (E) may be used alone or in combination of two or more types.

[0079] In the one-component dental adhesive composition of this embodiment, the content of the monovalent to tetravalent metal compound (E) per 1 mol of the strong acid monomer (a1) is 0.02 mol to 1 mol, preferably 0.05 mol to 0.8 mol, in terms of the number of moles of metal ions constituting the monovalent to tetravalent metal compound (E). <ii> Furthermore, in the one-component dental adhesive composition of this embodiment, the content of the monovalent to tetravalent metal compound (E) per 1 g of the carboxylic acid polymer-based polymerizable monomer (a2) is 0.0002 mol to 0.005 mol, preferably 0.0005 mol to 0.004 mol. By having the content of the monovalent to tetravalent metal compound (E) satisfy both the above and <ii>, it is possible to achieve both high adhesive strength and adhesive properties that are less likely to decrease even when the filler material is filled in a thicker layer, as well as storage stability. When two or more kinds of monovalent to tetravalent metal compounds (E) are used in combination, the "content of monovalent to tetravalent metal compounds (E)" means the total amount of the molar equivalent values ​​of metal ions constituting each of the monovalent to tetravalent metal compounds (E) in terms of , and means the total amount of the content of each of the monovalent to tetravalent metal compounds (E) in terms of <ii>.

[0080] The content of the monovalent to tetravalent metal compound (E) relative to 100 parts by mass of the polymerizable monomer (A) is not particularly limited as long as it satisfies the numerical ranges shown in and <ii> above, but is preferably 0.3 parts by mass to 40 parts by mass, and more preferably 0.7 parts by mass to 30 parts by mass.

[0081] 1-6. Aggregates The one-component dental adhesive composition of this embodiment contains aggregates. These aggregates are formed by bonding, via ionic bonds and / or coordinate bonds, between metal ions generated by dissociation from the monovalent to tetravalent metal compound (E) during the preparation process of the one-component dental adhesive composition and at least a part of the strong acid monomer (a1) contained in the one-component dental adhesive composition, and are substances soluble in the water-soluble organic solvent (D).

[0082] Because the aggregates are formed by the formation of ionic and / or coordinate bonds between metal ions and the strong acid monomer (a1), their molecular weights are much larger than those of the various low-molecular-weight components contained in the one-component dental adhesive composition, such as metal ions and the strong acid monomer (a1). Therefore, the presence of aggregates can be easily identified by confirming the weight-average molecular weight, calculated in terms of standard polystyrene, measured by GPC analysis. The weight-average molecular weight of the aggregates is not particularly limited, but is typically within the range of 1,000 to 6,000, with the more frequently observed range being 2,000 to 5,000. For reference, in the one-component dental adhesive composition of this embodiment, the weight-average molecular weight of the aggregates and the weight-average molecular weight of the carboxylic acid polymer-based polymerizable monomer (a2) may overlap. However, even in such cases, the molecular weight distribution of the aggregates differs from that of the carboxylic acid polymer-based polymerizable monomer (a2), and the two can be easily distinguished by focusing on their molecular weight distributions.

[0083] The presence of aggregates can also be confirmed by NMR (nuclear magnetic resonance) or EDS (energy dispersive X-ray) analysis using SEM (scanning electron microscope). For example, when a strong acid monomer (a1) containing a phosphorus atom in the molecule is used, a broad peak derived from the aggregate is confirmed in 31P NMR. In this aggregate, the strong acid monomer (a1) containing a phosphorus atom in the molecule forms an ionic bridge with a metal ion dissociated from the monovalent to tetravalent metal compound (E), which is expected to inhibit free rotation of the bond, resulting in peak broadening.

[0084] Furthermore, when solid particles are obtained by drying and solidifying a solution containing aggregates, the presence of aggregates can be confirmed by EDS analysis using a SEM. In this case, if a specific atom (e.g., phosphorus or sulfur constituting a strong acid group) derived from the strong acid monomer (a1) and a specific metal atom (e.g., Ti or Al) derived from the monovalent to tetravalent metal compound (E) can be simultaneously detected in a single solid particle obtained by drying and solidification by EDS analysis, the solid particle can be determined to be a particle composed of aggregates.

[0085] Furthermore, whether or not aggregates are present in the one-component dental adhesive composition prepared after all components have been mixed can also be easily determined by visually checking whether or not insoluble matter (ionomer formed by aggregation of the carboxylic acid polymer-based polymerizable monomer (a2) by metal ions dissociated from the monovalent to tetravalent metal compound (E)) has occurred in the one-component dental adhesive composition. If insoluble matter has occurred in the one-component dental adhesive composition or the intermediate composition, it means that the metal ions necessary for forming aggregates in the system have already been consumed for the formation of the ionomer, and as a result, aggregates cannot be formed (or a sufficient amount of aggregates cannot be formed).

[0086] 1-7. Other Components The one-component dental adhesive composition of this embodiment may contain other components in addition to the components (A) to (E) and the aggregate, as necessary. Examples of other components include a filler (F), a polymerization inhibitor (G), a photopolymerization accelerator (H), a colorant, and a thickener (such as polymethyl (meth)acrylate). Among these, it is preferable to blend the filler (F) and / or the polymerization inhibitor (G) into the one-component dental adhesive composition of this embodiment. Furthermore, since the one-component dental adhesive composition of this embodiment is basically used as a dental adhesive composition that is photocured after one exposure to light, it does not need to contain a chemical polymerization initiator (such as a redox initiator consisting of a combination of an oxidizing agent and a reducing agent).

[0087] The filler (F) is blended to improve the mechanical strength of the adhesive layer after curing. The filler (F) is not particularly limited, and known inorganic fillers and inorganic-organic composite fillers can be used. Fumed silica is preferred as the inorganic filler. When a filler is blended, the blending amount is preferably 5 to 30 parts by mass, more preferably 5 to 25 parts by mass, and even more preferably 8 to 20 parts by mass, relative to 100 parts by mass of the polymerizable monomer (A) contained in the one-component dental adhesive composition of this embodiment. By blending an amount of 5 parts by mass or more, higher adhesive strength can be easily obtained, and by blending an amount of 30 parts by mass or less, appropriate fluidity as a dental adhesive can be ensured, resulting in better operability. Only one type of filler may be used, or two or more types may be used in combination.

[0088] The polymerization inhibitor (G) has the function of improving the storage stability of the one-component dental adhesive composition of this embodiment. Any known polymerization inhibitor can be used as the polymerization inhibitor (G) without any limitations, and examples thereof include hydroquinone, hydroquinone monomethyl ether, and dibutylhydroxytoluene. Only one type of polymerization inhibitor (G) may be used, or two or more types may be used in combination. The blending amount of the polymerization inhibitor (G) is preferably 0.0001 to 10 parts by mass, and more preferably 0.001 to 5 parts by mass, per 100 parts by mass of the polymerizable monomer (A) contained in the one-component dental adhesive composition of this embodiment.

[0089] Any known photopolymerization accelerator can be used as the photopolymerization accelerator (H) without any limitations, but aromatic tertiary amine compounds are preferably used. Examples of aromatic tertiary amine compounds include 4-dimethylaminobenzoic acid, ethyl 4-dimethylaminobenzoate, lauryl 4-dimethylaminobenzoate, 3-dimethylaminobenzoic acid, ethyl 3-dimethylaminobenzoate, dimethylamino-p-toluidine, diethylamino-p-toluidine, and p-tolyldiethanolamine. The photopolymerization accelerator (H) may be used alone or in combination of two or more. The amount of the photopolymerization accelerator (H) is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the polymerizable monomer (A) contained in the one-component dental adhesive composition of this embodiment.

[0090] 2. Method for Producing One-Part Dental Adhesive Composition The method for producing the one-part dental adhesive composition of this embodiment is not particularly limited. For example, the one-part dental adhesive composition can be prepared by mixing all of the components constituting the one-part dental adhesive composition at once. However, when all of the components are mixed at once, the monovalent to tetravalent metal compound (E), the strong acid monomer (a1), and the carboxylic acid polymer-based polymerizable monomer (a2) coexist in the system. In such a system, metal ions generated by dissociation from the monovalent to tetravalent metal compound (E) may simultaneously react with the strong acid monomer (a1) to form aggregates and with the carboxylic acid polymer-based polymerizable monomer (a2) to form an insoluble matter (ionomer). This makes it difficult to intentionally control the progression of only one of the reactions. Therefore, even if a one-component dental adhesive composition is obtained by mixing all of the components at once, the one-component dental adhesive composition may contain insoluble matter (ionomer) immediately after preparation.

[0091] Therefore, in the method for producing the one-component dental adhesive composition of this embodiment, it is preferred that only the reaction for forming aggregates occurs selectively during the production process, and that no insoluble matter (ionomer) is formed immediately after the preparation of the one-component dental adhesive composition. Examples of such a production method include the production method described below.

[0092] That is, the method for producing a one-component dental adhesive composition of this embodiment is one that produces a one-component dental adhesive composition of this embodiment that does not contain insoluble matter (ionomer) by at least going through a raw material component preparation step, a first composition preparation step, and a second composition preparation step. Note that the method for producing a one-component dental adhesive composition of this embodiment may further include other steps as necessary (for example, a step of removing foreign matter from the solution or a third composition preparation step described below) in addition to the above three steps (raw material component preparation step, first composition preparation step, and second composition preparation step), or may consist of only the above three steps. Details of each step are described below.

[0093] <Raw material component preparation step> The raw material component preparation step is a step of preparing at least the strongly acidic group-containing polymerizable monomer (a1), the carboxylic acid polymer-based polymerizable monomer (a2), the photopolymerization initiator (B), water (C), the water-soluble organic solvent (D), and the monovalent to tetravalent metal compound (E) as raw material components used in the production of the one-component dental adhesive composition.

[0094] In the raw material component preparation step, components other than those listed above can also be prepared as needed, such as other acid monomers (a3), non-acid monomers (A2), fillers (F), polymerization inhibitors (G), and photopolymerization accelerators (H).

[0095] <First Composition Preparation Step> In the first composition preparation step, the carboxylic acid polymer-based polymerizable monomer (a2) is excluded from the options for mixing the raw material components prepared in the raw material component preparation step, and at least the strong acid monomer (a1), the water-soluble organic solvent (D), and the monovalent to tetravalent metal compound (E) are selected, and the selected raw material components are mixed. In this process, the mixing ratio of the strongly acidic group-containing polymerizable monomer (a1) to the metal ion constituting the monovalent to tetravalent metal compound (E) is set to 1 mol:0.02 mol to 1 mol. The mixing ratio is preferably 1 mol:0.05 mol to 0.8 mol.

[0096] In the first composition preparation step, the strong acid monomer (a1) and the monovalent to tetravalent metal compound (E) are mixed in the absence of the carboxylic acid polymer-based polymerizable monomer (a2) in the system, so that the metal ions dissociated from the monovalent to tetravalent metal compound (E) can reliably bond with the strong acid monomer (a1) to form aggregates.

[0097] The first composition preparation step is preferably carried out at a temperature near room temperature. Furthermore, to avoid overheating due to the heat of reaction generated during the preparation of the first composition, the first composition may be prepared while being cooled in an ice bath, as necessary. In the first composition preparation step, the raw material components used to prepare the first composition are mixed and stirred until the resulting mixture is sufficiently uniform. This results in sufficient production of aggregates. Whether sufficient aggregates have been produced in the first composition (whether the aggregate formation reaction has been completely completed) can be easily confirmed by determining whether insoluble matter (ionomer) is produced when a carboxylic acid polymer-based polymerizable monomer (a2) is added to the first composition.

[0098] Furthermore, when the strong acid monomer (a1) is a solid monomer, or when the viscosity increases significantly during the process of forming aggregates after mixing the components constituting the first composition, making mixing and stirring difficult, the first composition may be prepared using a non-acid monomer (A2) and / or water (C) in addition to the strong acid monomer (a1), the water-soluble organic solvent (D), and the monovalent to tetravalent metal compound (E). This is because these two components do not chemically react with the monovalent to tetravalent metal compound (E) and do not adversely affect the formation of aggregates. Note that, as long as the component does not chemically react with the monovalent to tetravalent metal compound (E), other components (e.g., a filler (F)) other than the above two components can also be used, if necessary, in preparing the first composition.

[0099] Furthermore, when the strong acid monomer (a1) is a solid monomer, or when the viscosity increases significantly during the process of forming aggregates after mixing the components constituting the first composition, making mixing and stirring difficult, the first composition may be prepared using a non-acid monomer (A2) and / or water (C) in addition to the strong acid monomer (a1), the water-soluble organic solvent (D), and the monovalent to tetravalent metal compound (E). However, the addition of these two components is limited to cases where they do not chemically react with the monovalent to tetravalent metal compound (E) and do not adversely affect the formation of aggregates. For example, when the monovalent to tetravalent metal compound (E) is an alkoxide compound (e2) of a monovalent to tetravalent metal, the use of water (C) is not preferred because it will chemically react with water (C). On the other hand, when the monovalent to tetravalent metal compound (E) is an acetate or acetylacetonate, water (C) can be used because it will not chemically react with water (C). In addition, other components (for example, a filler (F)) than the above two components can also be used in preparing the first composition as needed, as long as the component does not chemically react with the monovalent to tetravalent metal compound (E).

[0100] <Second Composition Preparation Step> In the second composition preparation step, at least the carboxylic acid polymer-based polymerizable monomer (a2) is selected from the raw material components not selected in the first composition preparation step (to prepare the first composition), and the selected raw material components are mixed with the first composition to prepare the second composition. In this step, the mixing ratio of the carboxylic acid polymer-based polymerizable monomer (a2) to the monovalent to tetravalent metal compound (E) is set to 1 g:0.0002 mol to 0.005 mol. The mixing ratio is preferably 1 g:0.0005 mol to 0.004 mol.

[0101] In the second composition preparation step, the first composition containing the aggregates is at least mixed with the carboxylic acid polymer-based polymerizable monomer (a2). This mixing results in the coexistence of the metal ions contained in the aggregates and the carboxylic acid polymer-based polymerizable monomer (a2) in the system. However, since the metal ions are stabilized in the state of being incorporated into the aggregates, they cannot react with the carboxylic acid polymer-based polymerizable monomer (a2). Therefore, no ionomer (insoluble matter) is formed in the second composition, and the aggregates can be stably present in the second composition.

[0102] If all of the raw materials prepared in the raw material component preparation step have been selected and used up by the time the second composition preparation step is completed, the second composition can be used as the one-component dental adhesive composition of this embodiment. In this case, for example, the first composition preparation step and the second composition preparation step can be performed as follows. First, in the first composition preparation step, a strong acid monomer (a1), a water-soluble organic solvent (D), and a monovalent to tetravalent metal compound (E) are mixed to prepare a first composition containing aggregates. Next, in the second composition preparation step, all of the raw materials prepared in the raw material component preparation step, excluding the above three components (i.e., components including at least the carboxylic acid polymer-based polymerizable monomer (a2)), are mixed with the first composition. This allows the second composition (in other words, the one-component dental adhesive composition of this embodiment) to be obtained.

[0103] Furthermore, if there are still raw material components (remaining raw material components) that have not been selected at the time of completion of the second composition preparation step among the raw material components prepared in the raw material component preparation step, a third composition preparation step is carried out in which the second composition and the remaining raw material components are mixed to prepare a third composition. In this case, the third composition can be used as the one-component dental adhesive composition of this embodiment.

[0104] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples in any way.

[0105] 1. Raw Material Components The names and abbreviations of the raw material components (excluding water (C) and water-soluble organic solvent (D)) used in preparing the one-component dental adhesive compositions of each of the Examples, Comparative Examples, and Reference Examples are shown below.

[0106] 1-1. Polymerizable Monomer (A) <<Acidic Group-Containing Polymerizable Monomer (Acid Monomer) (A1)>>

[0107] <Strongly acidic group-containing polymerizable monomer (strong acid monomer) (a1)> MDP: 10-methacryloxydecyl dihydrogen phosphate (molecular weight: 322 g / mol) SPM2: a mixture of mono(2-methacryloxyethyl) acid phosphate and bis(2-methacryloxyethyl) acid phosphate (molecular weight: 285 g / mol) PP-300P: a mixture of 11-(meth)acryloyloxytetrapropylene glycol hydrogen phosphate and 14-(meth)acryloyloxypentapropylene glycol hydrogen phosphate (molecular weight: 427 g / mol).

[0108] <Carboxylic Acid Polymer-Based Polymerizable Monomer (a2)> VBC: A compound represented by the following formula, in which a pendant methacrylate group has been introduced into the side chain of a copolymer of acrylic acid and itaconic acid (a compound synthesized according to Example 11 of U.S. Pat. No. 5,130,347 (Mitra)). The properties of VBC are an acid value of 530 mg KOH / g (calculated value) and a weight-average molecular weight of 7,000 to 8,000. The molecular weight was measured in the same manner as in Example 1 described below.

[0109]

[0110] ・Z230AA: Acid value 33-47mg・KOH / g, weight average molecular weight 10000-16000 ・Z250: Acid value 58-79mg・KOH / g, weight average molecular weight 19000-25000・Z254F: Acid value 58 to 79 mg / KOH / g, weight average molecular weight 10,000 to 18,000 ・Z300: Acid value 102 to 144 mg / KOH / g, weight average molecular weight 17,000 to 25,000・Z320: Acid value 126-144mg・KOH / g, weight average molecular weight 20000-26000

[0111] The above Z230AA, Z250, Z254F, Z300, and Z320 represent grades of the Cylomer-P (ACA) series (manufactured by Daicel Allnex Corporation). Each grade of compound is a polymer with a main chain similar to that of acrylic resin and a polymerizable group and a carboxyl group in the side chain. The weight-average molecular weight and acid value of each grade of compound are nominal values.

[0112] PAH20: PAH20 was synthesized according to the following procedure. First, 25 g of PAH (polyacrylic acid manufactured by Fujifilm Wako Chemical), 250 g of THF (tetrahydrofuran), 0.05 g of triphenylantimony, 0.35 g of dibutyltin dilaurate, and 11.8 g of 2-isocyanatoethyl methacrylate were weighed into a 500 mL eggplant-shaped flask equipped with a septum and a magnetic stirrer. The mixture of the above components was stirred at 40°C for 18 hours to allow the reaction to proceed. The resulting reaction mixture was precipitated in ethyl acetate in an amount 20 times its volume. The resulting precipitate was filtered, washed with ethyl acetate, and dried in vacuo. This yielded 29 g of the final product (PAH20) in an 86% yield. The properties of PAH20 were an acid value of 470 mg KOH / g and a weight-average molecular weight of 80,000 to 90,000. The molecular weight was measured using a method similar to that described in Example 1 below.

[0113] <Other Acidic Group-Containing Polymerizable Monomers (Other Acid Monomers) (a3)> MAC-10: 11-methacryloyloxy-1,1-undecanedicarboxylic acid

[0114] <<Polymerizable monomers not containing an acidic group (non-acid monomers) (A2)>> BisGMA: 2,2'-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane 3G: triethylene glycol dimethacrylate HEMA: 2-hydroxyethyl methacrylate UDMA: 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate.

[0115] 1-2. Photopolymerization initiator (B) CQ: camphorquinone BTPO: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide IC369: 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone (IRGACURE369, manufactured by BASF Japan Ltd.).

[0116] 1-3. Monovalent to Tetravalent Metal Compounds (E) <Salts of Monovalent to Tetravalent Metals (e1)> NaOH: sodium hydroxide (molecular weight: 40 g / mol) Mg(OAc) ２ : Magnesium acetate tetrahydrate (molecular weight: 214 g / mol) Zn(OAc) ２ : Zinc acetate dihydrate (molecular weight: 220 g / mol) ・Al (acac) ３ : Aluminum acetylacetonate (molecular weight: 324 g / mol) Al(EAA) ３ : Tris(ethylacetoacetato)aluminum (molecular weight: 414 g / mol) Ga(acac) ３ : Gallium acetylacetonate (molecular weight: 367 g / mol) Cu(OAc) ２ : Copper acetate monohydrate (molecular weight: 200g / mol)

[0117] <Alkoxide Compounds of Monovalent to Tetravalent Metals (e2)> Ti(OiPr) ４ : Titanium tetraisopropoxide (molecular weight: 284 g / mol) Zr(OPr) ４ : Zirconium tetrapropoxide (molecular weight: 328 g / mol) Al(OsBu) ３ : Aluminum trisec-butoxide (molecular weight: 246 g / mol).

[0118] 1-4. Filler (F) DM-30: dimethyldichlorosilane-treated silica particles with an average primary particle size of 7 nm (manufactured by Tokuyama Corporation)

[0119] 1-5. Polymerization inhibitor (G) BHT: dibutylhydroxytoluene.

[0120] 1-6. Photopolymerization accelerator (H) DMBE: ethyl 4-dimethylaminobenzoate.

[0121] 1-7. Other components PMMA: Polymethyl methacrylate (weight average molecular weight 1,000,000).

[0122] 2. Preparation of one-component dental adhesive composition (Example 1) <First composition preparation step> MDP, which is a strong acid monomer (a1), and acetone, which is a water-soluble organic solvent (D), were mixed and stirred to prepare a solution until MDP was dissolved in acetone. To this solution, Ti(OiPr) ４ The first composition was prepared by adding 292 parts by mass of MDP, acetone, and Ti(OiPr) ４ The mass ratio of the above was set to 35:250:7.

[0123] <Confirmation of Aggregate Formation> For the obtained first composition, a diluted solution was prepared by dissolving 1 part of the first composition in 10 times the amount of THF (tetrahydrofuran), and this diluted solution was used to measure the weight average molecular weight by GPC analysis under the conditions shown below. As a result, a weight average molecular weight was measured that significantly exceeded the molecular weight of each raw material component used in preparing the first composition, and the value was 3110 in standard polystyrene equivalent, as shown in Table 1. On the other hand, among the raw material components constituting the first composition, MDP and Ti(OiPr) ４ Only the Ti ions dissociated from MDP have the potential to bond with the Ti ions through ionic and / or coordinate bonds to form a compound with a larger molecular weight. Therefore, it is determined that aggregates of MDP and Ti ions (weight average molecular weight: 3110) are formed in the first composition.

[0124] [GPC analysis conditions] Measuring apparatus: Advanced Polymer Chromatography (manufactured by Nihon Waters) Column: ACQUITY APCTMXT45 1.7 μm ACQUITY APCTMXT125 2.5 μm Column temperature: 40° C. Developing solvent: THF (flow rate: 0.5 ml / min) Detector: Photodiode array detector 210 nm (PDA detector)

[0125] <Second Composition Preparation Step> Next, a one-component dental adhesive composition (second composition) was prepared by mixing 292 parts by mass of the first composition with 20 parts by mass of VBC, a carboxylic acid polymer-based polymerizable monomer; <ii> 15 parts by mass of Bis-GMA, 10 parts by mass of 3G, and 20 parts by mass of HEMA, which are non-acid monomers; <iii> 3 parts by mass of BTPO, a photopolymerization initiator; and <iv> 25 parts by mass of water. Visual inspection of the resulting one-component dental adhesive composition (second composition) revealed no evidence of precipitation or sedimentation of insoluble matter, indicating a completely homogeneous solution. Furthermore, a second GPC analysis was performed on the second composition under the same conditions as for the first composition to confirm its molecular weight distribution. As a result, a peak corresponding to the weight-average molecular weight attributable to the aggregates measured in the first GPC analysis of the first composition was observed. From the results of visual observation and the second GPC analysis, it was determined that no insoluble ionomer (VBC aggregated by Ti ions) was formed in the one-component dental adhesive composition (second composition), and that the aggregates formed in the first composition were also stably present in the second composition. Furthermore, the obtained one-component dental adhesive composition (second composition) was a completely homogeneous solution, with no precipitation or settling of insoluble matter observed even after 24 hours had passed since its preparation, just like at the time of preparation.

[0126] (Examples 2 to 37) The one-component dental adhesive compositions of Examples 2 to 37 were prepared by carrying out the first composition preparation step and the second composition preparation step in the same manner as in Example 1, except that the raw material components used in the preparation of the one-component dental adhesive compositions were changed as shown in Table 2 or Table 3, based on the premise that only the strong acid monomer (a1), the water-soluble organic solvent (D), and the monovalent to tetravalent metal compound (E) were used as raw material components for the preparation of the first composition. Note that in the first composition preparation step of Examples 2 to 7, 9, 14, 27 to 31, and 35 to 36, the first composition prepared in Example 1 was used instead of preparing a new first composition. Furthermore, the notation "↑" in Tables 2 to 3 and Table 4 described below means "same as above." For example, focusing on the column for non-acid monomer (A2) in Examples 1 to 8, it means that in Examples 2 to 8, a non-acid monomer (A2) having the same composition and blending amount as in Example 1 was used.

[0127] Here, for the first compositions prepared in Examples 8, 10 to 13, 15 to 26, and 32 to 34, the weight-average molecular weights were measured by GPC analysis in the same manner as in Example 1, to confirm whether or not a measured value significantly exceeded the molecular weight of the raw material components used in preparing the first composition. As a result, in all of the examples, a measured value significantly exceeded the molecular weight of the raw material components, and it was therefore determined that aggregates had formed in the first composition. Table 1 shows the weight-average molecular weights of the aggregates formed in the first composition.

[0128] Furthermore, visual inspection of the obtained one-component dental adhesive compositions (second compositions) of Examples 2 to 37 revealed no precipitation or settling of insoluble matter, indicating that they were completely homogeneous solutions. Furthermore, a second GPC analysis was performed on the second compositions under the same conditions as for the first composition to confirm their molecular weight distribution. As a result, a peak corresponding to the weight-average molecular weight attributed to the aggregates measured in the first GPC analysis of the first composition was confirmed in this molecular weight distribution. From the results of visual observation and the second GPC analysis, it was determined that no insoluble ionomer was formed in the one-component dental adhesive compositions (second compositions) of Examples 2 to 36, and that the aggregates formed in the first composition were stably present in the second composition. Furthermore, even after 24 hours from preparation, the one-component dental adhesive compositions (second compositions) of Examples 2 to 37 were completely homogeneous solutions, showing no precipitation or settling of insoluble matter, just as they were at the time of preparation.

[0129] (Comparative Example 1) A one-component dental adhesive composition was prepared by carrying out the first composition preparation step and the second composition preparation step in the same manner as in Example 1, except that 292 parts by mass of the first composition prepared in Example 1 was used as the first composition and the raw material components used in the preparation of the one-component dental adhesive composition were changed as shown in Table 4. In Comparative Example 1, the carboxylic acid polymer-based polymerizable monomer (a2) was not used in the preparation of the one-component dental adhesive composition.

[0130] When the obtained one-component dental adhesive composition (second composition) was visually inspected, no precipitation or settling of insoluble matter was observed, and it was found to be a completely homogeneous solution. Note that, in Comparative Example 1, since the carboxylic acid polymer-based polymerizable monomer (a2) was not used, there was no room for the formation of an insoluble ionomer in the one-component dental adhesive composition (second composition), and therefore, it is judged that the aggregates formed in the first composition were also stably present in the second composition.

[0131] (Comparative Example 2) A one-component dental adhesive composition was prepared by carrying out the first composition preparation step and the second composition preparation step in the same manner as in Example 1, except that the raw material components used in the preparation of the one-component dental adhesive composition were changed as shown in Table 4. In Comparative Example 2, only the strong acid monomer (a1) and the water-soluble organic solvent (D) were used as raw material components in the preparation of the first composition, and no monovalent to tetravalent metal compound (E) was used.

[0132] Here, the weight-average molecular weight of the obtained first composition was measured by GPC analysis in the same manner as in Example 1, to check whether a measured value significantly exceeded the molecular weight of the raw material components used in preparing the first composition. As a result, no measured value exceeding the molecular weight of the raw material components was obtained, and therefore it was determined that no aggregates had formed in the first composition.

[0133] Furthermore, when the obtained one-component dental adhesive composition (second composition) was visually inspected, no deposition or sedimentation of insoluble matter was observed, and it was found to be a completely homogeneous solution.

[0134] (Comparative Example 3) A one-component dental adhesive composition was prepared by carrying out the first composition preparation step and the second composition preparation step in the same manner as in Example 1, except that the raw material components used in the preparation of the one-component dental adhesive composition were changed as shown in Table 4. In Comparative Example 3, only the water-soluble organic solvent (D) and the monovalent to tetravalent metal compound (E) were used as raw material components in the preparation of the first composition, and no strong acid monomer (a1) was used.

[0135] Here, the weight-average molecular weight of the obtained first composition was measured by GPC analysis in the same manner as in Example 1, to check whether a measured value significantly exceeded the molecular weight of the raw material components used in preparing the first composition. As a result, no measured value exceeding the molecular weight of the raw material components was obtained, and therefore it was determined that no aggregates had formed in the first composition.

[0136] Furthermore, visual inspection of the obtained one-component dental adhesive composition (second composition) confirmed the presence of a large amount of insoluble matter. Therefore, the filtrate obtained by filtering and separating the insoluble matter from the second composition was subjected to molecular weight measurement by GPC analysis. As a result, the weight-average molecular weight corresponding to the carboxylic acid polymer-based polymerizable monomer (a2) could not be confirmed for this filtrate, indicating that the carboxylic acid polymer-based polymerizable monomer (a2) was not contained in the filtrate. From these results, it is concluded that, during the preparation of the second composition, metal ions dissociated from the (non-aggregate) monovalent to tetravalent metal compound (E) reacted with the carboxylic acid polymer-based polymerizable monomer (a2) to form an ionomer (insoluble matter).

[0137] Comparative Example 4 A first composition was prepared by carrying out the first composition preparation step in the same manner as in Example 1, except that the raw material components used in the preparation of the one-component dental adhesive composition were changed as shown in Table 4. The weight-average molecular weight of the obtained first composition was measured by GPC analysis in the same manner as in Example 1, to confirm whether a measured value significantly exceeded the molecular weight of the raw material components used in the preparation of the first composition. As a result, a measured value significantly exceeded the molecular weight of the raw material components, and it was determined that aggregates had formed in the first composition. Table 1 shows the weight-average molecular weights of the aggregates formed in the first composition.

[0138] Subsequently, a one-component dental adhesive composition (second composition) was prepared by carrying out the second composition preparation step in the same manner as in Example 1. Visual inspection of the obtained one-component dental adhesive composition (second composition) confirmed the presence of a large amount of insoluble matter. In the composition of Comparative Example 4 shown in Table 4, an excess amount of monovalent to tetravalent metal compound (E) relative to the strong acid monomer (a1) was used compared to the other Examples. Therefore, it is believed that a large amount of metal ions (excess metal ions) that could not participate in the formation of aggregates were generated in the first composition, and these excess metal ions reacted with the carboxylic acid polymer-based polymerizable monomer (a2) during the preparation of the second composition to form an ionomer (insoluble matter).

[0139] (Comparative Example 5) A one-component dental adhesive composition (second composition) was prepared by carrying out the first composition preparation step and the second composition preparation step in the same manner as in Example 1, except that the raw material components used in the preparation of the one-component dental adhesive composition were changed as shown in Table 4. In Comparative Example 5, the amount of monovalent to tetravalent metal compound (E) added was adjusted so that it was in excess relative to the carboxylic acid polymer-based polymerizable monomer (a2).

[0140] The weight-average molecular weight of the obtained first composition was measured by GPC analysis in the same manner as in Example 1 to confirm whether a measured value significantly exceeded the molecular weight of the raw material components used in preparing the first composition. As a result, a measured value significantly exceeded the molecular weight of the raw material components, and it was determined that aggregates had formed in the first composition. Table 1 shows the weight-average molecular weights of the aggregates formed in the first composition.

[0141] Furthermore, visual inspection of the obtained one-component dental adhesive composition (second composition) revealed no precipitation or settling of insoluble matter, indicating a completely homogeneous solution. Furthermore, a second GPC analysis was performed on the second composition under the same conditions as for the first composition to confirm its molecular weight distribution. As a result, a peak corresponding to the weight-average molecular weight resulting from the aggregates measured in the first GPC analysis of the first composition was confirmed in this molecular weight distribution. From the results of visual observation and the second GPC analysis, it was determined that no insoluble ionomer was formed in the one-component dental adhesive composition (second composition), and that the aggregates formed in the first composition were stably present in the second composition.

[0142] Comparative Example 6 In Comparative Example 6, an attempt was made to prepare a one-component dental adhesive composition according to the following procedure, without using the water-soluble organic solvent (D).

[0143] (i) 35 parts by mass of MDP, which is a strong acid monomer (a1), and (ii) 15 parts by mass of Bis-GMA, 10 parts by mass of 3G, and 20 parts by mass of HEMA, which are non-acid monomers (A2), were mixed until the MDP was completely dissolved with the other monomers to obtain a monomer mixture. Next, 3:9 parts by mass of Al(acac), which is a monovalent to tetravalent metal compound (E), was added to this monomer mixture and mixed for 1 hour to prepare a first composition.

[0144] Here, the weight-average molecular weight of the obtained first composition was measured by GPC analysis in the same manner as in Example 1 to confirm whether a measured value significantly exceeded the molecular weight of the raw material components used in preparing the first composition. As a result, a measured value significantly exceeded the molecular weight of the raw material components, and it was determined that aggregates had formed in the first composition. Table 1 shows the weight-average molecular weights of the aggregates formed in the first composition.

[0145] Next, to prepare a one-part dental adhesive composition (second composition), 20 parts by mass of VBC, which is a carboxylic acid polymer-based polymerizable monomer (a2), 3 parts by mass of BTPO, which is a photopolymerization initiator (B), 25 parts by mass of water (C), 20 parts by mass of DM-30, and 0.2 parts by mass of BHT were mixed with 89 parts by mass of the first composition. However, since this mixture did not contain the water-soluble organic solvent (D), the water and the monomers were not compatible with each other, and it was not possible to obtain a one-part dental adhesive composition (second composition).

[0146] Comparative Example 7 In Comparative Example 7, the first composition was prepared by carrying out the first composition preparation step in the same manner as in Example 1, except that MAC-10 containing a carboxyl group was used as the other acid monomer (a3) ​​with lower acidity instead of the strong acid monomer (a1) when preparing the first composition. The weight-average molecular weight of the obtained first composition was measured by GPC analysis in the same manner as in Example 1, to confirm whether a measured value significantly exceeded the molecular weight of the raw material components used in preparing the first composition. As a result, a measured value significantly exceeded the molecular weight of the raw material components, and it was determined that aggregates had formed in the first composition. Table 1 shows the weight-average molecular weights of the aggregates formed in the first composition.

[0147] Subsequently, a one-component dental adhesive composition (second composition) was prepared by carrying out the second composition preparation step in the same manner as in Example 1. When the obtained one-component dental adhesive composition (second composition) was visually inspected, it was confirmed that a large amount of insoluble matter was generated.

[0148] (Comparative Example 8) A one-component dental adhesive composition was prepared by carrying out the first composition preparation step and the second composition preparation step in the same manner as in Example 1, except that the raw material components used in preparing the one-component dental adhesive composition were changed as shown in Table 4.

[0149] Here, the weight-average molecular weight of the obtained first composition was measured by GPC analysis in the same manner as in Example 1 to confirm whether a measured value significantly exceeded the molecular weight of the raw material components used in preparing the first composition. As a result, a measured value significantly exceeded the molecular weight of the raw material components, and it was determined that aggregates had formed in the first composition. Table 1 shows the weight-average molecular weights of the aggregates formed in the first composition.

[0150] Furthermore, visual inspection of the obtained one-component dental adhesive composition (second composition) revealed no precipitation or sedimentation of insoluble matter, indicating a completely homogeneous solution. Furthermore, a second GPC analysis was performed on the second composition under the same conditions as for the first composition to confirm its molecular weight distribution. As a result, a peak corresponding to the weight-average molecular weight resulting from the aggregates measured in the first GPC analysis of the first composition was confirmed in this molecular weight distribution. From the results of visual observation and the second GPC analysis, it was determined that no insoluble ionomer was formed in the one-component dental adhesive composition (second composition), and that the aggregates formed in the first composition were stably present in the second composition.

[0151] (Reference Example 1) The raw material components shown in Table 5 were mixed and stirred at once to prepare a conventional one-component dental adhesive composition containing a highly active photopolymerization initiator similar to that described in Patent Document 4.

[0152] 3. Evaluation of Adhesive Strength The adhesive strengths shown in Tables 2 to 5 were evaluated by the following procedure. First, bovine anterior teeth extracted within 24 hours after slaughter were polished with waterproof abrasive paper P600 under running water, and the dentin plane was scraped off so that it was parallel to the labial surface and flat. Double-sided tape with a 3 mm diameter hole was then attached to the polished surface. Next, a one-component dental adhesive composition was applied to the adhesive surface of the polished surface exposed through the hole in the double-sided tape, and the polished surface was dried with an air blow for 10 seconds.

[0153] Next, a paraffin wax with a hole of 8 mm in diameter was attached to the adhesive surface coated with the one-component dental adhesive composition so that the hole in the paraffin wax and the hole in the double-sided tape were concentric, thereby creating a simulated cavity. In creating the simulated cavity, a paraffin wax with a thickness of 0.5 mm and a paraffin wax with a thickness of 2.0 mm were used to create a simulated cavity with a depth of 0.5 mm and a depth of 2.0 mm.

[0154] Then, two types of simulated cavities with different depths were filled with a composite resin (Estelite Universal Flow Medium A3, manufactured by Tokuyama Dental) as a light-curing filling material, and lightly pressed with polyester film. After that, they were irradiated with visible light (Eliper Deep Cure, manufactured by 3M, irradiation intensity 800 mW / cm). ２ The specimen was exposed to light for 10 seconds using a laser. This allowed the adhesive layer and filling material layer formed in the simulated cavity to be simultaneously photocured. A pre-polished SUS304 round rod (diameter 8 mm, height 18 mm) was then bonded to the surface of the cured filling material layer using resin cement (Estecem II, manufactured by Tokuyama Dental Co., Ltd.). Finally, the test piece with the rod attached was immersed in water at 37°C for 24 hours to obtain a sample for measuring adhesive strength.

[0155] The tensile adhesive strength of the prepared samples was measured using a Shimadzu autograph (crosshead speed: 2 mm / min). Tensile adhesive strength measurements were performed on five samples, and the average of the measured values ​​for each sample was calculated as the adhesive strength shown in Tables 2 to 5. The "CR thickness" shown in the tables refers to the thickness (mm) of the filling material layer formed in the simulated cavity using a photocurable filling material (composite resin). The "0.5" column represents the adhesive strength (MPa) when the CR thickness was 0.5 mm, and the "2.0" column represents the adhesive strength (MPa) when the CR thickness was 2.0 mm. The values ​​shown in the "Reduction Rate" column were calculated using the following formula: Reduction Rate (%) = {(Adhesion strength at CR thickness of 0.5 mm) - (Adhesion strength at CR thickness of 2.0 mm)} ÷ (Adhesion strength at CR thickness of 0.5 mm) × 100

[0156] 4. Evaluation Results Table 1 shows the weight-average molecular weights measured by GPC analysis of the first compositions prepared in each of the Examples, Comparative Examples, and Reference Examples (measurements deemed to correspond to aggregates), as well as the results of visual observation of the second compositions (one-part dental adhesive compositions). Tables 2 to 5 show the evaluation results of the adhesive strength and rate of decrease for each of the Examples, Comparative Examples, and Reference Examples.

[0157] In Tables 2 to 5, the numerical values ​​shown in the columns "Components (A) to (E)" and "Other Components" represent parts by mass. Furthermore, "ME / Ma1" represents the content (mol) of the monovalent to tetravalent metal compound (E) per 1 mol of the strong acid monomer (a1) in terms of the number of moles of metal ions constituting the monovalent to tetravalent metal compound (E), and "ME / a2" represents the content (mol) of the monovalent to tetravalent metal compound (E) per 1 g of the carboxylic acid polymer-based polymerizable monomer (a2).

[0158]

[0159]

[0160]

[0161]

[0162]

[0163] As shown in Tables 2 and 3, in all of the examples, the adhesive strength tends not to decrease even when the CR thickness increases from 0.5 mm to 2.0 mm, and it was found that a relatively high adhesive strength was obtained even when the CR thickness was 2.0 mm.

[0164] On the other hand, as shown in Table 4, Comparative Example 1 did not contain the carboxylic acid polymer-based polymerizable monomer (a2), and therefore the adhesive strength decreased significantly with increasing CR thickness. Comparative Example 2 did not contain the monovalent to tetravalent metal compound (E), and therefore the adhesive strength decreased significantly with increasing CR thickness.

[0165] In Comparative Example 3, a component (strong acid monomer (a1)) that stabilizes metal ions dissociated from the monovalent to tetravalent metal compound (E) as aggregates in the one-component dental adhesive composition was not used. Therefore, no aggregates were formed in the obtained one-component dental adhesive composition, and a large amount of insoluble matter (ionomer) was produced. As a result, the adhesive strength was significantly low, and the rate of decrease was also large. In Comparative Example 4, ME / Ma1 was set to exceed 1 mol / 1 mol. Therefore, a large amount of insoluble matter (ionomer) was produced in the obtained one-component dental adhesive composition. As a result, the adhesive strength was low, and the rate of decrease was also large.

[0166] In Comparative Example 5, ME / a2 was set to exceed 0.005 mol / g. Therefore, the adhesive strength significantly decreased with increasing CR thickness. In Comparative Example 6, a one-component dental adhesive composition could not be prepared because a water-soluble organic solvent (D) was not used. In Comparative Example 7, a one-component dental adhesive composition was prepared using a carboxyl group-containing polymerizable monomer as the other acid monomer (a3) ​​instead of the strong acid monomer (a1). However, insoluble matter was formed in the one-component dental adhesive composition. As a result, the adhesive strength was significantly low and the rate of decrease was also large. In Comparative Example 8, the formation of aggregates was confirmed by GPC analysis, and no insoluble matter was found in the one-component dental adhesive composition. However, because the values ​​of ME / Ma1 and ME / a2 were too small, the adhesive strength significantly decreased with increasing CR thickness.

[0167] Furthermore, in Reference Example 1, the adhesive strength of a conventional one-component dental adhesive composition containing the highly active photopolymerization initiator described in Patent Document 4 was evaluated. Although excellent adhesive strength was observed when the CR thickness was 0.5 mm, the adhesive strength significantly decreased when the CR thickness was 2.0 mm.

Claims

1. A composition for bonding a photocurable filling material to a tooth structure, comprising: a polymerizable monomer (A) containing an acidic group-containing polymerizable monomer (A1); a photopolymerization initiator (B); water (C); a water-soluble organic solvent (D); and a monovalent to tetravalent metal compound (E); wherein the acidic group-containing polymerizable monomer (A1) contains at least one radical polymerizable group and a phosphono group {-P(=O)(OH) ２ }, dihydrogen phosphate monoester group {—O—P(═O)(OH) ２ }, hydrogen phosphate diester group {(-O-) ２ P(=O)OH} and sulfo groups (-SO ３ and a carboxylic acid polymer-based polymerizable monomer (a2) having at least one radically polymerizable group and at least one carboxyl group in the molecule, not having the strongly acidic group, and having a weight average molecular weight (Mw) of 2000 to 120000, wherein the content of the mono- to tetravalent metal compound (E) per 1 mol of the strongly acidic group-containing polymerizable monomer (a1) is 0.02 mol to 1 mol in terms of the number of moles of metal ions constituting the mono- to tetravalent metal compound (E), and the content of the mono- to tetravalent metal compound (E) per 1 g of the carboxylic acid polymer-based polymerizable monomer (a2) is 0.0002 mol to 0.005 mol, a metal ion constituting the monovalent to tetravalent metal compound (E) forms an aggregate with at least a part of the strongly acidic group-containing polymerizable monomer (a1).

2. A one-component dental adhesive composition according to claim 1, comprising 6 to 60 parts by mass of the strongly acidic group-containing polymerizable monomer (a1) per 100 parts by mass of the polymerizable monomer (A).

3. A one-component dental adhesive composition according to claim 1 or 2, comprising 6 to 40 parts by mass of the carboxylic acid polymer-based polymerizable monomer (a2) per 100 parts by mass of the polymerizable monomer (A).

4. The one-liquid dental adhesive composition according to claim 1 or 2, wherein the aggregate has a weight average molecular weight in terms of standard polystyrene of 1,000 to 6,000 as measured by gel permeation chromatography analysis.

5. The one-liquid dental adhesive composition according to claim 1 or 2, wherein the acid value of the carboxylic acid polymer-based polymerizable monomer (a2) is 50 mg·KOH / g to 750 mg·KOH / g.

6. A one-component dental adhesive composition according to claim 1 or 2, comprising 10 to 500 parts by mass of the water-soluble organic solvent (D) per 100 parts by mass of the polymerizable monomer (A).

7. The one-component dental adhesive composition according to claim 1 or 2, further comprising a filler (F): 5 to 30 parts by mass per 100 parts by mass of the polymerizable monomer (A).

8. The one-component dental adhesive composition according to claim 1 or 2, wherein the monovalent to tetravalent metal compound (E) contains at least one metal selected from the group consisting of Na(I), Mg(II), Ti(IV), Zr(IV), Zn(II), Ga(III) and Al(III).

9. A raw material component preparation step of preparing at least the strongly acidic group-containing polymerizable monomer (a1), the carboxylic acid polymer-based polymerizable monomer (a2), the photopolymerization initiator (B), water (C), the water-soluble organic solvent (D), and the monovalent to tetravalent metal compound (E) as raw material components; a first composition preparation step of selecting at least the strongly acidic group-containing polymerizable monomer (a1), the water-soluble organic solvent (D), and the monovalent to tetravalent metal compound (E) from among the raw material components prepared in the raw material component preparation step, and mixing the selected raw material components to prepare a first composition; and a second composition preparation step of selecting at least the carboxylic acid polymer-based polymerizable monomer (a2) from among the raw material components not selected in the first composition preparation step, and mixing the selected raw material components with the first composition to prepare a second composition. a first composition preparation step of setting a mixing ratio of the strongly acidic group-containing polymerizable monomer (a1) to a metal ion constituting the monovalent to tetravalent metal compound (E) to be 1 mol:0.02 mol to 1 mol; and a second composition preparation step of setting a mixing ratio of the carboxylic acid polymer-based polymerizable monomer (a2) to the monovalent to tetravalent metal compound (E) to be 1 g:0.0002 mol to 0.005 mol.

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