JP7708637B2 - Two-part dental paste hardenable composition - Google Patents

Description

The present invention relates to a two-component dental hardenable composition in the form of a paste, which is used in dental treatment for bonding dental prostheses such as crowns, inlays, and bridges to tooth structure, and for building abutments. More specifically, the present invention relates to a two-component dental hardenable composition in the form of a paste, which has an appropriate handling time, excellent adhesive strength to precious metals and dentin, and little decrease in adhesive strength to dentin during long-term storage, as well as a low risk of the paste solidifying and little variation in hardening time.

Adhesive materials and filling and restorative materials are widely used for the repair of missing tooth sites damaged by caries, fractures, etc. Resin-based dental hardenable compositions containing polymerizable monomers, polymerization initiators, fillers, etc. are commonly used as adhesive and filling and restorative materials for tooth repair.

Among the resin-based dental hardenable compositions, the material used to bond dental prostheses to tooth structure is called dental resin cement. In addition, in the repair treatment of deep caries that reaches the dental pulp, it is necessary to remove the dental pulp and construct an abutment tooth, and the material used for this is called a composite resin for dental core construction. Both dental resin cement and composite resin for dental core construction are paste-like compositions, and are generally manufactured by mixing a liquid polymerizable monomer-containing composition in which a polymerizable monomer, a polymerization initiator system, a stabilizer, etc. are dissolved with a powdered filler, etc., and are provided to the user, the dentist, in a container filled state. Dental hardenable compositions are required to maintain a certain level of performance within their expiration date.

(Meth)acrylates are generally used as polymerizable monomers contained in dental resin cements or composite resins for dental core construction. Polymerizable monomers with acidic groups such as phosphate groups or carboxyl groups are also blended into dental resin cements to impart adhesive properties to teeth or prostheses. Dental resin cements that have been given adhesive properties are called self-adhesive dental resin cements.

In order to polymerize and harden these dental hardenable compositions, a redox-type polymerization initiator system consisting of an oxidizing agent, a reducing agent, etc. may be used. The oxidizing agent and reducing agent of the polymerization initiator system are packaged, for example, in a first agent containing an oxidizing agent and a second agent containing a reducing agent, and the two-component dental hardenable composition is provided to the user, the dentist. Just before the dentist uses this two-component dental hardenable composition, the first agent containing an oxidizing agent and the second agent containing a reducing agent are mixed together, whereby radicals are generated by a redox reaction, and the polymerization and hardening of the dental hardenable composition proceeds.

Conventionally, a polymerization initiator system consisting of benzoyl peroxide and an aromatic amine compound has been widely used as a redox-type polymerization initiator system for dental hardenable compositions. However, when this polymerization initiator system is used, there is a problem that the storage stability of the composition is low due to the low thermal stability of benzoyl peroxide. Specifically, when a composition containing benzoyl peroxide is stored for a long period of time in a temperature environment above room temperature, problems such as a decrease in hardening due to decomposition of benzoyl peroxide and solidification of the composition before use may occur. Therefore, when providing a composition containing benzoyl peroxide to users such as dentists, measures such as specifying the storage temperature to be lower than room temperature and setting a short expiration date are necessary, and there is room for improvement in terms of usability and quality stability.

In recent years, therefore, polymerization initiator systems have been proposed that use various organic peroxides, which are more stable than benzoyl peroxide, as oxidizing agents. For example, Patent Document 1 proposes a dental cement that contains a polymerization initiator system consisting of an organic peroxide, a vanadium compound, an ascorbate, and a thiourea derivative.

Patent Document 2 proposes a polymerization initiator system consisting of an organic peroxide selected from hydroperoxides and diperoxides, a transition metal compound, and ascorbic acid or a derivative thereof. It is described that a two-component self-adhesive dental composition containing this polymerization initiator system has good mechanical properties, aesthetic properties, and good adhesion.

Patent Document 3 discloses a two-component self-adhesive dental composition that further contains a stabilizer selected from phosphites or sulfites that contributes to the stabilization of ascorbic acid or its derivatives in a polymerization initiator system consisting of an organic peroxide, a transition metal compound, and ascorbic acid or its derivatives.

International Publication No. 2017/038218 International Publication No. 2016/007453 International Publication No. 2017/100231

As a result of the inventors' investigations, it was found that dental cements containing the thiourea derivatives described in Patent Document 1 have poor adhesion to dental precious metals. This is thought to be because the thiourea derivatives chemically adsorb to the precious metals and inhibit the chemical adhesion of the acidic group-containing polymerizable monomer to the precious metals. Furthermore, it was found that there is room for improvement in storage stability and adhesion to dentin.

Patent Documents 2 and 3 propose blending an organic peroxide with an acidic group-containing polymerizable monomer and a transition metal component in the same agent. The organic peroxides described as preferred compounds in Patent Documents 2 and 3 are more stable than benzoyl peroxide, but in general, organic peroxides are accelerated in decomposition under acidic conditions, and radicals are generated during storage, which may cause the paste to solidify. Furthermore, it was found that the coexistence of an organic peroxide and a transition metal component under acidic conditions further accelerates the decomposition reaction, increasing the risk of the paste solidifying during storage. Therefore, it was found that there is room for further improvement in terms of storage stability in the compositions described in Patent Documents 2 and 3, as the paste may solidify if stored for a long period of time, and it is necessary to set the storage period to be short.

The present invention therefore aims to provide a paste-like two-component dental hardenable composition that has an appropriate operating time, excellent adhesive strength to precious metals and dentin, and little loss of adhesive strength to dentin during long-term storage, as well as a low risk of the paste solidifying and little variation in hardening time.

That is, the present invention provides the following inventions.
[1] A first agent containing an acidic group-containing polymerizable monomer (A), a polymerizable monomer not having an acidic group (B), an organic peroxide (C), a filler (D), and a ligand containing a nitrogen atom (G);
a second agent containing a polymerizable monomer (B) having no acidic group, a filler (D), and an ascorbic acid compound (F), and substantially not containing a thiourea compound;
At least one of the first agent and the second agent contains a transition metal compound (E);
A paste-like two-component dental hardenable composition.
[2] The paste-like two-component dental hardenable composition according to [1], wherein the nitrogen atom-containing ligand (G) includes a ligand having two or more nitrogen atoms in the molecule.
[3] The nitrogen-containing ligand (G) is at least one compound selected from the group consisting of a compound represented by the following general formula (1), a compound represented by the following general formula (2), and a multidentate ligand containing a nitrogen-containing heterocycle (3):
The paste-like two-component dental curable composition according to [2], wherein the multidentate ligand (3) containing a nitrogen-containing heterocycle contains a five- or six-membered ring containing a nitrogen atom, has two or more nitrogen atoms in the molecule, and is a bidentate or higher ligand compound.
R ₁ R ₂ N-X ₁ -NR ₃ R ₄ (1)
(R ₁ to R ₄ each independently represent an alkyl group which may have a substituent, and X ₁ represents a divalent aliphatic group which may have a substituent.)
( _R5 , _R6 , and _R7 each independently represent an alkyl group which may have a substituent, _X2 and _X3 each independently represent a divalent aliphatic group which may have a substituent and which may contain an oxygen atom and/or a nitrogen atom, m and n each independently represent an integer of 1 or more, Y represents a monoalkylamino group or a dialkylamino group which may have a substituent, and any two or more of _R5 , _R6 , _R7 , and Y may be bonded together to form a ring. When a plurality of _R6 , _R7 , _X2 , and _X3 are present, they may be the same or different.)
[4] The paste-like two-component dental hardenable composition according to any one of [1] to [3], wherein the ascorbic acid compound (F) is at least one compound selected from the group consisting of salts and esters of ascorbic acid.
[5] The paste-like two-component dental hardenable composition according to any one of [1] to [4], wherein the transition metal compound (E) is a copper compound and/or a vanadium compound.
[6] The paste-like two-component dental hardenable composition according to any one of [1] to [5], wherein the first agent does not contain a transition metal compound (E).
[7] The paste-like two-component dental hardenable composition according to any one of [1] to [6], which is a self-adhesive composition.

According to the present invention, it is possible to provide a two-component dental hardenable composition in the form of a paste, which has an appropriate operating time, excellent adhesive strength to precious metals and dentin, and little decrease in adhesive strength to dentin during long-term storage, as well as a low risk of the paste solidifying and little variation in hardening time.

The dental curable composition of the present invention comprises a first agent containing an acidic group-containing polymerizable monomer (A), a polymerizable monomer (B) having no acidic group, an organic peroxide (C), a filler (D), and a ligand (G) containing a nitrogen atom, and a second agent containing a polymerizable monomer (B) having no acidic group, a filler (D), and an ascorbic acid compound (F), and substantially not containing a thiourea compound. The second agent substantially does not contain a thiourea compound. In addition, at least one of the first agent or the second agent contains a transition metal compound (E). Since the second agent substantially does not contain a thiourea compound, the adhesiveness to a precious metal is high, and by blending the ligand (G) containing a nitrogen atom in the first agent, the storage stability of the organic peroxide (C) contained in the first agent is improved, and even when a transition metal compound (E) is blended in the first agent, it is possible to provide a dental curable composition with high storage stability with little risk of solidification due to decomposition and little variation in hardening time.

First Agent The first agent in the dental curable composition of the present invention contains an acidic group-containing polymerizable monomer (A), a polymerizable monomer not containing an acidic group (B), an organic peroxide (C), a filler (D), and a ligand containing a nitrogen atom (G).

The acidic group-containing polymerizable monomer (A) is an essential component for the dental hardenable composition of the present invention to exhibit adhesiveness. The acidic group-containing polymerizable monomer (A) has the effect of demineralizing tooth tissue. The acidic group-containing polymerizable monomer (A) is a polymerizable monomer having at least one acidic group such as a phosphoric acid group, a phosphonic acid group, a pyrophosphoric acid group, a thiophosphoric acid group, a carboxylic acid group, or a sulfonic acid group, and having at least one polymerizable group such as an acryloyl group, a methacryloyl group, an acrylamide group, or a methacrylamide group. From the viewpoint of adhesiveness to tooth tissue, the acidic group-containing polymerizable monomer (A) is preferably monofunctional having one of an acryloyl group, a methacryloyl group, an acrylamide group, or a methacrylamide group as a polymerizable group. Specific examples include the following.

Examples of the phosphate group-containing polymerizable monomer include 2-(meth)acryloyloxyethyl dihydrogen phosphate, 3-(meth)acryloyloxypropyl dihydrogen phosphate, 4-(meth)acryloyloxybutyl dihydrogen phosphate, 5-(meth)acryloyloxypentyl dihydrogen phosphate, 6-(meth)acryloyloxyhexyl dihydrogen phosphate, 7-(meth)acryloyloxyheptyl dihydrogen phosphate, and 8-(meth)acryloyloxyoctyl dihydrogen phosphate. ester, 9-(meth)acryloyloxynonyl dihydrogen phosphate, 10-(meth)acryloyloxydecyl dihydrogen phosphate, 11-(meth)acryloyloxyundecyl dihydrogen phosphate, 12-(meth)acryloyloxydodecyl dihydrogen phosphate, 16-(meth)acryloyloxyhexadecyl dihydrogen phosphate, 20-(meth)acryloyloxyeicosyl dihydrogen phosphate, 2-(meth)acryloyloxyethyl phenyl hydrogen phosphate, 2- Phosphate group-containing monofunctional (meth)acrylate compounds such as (meth)acryloyloxyethyl-2-bromoethyl hydrogen phosphate, 2-(meth)acryloyloxyethyl-(4-methoxyphenyl)hydrogen phosphate, and 2-(meth)acryloyloxypropyl-(4-methoxyphenyl)hydrogen phosphate, as well as their acid chlorides, alkali metal salts, ammonium salts, and amine salts; bis[2-(meth)acryloyloxyethyl]hydrogen phosphate, bis[4-(meth)acryloyloxybutyl]hydrogen phosphate, and the like; Examples of such compounds include difunctional (meth)acrylate compounds containing a phosphate group, such as bis[6-(meth)acryloyloxyhexyl]hydrogenphosphate, bis[8-(meth)acryloyloxyoctyl]hydrogenphosphate, bis[9-(meth)acryloyloxynonyl]hydrogenphosphate, bis[10-(meth)acryloyloxydecyl]hydrogenphosphate, and 1,3-di(meth)acryloyloxypropyl dihydrogenphosphate, as well as their acid chlorides, alkali metal salts, ammonium salts, and amine salts.

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

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

Examples of thiophosphate group-containing polymerizable monomers include 2-(meth)acryloyloxyethyl dihydrogen thiophosphate, 3-(meth)acryloyloxypropyl dihydrogen thiophosphate, 4-(meth)acryloyloxybutyl dihydrogen thiophosphate, 5-(meth)acryloyloxypentyl dihydrogen thiophosphate, 6-(meth)acryloyloxyhexyl dihydrogen thiophosphate, 7-(meth)acryloyloxyheptyl dihydrogen thiophosphate, and 8-(meth)acryloyloxyoctyl dihydrogen thiophosphate. thiophosphate, 9-(meth)acryloyloxynonyl dihydrogen thiophosphate, 10-(meth)acryloyloxydecyl dihydrogen thiophosphate, 11-(meth)acryloyloxyundecyl dihydrogen thiophosphate, 12-(meth)acryloyloxydodecyl dihydrogen thiophosphate, 16-(meth)acryloyloxyhexadecyl dihydrogen thiophosphate, 20-(meth)acryloyloxyeicosyl dihydrogen thiophosphate, and their acid chlorides, alkali metal salts, and ammonium salts.

Examples of carboxylic acid group-containing polymerizable monomers include (meth)acrylic acid, 4-[2-[(meth)acryloyloxy]ethoxycarbonyl]phthalic acid, 4-(meth)acryloxyethyltrimellitic acid, 4-(meth)acryloyloxybutyloxycarbonylphthalic acid, 4-(meth)acryloyloxyhexyloxycarbonylphthalic acid, 4-(meth)acryloyloxyoctyloxycarbonylphthalic acid, 4-(meth)acryloyloxydecyloxycarbonylphthalic acid, and 4-(meth)acryloyloxydecyloxycarbonylphthalic acid. carbonylphthalic acid and their acid anhydrides; 5-(meth)acryloylaminopentylcarboxylic acid, 6-(meth)acryloyloxy-1,1-hexanedicarboxylic acid, 8-(meth)acryloyloxy-1,1-octanedicarboxylic acid, 10-(meth)acryloyloxy-1,1-decanedicarboxylic acid, 11-(meth)acryloyloxy-1,1-undecanedicarboxylic acid, their acid chlorides, alkali metal salts, ammonium salts, and amine salts.

Examples of sulfonic acid group-containing polymerizable monomers include 2-(meth)acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl (meth)acrylate, and acid chlorides, alkali metal salts, ammonium salts, and amine salts thereof.

Among the acidic group-containing polymerizable monomers (A), phosphate group-containing polymerizable monomers, pyrophosphate group-containing polymerizable monomers, and carboxylic acid group-containing polymerizable monomers are preferred because they exhibit superior adhesion to tooth structure, and phosphate group-containing polymerizable monomers and carboxylic acid group-containing polymerizable monomers are particularly preferred. Among them, phosphate group-containing (meth)acrylate-based monofunctional polymerizable monomers having an alkyl group with 6 to 20 carbon atoms or an alkylene group with 6 to 20 carbon atoms as the main chain in the molecule or carboxylic acid group-containing (meth)acrylate-based monofunctional polymerizable monomers having an alkylene group with 8 to 12 carbon atoms as the main chain in the molecule are more preferred, and phosphate group-containing (meth)acrylate-based monofunctional polymerizable monomers having an alkylene group with 8 to 12 carbon atoms as the main chain in the molecule are even more preferred. Furthermore, 10-methacryloyloxydecyl dihydrogen phosphate, 4-(meth)acryloxyethyl trimellitic acid and 4-(meth)acryloxyethyl trimellitic anhydride are preferred, and 10-methacryloyloxydecyl dihydrogen phosphate is most preferred.

The acidic group-containing polymerizable monomer (A) may be blended alone or in combination of two or more kinds. The content of the acidic group-containing polymerizable monomer (A) is not particularly limited as long as the effects of the present invention are achieved, but in terms of superior adhesion, the content is preferably in the range of 1 to 50 parts by mass, more preferably in the range of 2 to 25 parts by mass, and even more preferably in the range of 2 to 15 parts by mass, based on 100 parts by mass of the total amount of the polymerizable monomer components of the dental curable composition of the present invention. In this specification, "100 parts by mass of the total amount of the polymerizable monomer components of the dental curable composition" means the case where the total amount of the polymerizable monomers contained in the first agent and the polymerizable monomers contained in the second agent is converted to 100 parts by mass.

The polymerizable monomer (B) that does not contain an acidic group is a polymerizable monomer that undergoes a radical polymerization reaction in the presence of a polymerization initiator system to form a polymer. The polymerizable monomer that constitutes the polymerizable monomer (B) that does not contain an acidic group in the present invention is not limited to one type, and may be two or more types. Suitable examples of the polymerizable monomer (B) that does not contain an acidic group include the following hydrophilic polymerizable monomer (B-1) and hydrophobic polymerizable monomer (B-2).

Hydrophilic polymerizable monomer (B-1) refers to a polymerizable monomer having a solubility in water of 10% by mass or more at 25°C. Preferably, the solubility is 30% by mass or more, and more preferably, the monomer is soluble in water at any ratio at 25°C. The hydrophilic polymerizable monomer (B-1) promotes the penetration of the components of the dental hardenable composition into the tooth structure, and also penetrates into the tooth structure itself and adheres to the organic components (collagen) in the tooth structure. Examples of the hydrophilic polymerizable monomer (B-1) include monofunctional (meth)acrylic acid ester polymerizable monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate (hereinafter sometimes abbreviated as "HEMA"), 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 1,3-dihydroxypropyl (meth)acrylate, 2,3-dihydroxypropyl (meth)acrylate, and 2-((meth)acryloyloxy)ethyl trimethylammonium chloride; and bifunctional (meth)acrylic acid ester polymerizable monomers such as polyethylene glycol di(meth)acrylate (having 9 or more oxyethylene groups). From the viewpoint of adhesion to tooth tissue, 2-hydroxyethyl (meth)acrylate is preferred. In this specification, "(meth)acrylic" means acrylic and methacrylic, and the same applies to expressions such as "(meth)acryloyl" and "(meth)acrylate".

Hydrophobic polymerizable monomer (B-2) refers to a crosslinkable polymerizable monomer having a solubility in water at 25°C of less than 10% by mass. Examples of crosslinkable polymerizable monomer (B-2) include bifunctional polymerizable monomers of aromatic compounds, bifunctional polymerizable monomers of aliphatic compounds, and trifunctional or higher polymerizable monomers. Hydrophobic polymerizable monomer (B-2) improves the mechanical strength, handleability, etc. of the dental curable composition.

Examples of the aromatic compound-based bifunctional polymerizable monomer include aromatic di(meth)acrylates. Specific examples of aromatic bifunctional polymerizable monomers include 2,2-bis((meth)acryloyloxyphenyl)propane, 2,2-bis[4-(3-acryloyloxy-2-hydroxypropoxy)phenyl]propane, 2,2-bis[4-(3-methacryloyloxy-2-hydroxypropoxy)phenyl]propane (hereinafter sometimes abbreviated as "Bis-GMA"), 2,2-bis(4-(meth)acryloyloxyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxypolyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxydiethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytriethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytetra ...tetraethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytetraethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytetraethoxyphenyl)propane, 2,2- p) acryloyloxypentaethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxydipropoxyphenyl)propane, 2-(4-(meth)acryloyloxydiethoxyphenyl)-2-(4-(meth)acryloyloxyethoxyphenyl)propane, 2-(4-(meth)acryloyloxydiethoxyphenyl)-2-(4-(meth)acryloyloxytriethoxyphenyl)propane, 2-(4-(meth)acryloyloxydipropoxyphenyl)-2-(4-(meth)acryloyloxytriethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxypropoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxyisopropoxyphenyl)propane, 1,4-bis(2-(meth)acryloyloxyethyl)pyromellitate, and the like. Among these, 2,2-bis[4-(3-methacryloyloxy-2-hydroxypropoxy)phenyl]propane and 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane (average number of moles of ethoxy groups added: 2.6) (hereinafter sometimes abbreviated as "D-2.6E") are preferred.

Examples of aliphatic compound-based bifunctional polymerizable monomers include erythritol di(meth)acrylate, sorbitol di(meth)acrylate, mannitol di(meth)acrylate, pentaerythritol di(meth)acrylate, dipentaerythritol di(meth)acrylate, glycerol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate (hereinafter sometimes abbreviated as "TEGDMA"), propylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1, Examples of the polymerizable monomer include bifunctional (meth)acrylic acid ester polymerizable monomers such as 5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate, and 1,2-bis(3-methacryloyloxy-2-hydroxypropyloxy)ethane; and (meth)acrylamide polymerizable monomers such as N-methacryloyloxyethylacrylamide, N-methacryloyloxypropylacrylamide, N-methacryloyloxybutylacrylamide, N-(1-ethyl-(2-methacryloyloxy)ethyl)acrylamide, and N-(2-(2-methacryloyloxyethoxy)ethyl)acrylamide. Among these, glycerol dimethacrylate, triethylene glycol di(meth)acrylate, neopentyl glycol dimethacrylate, 2,2,4-trimethylhexamethylene bis(2-carbamoyloxyethyl) dimethacrylate, and 1,2-bis(3-methacryloyloxy-2-hydroxypropyloxy)ethane are preferred.

Examples of the trifunctional or higher polymerizable monomers include trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolmethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, N,N-(2,2,4-trimethylhexamethylene)bis[2-(aminocarboxy)propane-1,3-diol]tetramethacrylate, and 1,7-diacryloyloxy-2,2,6,6-tetraacryloyloxymethyl-4-oxaheptane.

Among the above-mentioned hydrophobic polymerizable monomers (B-2), Bis-GMA, D-2.6E, and TEGDMA are preferably used from the viewpoint of the mechanical strength and polymerization hardening property of the dental hardenable composition of the present invention.

The above-mentioned polymerizable monomer (B) not containing an acidic group (hydrophilic polymerizable monomer (B-1) and hydrophobic polymerizable monomer (B-2)) may be blended alone or in combination of two or more kinds. The content of the polymerizable monomer (B) not containing an acidic group is not particularly limited as long as the effects of the present invention are achieved. However, in terms of high penetration into tooth structure and excellent adhesion of the dental hardenable composition, and in terms of sufficient mechanical strength of the cured product, the content is preferably in the range of 50 to 99 parts by mass, more preferably in the range of 60 to 98 parts by mass, and even more preferably in the range of 70 to 95 parts by mass, based on 100 parts by mass of the total amount of the polymerizable monomer components in the dental hardenable composition of the present invention.

Examples of organic peroxides (C) include diacyl peroxides, peroxy esters, dialkyl peroxides, peroxy ketals, ketone peroxides, and hydroperoxides. Specific examples of diacyl peroxides include benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, and m-toluoyl peroxide. Specific examples of peroxy esters include t-butyl peroxybenzoate, bis(t-butylperoxy)isophthalate, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, t-butylperoxy-2-ethylhexanoate, and t-butylperoxyisopropyl carbonate. Specific examples of dialkyl peroxides include dicumyl peroxide, di-t-butyl peroxide, and lauroyl peroxide. Specific examples of peroxyketals include 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, etc. Specific examples of ketone peroxides include methyl ethyl ketone peroxide, cyclohexanone peroxide, methyl acetoacetate peroxide, etc. Specific examples of hydroperoxides include t-butyl hydroperoxide, cumene hydroperoxide, p-diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, etc.

Among the organic peroxides (C), hydroperoxides and peroxyesters are particularly preferred. Among the hydroperoxides, t-butyl hydroperoxide, cumene hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide are preferably used. Also, among the peroxyesters, t-butyl peroxybenzoate is preferably used.

The organic peroxide (C) may be used alone or in combination of two or more. From the viewpoints of hardening, mechanical strength of the hardened product, and adhesion to tooth structure, the content of the organic peroxide (C) is preferably in the range of 0.01 to 10 parts by mass, more preferably in the range of 0.1 to 5 parts by mass, and even more preferably in the range of 0.5 to 3 parts by mass, per 100 parts by mass of the total amount of the polymerizable monomer components in the dental hardenable composition.

The first agent in the dental hardenable composition of the present invention is in a paste form and contains a filler (D) to obtain sufficient workability of the composition and sufficient X-ray opacity and mechanical strength of the cured product.

As the filler (D), any filler can be used as long as it does not impair the effects of the present invention, and examples of such fillers include inorganic fillers, organic fillers, and composite fillers of inorganic fillers and organic fillers. The filler (D) may be blended alone or in combination of two or more types. The average particle size of the filler (D) is preferably 0.001 to 10 μm, and more preferably 0.001 to 5 μm.

Examples of inorganic filler materials include quartz, silica, alumina, silica-titania, silica-titania-barium oxide, silica-zirconia, silica-alumina, lanthanum glass, borosilicate glass, soda glass, barium glass, strontium glass, glass ceramic, aluminosilicate glass, barium boroaluminosilicate glass, strontium boroaluminosilicate glass, fluoroaluminosilicate glass, calcium fluoroaluminosilicate glass, strontium fluoroaluminosilicate glass, barium fluoroaluminosilicate glass, strontium calcium fluoroaluminosilicate glass, ytterbium oxide, and silica-coated ytterbium fluoride. In terms of ease of handling, fine silica particles with an average particle size of 0.001 to 0.1 μm are preferably used as inorganic fillers. Commercially available products include "Aerosil (registered trademark) OX50", "Aerosil (registered trademark) 50", "Aerosil (registered trademark) 200", "Aerosil (registered trademark) 380", "Aerosil (registered trademark) R972", "Aerosil (registered trademark) 130", and "AEROXIDE (registered trademark) Alu C" (all of which are product names manufactured by Nippon Aerosil Co., Ltd.). In the present invention, when the inorganic filler is surface-treated as described below, the average particle size of the inorganic filler means the average particle size before the surface treatment.

Examples of organic fillers include polymethyl methacrylate, polyethyl methacrylate, polyfunctional methacrylate polymers, polyamide, polystyrene, polyvinyl chloride, chloroprene rubber, nitrile rubber, and styrene-butadiene rubber.

Examples of composite fillers made of inorganic and organic fillers include those in which inorganic fillers are dispersed in organic fillers, and inorganic/organic composite fillers in which inorganic fillers are coated with various polymers.

Among the above fillers (D), from the viewpoint of the transparency and mechanical strength of the resulting dental hardenable composition, inorganic fillers such as quartz, silica, silica-zirconia, barium glass, ytterbium oxide, and silica-coated ytterbium fluoride are preferred, with quartz, silica, silica-zirconia, barium glass, and silica-coated ytterbium fluoride being more preferred.

In the first agent, a combination of either quartz or silica and silica-coated ytterbium fluoride is more preferably used as the filler (D) from the viewpoint that the interaction with the acidic group-containing polymerizable monomer (A) is small and the change in paste properties is small even when stored for a long period of time. In this case, the X-ray contrast property of the obtained first agent can be adjusted by appropriately adjusting the content of silica-coated ytterbium fluoride.

To improve curability, mechanical strength, and handling, the filler (D) may be surface-treated with a known surface treatment agent such as a silane coupling agent before use. Examples of surface treatment agents include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, vinyltri(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, etc.

The average particle size (average primary particle size) can be determined by laser diffraction scattering or electron microscope observation of the particles. Specifically, the laser diffraction scattering method is convenient for measuring the particle size of particles of 0.1 μm or more, and the electron microscope observation is convenient for measuring the particle size of ultrafine particles of less than 0.1 μm. In the present invention, 0.1 μm is a value measured by the laser diffraction scattering method. For example, the laser diffraction scattering method can be performed using a 0.2% sodium hexametaphosphate aqueous solution as a dispersion medium and a laser diffraction type particle size distribution measuring device (SALD-2300, manufactured by Shimadzu Corporation) on a volume basis. For electron microscope observation, a scanning electron microscope (SU3800, S-4000, etc., manufactured by Hitachi High-Technologies Corporation) can be used. Electron microscope observation can be performed by taking an electron microscope photograph of the particles and measuring the particle size of the particles (200 or more) observed within a unit field of view of the photograph using image analysis particle size distribution measurement software (Mac-View (Mountec Co., Ltd.)). In this case, the particle size is calculated as the arithmetic mean value of the longest and shortest lengths of the particles, and the average primary particle size is calculated from the number of particles and their particle size.

The content of the filler (D) contained in the first agent is not particularly limited as long as the effects of the present invention are achieved, but is preferably in the range of 50 to 350 parts by mass, and more preferably in the range of 100 to 300 parts by mass, relative to 100 parts by mass of the total amount of the polymerizable monomer components contained in the first agent of the dental curable composition of the present invention. When silica-coated ytterbium fluoride is used as part of the filler (D) in the first agent, from the viewpoint of X-ray contrast properties, the content of silica-coated ytterbium fluoride is preferably in the range of 2 to 40 parts by mass, more preferably in the range of 5 to 30 parts by mass, and even more preferably in the range of 10 to 25 parts by mass, relative to 100 parts by mass of the total amount of the first agent.

The dental hardenable composition of the present invention contains an organic peroxide (C) in the first agent and an ascorbic acid compound (F) in the second agent as a polymerization initiator system, at least one of the first agent or the second agent contains a transition metal compound (E), and the first agent further contains a ligand (G) containing a nitrogen atom. The ligand (G) containing a nitrogen atom acts as a polymerization accelerator in the dental hardenable composition of the present invention, improving adhesion to dentin, and contributing to reducing the risk of solidification of the first agent during long-term storage and stabilizing the hardening time.

The nitrogen-containing ligand (G) is a ligand having one or more nitrogen atoms in the molecule, preferably a ligand having two or more nitrogen atoms in the molecule, and more preferably a multidentate ligand having two or more nitrogen atoms in the molecule. Examples of the nitrogen-containing ligand (G) include a compound represented by the following general formula (1), a compound represented by general formula (2), a multidentate ligand containing a nitrogen-containing heterocycle (3), and tertiary aliphatic amines having one amino group.

A preferred embodiment is a paste-like two-component dental hardenable composition in which the first agent contains a ligand (G) containing a nitrogen atom, and the ligand (G) containing a nitrogen atom is at least one compound selected from the group consisting of a compound represented by the following general formula (1), a compound represented by the following general formula (2), and a multidentate ligand containing a nitrogen-containing heterocycle (3).

The reason why multidentate ligands (G) containing nitrogen atoms are more effective is believed to be as follows. That is, it is thought that the nitrogen-containing ligand (G) contributes to the stabilization of the organic peroxide (C) by forming a salt with the acidic group-containing polymerizable monomer (A). In the first agent paste, the movement of the nitrogen-containing ligand (G) molecules is restricted, and therefore the greater the number of nitrogen atoms contained per molecule, the higher the probability of contact with the acidic group-containing polymerizable monomer (A), making the reaction more physicochemically favorable.

R ₁ R ₂ N-X ₁ -NR ₃ R ₄ (1)
(R ₁ to R ₄ each independently represent an alkyl group which may have a substituent, and X ₁ represents a divalent aliphatic group which may have a substituent.)

( _R5 , _R6 , and _R7 each independently represent an alkyl group which may have a substituent, _X2 and _X3 each independently represent a divalent aliphatic group which may have a substituent and which may contain an oxygen atom and/or a nitrogen atom, m and n each independently represent an integer of 1 or more, Y represents a monoalkylamino group or a dialkylamino group which may have a substituent, and any two or more of _R5 , _R6 , _R7 , and Y may be bonded together to form a ring. When a plurality of _R6 , _R7 , _X2 , and _X3 are present, they may be the same or different.)

The alkyl group of R ₁ to R ₄ which may have a substituent may be either linear or branched. The number of carbon atoms of the alkyl group of R ₁ to R ₄ is not particularly limited, and is preferably 1 to 12, more preferably 1 to 6, further preferably 1 to 4, and particularly preferably 1 to 3. Examples of the alkyl group of _{R 1} to R ₄ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a neopentyl group, an n-hexyl group, an isohexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, and an n-dodecyl group. The alkyl group of _{R 1} to R ₄ may be unsubstituted. Examples of the substituents on the alkyl groups of R ₁ to R ₄ include halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms), hydroxy groups, alkoxy groups having 1 to 6 carbon atoms, dialkylamino groups all of which have an alkyl group having 1 to 6 carbon atoms, and amino groups.

R ₁ to R ₄ may be the same or different, and may be, for example, some of R ₁ to R ₄ (for example, R ₁ and R ₃ ) being the same alkyl group.

The divalent aliphatic group of X ₁ , which may have a substituent, may be either linear or branched. The number of carbon atoms of the divalent aliphatic group is preferably 1 to 20, more preferably 1 to 16, still more preferably 1 to 12, and particularly preferably 1 to 8. Examples of the divalent aliphatic group include an alkylene group, an alkenylene group, and an alkynylene group, and an alkylene group is preferred. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a methylpropylene group, a dimethylpropylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, a decamethylene group, an undecamethylene group, and a dodecamethylene group. Examples of the substituent of the divalent aliphatic group of X ₁ include the same as the substituent of the alkyl group of R ₁ to R ₄ .

One preferred embodiment is a paste-like two-component dental curable composition in which the ligand (G) containing a nitrogen atom is a compound represented by general formula (1), in which R ₁ to R ₄ each independently represent a linear or branched alkyl group having 1 to 6 carbon atoms which may have a substituent, and X ₁ is a compound representing a linear or branched alkylene group having 1 to 8 carbon atoms which may have a substituent.

The alkyl groups which may have a substituent of R ₅ , R ₆ , and R ₇ are the same as the alkyl groups which may have a substituent of R ₁ to R _4. The number of carbon atoms of the monoalkylamino group (-NHR ^a (R ^a represents an alkyl group)) and dialkylamino group (-NR ^b R ^c (R ^b and R ^c represent an alkyl group)) of Y is not particularly limited, and is preferably 1 to 12, more preferably 1 to 6, further preferably 1 to 4, and particularly preferably 1 to 3. The alkyl groups of the monoalkylamino group and dialkylamino group of Y include those which may have a substituent of R ₁ to R ₄ and satisfy the above carbon number. As the dialkylamino group, each alkyl group may have the above carbon number. Examples of the monoalkylamino group which may have a substituent of Y include a methylamino group, an ethylamino group, a propylamino group, an isopropylamino group, a butylamino group, an isobutylamino group, a t-butylamino group, a pentylamino group, and a hexylamino group. Examples of the dialkylamino group of Y which may have a substituent include a dimethylamino group, a diethylamino group, a dipropylamino group, a diisopropylamino group, a dibutylamino group, a diisobutylamino group, a dipentylamino group, a dihexylamino group, and an ethylmethylamino group. The alkyl group of the monoalkylamino group and the dialkylamino group of Y may be substituted with a substituent. Examples of the substituent include the same as the substituent of the alkyl group of R ₁ to R ₄ .

The divalent aliphatic groups of _X2 and _X3 are similar to the divalent aliphatic groups of _X1 which may have a substituent, except that they may contain an oxygen atom and/or a nitrogen atom. _X2 and _X3 are
They may be the same or different. The number of oxygen atoms and nitrogen atoms contained in the divalent aliphatic groups of _X2 and _X3 is 1 or more, and may be 2 or more. When the divalent aliphatic groups of _X2 and _X3 contain a nitrogen atom, the divalent aliphatic groups of _X2 and _X3 may contain -NH- ^{or -NRd} ( ^Rd represents an alkyl group having 1 to 6 carbon atoms)-.

m and n each independently represent an integer of 1 or more, preferably an integer of 1 to 8, more preferably an integer of 1 to 6, further preferably an integer of 1 to 5, and particularly preferably an integer of 1 to 3. m and n may be the same or different. When m and n are 2 or more and a plurality of _X2 and _X3 are present, _X2 and _X3 may be the same or different.

Any two or more of R ₅ , R ₆ , R ₇ and Y may be combined to form a ring.
For example, R ₅ , R ₆ , or R ₇ may be combined with Y to form a ring. R ₅ and Y, and R ₆ and R ₇ may be combined with each other to form a ring, and the compound may have two rings. Furthermore, the nitrogen atom of the amino group of Y and R ₅ may be combined with each other to form a ring. The ring may contain an oxygen atom and/or a nitrogen atom. Furthermore, in one embodiment, the compound represented by general formula (2) may be a compound having a bicyclo ring. For example, in another embodiment, the compound represented by general formula (2) may be a compound having a bicyclo ring, which has a ring formed by Y and R ₅ combined with each other and a ring formed by R ₆ or R ₇ combined with Y.

In a preferred embodiment, R ₅ , R ₆ and R ₇ are linear or branched alkyl groups having 1 to 6 carbon atoms which may have a substituent.

Another preferred embodiment is a paste-like two-component dental curable composition in which the ligand (G) containing a nitrogen atom is a compound represented by general formula (2), and in the compound represented by general formula (2), R ₅ , R ₆ , and R ₇ each represent a linear or branched alkyl group having 1 to 6 carbon atoms which may have a substituent, the divalent aliphatic groups of X ₂ and X ₃ each represent an alkylene group which does not contain an oxygen atom or a nitrogen atom, m and n each independently represent an integer of 1 or more, Y represents a monoalkylamino group or a dialkylamino group which may have a substituent, and R ₅ , R ₆ , or R ₇ together with Y form a ring.

In another preferred embodiment, the nitrogen atom-containing ligand (G) is represented by the general formula (2):
and n is 2, and the compound as a whole contains 4 nitrogen atoms.

The multidentate ligand (3) containing a nitrogen-containing heterocycle contains a heterocycle containing a 5- or 6-membered ring containing a nitrogen atom, has two or more nitrogen atoms in the molecule, and represents a bidentate or more ligand compound. The number of nitrogen atoms contained in the molecule of the multidentate ligand (3) is two or more, and may be three or more. The number of heterocycles contained in the multidentate ligand (3) may be one or more. Examples of the nitrogen-containing heterocycle include nitrogen-containing 5-membered rings such as pyrrole rings, pyrazole rings, and imidazole rings; nitrogen-containing 6-membered rings such as pyridine rings, pyrazine rings, pyridazine rings, piperazine rings, pyrimidine rings, and triazine rings. The nitrogen-containing heterocycle may be a condensed ring of the 5- or 6-membered ring containing the nitrogen atom and another ring (e.g., an aromatic ring), or a condensed ring of 5- or 6-membered rings containing nitrogen atoms. Examples of the condensed ring of a 5- or 6-membered ring containing a nitrogen atom and an aromatic ring include a quinoline ring, an isoquinoline ring, an indole ring, a benzimidazole ring, and a benzotriazole ring. The multidentate ligand (3) may contain a heterocyclic ring containing a 5- or 6-membered ring containing a nitrogen atom, and examples of the multidentate ligand (3) include a ligand compound containing a condensed ring such as an indole ring, a benzimidazole ring, or a benzotriazole ring, and a heterocyclic ring containing a 5- or 6-membered ring containing a nitrogen atom. The multidentate nature of the multidentate ligand (3) may be two or more dentates, and may be three or four dentates, etc.

Examples of compounds represented by the above general formula (1) include bidentate polydentate amine compounds such as N,N,N',N'-tetramethylethylenediamine (hereinafter sometimes abbreviated as "TMEDA"), N,N,N',N'-tetramethylpropylenediamine (hereinafter sometimes abbreviated as "TMPDA"), N,N,N',N'-tetramethyl-1,4-diaminobutane, N,N,N',N'-tetraethylethylenediamine (hereinafter sometimes abbreviated as "TEEDA"), and N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine.

Examples of the compound represented by the above general formula (2) include compounds having a cyclo ring such as 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane; compounds having a bicyclo ring such as 4,11-dimethyl-1,4,8,11-tetraazabicyclohexadecane; compounds having a 2,5,9,12-tetramethyl-2,5,9,12-tetraazatetradecane, 2,6,9,13-tetramethyl-2,6,9,13-tetraazatetradecane, 2,5,8 Examples of suitable amine compounds include polydentate amine compounds such as compounds having no ring, such as N,12-tetramethyl-2,5,8,12-tetraazatetradecane, N,N,N,N',N'',N''-pentamethyldiethylenetriamine (hereinafter sometimes abbreviated as "PMDETA"), hexamethyltris(2-aminoethyl)amine, N,N-bis(2-dimethylaminoethyl)-N,N'-dimethylethylenediamine (hereinafter sometimes abbreviated as "HMTETA"), and tris[2-(dimethylamino)ethyl]amine (hereinafter sometimes abbreviated as "Me ₆ TREN").

Examples of the polydentate ligand (3) containing a nitrogen-containing heterocycle include polydentate ligands having one nitrogen-containing heterocycle, such as N-(n-propyl)pyridylmethanimine and N-(n-octyl)pyridylmethanimine; 2,2-bipyridine, 4,4'-di-(5-nonyl)-2,2'-bipyridine, N-propyl-N,N-di(2-pyridylmethyl)amine, N',N''-dimethyl-N',N''-bis(pyridine-2-yl)amine, and N-(n-octyl)pyridylmethanimine. N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine, 2,4,6-tri(2-pyridyl)-
Examples include multidentate ligands having two or more nitrogen-containing heterocycles such as 1,3,5-triazine.

Examples of tertiary aliphatic amines having one amino group include N-methyldiethanolamine, trimethylamine, triethylamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-n-butyldiethanolamine, N-lauryldiethanolamine, triethanolamine, 2-(dimethylamino)ethyl(meth)acrylate, N-methyldiethanolamine di(meth)acrylate, N-ethyldiethanolamine di(meth)acrylate, triethanolamine mono(meth)acrylate, triethanolamine di(meth)acrylate, and triethanolamine tri(meth)acrylate.

Among the above-mentioned nitrogen atom-containing ligands (G), at least one compound selected from the group consisting of compounds represented by general formula (1), compounds represented by general formula (2), and nitrogen-containing heterocycle-containing polydentate amines (3) is more preferred because it is excellent at reducing the risk of the first agent solidifying during long-term storage, and in particular, the compounds represented by general formula (1) and general formula (2) are even more preferred because they are more excellent at stabilizing the curing time.

In addition, the mixing ratio (mass ratio) of the acidic group-containing polymerizable monomer (A) to the nitrogen atom-containing ligand (G) in the first agent is preferably 40:1 to 2:1, more preferably 30:1 to 4:1, and even more preferably 20:1 to 5:1.

The nitrogen atom-containing ligand (G) may be used alone or in combination of two or more kinds. From the viewpoints of hardening property, mechanical strength of the hardened product, and adhesion to tooth structure, the content of the nitrogen atom-containing ligand (G) is preferably in the range of 0.05 to 10 parts by mass, more preferably in the range of 0.1 to 8 parts by mass, and even more preferably in the range of 0.5 to 5 parts by mass, relative to 100 parts by mass of the total amount of the polymerizable monomer components in the dental hardenable composition.

One preferred embodiment is a two-component dental hardenable composition in the form of a paste, in which the first component does not contain a transition metal compound (E), because the risk of the paste solidifying is low and the storage stability is excellent. Examples of the transition metal compound (E) include copper compounds and vanadium compounds.

Another preferred embodiment is a paste-like two-component dental hardenable composition in which the first component contains a transition metal compound (E) from the viewpoint of storage stability.

Second Agent The second agent in the dental hardenable composition of the present invention contains a polymerizable monomer (B) not containing an acidic group, a filler (D), and an ascorbic acid compound (F), and is substantially free of a thiourea compound.

The polymerizable monomer (B) not containing an acidic group in the second agent is the same in type and content as the polymerizable monomer (B) not containing an acidic group used in the first agent.

In a preferred embodiment, from the viewpoint of further reducing the variation in the curing time, the second agent is a paste-like two-component dental curable composition that does not contain the acidic group-containing polymerizable monomer (A).

Examples of the filler (D) in the second agent include the same filler (D) used in the first agent.

As in the case of use in the first agent, the filler (D) may be surface-treated in advance with a known surface treatment agent such as a silane coupling agent to improve curability, mechanical strength, and handleability. Examples of the surface treatment agent include the same silane coupling agents as those exemplified for the first agent.

In the second agent, from the viewpoint of the transparency and mechanical strength of the dental hardenable composition obtained, quartz, silica, silica-zirconia, barium glass, and silica-coated ytterbium fluoride are preferred as the filler (D). Furthermore, from the viewpoint of X-ray contrast, a combination of at least one selected from the group consisting of quartz, silica, and silica-zirconia with silica-coated ytterbium fluoride, or barium glass is more preferably used.

The content of the filler (D) contained in the second agent is not particularly limited as long as the effects of the present invention are achieved, but is preferably in the range of 50 to 350 parts by mass, and more preferably in the range of 100 to 300 parts by mass, relative to 100 parts by mass of the total amount of the polymerizable monomer components contained in the second agent of the dental hardenable composition of the present invention.

Examples of the ascorbic acid compound (F) include salts, esters, and ethers of ascorbic acid. Among these, salts and esters of ascorbic acid are preferred.

Salts of ascorbic acid include sodium L-ascorbate, calcium L-ascorbate, potassium ascorbate, and stereoisomers thereof (e.g., sodium isoascorbate, etc.). Of these, sodium L-ascorbate is preferred.

Esters of ascorbic acid include those formed by reacting one or more of the hydroxy groups of ascorbic acid with a carboxylic acid. Suitable examples of carboxylic acids include fatty acids such as saturated or unsaturated fatty acids having 6 to 30 carbon atoms, such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoleelaidic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexaenoic acid. The number of carbon atoms of the fatty acid is preferably 10 to 28, more preferably 12 to 26, and even more preferably 14 to 24. Among these, esters of stearic acid and ascorbic acid, and esters of palmitic acid and ascorbic acid (ascorbyl palmitate) are particularly suitable.

Examples of ethers of ascorbic acid include ethyl ether ascorbate and cetyl ether ascorbate.

Ascorbic acid compounds (F) may be used alone or in combination of two or more. From the viewpoints of hardening, mechanical strength of the hardened product, and adhesion to tooth structure, the content of ascorbic acid compounds (F) is preferably in the range of 0.01 to 8 parts by mass, more preferably in the range of 0.1 to 5 parts by mass, and even more preferably in the range of 0.3 to 3 parts by mass, per 100 parts by mass of the total amount of the polymerizable monomer components in the dental hardenable composition.

The ascorbic acid compound (F) is blended in the second agent from the viewpoint of storage stability. The ascorbic acid compound (F) may be dissolved in the second agent or may be dispersed in the form of a powder in the composition of the second agent.

When the ascorbic acid compound (F) is dispersed as a powder, if the average particle size is too large, the operability or curability is likely to decrease, so the average particle size is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less.

The average particle size of the powder of ascorbic acid compound (F) can be calculated as the volume average particle size after performing image analysis using image analysis type particle size distribution measurement software (Mac-View; manufactured by Mountec Co., Ltd.) based on electron micrographs of 100 or more particles.

When the ascorbic acid compound (F) is dispersed in powder form, the particle shape may be, but is not limited to, various shapes such as spherical, needle-like, plate-like, and crushed. The ascorbic acid compound (F) can be prepared by a conventional method such as a pulverization method, a freeze-drying method, or a reprecipitation method, and the pulverization method and the freeze-drying method are preferred from the viewpoint of the average particle size of the resulting powder.

The dental hardenable composition of the present invention is substantially free of thiourea compounds. In the present invention, the content of the thiourea compound is preferably less than 0.1 mass%, more preferably less than 0.01 mass%, even more preferably less than 0.001 mass%, and particularly preferably 0 mass%, based on the total amount of the dental hardenable composition. When the thiourea compound is equal to or less than the lower limit, the dental hardenable composition is likely to have excellent adhesion to precious metals. The thiourea compound is not particularly limited, and examples thereof include ethylene thiourea, 4,4-dimethylethylene thiourea, N,N'-dimethyl thiourea, N,N'-diethyl thiourea, N,N'-di-n-propyl thiourea, dicyclohexyl thiourea, trimethyl thiourea, triethyl thiourea, tri-n-propyl thiourea, tricyclohexyl thiourea, tetramethyl thiourea, tetraethyl thiourea, tetra-n-propyl thiourea, dicyclohexyl thiourea, tetracyclohexyl thiourea, N-acetyl thiourea, N-benzoyl thiourea, diphenyl thiourea, pyridyl thiourea, and salts thereof (hydrochloride, sulfonate, complex salt, etc.).

At least one of the first agent and the second agent contains a transition metal compound (E). The transition metal compound (E) is not particularly limited, but examples thereof include copper compounds and vanadium compounds.

Examples of copper compounds include copper(II) carboxylates, β-diketone copper(II), β-ketoester copper(II), copper alkoxides, copper dithiocarbamate, and salts of copper and inorganic acids. Examples of copper(II) carboxylates include copper(II) citrate, copper(II) acetate, copper(II) phthalate, copper(II) tartrate, copper(II) oleate, copper(II) octylate, copper(II) octenate, copper(II) naphthenate, copper(II) methacrylate, and copper(II) 4-cyclohexylbutyrate. Examples of copper(II) diketones include copper(II) acetylacetone, copper(II) trifluoroacetylacetone, copper(II) hexafluoroacetylacetone, copper(II) 2,2,6,6-tetramethyl-3,5-heptanedionato, and copper(II) benzoylacetone. Examples of copper(II) β-ketoesters include copper(II) ethyl acetoacetate. Examples of copper alkoxides include copper(II) methoxide, copper(II) ethoxide, copper(II) isopropoxide, copper(II) 2-(2-butoxyethoxy)ethoxide, and copper(II) 2-(2-methoxyethoxy)ethoxide. Examples of copper dithiocarbamate include copper(II) dimethyldithiocarbamate. Examples of salts of copper and inorganic acids include copper(II) nitrate, copper(II) bromide, and copper(II) chloride. These may be used alone or in combination of two or more. Among these, from the viewpoint of solubility and reactivity with polymerizable monomers, copper(II) carboxylate, copper(II) β-diketone, and copper(II) β-ketoester are preferred, and copper(II) acetate and copper(II) acetylacetonate are more preferred.

The vanadium compound is preferably a tetravalent and/or pentavalent vanadium compound. Examples of the tetravalent and/or pentavalent vanadium compound include divanadium(IV) tetroxide, vanadyl acetylacetonate(IV), vanadium oxide stearate(IV), oxovanadium(IV) oxalate, vanadyl(IV) sulfate, vanadium naphthenate, vanadium benzoylacetonate, bis(maltolato)oxovanadium(IV), oxobis(1-phenyl-1,3-butanedionato)vanadium(IV), pentavalent vanadium(IV), and the like. Examples of the vanadium compound include vanadium(V) oxide, vanadium(V) oxytriisopropoxide, sodium metavanadate(V), and ammonium metavanadate(V), and among these, vanadium acetylacetonate, vanadyl acetylacetonate(IV), and bis(maltolato)oxovanadium(IV) are preferred from the viewpoint of adhesion, etc., and vanadyl acetylacetonate(IV) and bis(maltolato)oxovanadium(IV) are preferred. The vanadium compound may be used alone or in combination of two or more.

The transition metal compound (E) may be used alone or in combination of two or more. The transition metal compound is preferably used in the second agent from the viewpoint of storage stability, and the content thereof is preferably in the range of 0.0001 to 1 part by mass, more preferably in the range of 0.0005 to 0.5 parts by mass, and even more preferably in the range of 0.001 to 0.3 parts by mass, relative to 100 parts by mass of the total amount of the polymerizable monomer components in the dental hardenable composition from the viewpoints of hardenability, mechanical strength of the hardened product, and adhesion to tooth structure.

Next, we will explain the optional components of the dental hardenable composition of the present invention.

The dental curable composition of the present invention contains a redox-type polymerization initiator, but in order to make it a dual-cure composition that also initiates polymerization by light irradiation, a conventionally known photopolymerization initiator may be further blended into at least one of the first and second agents as a component separate from the above-mentioned polymerization initiator system.

Photopolymerization initiators include α-diketones, ketals, thioxanthones, (bis)acylphosphine oxides, and α-aminoacetophenones.

Examples of α-diketones include dl-camphorquinone (commonly known as "CQ"), benzil, and 2,3-pentanedione.

Examples of ketals include benzyl dimethyl ketal and benzyl diethyl ketal.

Examples of thioxanthones include 2-chlorothioxanthone and 2,4-diethylthioxanthone.

Among the (bis)acylphosphine oxides, examples of the acylphosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,3,5,6-tetramethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylmethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, benzoylbis(2,6-dimethylphenyl)phosphine oxide, water-soluble acylphosphine oxide compounds disclosed in JP-B-3-57916, and salts thereof (for example, sodium salts, potassium salts, ammonium salts), and the like. Examples of bisacylphosphine oxides include bis(2,4,6-trimethylbenzoyl)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, dibenzoylphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)phenylphosphine oxide, tris(2,4-dimethylbenzoyl)phosphine oxide, tris(2-methoxybenzoyl)phosphine oxide, and salts thereof (e.g., sodium salts, potassium salts, ammonium salts), and the like. Among these (bis)acylphosphine oxides, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylmethoxyphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoylphenylphosphine oxide sodium salt are preferred.

Examples of α-aminoacetophenones include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-benzyl-2-diethylamino-1-(4-morpholinophenyl)-1-butanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-propanone, 2-benzyl-2-diethylamino-1-(4-morpholinophenyl)-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-pentanone, and 2-benzyl-2-diethylamino-1-(4-morpholinophenyl)-1-pentanone.

The photopolymerization initiator may be used alone or in combination of two or more kinds. The content of the photopolymerization initiator is not particularly limited, but from the viewpoint of the curability of the obtained dental curable composition, it is preferably 0.001 to 10 parts by mass, more preferably 0.005 to 5 parts by mass, and even more preferably 0.01 to 3 parts by mass, relative to 100 parts by mass of the total amount of the polymerizable monomer components.

In addition, to enhance photocurability, a photopolymerization initiator may be used in combination with a polymerization accelerator for the photopolymerization initiator. Examples of polymerization accelerators for the photopolymerization initiator include tertiary amines, aldehydes, thiol compounds, and triazine compounds substituted with a trihalomethyl group.

Examples of tertiary amines include N,N-dimethylaniline, N,N-dimethyl-p-toluidine, N,N-dimethyl-m-toluidine, N,N-diethyl-p-toluidine, N,N-dimethyl-3,5-dimethylaniline, N,N-dimethyl-3,4-dimethylaniline, N,N-dimethyl-4-ethylaniline, N,N-dimethyl-4-isopropylaniline, N,N-dimethyl-4-t-butylaniline, N,N-dimethyl-3,5-di-t-butylaniline, N,N-bis(2-hydroxyethyl)-3,5-dimethylaniline, N,N-bis(2-hydroxyethyl)-p-toluidine, N,N-bis(2-hydroxyethyl)-3,4-dimethylaniline, N,N-bis(2-hydroxyethyl)-4-ethylaniline, and N,N-bis(2-hydroxyethyl)-4-isopropylaniline. Aromatic tertiary amines such as aniline, N,N-bis(2-hydroxyethyl)-4-t-butylaniline, N,N-bis(2-hydroxyethyl)-3,5-diisopropylaniline, N,N-bis(2-hydroxyethyl)-3,5-di-t-butylaniline, 4-(N,N-dimethylamino)benzoic acid n-butoxyethyl, 4-(N,N-dimethylamino)benzoic acid 2-(methacryloyloxy)ethyl, 4-(N,N-dimethylamino)benzoic acid ethyl, 4-(N,N-dimethylamino)benzoic acid butyl, and 4-(N,N-dimethylamino)benzophenone; N-methyldiethanolamine, trimethylamine, triethylamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-n-butyldiethanolamine, N-lauryldiethanolamine, triethanolamine, 2-
Examples of the tertiary amine include aliphatic tertiary amines such as (dimethylamino)ethyl (meth)acrylate, N-methyldiethanolamine di(meth)acrylate, N-ethyldiethanolamine di(meth)acrylate, triethanolamine mono(meth)acrylate, triethanolamine di(meth)acrylate, and triethanolamine tri(meth)acrylate. However, only when the first agent contains a polymerization accelerator for a photopolymerization initiator and the polymerization accelerator is an aliphatic tertiary amine, the aliphatic tertiary amine belongs to the ligand (G) containing a nitrogen atom and is excluded from the polymerization accelerator for a photopolymerization initiator.

Examples of aldehydes include terephthalaldehyde and benzaldehyde derivatives. Examples of benzaldehyde derivatives include dimethylaminobenzaldehyde, p-methoxybenzaldehyde, p-ethoxybenzaldehyde, and p-n-octyloxybenzaldehyde. Examples of thiol compounds include 3-mercaptopropyltrimethoxysilane, 2-mercaptobenzoxazole, decanethiol, and thiobenzoic acid. As triazine compounds substituted with trihalomethyl groups, any known s-triazine compound having at least one trihalomethyl group such as a trichloromethyl group or a tribromomethyl group can be used without any restrictions.

The polymerization accelerator for the photopolymerization initiator may be used alone or in combination of two or more kinds. The content of the polymerization accelerator for the photopolymerization initiator is not particularly limited, but from the viewpoint of the curability of the obtained dental curable composition, it is preferably 0.01 to 2 parts by mass, more preferably 0.02 to 1.5 parts by mass, and even more preferably 0.05 to 0.8 parts by mass, relative to 100 parts by mass of the total amount of the polymerizable monomer components. When the content of the polymerization accelerator for the photopolymerization initiator is equal to or more than the lower limit, photopolymerization is easily progressed, while when the content of the polymerization accelerator for the photopolymerization initiator is equal to or less than the upper limit, discoloration of the cured product of the dental curable composition is easily suppressed within an acceptable range.

The dental hardenable composition of the present invention may contain a polymerization accelerator for other chemical polymerization initiators. Examples of polymerization accelerators for other chemical polymerization initiators include sulfinic acid and its salts, sulfites, hydrogen sulfites, borate compounds, barbituric acid compounds, etc. Each of these may be used alone or in combination of two or more.

Examples of sulfinic acid and its salts include p-toluenesulfinic acid, sodium p-toluenesulfinate, potassium p-toluenesulfinate, lithium p-toluenesulfinate, calcium p-toluenesulfinate, benzenesulfinic acid, sodium benzenesulfinate, potassium benzenesulfinate, lithium benzenesulfinate, calcium benzenesulfinate, 2,4,6-trimethylbenzenesulfinic acid, sodium 2,4,6-trimethylbenzenesulfinate, potassium 2,4,6-trimethylbenzenesulfinate, lithium 2,4,6-trimethylbenzenesulfinate, and 2,4,6-trimethylbenzenesulfinate. Examples of suitable sulfinates include calcium benzenesulfinate, 2,4,6-triethylbenzenesulfinic acid, sodium 2,4,6-triethylbenzenesulfinate, potassium 2,4,6-triethylbenzenesulfinate, lithium 2,4,6-triethylbenzenesulfinate, calcium 2,4,6-triethylbenzenesulfinate, 2,4,6-triisopropylbenzenesulfinic acid, sodium 2,4,6-triisopropylbenzenesulfinate, potassium 2,4,6-triisopropylbenzenesulfinate, lithium 2,4,6-triisopropylbenzenesulfinate, and calcium 2,4,6-triisopropylbenzenesulfinate. Among these, sodium benzenesulfinate, sodium p-toluenesulfinate, 2,4,6-triisopropylbenzenesulfinic acid, and sodium 2,4,6-triisopropylbenzenesulfinate are preferred.

Examples of sulfites include sodium sulfite, potassium sulfite, calcium sulfite, and ammonium sulfite. Examples of hydrogen sulfites include sodium hydrogen sulfite and potassium hydrogen sulfite. Examples of borate compounds include arylborate compounds having 1 to 4 aryl groups in one molecule (e.g., tetraphenylboron, tetrakis(p-chlorophenyl)boron, etc.) and salts thereof. Examples of barbituric acid compounds include barbituric acid, 5-butylbarbituric acid, 1,3,5-trimethylbarbituric acid, 1-cyclohexyl-5-ethylbarbituric acid, 1-benzyl-5-phenylbarbituric acid, and salts thereof.

In the dental hardenable composition of the present invention, the second agent may contain a ligand (G) containing a nitrogen atom. An embodiment includes a paste-like two-component dental hardenable composition in which the second agent further contains a ligand (G) containing a nitrogen atom as necessary. The ligand (G) containing a nitrogen atom contained in the second agent is the same as the ligand (G) containing a nitrogen atom contained in the first agent.

At least one of the first agent and the second agent of the dental hardenable composition of the present invention may further contain a fluoride ion releasing substance. By blending a fluoride ion releasing substance, the composition can be used as a dental resin cement that can impart acid resistance to tooth structure. Examples of the fluoride ion releasing substance include fluoride ion releasing polymers such as copolymers of methyl methacrylate and methacrylic acid fluoride; hydrofluorides of aliphatic or alicyclic primary, secondary or tertiary amines such as cetylamine hydrofluoride, cyclohexylamine hydrofluoride, diisobutylamine hydrofluoride, and triethylamine trihydrofluoride; and metal fluorides such as sodium fluoride, potassium fluoride, sodium monofluorophosphate, lithium fluoride, and ytterbium fluoride. The fluoride ion releasing substance may be used alone or in combination of two or more types.

In the individually packaged dental hardenable composition of the present invention, at least one of the first agent and the second agent may contain a pH adjuster. The pH adjuster is used for the purpose of adjusting and stabilizing the pH of the individually packaged dental hardenable composition of the present invention. There are no particular limitations on the pH adjuster as long as it achieves the effects of the present invention, but acids such as lactic acid, succinic acid, gluconic acid, citric acid, phosphoric acid, and carbonic acid, and salts thereof are preferably used.

Examples of phosphates include alkali metal phosphates such as trisodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, tripotassium phosphate, dipotassium hydrogen phosphate, and potassium dihydrogen phosphate; alkali metal alkyl phosphates such as sodium dodecyl phosphate, sodium glycerophosphate, and disodium glycerophosphate; alkali metal hydrogen phosphates or alkali metal dihydrogen phosphates; alkaline earth metal phosphates such as tricalcium phosphate, calcium hydrogen phosphate, and calcium dihydrogen phosphate; alkaline earth metal hydrogen phosphates or alkaline earth metal dihydrogen phosphates; trimagnesium phosphate, magnesium hydrogen phosphate, and the like. Among these, disodium hydrogen phosphate, sodium dodecyl phosphate, sodium glycerophosphate, and disodium glycerophosphate are preferably used.

In addition, in the dental curable composition of the present invention, additives such as a pH adjuster, a polymerization inhibitor, an ultraviolet absorber, a solvent (e.g., water, an organic solvent), a thickener, a colorant, an antibacterial agent, and a fragrance may be blended in at least one of the first and second agents, as long as they do not impair the effects of the present invention. These may be blended alone or in combination of two or more. Examples of polymerization inhibitors include hydroquinone, hydroquinone monomethyl ether, dibutyl hydroquinone, dibutyl hydroquinone monomethyl ether, t-butyl catechol, 2-t-butyl-4,6-dimethylphenol, 2,6-di-t-butylphenol, 2,6-di-
Examples of the polymerization inhibitor include t-butyl-4-methylphenol. The content of the polymerization inhibitor is preferably 0.001 to 1.0 parts by mass relative to 100 parts by mass of the total amount of the polymerizable monomer components of the dental hardenable composition. In an embodiment, the content of the solvent (e.g., water, organic solvent) in the paste-like two-component dental hardenable composition is preferably less than 1% by mass, more preferably less than 0.1% by mass, and even more preferably less than 0.01% by mass, based on the total amount of the paste-like two-component dental hardenable composition. The dental hardenable composition of the present invention can also be suitably used as a self-adhesive composition. The dental hardenable composition of the present invention can also be suitably used as, for example, a dental resin cement or a composite resin for dental core construction.

The present invention includes embodiments that combine the above configurations in various ways within the scope of the technical concept of the present invention, as long as the effects of the present invention are achieved.

The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. The abbreviations and symbols used below are as follows. The compounds and fillers used in the following examples and comparative examples were commercially available products, except where the manufacturing method is specifically described.

[Acidic Group-Containing Polymerizable Monomer (A)]
MDP: 10-methacryloyloxydecyl dihydrogen phosphate

[Polymerizable monomer (B) not containing an acidic group]
Bis-GMA: 2,2-bis[4-(3-methacryloyloxy-2-hydroxypropoxy)phenyl]propane D-2.6E: 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane (average number of moles of ethoxy groups added: 2.6)
TEGDMA: Triethylene glycol dimethacrylate HEMA: 2-hydroxyethyl methacrylate

[Organic peroxide (C)]
THP: 1,1,3,3-tetramethylbutyl hydroperoxide CHP: cumene hydroperoxide BPB: t-butyl peroxybenzoate

[Filler (D)]
Filler 1: Silane-treated Silica A commercially available product (methacrylic silane-treated spherical silica fine powder manufactured by Admatechs Co., Ltd., product name "Admanano (registered trademark) YA010C-SM1", average primary particle size: 10 nm, BET specific surface area: 300 m ² /g) was used as is.

Filler 2: Silane-treated silica-coated ytterbium fluoride. A commercially available product (SG-YBF100WSCMP10, average particle size: 110 nm, spherical, refractive index: 1.53, manufacturer: Sukgyung AT) was used as is.

Filler 3: Silane-treated barium glass:
Barium glass (manufactured by Estec Co., Ltd., product code "E-3000") was pulverized in a ball mill to obtain barium glass powder. The average particle size of the obtained barium glass powder was measured on a volume basis using a laser diffraction type particle size distribution measuring device (manufactured by Shimadzu Corporation, model "SALD-2300") and found to be 2.4 μm. 100 parts by mass of this barium glass powder was surface-treated with 3 parts by mass of γ-methacryloyloxypropyltrimethoxysilane by a conventional method to obtain a silane-treated barium glass powder.

Filler 4: Alumina A commercially available product (AEROXIDE (registered trademark) Alu C, average particle size: 20 nm, manufactured by Nippon Aerosil Co., Ltd.) was used as it was.

[Transition metal compound (E)]
VOAA: Vanadyl acetylacetonate (IV)
BMOV: bis(maltolato)oxovanadium(IV)
CuA: Copper (II) acetate

[Ascorbic acid compound (F)]
PA: Ascorbyl palmitate ANa: Sodium L-ascorbate

[Nitrogen-containing ligand (G)]
TTA: Triethanolamine TEEDA: N,N,N',N'-Tetraethylethylenediamine TMPDA: N,N,N',N'-Tetramethylpropylenediamine PMDETA: N,N,N,N',N'',N''-Pentamethyldiethylenetriamine Me ₆ TREN: Tris[2-(dimethylamino)ethyl]amine DPP: 2,6-bis(1-pyrazole)-pyridine

[Polymerization inhibitor]
BHT: 2,6-di-t-butyl-4-methylphenol

(Examples 1 to 11 and Comparative Examples 1 to 3)
Among the components listed in Table 1, the components other than the filler and the ascorbic acid compound were mixed at room temperature to obtain a uniform liquid component, and then the obtained liquid component, the ascorbic acid compound, and the filler were kneaded to prepare dental hardenable compositions of Examples 1 to 11 and Comparative Examples 1 to 3. Next, using these dental hardenable compositions, the operation time at 23°C, the adhesive strength to bovine dentin, the adhesive strength to gold alloy, and the adhesive durability were measured immediately after production according to the method described below. In addition, after three weeks of storage at 60°C, the operation time at 23°C, the adhesive strength to bovine dentin, and the solidification of the paste were measured. Table 1 shows the compounding ratio (parts by mass) and the test results of this dental hardenable composition. Note that the dental hardenable composition of Comparative Example 2 could not be measured after three weeks of storage at 60°C because the first agent solidified after three weeks of storage at 60°C. In addition, the dental hardenable composition of Comparative Example 3 could not be measured at all because the first agent solidified after preparation.

[Working time of dental hardenable composition at 23° C.]
The first and second agents were mixed in a mass ratio of 1:1 in a thermostatic chamber at 23°C, and thoroughly mixed with a spatula to obtain one agent. The time from the time of mixing to the time when the temperature started to rise due to the start of hardening of the paste (operation time) was measured using a thermocouple (manufactured by Okazaki Manufacturing Co., Ltd.) connected to a recorder (manufactured by Yokogawa Electric Corporation). The operation time (referred to as "23°C operation time" in the table below) is the average value of the measured values for five test samples. The practical operation time is 2 to 8 minutes. In addition, 4 g each of the first and second agents of the two-agent dental hardenable composition of the present invention was filled into a product container of "SA Louting (registered trademark) Multi" (manufactured by Kuraray Noritake Dental Co., Ltd.), and stored for three weeks in a dry atmosphere at 60°C, and then the operation time was measured using this in the same manner.

[Adhesive strength of dental hardenable composition to bovine dentin]
The labial surface of the bovine mandibular anterior tooth was polished with #80 silicon carbide paper (manufactured by Nihon Kenshi Co., Ltd.) under running water to expose the flat surface of the dentin. The exposed flat surface was further polished with #1000 silicon carbide paper (manufactured by Nihon Kenshi Co., Ltd.) under running water. After polishing, the water on the surface was dried by air blowing. An adhesive tape with a thickness of about 150 μm having a round hole with a diameter of 3 mm was attached to the smooth surface after drying to determine the adhesive area. The first and second agents of each dental hardenable composition of the Examples and Comparative Examples were taken in equal amounts and mixed for 10 seconds, and the resulting mixture was piled up on one end surface (circular cross section) of a stainless steel cylindrical rod (diameter 7 mm, length 2.5 cm). Next, the end face on the side where the dental curable composition was built up was placed on the smooth surface (adhering surface) in the round hole so that the center of the round hole and the center of the stainless steel cylindrical rod were approximately aligned, and the stainless steel cylindrical rod was pressed perpendicularly against the smooth surface to adhere to the smooth surface, thereby preparing a test sample. Five test samples were prepared. The test samples were left at 25°C for 30 minutes and then immersed in distilled water. The test samples immersed in distilled water were left at 37°C for 24 hours in an incubator maintained at 37°C. The tensile bond strength of the test samples to bovine dentin after leaving them at 37°C for 24 hours was measured. The tensile bond strength was measured using a universal testing machine (Shimadzu Corporation, Autograph "AG-I 100kN") with a crosshead speed set to 2mm/min.
In the table, regarding the properties immediately after preparation, the tensile bond strength to dentin is the average value of the measured values of the tensile bond strength to bovine dentin for five test samples after standing at 37°C for 24 hours. In addition, 4 g of each of the first and second agents of the two-component dental hardenable composition of the present invention was filled into a product container of "SA Louting (registered trademark) Multi" (manufactured by Kuraray Noritake Dental Co., Ltd.), and after storing for three weeks in a dry atmosphere at 60°C, the adhesive strength was measured using this in the same manner as after storing for 24 hours at 37°C. Regarding the properties of the temperature accelerated product in the table, the tensile bond strength to dentin is the average value of the measured values of the tensile bond strength to bovine dentin for five test samples after storing for three weeks in a dry atmosphere at 60°C.

[Tensile adhesive strength and adhesive durability of dental hardenable composition to gold alloy]
The surface of a cubic gold alloy casting (manufactured by GC Corporation, product name "Casting Gold M.C. Type IV") with each side being 1 cm long was polished with #1000 silicon carbide paper under running water to make a smooth surface, and then the water on the surface was dried by blowing air. An adhesive tape with a thickness of about 150 μm having a round hole with a diameter of 5 mm was attached to the smooth surface after drying, and the adhesive area was specified. The first agent and the second agent of each dental hardenable composition of the Examples and Comparative Examples were taken in equal amounts and mixed for 10 seconds, and the resulting mixture was piled up on one end surface (circular cross section) of a stainless steel cylindrical rod (diameter 7 mm, length 2.5 cm). Next, the end surface on the side where the dental hardenable composition was piled up was placed on the smooth surface (adhering surface) in the round hole so that the center of the round hole and the center of the stainless steel cylindrical rod were approximately aligned, and a stainless steel cylindrical rod was pressed and bonded perpendicularly to the smooth surface to prepare a test sample. Ten test samples were prepared. The test samples were left at 25°C for 30 minutes, immersed in distilled water, and then left at rest in an incubator maintained at 37°C for 24 hours. Five of the ten test samples were examined for tensile bond strength after 24 hours at 37°C. This tensile bond strength indicates the bond strength at the initial stage of adhesion. The remaining five test samples were subjected to a thermal cycle load of immersing the samples in a 4°C water bath and a 60°C water bath for 1 minute each, 4000 times, and then the tensile bond strength was measured. The adhesion durability was evaluated by the tensile bond strength after the thermal cycle load. The tensile bond strength was measured using a universal testing machine (Shimadzu Corporation, Autograph "AG-I 100kN") with a crosshead speed set to 2mm/min. In the table, the tensile bond strength to the gold alloy and the adhesion durability to the gold alloy (tensile bond strength after thermal cycle load) are the average values of the measured values for the five test samples.

[Solidification of dental hardenable composition (paste)]
The first and second parts of the dental hardenable composition of the present invention are referred to as "SA Louting (registered trademark)".
4 g of each was filled into a product container of "Multi" (Kuraray Noritake Dental Co., Ltd.) and stored for 3 weeks in a dry atmosphere at 60°C, and the presence or absence of hardened matter was confirmed for each of the first and second agents. If a hardened matter was present, it was judged as "solidified", and if no hardened matter was present, it was judged as "not solidified". The confirmation of the presence or absence of solidification was carried out for five samples, and if the presence of hardened matter was confirmed in even one sample, it was judged as "solidified".

As shown in Table 1, the dental hardenable compositions according to the present invention (Examples 1 to 11) had an appropriate handling time at 23°C immediately after preparation, and showed excellent adhesive strength to bovine dentin, adhesive strength to gold alloys, and adhesive durability. In addition, no solidification was observed in the paste after storage at 60°C for 3 weeks, and the handling time at 23°C after storage and the adhesive strength to bovine dentin showed little change compared to immediately after production. In addition, in Examples 2 to 9, when the first agent contained a ligand having two or more nitrogen atoms in the molecule as the nitrogen-containing ligand (G) and the second agent contained a transition metal compound (E), the handling time at 23°C after storage and the adhesive strength to bovine dentin showed less change compared to immediately after production. In addition, in Examples 10 to 11, when the first agent contained a ligand having two or more nitrogen atoms in the molecule as the nitrogen-containing ligand (G) and a transition metal compound (E), the variation in operation time at 23°C after storage at 60°C for three weeks was somewhat large compared to immediately after preparation, but was within the acceptable range, and solidification of the paste did not occur in the first agent after storage at 60°C for three weeks, as in Comparative Example 2.

On the other hand, the dental hardenable composition containing the thiourea compound of Comparative Example 1 had poor adhesion strength and adhesion durability to gold alloys. In addition, the first agent of the dental hardenable composition of Comparative Example 2, which did not contain a ligand containing a nitrogen atom (G) and contained an acidic group-containing polymerizable monomer (A), an organic peroxide (C), and copper acetate (II), a transition metal compound, in the same agent, solidified after storage at 60°C for 3 weeks. Furthermore, the first agent of the dental hardenable composition of Comparative Example 3, which did not contain a ligand containing a nitrogen atom (G) and contained an acidic group-containing polymerizable monomer (A), an organic peroxide (C), and a transition metal compound (E) in the same agent, solidified immediately after preparation.

The dental hardenable composition of the present invention can be suitably used in dental treatment for bonding dental prostheses such as crowns, inlays, and bridges to tooth structure (e.g., dental cement), and for building abutments (e.g., composite resins for building dental abutments).

Claims (4)

A first agent containing an acidic group-containing polymerizable monomer (A), a polymerizable monomer having no acidic group (B), an organic peroxide (C), a filler (D), and a ligand containing a nitrogen atom (G);
a second agent containing a polymerizable monomer (B) having no acidic group, a filler (D), and an ascorbic acid compound (F), and substantially not containing a thiourea compound;
At least one of the first agent and the second agent contains a transition metal compound (E);
the transition metal compound (E) is a copper compound and/or a vanadium compound,
the copper compound is at least one selected from the group consisting of copper(II) carboxylate, copper(II) β-diketone, copper(II) β-ketoester, copper alkoxide, copper dithiocarbamate, and a salt of copper and an inorganic acid;
The vanadium compound is a tetravalent and/or pentavalent vanadium compound,
the ascorbic acid compound (F) is at least one compound selected from the group consisting of salts and esters of ascorbic acid,
The salt of ascorbic acid is sodium L-ascorbate, calcium L-ascorbate, potassium ascorbate, or a stereoisomer thereof;
The ester of ascorbic acid is obtained by reacting one or more hydroxy groups of ascorbic acid with a fatty acid, such as a saturated fatty acid or an unsaturated fatty acid having 6 to 30 carbon atoms,
The nitrogen-containing ligand (G) is at least one compound selected from a compound represented by the following general formula (1), a compound represented by the following general formula (2), and a multidentate ligand (3) containing a nitrogen-containing heterocycle:
The multidentate ligand (3) containing a nitrogen-containing heterocycle contains a five- or six-membered ring containing a nitrogen atom, has two or more nitrogen atoms in the molecule, and is a bidentate or higher ligand compound.
R ₁ R ₂ N-X ₁ -NR ₃ R ₄ (1)
(R ₁ to R ₄ each independently represent an alkyl group which may have a substituent, and X ₁ represents a divalent aliphatic group which may have a substituent.)
(R5 _, R6 _, and R7 _each independently represent an alkyl group which may have a substituent, X2 _and X3 _each independently represent a divalent aliphatic group which may have a substituent and which may contain an oxygen atom and/or a nitrogen atom, m and n each independently represent an integer of 1 or more, Y represents a monoalkylamino group or a dialkylamino group which may have a substituent, and any two or more of R5 _, R6 _, R7 _, and Y may be bonded together to form a ring. When a plurality of _R6 , R7 _, X2 _, and X3 _are present, they may be the same or different.)
A paste-like two-component dental hardenable composition. 2. The paste-like two-component dental hardenable composition according to claim 1, wherein the IV and/or V vanadium compounds are at least one compound selected from divanadium(IV) tetroxide, vanadyl acetylacetonate(IV), vanadium oxide stearate(IV), oxovanadium(IV) oxalate, vanadyl(IV) sulfate, vanadium naphthenate, vanadium benzoylacetonate, bis(maltolate)oxovanadium(IV), oxobis(1-phenyl-1,3-butanedionate)vanadium(IV), vanadium(V) pentoxide, vanadium(V) oxytriisopropoxide, sodium metavanadate(V), and ammonium metavanadate(V). 3. The paste-like two-component dental hardenable composition according to claim 1 , wherein the first component does not contain a transition metal compound (E). The paste-like two-component dental hardenable composition according to any one of claims 1 to 3 , which is a self-adhesive composition.