JP7464359B2 - Dental hardenable composition - Google Patents

Description

The present invention relates to a dental hardenable composition. More specifically, the present invention relates to a dental hardenable composition that is self-adhesive, has sustained calcium release properties, adhesion to tooth structure, and high marginal sealing properties.

The most common cause of tooth loss is said to be root fracture. Most teeth with root fractures do not have a pulp, and have undergone a procedure to remove the pulp (pulp removal) in the past due to caries or other reasons. During pulp removal, the blood vessels that supply nutrients to the tooth are removed along with the pulp, making the tooth brittle and more likely to break. It also reduces resistance to bacteria, making the tooth more susceptible to caries. Therefore, protecting the pulp is essential to extending the lifespan of teeth.

In cases where caries has progressed to the deep dentin adjacent to the pulp, the pulp may become exposed or be on the verge of being exposed when the infected dentin is removed. In order to protect the exposed or on the verge of being exposed pulp, a procedure to cover the pulp, i.e., a pulp capping procedure, is required. In conventional pulp capping procedures, calcium hydroxide preparations and pulp capping materials mainly composed of calcium silicate, called MTA (Mineral Trioxide Aggregate) cement, have been used. These pulp capping materials are known to exert a pulp protection effect by gradually releasing calcium ions, which induces the formation of dentin-like hard tissue on the exposed or on the verge of being exposed pulp surface. However, although calcium hydroxide preparations show high antibacterial properties, they are highly cytotoxic and prone to necrosis of pulp cells. In addition, they do not have adhesive properties to dentin, and because they are highly soluble, the pulp capping material itself disappears within 1 to 2 years after treatment, making it easier for bacteria to invade the defect site. Because of these phenomena, the success rate of pulp capping treatment using calcium hydroxide preparations is low, and as a result, pulp removal is often necessary. On the other hand, although MTA cement does not have adhesive properties to tooth structure, it is hydraulic and has good sealing properties due to its water absorption and expansion, so the success rate of treatment is high. However, MTA cement is used in a paste form by mixing powder and water, and there are issues such as difficulty in mixing, difficulty in filling, time required for hardening, and low strength.

In response, a paste-type dental resin material that contains calcium silicate and is easy to handle has been proposed. For example, Patent Document 1 describes a resin-based self-adhesive resin cement that contains a basic filler whose main component is calcium silicate and a polymerizable monomer having an acidic group. Patent Document 2 describes a pulp protection material that contains a calcium component, maintains its basicity for a long period of time, and is capable of inducing hard tissue formation in exposed dental pulp.

International Publication No. 2018/057353 International Publication No. 2018/103712

Patent Document 1 describes that a self-adhesive resin cement containing calcium silicate has the effects of remineralizing tooth tissue, promoting the healing of dental pulp tissue, inhibiting bacterial infection, and the like. However, nothing is described regarding the sustained release of calcium ions. Furthermore, the inventors' investigations revealed that when a polymerizable monomer having an acidic group within the range described in Patent Document 1 is used in combination with a general basic filler, the sustained release of calcium is very low due to the interaction between the two, and that simply mixing these together does not provide a sufficient effect of promoting the healing of dental pulp tissue.

Patent Document 2 describes a composition containing a calcium component in combination with a neutral or weakly acidic hydrophilic resin. It describes the results that the hardened product of this composition maintains its basicity for a long period of time, but does not describe any adhesive performance to tooth structure. In order to form hard tissue with the calcium component, the sustained release of the calcium component is necessary, but the adhesive component to tooth structure is prone to interact with the calcium component, and it is generally difficult to achieve both adhesion to tooth structure and sustained release of the calcium component. If adhesion to tooth structure is not obtained, leakage may occur due to low sealing properties, and the success rate of treatment due to bacterial infection, etc. may decrease.

In view of the above circumstances, the present invention aims to provide a dental hardenable composition that is self-adhesive and has excellent sustained calcium release properties, adhesion to tooth structure, and high marginal sealing properties.

The inventors conducted extensive research to find a self-adhesive dental hardenable composition that simultaneously provides the sustained calcium release required for the healing of dental pulp tissue and adhesion to tooth tissue, properties that are generally difficult to achieve together. As a result, they discovered that by using calcium silicate in a specific particle size range, it is possible to provide a dental hardenable composition that achieves both of the above properties, has high marginal sealing properties, and is easy to handle. Further research led to the completion of the present invention.

After applying the dental hardenable composition of the present invention to the affected area and hardening it, calcium ion sustained release can be obtained by calcium silicate in the hardened product. In order to obtain the desired calcium ion sustained release, calcium silicate needs to be appropriately dispersed and dissolve in contact with water that penetrates into the hardened product. On the other hand, in order to impart adhesion to tooth structure to the dental hardenable composition of the present invention, it is essential to add an acidic group-containing polymerizable monomer, but calcium silicate may interact with the acidic group-containing polymerizable monomer and inhibit adhesion to tooth structure, etc. The present inventors believed that as long as the average particle size of calcium silicate is not too small, calcium ions can be eluted from areas other than those where calcium silicate interacts with the acidic group-containing polymerizable monomer, and as a result of further investigations, they found that by setting the average particle size within a specific range, an appropriate amount of calcium ion sustained release can be obtained, and the dental hardenable composition of the present invention achieves both adhesion to tooth structure and sustained calcium ion release.

That is, the present invention relates to the following.
[1] A dental hardenable composition comprising: (a) a polymerizable monomer having an acidic group; (b) a polymerizable monomer not having an acidic group; (c) a polymerization initiator; and (d) calcium silicate having an average particle size of 0.5 μm or more and less than 20 μm.
[2] The dental hardenable composition according to [1], further comprising a calcium salt (e) (excluding the calcium silicate (d)).
[3] The dental hardenable composition according to [2], wherein the calcium salt (e) contains at least one selected from the group consisting of calcium oxide, calcium hydroxide, calcium chloride, calcium carbonate, calcium sulfate, calcium sulfite, calcium phosphate, and calcium pyrophosphate.
[4] The dental hardenable composition according to [2], wherein the calcium salt (e) contains calcium oxide and/or calcium hydroxide.
[5] The dental curable composition according to any one of [2] to [4], wherein the average particle size of the calcium salt (e) is 0.5 μm or more and 25 μm or less.
[6] The dental hardenable composition according to any one of [1] to [5], wherein the calcium silicate (d) contains at least one selected from the group consisting of tricalcium silicate, dicalcium silicate, and calcium silicate hydrate.
[7] The dental hardenable composition according to any one of [1] to [5], wherein the calcium silicate (d) contains tricalcium silicate.
[8] The dental hardenable composition according to any one of [1] to [7], wherein the average particle size of the calcium silicate (d) is 1.0 μm or more and less than 15 μm.
[9] The dental hardenable composition according to any one of [1] to [8], wherein the content of calcium silicate (d) is 5 to 50 parts by mass per 100 parts by mass of the total amount of the dental hardenable composition of the present invention.
[10] The dental hardenable composition according to any one of [2] to [9], wherein the total amount of the calcium silicate (d) and the calcium salt (e) is 5 to 50 parts by mass in a total of 100 parts by mass of the dental hardenable composition of the present invention.
[11] The dental curable composition according to any one of [2] to [10], wherein the content ratio of the acidic group-containing polymerizable monomer (a) to the calcium silicate (d) and the calcium salt (e) is 1:6 to 1:18 by mass.
[12] The dental curable composition according to any one of [1] to [11], wherein the polymerization initiator (c) contains a photopolymerization initiator (c-1).
[13] The dental curable composition according to any one of [1] to [12], wherein the polymerization initiator (c) contains a chemical polymerization initiator (c-2), and the chemical polymerization initiator (c-2) is a combination of a redox initiator (c-2-1) and a chemical polymerization accelerator (c-2-2).
[14] The dental curable composition according to any one of [1] to [13], further comprising a filler (f) (excluding the calcium silicate (d) and the calcium salt (e)).
[15] The dental curable composition according to any one of [1] to [14], which is a two-paste type composed of a first paste and a second paste.
[16] The dental curable composition according to [15], wherein the first paste contains a redox initiator (c-2-1) and the second paste contains a chemical polymerization accelerator (c-2-2).
[17] The dental curable composition according to [15] or [16], wherein the first paste contains a polymerizable monomer (a) having an acidic group and a polymerizable monomer (b) not having an acidic group, and the second paste contains a polymerizable monomer (b) not having an acidic group and calcium silicate (d) having an average particle size of 0.5 μm or more and less than 20 μm.
[18] The dental hardenable composition according to any one of [15] to [17], wherein the second paste contains a calcium salt (e) (excluding the calcium silicate (d)).

The dental hardenable composition of the present invention has the sustained calcium release required for the healing of dental pulp tissue, and has excellent adhesion to tooth tissue and high marginal sealing properties. In addition, the dental hardenable composition of the present invention is easy to handle.

The dental curable composition of the present invention contains a polymerizable monomer (a) having an acidic group (hereinafter referred to as "acidic group-containing polymerizable monomer (a)"). By including the acidic group-containing polymerizable monomer (a), adhesion to tooth structure can be imparted.

Examples of the acidic group-containing polymerizable monomer (a) include polymerizable monomers having at least one acidic group such as a phosphate group, a pyrophosphate group, a thiophosphate group, a phosphonic acid group, a sulfonic acid group, or a carboxylic acid group, and at least one polymerizable group such as an acryloyl group, a methacryloyl group, a vinyl group, or a styrene group. The acidic group-containing polymerizable monomer (a) has affinity for the adherend and has a demineralizing effect on the tooth structure. Specific examples of the acidic group-containing polymerizable monomer (a) are described below. In this specification, "(meth)acrylic" means acrylic and methacrylic, and "(meth)acryloyl" means acryloyl and methacryloyl.

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, 8-(meth)acryloyloxyethyl dihydrogen phosphate, 9-(meth)acryloyloxypropyl dihydrogen phosphate, 10-(meth)acryloyloxybutyl dihydrogen phosphate, 11-(meth)acryloyloxybutyl dihydrogen phosphate, 12-(meth)acryloyloxybutyl dihydrogen phosphate, 13-(meth)acryloyloxypentyl dihydrogen phosphate, 14-(meth)acryloyloxyhexyl dihydrogen phosphate, 15-(meth)acryloyloxyhexyl dihydrogen phosphate, 16-(meth)acryloyloxyhexyl dihydrogen phosphate, 17-(meth)acryloyloxyheptyl dihydrogen phosphate, 18-(meth)acryloyloxybutyl dihydrogen phosphate, 19-(meth)acryloyloxybutyl dihydrogen phosphate, 20-(meth)acryloyloxybutyl dihydrogen phosphate, 21-(meth)acryloyloxybutyl dihydrogen phosphate, 22-(meth)acryloyloxybutyl dihydrogen phosphate, 23-(meth)acryloyloxypentyl dihydrogen phosphate, 24-(meth)acryloyloxyhexyl dihydrogen phosphate, 25-(meth)acryloyloxyhexyl dihydrogen phosphate, 26-(meth)acryloyloxyhexyl dihydrogen phosphate, 27-(meth)acryloyloxyhexyl dihydrogen Acryloyloxyoctyl dihydrogen phosphate, 9-(meth)acryloyloxynonyl dihydrogen phosphate, 10-acryloyloxydecyl dihydrogen phosphate, 10-methacryloyloxydecyl dihydrogen phosphate (hereinafter sometimes abbreviated as "MDP"), 11-(meth)acryloyloxyundecyl dihydrogen phosphate, 12-(meth)acryloyloxydodecyl dihydrogen phosphate, 16-(meth)acryloyloxyhexadecyl diha hydrogen phosphate, 20-(meth)acryloyloxyeicosyl dihydrogen phosphate, bis[2-(meth)acryloyloxyethyl]hydrogen phosphate, bis[4-(meth)acryloyloxybutyl]hydrogen phosphate, bis[6-(meth)acryloyloxyhexyl]hydrogen phosphate, bis[8-(meth)acryloyloxyoctyl]hydrogen phosphate, bis[9-(meth)acryloyloxynonyl]hydrogen phosphate, bis Examples include [10-(meth)acryloyloxydecyl]hydrogen phosphate, 1,3-di(meth)acryloyloxypropyl dihydrogen phosphate, 2-(meth)acryloyloxyethylphenyl hydrogen phosphate, 2-(meth)acryloyloxyethyl-2-bromoethyl hydrogen phosphate, bis[2-(meth)acryloyloxy-(1-hydroxymethyl)ethyl]hydrogen phosphate, and their acid chlorides, alkali metal salts, and ammonium salts.

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

Examples of sulfonic acid group-containing polymerizable monomers include 2-(meth)acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid, and 2-sulfoethyl (meth)acrylate.

Carboxylic acid group-containing polymerizable monomers include polymerizable monomers having one carboxy group in the molecule and polymerizable monomers having multiple carboxy groups in the molecule.

Examples of polymerizable monomers having one carboxy group in the molecule include (meth)acrylic acid, N-(meth)acryloylglycine, N-(meth)acryloylaspartic acid, O-(meth)acryloyltyrosine, N-(meth)acryloyltyrosine, N-(meth)acryloylphenylalanine, N-(meth)acryloyl-p-aminobenzoic acid, N-(meth)acryloyl-o-aminobenzoic acid, p-vinylbenzoic acid, and 2-(meth)acryloyloxybenzoic acid. Examples of such compounds include benzoic acid, 3-(meth)acryloyloxybenzoic acid, 4-(meth)acryloyloxybenzoic acid, N-(meth)acryloyl-5-aminosalicylic acid, N-(meth)acryloyl-4-aminosalicylic acid, 2-(meth)acryloyloxyethyl hydrogen succinate, 2-(meth)acryloyloxyethyl hydrogen phthalate, 2-(meth)acryloyloxyethyl hydrogen maleate, and acid halides thereof.

Examples of polymerizable monomers having multiple carboxy groups in the molecule include 6-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 9-(meth)acryloyloxynonane-1,1-dicarboxylic acid, 10-(meth)acryloyloxydecane-1,1-dicarboxylic acid, 11-(meth)acryloyloxyundecane-1,1-dicarboxylic acid, 12-(meth)acryloyloxydodecane-1,1-dicarboxylic acid, 13-(meth)acryloyloxytridecane-1,1-dicarboxylic acid, 4 ...4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyl Examples include acryloyloxyethyl trimellitate, 4-(meth)acryloyloxyethyl trimellitate anhydride, 4-(meth)acryloyloxybutyl trimellitate, 4-(meth)acryloyloxyhexyl trimellitate, 4-(meth)acryloyloxydecyl trimellitate, 2-(meth)acryloyloxyethyl-3'-(meth)acryloyloxy-2'-(3,4-dicarboxybenzoyloxy)propyl succinate, and acid anhydrides or acid halides thereof.

The above-mentioned acidic group-containing polymerizable monomer (a) may be used alone or in combination of two or more. Among these acidic group-containing polymerizable monomers (a), in terms of high adhesive strength to dental adherends, one or more selected from the group consisting of phosphoric acid group-containing polymerizable monomers, carboxylic acid group-containing polymerizable monomers, and sulfonic acid group-containing polymerizable monomers are preferred, and one or more selected from the group consisting of phosphoric acid group-containing polymerizable monomers having two or more hydroxyl groups bonded to phosphorus atoms, polymerizable monomers having multiple carboxy groups in the molecule, and sulfonic acid group-containing polymerizable monomers are more preferred, and 10-(meth)acryloyloxydecyl dihydride is more preferred. More preferred is one or more selected from the group consisting of acryloyloxypropyl dihydrogen phosphate, 1,3-di(meth)acryloyloxypropyl dihydrogen phosphate, 2-(meth)acryloyloxyethyl dihydrogen phosphate, 4-(meth)acryloyloxyethyl trimellitate anhydride, 4-(meth)acryloyloxyethyl trimellitate, 2-(meth)acrylamido-2-methylpropanesulfonic acid, and 11-(meth)acryloyloxyundecane-1,1-dicarboxylic acid.

The content of the acidic group-containing polymerizable monomer (a) is preferably 0.5 to 15 parts by mass, more preferably 1 to 12 parts by mass, and even more preferably 1.5 to 10 parts by mass in the total amount of 100 parts by mass of the dental hardenable composition of the present invention. When the content of the acidic group-containing polymerizable monomer (a) is 0.5 parts by mass or more, it is easy to obtain high adhesion to teeth and various dental adherends, and when the content of the acidic group-containing polymerizable monomer is 15 parts by mass or less, it is easy to maintain a balance between polymerizability and adhesion. In the present invention, the total amount of the dental hardenable composition refers to the total mass of all components such as the polymerizable monomer (a) having an acidic group, the polymerizable monomer (b) not having an acidic group, the polymerization initiator (c), and calcium silicate (d) having an average particle size of 0.5 μm or more and less than 20 μm, and other additives contained as necessary.

The dental curable composition of the present invention contains a polymerizable monomer (b) that does not have an acidic group. The polymerizable monomer (b) that does not have an acidic group is a polymerizable monomer that undergoes a radical polymerization reaction with a polymerization initiator (c) to become a polymer. The polymerizable monomer that constitutes the polymerizable monomer (b) that does not have 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 have an acidic group include the following water-soluble polymerizable monomer (b-1) and hydrophobic polymerizable monomer (b-2).

Water-soluble polymerizable monomer (b-1) refers to a polymerizable monomer having a solubility in water of 10% by mass or more at 25°C. A solubility of 30% by mass or more is preferred, and one that can dissolve in water at any ratio at 25°C is more preferred. The water-soluble 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 water-soluble 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)acroyloxy)ethyltrimethylammonium chloride; and bifunctional (meth)acrylic acid ester polymerizable monomers such as polyethylene glycol di(meth)acrylate (having 9 or more oxyethylene groups), with 2-hydroxyethyl (meth)acrylate being preferred.

The 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 the crosslinkable polymerizable monomer (b-2) include bifunctional polymerizable monomers of aromatic compounds, bifunctional polymerizable monomers of aliphatic compounds, and trifunctional or higher polymerizable monomers. The hydrophobic polymerizable monomer (b-2) improves the mechanical strength, handleability, etc. of the dental curable composition.

Examples of aromatic compound-based bifunctional polymerizable monomers 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 ... 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-hydroxypropoxyphenyl)propane, 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane (average number of moles of ethoxy groups added: 2.6) (hereinafter sometimes abbreviated as "D2.6E") is 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, 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, 1,5-pentanediol di Examples of the polymerizable monomer include bifunctional (meth)acrylic acid ester polymerizable monomers such as (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 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, 1,7-diacryloyloxy-2,2,6,6-tetraacryloyloxymethyl-4-oxyheptane, and the like.

The above-mentioned polymerizable monomer (b) having no acidic group (water-soluble 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) having no acidic group is preferably 5 to 60 parts by mass, more preferably 10 to 50 parts by mass, and even more preferably 15 to 40 parts by mass in the total amount of 100 parts by mass of the dental curable composition of the present invention. The content of the water-soluble polymerizable monomer (b-1) is preferably 1 to 30 parts by mass, more preferably 1 to 25 parts by mass, and even more preferably 2 to 20 parts by mass in the total amount of 100 parts by mass of the dental curable composition of the present invention. The content of the hydrophobic polymerizable monomer (b-2) is preferably 5 to 50 parts by mass, more preferably 10 to 45 parts by mass, and even more preferably 15 to 40 parts by mass in the total amount of 100 parts by mass of the dental curable composition.

The dental curable composition of the present invention contains a polymerization initiator (c).

The polymerization initiator (c) is classified into a photopolymerization initiator (c-1) and a chemical polymerization initiator (c-2), and these may be blended alone or in combination of two or more types.

Examples of photopolymerization initiators (c-1) 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 (e.g., sodium salt, potassium salt, ammonium salt), etc. 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 (c-1) may be used alone or in combination of two or more kinds. The content of the photopolymerization initiator (c-1) is preferably in the range of 0.001 to 10 parts by mass, more preferably in the range of 0.005 to 5 parts by mass, per 100 parts by mass of the total amount of the dental curable composition of the present invention.

In addition, to enhance photocurability, the photopolymerization initiator (c-1) may be used in combination with a polymerization accelerator for the photopolymerization initiator (c-1), such as tertiary amines, aldehydes, thiol compounds, or 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-di(2-hydroxyethyl)-p-toluidine, N,N-bis(2-hydroxyethyl)-3,4-dimethylaniline, N,N-bis(2-hydroxyethyl)-4-ethylaniline, N,N-bis(2-hydroxyethyl)-4-isopropylaniline, N,N-bis(2-hydroxyethyl)-4-t-butylaniline, N,N-bis(2-hydroxyethyl)-3,5-diisopropylaniline, N , N-bis(2-hydroxyethyl)-3,5-di-t-butylaniline, 4-(N,N-dimethylamino)benzoate n-butoxyethyl, 4-(N,N-dimethylamino)benzoate 2-(methacryloyloxy)ethyl, 4-(N,N-dimethylamino)benzoate ethyl, 4-(N,N-dimethylamino)benzoate butyl, N-methyldiethanolamine, 4-(N,N-dimethylamino)benzophenone, 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, triethanolamine tri(meth)acrylate, and the like. Examples of aldehydes include terephthalaldehyde and benzaldehyde derivatives. Examples of benzaldehyde derivatives include dimethylaminobenzaldehyde, p-methyloxybenzaldehyde, p-ethyloxybenzaldehyde, 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 (c-1) may be used alone or in combination of two or more types.

As to the triazine compound, one type may be used alone, or two or more types may be used in combination, as necessary.

As the chemical polymerization initiator (c-2), a combination of a redox initiator (c-2-1) and a chemical polymerization accelerator (c-2-2) is preferably used. Examples of the redox initiator (c-2-1) include organic peroxides, inorganic peroxides, and transition metal complexes. These are not particularly limited and known ones can be used. The organic peroxides, inorganic peroxides, and transition metal complexes may be blended alone or in combination of two or more kinds. The redox initiator (c-2-1) and the chemical polymerization accelerator (c-2-2) are packaged separately, and the two need to be mixed immediately before use.

Representative organic peroxides include hydroperoxides, peroxyesters, ketone peroxides, peroxyketals, dialkyl peroxides, diacyl peroxides, and peroxydicarbonates. Among these, hydroperoxides and peroxyesters are particularly preferred, and peroxyesters are most preferred because the operational time of the dental hardenable composition of the present invention varies little even when the composition is stored for a long period of time. One type of organic peroxide may be used alone, or two or more types may be used in combination.

More specifically, hydroperoxides include cumene hydroperoxide, t-butyl hydroperoxide, t-hexyl hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide (hereinafter sometimes abbreviated as "THP").

Any known peroxy ester can be used without any restrictions as long as it has an acyl group on one side of a peroxy group (-OO- group) and a hydrocarbon group (or a group similar thereto) on the other side. Specific examples include α,α-bis(neodecanoylperoxy)diisopropylbenzene, cumyl peroxy neodecanoate, 1,1,3,3-tetramethylbutyl peroxy neodecanoate, 1-cyclohexyl-1-methylethyl peroxy neodecanoate, t-hexyl peroxy neodecanoate, t-butyl peroxy neodecanoate, t-hexyl peroxy pivalate, t-butyl peroxy pivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, 1-cyclohexyl-1-methylethyl peroxy-2-ethylhexanoate, t-hexyl peroxy 2-ethylhexanoate, t-butyl peroxy 2-ethylhexanoate, and t-butyl peroxy 2-ethylhexanoate. Examples of the peroxyalkylene compounds include ethyl peroxyisobutyrate, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-bis(m-toluoylperoxy)hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, t-butylperoxyacetate, t-butylperoxy-m-toluoylbenzoate, t-butylperoxybenzoate (hereinafter sometimes abbreviated as "BPB"), and bis(t-butylperoxy)isophthalate. These compounds may be used alone or in appropriate combination of two or more. Among these, from the viewpoints of storage stability and reactivity, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxybenzoate, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, and t-butylperoxyacetate are preferred, with t-butylperoxybenzoate being more preferred.

Examples of ketone peroxides include methyl ethyl ketone peroxide, cyclohexanoperoxide, methylcyclohexanone peroxide, methylacetoacetate peroxide, and acetylacetone peroxide.

Examples of peroxyketals include 1,1-bis(t-hexylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexanone, 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)cyclodecane, 2,2-bis(t-butylperoxy)butane, n-butyl-4,4-bis(t-butylperoxy)valerate, and 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane.

Examples of dialkyl peroxides include α,α-bis(t-butylperoxy)diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-butyl peroxide, and 2,5-dimethyl-2,5-bis(t-butylperoxy)3-hexyne.

Examples of diacyl peroxides include isobutyryl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearyl peroxide, succinic acid peroxide, m-toluoylbenzoyl peroxide, and benzoyl peroxide.

Examples of peroxydicarbonates include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis(4-t-butylcyclohexyl) peroxydicarbonate, di(2-ethoxyethyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, di(2-methoxybutyl) peroxydicarbonate, and di(3-methyl-3-methoxybutyl) peroxydicarbonate.

Inorganic peroxides include peroxodisulfates and peroxodiphosphates, and among these, peroxodisulfates are preferred in terms of curability. Specific examples of peroxodisulfates include sodium peroxodisulfate, potassium peroxodisulfate (hereinafter sometimes abbreviated as KPS), aluminum peroxodisulfate, and ammonium peroxodisulfate.

From the viewpoint of hardening, the content of the organic peroxide and the inorganic peroxide is preferably 0.01 to 10 parts by mass, and more preferably 0.02 to 5 parts by mass, per 100 parts by mass of the total amount of the dental hardenable composition of the present invention.

Transition metal complexes include copper compounds and vanadium compounds.

As the copper compound, a compound that is soluble in the polymerizable monomer component is preferable. Specific examples of copper carboxylates include copper (II) acetate, copper (II) isobutyrate, copper (II) gluconate, copper (II) citrate, copper (II) phthalate, copper (II) tartrate, copper (II) oleate, copper (II) octylate, copper (II) octenoate, copper (II) naphthenate, copper (II) methacrylate, and copper (II) 4-cyclohexylbutyrate; and β-diketone copper includes copper (II) acetylacetone, copper (II) trifluoroacetylacetone, copper (II) hexafluoroacetylacetone, and copper (II) 2,2,6,6-tetrafluoroacetylacetone. Examples of copper dithiocarbamate include copper(II) dimethyldithiocarbamate; and salts of copper and inorganic acids include copper(II) nitrate; 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 particularly preferred.

From the viewpoint of hardening, the content of the copper compound is preferably 0.000005 to 1 part by mass per 100 parts by mass of the total amount of the polymerizable monomer components in the dental hardenable composition of the present invention.

Examples of vanadium compounds include vanadium acetylacetonate, vanadyl acetylacetonate (hereinafter sometimes abbreviated as "VOAA"), vanadyl stearate, vanadium naphthenate, vanadium benzoylacetonate, etc., with vanadium acetylacetonate and vanadyl acetylacetonate being particularly preferred.

From the viewpoint of hardening, the content of the vanadium compound is preferably 0.005 to 1 part by mass per 100 parts by mass of the total amount of the polymerizable monomer components in the dental hardenable composition of the present invention.

Examples of the chemical polymerization accelerator (c-2-2) include transition metal complexes, aromatic amines, aliphatic amines, aromatic sulfinates, sulfur-containing reductive inorganic compounds, thiourea derivatives, benzotriazole compounds, and benzimidazole compounds. The chemical polymerization accelerator (c-2-2) may be used alone or in combination of two or more. Examples of the transition metal complex include the same ones as those exemplified for the redox initiator (c-2-1).

As the aromatic amine used as the chemical polymerization accelerator (c-2-2), known aromatic secondary amines, aromatic tertiary amines, etc. may be used, and tertiary aromatic amines that do not have an electron-withdrawing group on the aromatic ring are preferred. Examples of tertiary aromatic amines that do not have an electron-withdrawing group on the aromatic ring include N,N-bis(2-hydroxyethyl)-3,5-dimethylaniline, N,N-bis(2-hydroxyethyl)-p-toluidine (hereinafter sometimes abbreviated as "DEPT"), N,N-bis(2-hydroxyethyl)-3,4-dimethylaniline, N,N-bis(2-hydroxyethyl)-4-ethylaniline, N,N-bis(2-hydroxyethyl)-4-isopropylaniline, N,N-bis(2-hydroxyethyl)-4-t-butylaniline, N,N-bis(2-hydroxyethyl)-4-t-butylaniline, and N,N-bis(2-hydroxyethyl)-4-t-butylaniline. )-3,5-di-isopropylaniline, N,N-bis(2-hydroxyethyl)-3,5-di-t-butylaniline, N,N-dimethylaniline, N,N-dimethyl-p-toluidine, N,N-dimethyl-m-toluidine, N,N-diethyl-p-toluidine, N,N-dimethyl-3,5-dimethylaniline, N,N-dimethyl-3,4-dimethylaniline, N,N-dimethyl-4-ethylaniline, N,N-dimethyl-4-isopropylaniline, N,N-dimethyl-4-t-butylaniline, and N,N-dimethyl-3,5-di-t-butylaniline. Among these, N,N-bis(2-hydroxyethyl)-p-toluidine is preferred in terms of redox reactivity.

Examples of aliphatic amines include primary aliphatic amines such as n-butylamine, n-hexylamine, and n-octylamine; secondary aliphatic amines such as diisopropylamine, dibutylamine, and N-methylethanolamine; and tertiary aliphatic amines such as N-methyldiethanolamine, N-ethyldiethanolamine, N-n-butyldiethanolamine, N-lauryldiethanolamine, 2-(dimethylamino)ethyl(meth)acrylate, N-methyldiethanolamine di(meth)acrylate, N-ethyldiethanolamine di(meth)acrylate, triethanolamine tri(meth)acrylate, triethanolamine, trimethylamine, triethylamine, and tributylamine. Among these, tertiary aliphatic amines are preferred in terms of redox reactivity, and N-methyldiethanolamine, triethanolamine, and 2-(dimethylamino)ethyl methacrylate are particularly preferred.

The content of aromatic amine or aliphatic amine is preferably 0.01 to 10 parts by mass, more preferably 0.02 to 7 parts by mass, and even more preferably 0.05 to 25 parts by mass, in a total of 100 parts by mass of the dental hardenable composition of the present invention. If the content is less than 0.01 parts by mass, the adhesiveness of the resulting dental hardenable composition to a wet body such as tooth structure may decrease. On the other hand, if the content exceeds 10 parts by mass, the color stability of the resulting dental hardenable composition may decrease.

Examples of aromatic sulfinic acid salts include lithium salts, sodium salts, potassium salts, rubidium salts, cesium salts, magnesium salts, calcium salts, strontium salts, iron salts, zinc salts, ammonium salts, tetramethylammonium salts, and tetraethylammonium salts of benzenesulfinic acid, p-toluenesulfinic acid, o-toluenesulfinic acid, ethylbenzenesulfinic acid, decylbenzenesulfinic acid, dodecylbenzenesulfinic acid, 2,4,6-trimethylbenzenesulfinic acid, 2,4,6-triisopropylbenzenesulfinic acid (the sodium salt may be abbreviated as "TPBSS" below), p-chlorobenzenesulfinic acid, and naphthalenesulfinic acid. Among these, in terms of the hardenability and storage stability of the resulting dental hardenable composition, the lithium salt, sodium salt, potassium salt, magnesium salt, and calcium salt of 2,4,6-trimethylbenzenesulfinic acid and 2,4,6-triisopropylbenzenesulfinic acid are preferred, and the lithium salt, sodium salt, potassium salt, magnesium salt, and calcium salt of 2,4,6-triisopropylbenzenesulfinic acid are more preferred.

The content of the aromatic sulfinate is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, and even more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the total amount of the dental hardenable composition of the present invention. If the content is less than 0.01 parts by mass or more than 5 parts by mass, the mechanical strength of the hardened product of the dental hardenable composition obtained may decrease.

Examples of reducing inorganic compounds containing sulfur include sulfites, bisulfites, pyrosulfites, thiosulfates, thionates, and dithionites. Of these, sulfites and bisulfites are preferred. Specific examples include sodium sulfite, potassium sulfite, calcium sulfite, ammonium sulfite, sodium hydrogen sulfite, and potassium hydrogen sulfite. One type may be used alone, or two or more types may be used in combination.

The content of the reducing inorganic compound is preferably 0.01 to 15 parts by mass, more preferably 0.05 to 10 parts by mass, and even more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the total amount of the polymerizable monomer components in the dental hardenable composition of the present invention. If the content is less than 0.01 parts by mass, the adhesive strength of the resulting dental hardenable composition to a wet body such as tooth structure may decrease. On the other hand, if the content exceeds 15 parts by mass, the mechanical strength of the hardened product of the resulting dental hardenable composition may decrease.

Examples of thiourea derivatives 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, and pyridyl thiourea. Of these, 4,4-dimethylethylene thiourea, pyridyl thiourea, and N-benzoyl thiourea are preferred.

Benzotriazole compounds and/or benzimidazole compounds include compounds represented by the following general formulas [I] and [II], respectively.

In the above general formulas [I] and [II], R ¹ to R ⁸ each independently represent a hydrogen atom, a hydroxyl group, an alkyl group, an aryl group, an alkoxy group, an alkenyl group, an aralkyl group, or a halogen atom.

The alkyl groups represented by R ¹ to R ⁸ may be linear, branched, or cyclic, and preferably have 1 to 10 carbon atoms. Specific examples include methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, cyclopentyl, n-hexyl, isohexyl, cyclohexyl, n-heptyl, cycloheptanyl, n-octyl, 2-ethylhexyl, cyclooctyl, n-nonyl, cyclononyl, and n-decyl. Of these, methyl and ethyl groups are particularly preferred.

The aryl group represented by R ¹ to R ⁸ preferably has 6 to 10 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthryl group.

The alkoxy groups represented by R ¹ to R ⁸ may be linear, branched, or cyclic, and preferably have a carbon number of 1 to 8. Specific examples include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a tert-butoxy group, an n-hexyloxy group, a cyclohexyloxy group, an n-octyloxy group, and a 2-ethylhexyloxy group.

The alkenyl groups represented by R ¹ to R ⁸ may be linear, branched, or cyclic, and preferably have a carbon number of 1 to 6. Specific examples include a vinyl group, an allyl group, a methylvinyl group, a propenyl group, a butenyl group, a pentenyl group, a hexenyl group, a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, and a cyclohexenyl group.

Examples of the aralkyl group represented by R ¹ to R ⁸ include an alkyl group (particularly, an alkyl group having 1 to 10 carbon atoms) substituted with an aryl group (particularly, an aryl group having 6 to 10 carbon atoms), and specific examples include a benzyl group.

Examples of the halogen atom represented by R ¹ to R ⁸ include a chlorine atom, a bromine atom, and an iodine atom.

R ¹ to R ⁸ are preferably a hydrogen atom or a methyl group.

The benzotriazole compounds and benzimidazole compounds may be used alone or in combination of two or more. Specific examples of benzotriazole compounds and benzimidazole compounds include 1H-benzotriazole (hereinafter sometimes abbreviated as "BTA"), 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H-benzotriazole, benzimidazole, 5-methylbenzimidazole, and 5,6-dimethylbenzimidazole. Among these, 1H-benzotriazole and 5-methyl-1H-benzotriazole are preferred in terms of the color tone and storage stability of dental hardenable compositions.

The dental hardenable composition of the present invention contains calcium silicate (d).

Calcium silicate (d) is used to impart calcium ion sustained release properties to the dental hardenable composition of the present invention and induce the formation of dentin-like hard tissue in exposed (or about to be exposed) dental pulp. Examples of calcium silicate (d) include tricalcium silicate, dicalcium silicate, calcium silicate hydrate, etc. One type of calcium silicate (d) may be used alone, or two or more types may be used in combination. Among these, tricalcium silicate is more preferably used in terms of sustained calcium ion release properties.

The average particle size of calcium silicate (d) contained in the dental hardenable composition of the present invention is 0.5 μm or more and less than 20 μm, more preferably 1.0 μm or more and less than 15 μm, and even more preferably 2.0 μm or more and less than 10 μm. In order to obtain the desired calcium ion sustained release by calcium silicate (d) in the hardened product after applying the dental hardenable composition of the present invention to the affected area and hardening it, it is necessary for calcium silicate (d) to be appropriately dispersed and to come into contact with moisture that penetrates into the hardened product and dissolve. On the other hand, calcium silicate (d) may interact with the acidic group of the acidic group-containing polymerizable monomer (a) and inhibit adhesion to tooth structure, etc., but if the average particle size of calcium silicate (d) is in a moderately large range, calcium ions can be eluted from areas other than the area where calcium silicate (d) interacts with the acidic group-containing polymerizable monomer (a). Therefore, by having the average particle size in the above range, an appropriate amount of calcium ion sustained release can be obtained. Therefore, the dental hardenable composition of the present invention can achieve both adhesion to tooth structure and sustained calcium ion release. If it is less than 0.5 μm, the contact area with the acidic group-containing polymerizable monomer (a) blended in the dental hardenable composition of the present invention increases, and the calcium ion release and adhesion to tooth structure are significantly reduced due to the interaction. On the other hand, if it is 20 μm or more, the interaction with the acidic group-containing polymerizable monomer (a) is suppressed, but the surface area of calcium silicate (d) is reduced, resulting in a decrease in the sustained calcium ion release.

The content of calcium silicate (d) is preferably 5 to 50 parts by mass, more preferably 10 to 40 parts by mass, and even more preferably 15 to 35 parts by mass, in a total of 100 parts by mass of the dental hardenable composition of the present invention. When the content of calcium silicate (d) is 5 parts by mass or more, it is easy to obtain high sustained release of calcium ions, and when the content of calcium silicate (d) is 50 parts by mass or less, it is easy to maintain a balance with adhesion to tooth tissue.

In this specification, the average particle size of calcium silicate (d), calcium salt (e) and filler (f) 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, while the electron microscope observation is convenient for measuring the particle size of ultrafine particles of less than 0.1 μm. 0.1 μm is a value measured by the laser diffraction scattering method.

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

The dental hardenable composition of the present invention may contain a calcium salt (e).

Calcium salt (e) is used to assist the sustained release of calcium ions from the dental hardenable composition of the present invention. As calcium salt (e), calcium oxide, calcium hydroxide, calcium chloride, calcium carbonate, calcium sulfate, calcium sulfite, calcium phosphate, calcium pyrophosphate, etc. are preferably used, and calcium oxide and calcium hydroxide are particularly preferred because they have the ability to assist and enhance the sustained release of calcium ions and do not inhibit the polymerization hardening. In this specification, calcium salt (e) does not include calcium silicate (d). Calcium salt (e) may be used alone or in combination of two or more types.

The average particle size of the calcium salt (e) is preferably 0.5 μm or more and 25 μm or less, more preferably 1.0 μm or more and less than 20 μm, and even more preferably 2.0 μm or more and less than 15 μm. By having the average particle size of the calcium salt (e) in this range, it is possible to improve the sustained release of calcium ions without impairing the adhesion of the dental hardenable composition of the present invention to tooth structure. If it is less than 0.5 μm, the contact area with the acidic group-containing polymerizable monomer (a) blended in the dental hardenable composition of the present invention increases, and the calcium ion sustained release and tooth structure adhesive strength are significantly reduced due to the interaction. On the other hand, if it is 15 μm or more, the interaction with the acidic group-containing polymerizable monomer (a) is suppressed, but the calcium ion sustained release is reduced.

The content of calcium salt (e) is preferably 1 to 30 parts by mass, more preferably 2 to 25 parts by mass, and even more preferably 5 to 20 parts by mass, in a total of 100 parts by mass of the dental hardenable composition of the present invention. If the content of calcium salt (e) is less than 1 part by mass, the effect of supporting the sustained release of calcium ions is not obtained, and if it is 30 parts by mass or more, it becomes difficult to achieve both adhesion to tooth structure.

The total amount of calcium silicate (d) and calcium salt (e) is preferably 5 to 50 parts by mass, and more preferably 10 to 40 parts by mass, when the total amount of the dental hardenable composition of the present invention is 100 parts by mass. When the total amount of calcium silicate (d) and calcium salt (e) is 5 parts by mass or more, it is easy to obtain high sustained release of calcium ions, and when the total amount of calcium silicate (d) and calcium salt (e) is 50 parts by mass or less, it is easy to maintain a balance with adhesion to tooth tissue.

The ratio of the content of the acidic group-containing polymerizable monomer (a) to the powdered components (calcium silicate (d) and calcium salt (e)) is preferably 1:6 to 1:18 by mass, and more preferably 1:6 to 1:15. When these ratios are within this range, the adhesion to tooth structure and the sustained release of calcium ions are optimal.

The dental hardenable composition of the present invention may contain a filler (f).

As the filler (f), any filler can be used as long as it does not impair the effects of the present invention, including inorganic fillers, organic fillers, and composite fillers of inorganic and organic fillers. The filler (f) may be blended alone or in combination of two or more types. In this specification, the filler (f) does not include calcium salt (e) and calcium silicate (d). The average particle size of the filler (f) is preferably 0.001 to 10 μm, and more preferably 0.001 to 5 μm.

Examples of inorganic fillers include silica; minerals based on silica, such as _kaolin , clay, mica, and mica _; ceramics and glasses based on silica and containing _Al2O3 , _B2O3 , _TiO2 , _ZrO2 , _BaO , _La2O3 , SrO, ZnO, CaO, _P2O5 , _Li2O , and _Na2O . Examples of glasses include lithium borosilicate glass, borosilicate glass, bioglass, lanthanum glass, barium glass, strontium glass, soda glass, zinc glass, _and fluoroaluminosilicate glass. Examples of inorganic fillers that can be used include crystalline quartz, hydroxyapatite, alumina, titanium oxide, yttrium oxide, zirconia, barium sulfate, aluminum hydroxide, sodium fluoride, potassium fluoride, sodium monofluorophosphate, lithium fluoride, and ytterbium fluoride. In terms of adhesive strength and ease of handling, fine particle silica having an average particle size of 0.001 to 10 μm is preferably used. Commercially available products include Aerosil OX50, Aerosil 50, Aerosil 200, Aerosil 380, Aerosil R972, and Aerosil 130 (all of which are product names manufactured by Nippon Aerosil Co., Ltd.).

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.

To improve curability, mechanical strength, and handling, the filler (f) 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 content of the filler (f) is preferably 5 to 80 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 20 to 50 parts by mass, per 100 parts by mass of the dental hardenable composition of the present invention.

In the dental hardenable composition of the present invention, in order to obtain the desired sustained calcium ion release from calcium silicate (d) in the hardened product while maintaining adhesion to tooth structure, the mass ratio of calcium silicate (d) to filler (f) ((d):(f)) is preferably 1:4 to 4:1, more preferably 1:4 to 3:1, and even more preferably 1:3 to 2:1, in order to adequately disperse calcium silicate (d).

In the dental hardenable composition of the present invention, the mass ratio ((e):(f)) of the calcium salt (e) to the filler (f) is preferably 1:1 to 1:20, and more preferably 1:2 to 1:15.

The dental hardenable composition of the present invention may contain a fluoride ion-releasing substance in order to 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, fluoride ion-releasing substances such as cetylamine hydrofluoride, and inorganic fillers such as the fluoroaluminosilicate glass, sodium fluoride, potassium fluoride, sodium monofluorophosphate, lithium fluoride, and ytterbium fluoride.

The dental hardenable composition of the present invention may contain additives such as stabilizers (polymerization inhibitors), colorants, fluorescent agents, and ultraviolet absorbers. It may also contain antibacterial substances such as cetylpyridinium chloride, benzalkonium chloride, (meth)acryloyloxydodecylpyridinium bromide, (meth)acryloyloxyhexadecylpyridinium chloride, (meth)acryloyloxydecylammonium chloride, and triclosan.

The dental hardenable composition of the present invention may contain known dyes and pigments.

The dental hardenable composition of the present invention may be a one-paste type or a two-paste or more type, but a two-paste type is preferred because it has good storage stability and can be imparted with chemical hardening properties.

A preferred embodiment (X-1) is a dental hardenable composition of two paste type consisting of a first paste and a second paste, the first paste containing a polymerizable monomer (a) having an acidic group, a polymerizable monomer (b) not having an acidic group, and a polymerization initiator (c), the polymerization initiator (c) containing a photopolymerization initiator (c-1), and the second paste containing a polymerizable monomer (b) not having an acidic group, and calcium silicate (d). In order to avoid interaction between calcium silicate (d) and the acidic group of the acidic group-containing polymerizable monomer (a) during storage, and in the case where calcium silicate (d) is contained in the first paste in a two-paste dental hardenable composition, it is preferable that calcium silicate (d) and the acidic group-containing polymerizable monomer (a) are packaged separately from each other, since it becomes difficult to form a paste and it becomes impossible to mix a sufficient amount of calcium silicate (d) to obtain the desired sustained calcium release.

A preferred embodiment (X-2) is a two-paste dental hardenable composition consisting of a first paste and a second paste, the first paste containing a polymerizable monomer (a) having an acidic group, a polymerizable monomer (b) not having an acidic group, and a polymerization initiator (c), the polymerization initiator (c) containing a photopolymerization initiator (c-1), and the second paste containing a polymerizable monomer (b) not having an acidic group, calcium silicate (d), and a calcium salt (e). In order to avoid interaction between the calcium salt (e) and the acidic group of the acidic group-containing polymerizable monomer (a) during storage, it is preferable that the calcium salt (e) and the acidic group-containing polymerizable monomer (a) are packaged separately.

A preferred embodiment (X-3) is a two-paste dental hardenable composition consisting of a first paste and a second paste, in which the first paste contains a polymerizable monomer (a) having an acidic group, a polymerizable monomer (b) not having an acidic group, a polymerization initiator (c), and a filler (f), the polymerization initiator (c) contains a photopolymerization initiator (c-1), and the second paste contains a polymerizable monomer (b) not having an acidic group, calcium silicate (d), a calcium salt (e), and a filler (f).

One preferred embodiment (X-4) is a two-paste dental hardenable composition consisting of a first paste and a second paste, in which the first paste contains a polymerizable monomer (a) having an acidic group, a polymerizable monomer (b) not having an acidic group, and a redox initiator (c-2-1) as the polymerization initiator (c), and the second paste contains a polymerizable monomer (b) not having an acidic group, calcium silicate (d), and a chemical polymerization accelerator (c-2-2) as the polymerization initiator (c).

A preferred embodiment (X-5) is a two-paste dental hardenable composition consisting of a first paste and a second paste, in which the first paste contains a polymerizable monomer (a) having an acidic group, a polymerizable monomer (b) not having an acidic group, and a redox initiator (c-2-1) as the polymerization initiator (c), and the second paste contains a polymerizable monomer (b) not having an acidic group, calcium silicate (d), a calcium salt (e), and a chemical polymerization accelerator (c-2-2) as the polymerization initiator (c).

A preferred embodiment (X-6) is a two-paste dental hardenable composition consisting of a first paste and a second paste, in which the first paste contains a polymerizable monomer (a) having an acidic group, a polymerizable monomer (b) not having an acidic group, a redox initiator (c-2-1) as the polymerization initiator (c), and a filler (f), and the second paste contains a polymerizable monomer (b) not having an acidic group, calcium silicate (d), a calcium salt (e), a filler (f), and a chemical polymerization accelerator (c-2-2) as the polymerization initiator (c).

Another preferred embodiment (X-7) is a two-paste dental hardenable composition consisting of a first paste and a second paste, the first paste containing a polymerizable monomer (a) having an acidic group, a polymerizable monomer (b) not having an acidic group, a photopolymerization initiator (c-1), a redox initiator (c-2-1), and a filler (f), and the second paste containing a polymerizable monomer (b) not having an acidic group, a chemical polymerization accelerator (c-2-2), calcium silicate (d), a calcium salt (e), and a filler (f). In the above-mentioned two-paste dental hardenable composition embodiments (X-1) to (X-7), the type and content of each component can be appropriately changed based on the above-mentioned description of the present specification, and any component can be added, deleted, or otherwise modified. In addition, in the above-mentioned two-paste dental hardenable composition embodiments (X-1) to (X-7), the composition and the values of each characteristic (calcium release amount, tensile adhesive strength, etc.) of each dental hardenable composition can be appropriately changed and combined. However, the two-paste type dental hardenable composition is not limited to the above configuration.

The amount of calcium ions released from the dental hardenable composition of the present invention is preferably 7.0 mg/g or more, more preferably 8.5 mg/g or more, and even more preferably 9.5 mg/g or more. The method for measuring the amount of calcium ions released is as described in the Examples below.

The tensile bond strength of the cured product of the dental curable composition of the present invention is preferably 6.5 MPa or more, more preferably 7.5 MPa or more, and even more preferably 8.5 MPa or more. The method for measuring the tensile bond strength is as described in the Examples below.

The dental hardenable composition of the present invention can be produced, for example, by mixing all ingredients except the powdered ingredients (calcium silicate (d), calcium salt (e), and filler (f)), obtaining a solution, and adding the powdered ingredients.

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.

Next, the present invention will be explained in more detail with reference to examples. However, the present invention is not limited to these examples in any way, and many modifications are possible within the scope of the technical concept of the present invention by those with ordinary skill in the art. The abbreviations and abbreviations used below are as follows.

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

[Polymerizable monomer (b) having no acidic group]
HEMA: 2-hydroxyethyl methacrylate Bis-GMA: 2,2-bis[4-(3-methacryloyloxy-2-hydroxypropoxy)phenyl]propane D2.6E: 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane (average number of moles of ethoxy groups added: 2.6)
3G: Triethylene glycol dimethacrylate

[Photopolymerization initiator (c-1)]
CQ: dl-camphorquinone

[Redox initiator (c-2-1)]
BPO: Benzoyl peroxide KPS: Potassium peroxodisulfate

[Chemical polymerization accelerator (c-2-2)]
TPBSS: Sodium 2,4,6-triisopropylbenzenesulfinate DEPT: N,N-bis(2-hydroxyethyl)-p-toluidine Na ₂ SO ₃ : Sodium sulfite

[Calcium silicate (d)]
TCS: Tricalcium silicate (Mineral Research Processing)

[Calcium salt (e)]
CaO: Calcium oxide Ca(OH) ₂ : Calcium hydroxide (average particle size: 9.7 μm)

[Filler (f)]
F1: Silane-treated quartz powder:
Quartz (manufactured by Maruwa Quartz) was pulverized in a ball mill to obtain a quartz powder with an average particle size of about 4.5 μm. 100 parts by mass of this quartz powder was surface-treated with 3 parts by mass of γ-methacryloyloxypropyltrimethoxysilane in a conventional manner to obtain a silane-treated quartz powder (F1).
R972: Nippon Aerosil Co., Ltd., fine particle silica "Aerosil (registered trademark) R-972", average particle size: 16 nm
YBF3: Sukgyung AT, silica-coated ytterbium fluoride "SG-YBF100WSCMP10", average particle size: 110 nm, spherical particles)
Alumina: Aluminum oxide "Aluminum Oxide C" manufactured by Nippon Aerosil Co., Ltd., average particle size: 20 nm

〔others〕
PDE: ethyl 4-(N,N-dimethylamino)benzoate (polymerization accelerator for photopolymerization initiator)
BHT: 2,6-di-t-butyl-4-methylphenol (stabilizer)

[Examples 1 to 9 and Comparative Examples 1 to 4]
The first paste and the second paste having the composition shown in Table 1 were prepared. The first paste was prepared by mixing the components other than the powdered component (filler), stirring to form a uniform solution, and then kneading and defoaming the powdered component. The powdered components in the first paste were in a powdery, dispersed state. The second paste was prepared by mixing the components other than the powdered components (filler, calcium silicate, calcium salt, sodium sulfite, and TPBSS), stirring to form a uniform solution, and then kneading and defoaming the powdered components. The powdered components in the second paste were in a powdery, dispersed state. The first paste and the second paste were kneaded in a mass ratio of 1:1, and the mixture was used for evaluation as a dental hardenable composition. The 25°C hardening start time, tensile adhesive strength to bovine dentin, calcium ion sustained release, and marginal sealing ability to human teeth were tested by the methods shown below. The results are shown in Table 1.

[Examples 10 to 13 and Comparative Examples 5 to 6]
A dental hardenable composition having the composition shown in Table 2 was prepared. After mixing all the components except for the powdered components (filler, calcium silicate, calcium salt), the mixture was stirred to obtain a uniform solution, and the powdered components were then kneaded and degassed to prepare the dental hardenable composition. The powdered components in the dental hardenable composition were in a powdered, dispersed state. This one-paste type dental hardenable composition was used for evaluation. The tensile adhesive strength to bovine dentin, sustained release of calcium ions, and marginal sealing ability to human teeth were tested using the methods described below. The results are shown in Table 2.

[25°C curing start time]
The first paste and the second paste were collected in equal amounts, then mixed, and the resulting mixture was filled into a microtube. After a predetermined time had elapsed since the start of mixing, the mixture was taken out, sandwiched between microscope slides, and pressed so as to apply a shear force, and the mixture was visually inspected for the presence or absence of unevenness. This inspection was repeated by extending the time from the start of mixing to the application of shear force to the mixture by 10 seconds each time, until the hardening was completed. The time at which the unevenness occurred was taken as the hardening start time (n = 3).

[Tensile bond strength 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 adhesion area. Each dental hardenable composition of the Examples and Comparative Examples was piled up in the round hole of the adhesive tape on the smooth surface of the dentin and covered with a release film (polyester). Next, a slide glass was placed on the release film and pressed against it to smooth the built-up surface of the dental hardenable composition. Next, the dental hardenable composition was irradiated with light for 20 seconds using a dental polymerization light irradiator (manufactured by Morita Seisakusho Co., Ltd., product name "Pencure 2000") through the release film to harden the dental hardenable composition. A test sample was prepared by bonding one end (circular cross section) of a stainless steel cylindrical rod (diameter 7 mm, length 2.5 cm) to the cured surface of the obtained dental curable composition using a commercially available dental resin cement (manufactured by Kuraray Noritake Dental Co., Ltd., product name "SA Cement Plus Automix (registered trademark)"). Five test samples were prepared. The test sample was left at 25 ° C for 30 minutes and immersed in distilled water. The test sample immersed in distilled water was left at 37 ° C for 24 hours in an incubator maintained at 37 ° C. The tensile bond strength of this test sample after 24 hours of standing at 37 ° C. was examined. The tensile bond strength was measured with a universal testing machine (manufactured by Shimadzu Corporation, autograph "AG-I 100kN") with a crosshead speed set to 2 mm / min. The tensile bond strength after 24 hours of standing at 37 ° C. in the table is the average value of the measured values for the five test samples.

[Slow release of calcium ions]
The dental curable composition was filled into a mold with a diameter of 15 mm and a thickness of 1 mm, and irradiated with light for 20 seconds each at five points on both sides with a dental polymerization light irradiator (manufactured by Morita Seisakusho Co., Ltd., product name "Pencure 2000") to cure. Next, the cured product was left to stand in a thermostatic chamber at 37°C for 15 minutes, and then removed from the mold and immersed in 5 ml of ion-exchanged water (37°C). After immersing in ion-exchanged water (37°C) for 28 days, 10 μl of 5 mol/l hydrochloric acid and 15 ml of trishydroxyaminomethane buffer solution with a pH of about 7 were added and stirred, and then 1 ml of KCl aqueous solution (3.75 g/l) was added, and the calcium ion dissolved in the ion-exchanged water was quantified using a calcium ion electrode (manufactured by Horiba Seisakusho Co., Ltd.) (n=2).

[Marginal Seal]
A dental air turbine was used to form a cavity with a diameter of about 2 mm and a depth of about 1 mm so that the cervical line of the molar of a human extracted tooth was in the center. A dental hardening composition was filled into the cavity and hardened by irradiating light for 20 seconds with a dental polymerization light irradiator (manufactured by Morita Seisakusho Co., Ltd., product name "Pencure 2000"). Next, in order to prevent the infiltration of dye from the root apex and the crown fissure, etc., a commercially available dental adhesive (manufactured by Kuraray Noritake Dental Co., Ltd., product name "Clearfil (registered trademark) Megabond (registered trademark)") was applied to the cavity repair part and its surrounding area, and hardened by irradiating light for 30 seconds with the above-mentioned light irradiator. The test piece was immersed in a 0.2% basic fuchsin aqueous solution (aqueous solution containing a dye) at 25°C for 24 hours, and then subjected to a thermal cycle of immersing in cold water at 4°C and warm water at 60°C for 1 minute each, 3000 times. After that, the test specimen was immersed again in 0.2% basic fuchsin aqueous solution for 10 minutes, and then removed and washed with water. The test specimen was divided vertically into three sections at the filled part using a low-speed diamond cutter, and three sections were prepared for each tooth. A total of nine sections were prepared from three human molar teeth. When no dye penetration was observed in all nine sections, it was marked with an ◯, and when dye penetration was observed in one or more sections, it was marked with an ×.

As shown in Table 1, the two-paste type dental hardenable composition exhibited chemical polymerization hardening properties at 25°C.
Furthermore, as shown in Tables 1 and 2, the dental hardenable compositions of the present invention prepared in Examples 1 to 13 exhibited high tensile bond strength to bovine dentin, high sustained calcium ion release, and marginal sealing. On the other hand, it was difficult for the dental hardenable compositions prepared in Comparative Examples 1 to 6 to achieve both tensile bond strength to bovine dentin and sustained calcium ion release. This is believed to be because the average particle size of calcium silicate (d) was not within an appropriate range. Furthermore, samples that did not exhibit high tensile bond strength to bovine dentin also showed low marginal sealing.

The dental hardenable composition of the present invention can be suitably used in dental restorative treatment. The dental hardenable composition of the present invention can also be suitably used as a dental cement, a filling material for root canals, a pulp capping material, and a material for treating root caries.

Claims (11)

the composition is of a one-paste type or a two-paste type composed of a first paste and a second paste, the composition comprising: a polymerizable monomer having an acidic group (a), a polymerizable monomer not having an acidic group (b), a polymerization initiator (c) , and calcium silicate (d) having an average particle size of 0.5 μm or more and less than 20 μm, and further comprising a calcium salt (e) (excluding the calcium silicate (d)) as required;
In the case of the one-paste type, the polymerization initiator (c) contains a photopolymerization initiator (c-1) and does not contain a chemical polymerization initiator (c-2),
In the case of the two-paste type, the polymerization initiator (c) contains a chemical polymerization initiator (c-2), and the chemical polymerization initiator (c-2) is a combination of a redox initiator (c-2-1) and a chemical polymerization accelerator (c-2-2);
the first paste contains a polymerizable monomer (a) having an acidic group, a polymerizable monomer (b) not having an acidic group, and a polymerization initiator (c), the polymerization initiator (c) contains a photopolymerization initiator (c-1) and/or a redox initiator (c-2-1);
the second paste contains a polymerizable monomer (b) having no acidic group, calcium silicate (d), and further contains a calcium salt (e) (excluding the calcium silicate (d)) as necessary, and when the first paste contains a redox initiator (c-2-1), it contains a chemical polymerization accelerator (c-2-2) as a polymerization initiator (c);
A dental hardenable composition which is used by kneading the first paste and the second paste. 2. The dental hardenable composition according to claim 1 , wherein the calcium salt (e) comprises at least one selected from the group consisting of calcium oxide, calcium hydroxide, calcium chloride, calcium carbonate, calcium sulfate, calcium sulfite, calcium phosphate, and calcium pyrophosphate. The dental hardenable composition according to claim 1 , wherein the calcium salt (e) contains calcium oxide and/or calcium hydroxide. The dental hardenable composition according to claim 1 , wherein the calcium salt (e) has an average particle size of 0.5 μm or more and 25 μm or less. The dental hardenable composition according to any one of claims 1 to 4 , wherein the calcium silicate (d) contains at least one selected from the group consisting of tricalcium silicate, dicalcium silicate, and calcium silicate hydrate. The dental hardenable composition according to any one of claims 1 to 4 , wherein the calcium silicate (d) contains tricalcium silicate. The dental hardenable composition according to any one of claims 1 to 6 , wherein the average particle size of the calcium silicate (d) is 1.0 µm or more and less than 15 µm. The dental hardenable composition according to any one of claims 1 to 7 , wherein the content of calcium silicate (d) is 5 to 50 parts by mass in 100 parts by mass of the total amount of the dental hardenable composition. The dental hardenable composition according to any one of claims 1 to 8 , wherein a total amount of the calcium silicate (d) and the calcium salt (e) is 5 to 50 parts by mass in 100 parts by mass of the total amount of the dental hardenable composition. The dental hardenable composition according to any one of claims 1 to 9 , wherein a content ratio of the acidic group-containing polymerizable monomer (a) to the calcium silicate (d) and the calcium salt (e) is 1:6 to 1:18 in terms of mass ratio. The dental hardenable composition according to any one of claims 1 to 10 , further comprising a filler (f) (excluding the calcium silicate (d) and the calcium salt (e)).