Dental composition

Abstract

The purpose of the present invention is to provide a dental composition that exhibits little polymerization shrinkage stress and an excellent mechanical strength. The present invention relates to a dental composition comprising a compound (A), a monomer (B) that exhibits a solubility in acetone at 25°C of at least 50 g / L, and a polymerization initiator (C). The compound (A) has a weight-average molecular weight of 1,000-80,000, includes a Tg of less than 40°C, and has a solubility in acetone at 25°C of less than 50 g / L. The compound (A) preferably comprises a compound that has a polymerizable group.

Description

[Technical Field]

[0001] The present invention relates to a dental composition used in the field of dentistry. [Background technology]

[0002] When treating dental caries and the resulting defects, restoration using dental bonding material and dental composite resin has traditionally been the norm. Restorative treatment typically involves the following steps: First, the carious area is removed to form a cavity, and then dental bonding material is applied to the cavity. Visible light is then irradiated onto the applied area to harden it. Next, dental composite resin is applied on top of the hardened dental bonding material, and finally, visible light is irradiated onto the applied dental composite resin to harden it.

[0003] Dental composite resins have recently been widely used, replacing traditional metal materials, due to their aesthetic properties and ease of use, similar to those of natural teeth. Dental composite resins are generally composed of a polymerizable monomer, a polymerization initiator, and a filler. To date, radically polymerizable polyfunctional (meth)acrylates have been commonly used as polymerizable monomers due to their safety in vivo and the mechanical strength and abrasion resistance of the cured product. Among these, 2,2-bis[4-(3-methacryloyloxy-2-hydroxypropoxy)phenyl]propane (Bis-GMA) and 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate (UDMA) are widely used. Because of their high viscosity, Bis-GMA and UDMA are typically diluted with a relatively low-viscosity polymerizable monomer, such as triethylene glycol dimethacrylate (3G).

[0004] Although dental composite resins have come to be widely used clinically today, improvements are desired in the following respects: It has been pointed out that there is still much room for improvement in the workability of the paste of the polymerizable composition used as the dental composite resin, improvement of the flexural strength, elastic modulus, and abrasion resistance of the cured product, reduction of water absorption and discoloration, reduction of polymerization shrinkage stress during curing, and aesthetic properties similar to those of natural teeth.

[0005] In recent years, there has been a strong demand for reducing polymerization shrinkage stress as much as possible, as it can cause dental composite resins to peel off from the adhesive surface, resulting in a contraction gap. The occurrence of a contraction gap can lead to secondary caries, pulp irritation, discoloration, and loss of restorations.

[0006] One technique proposed for reducing such polymerization shrinkage stress is to incorporate a polymer into a dental composition. Patent Document 1 discloses a dental composition in which polymerization shrinkage stress is suppressed by using a dendritic polymer. Patent Document 2 discloses a dental composition in which polymerization shrinkage stress is suppressed by using a macrocyclic oligomer. Patent Document 3 discloses a particle composite material composed of an organic binder and an inorganic filler. Patent Document 4 discloses a dental material composed of a composition containing a metal fine powder, (meth)acrylic polymer particles, a polymerizable monomer component, and a polymerization catalyst. Patent Document 5 discloses a dental filling and restoration kit comprising a transparent external filler composed of particles with a maximum diameter of 0.5 mm to 4.0 mm and a dental polymerizable composition containing a radically polymerizable monomer and a photopolymerization initiator.

[0007] However, in Patent Document 1, the suppression of polymerization shrinkage stress is still insufficient. Furthermore, since the weight-average molecular weight of the dendritic polymer is 20,000 or more, the viscosity of the composition is high, preventing the inorganic filler filling rate from being fully increased, and the strength is also insufficient. In Patent Document 2, the suppression of polymerization shrinkage stress is also insufficient even with this measure. Furthermore, similar to Patent Document 1, the inclusion of macrocyclic oligomers results in high viscosity, preventing the inorganic filler filling rate from being fully increased, and the strength is also insufficient. Furthermore, in Patent Document 3, the paste is rough due to the inclusion of a large amount of a particulate composite material with a large particle size. Furthermore, since the particulate composite material is treated with a polymerizable monomer, polymerization occurs during curing, resulting in an insufficient reduction of polymerization shrinkage stress. In Patent Document 4, since most of the components in the dental material are (meth)acrylic polymer particles, the mechanical strength is insufficient, similar to Patent Document 3. In Patent Document 5, as in Patent Document 3, the mechanical strength was insufficient and the particle size was too large, so when a small amount of paste was used in clinical practice, the particles were sometimes contained in the paste and sometimes not, and the paste was not reliably effective.

[0008] On the other hand, dental compositions containing oligomers are known (for example, Patent Documents 6 to 9). However, in Patent Documents 6 to 9, the oligomers are blended with the intention of improving mechanical strength, and there is no intention to reduce polymerization shrinkage stress. In addition, the inventors' investigations have not confirmed the desired effect of reducing polymerization shrinkage stress. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-24775 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-188672 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-256010 [Patent Document 4] Japanese Patent Application Publication No. 11-29428 [Patent Document 5] Japanese Patent Application Laid-Open No. 2016-175851 [Patent Document 6] Japanese Patent Application Publication No. 50-042696 [Patent Document 7] Special Publication No. 2006-510583 [Patent Document 8] Japanese Patent Application Laid-Open No. 2009-184971 [Patent Document 9] Japanese Patent Application Laid-Open No. 2011-144121 Summary of the Invention [Problem to be solved by the invention]

[0010] As described above, in the prior art, no dental composition has been found that has low polymerization shrinkage stress and provides a cured product with excellent mechanical strength.

[0011] Therefore, an object of the present invention is to provide a dental composition that has low polymerization shrinkage stress and exhibits excellent mechanical strength in the cured product. [Means for solving the problem]

[0012] As a result of extensive research, the inventors discovered that a dental composition having a weight-average molecular weight of a certain value or more and a solubility in acetone of a specific amount or less can solve the above-mentioned problems, and after further research, they have completed the present invention.

[0013] That is, the present invention is [1] A method for producing a polymerizable composition comprising: a compound (A); a monomer (B) having a solubility in acetone at 25°C of 50 g / L or more; and a polymerization initiator (C); a dental composition, wherein the compound (A) has a weight-average molecular weight of 1,000 to 80,000, a Tg of less than 40°C, and a solubility in acetone at 25°C of less than 50 g / L; [2] The dental composition according to [1], wherein the compound (A) contains a compound having a polymerizable group; [3] The dental composition according to either [1] or [2], wherein the content of the compound (A) is 0.1 to 50 parts by mass per 100 parts by mass of the total of the compound (A) and the monomer (B); [4] The dental composition according to [2] or [3], wherein the compound having a polymerizable group includes a urethane-modified (meth)acrylic compound (A-1) having a urethane bond; [5] The dental composition according to any one of [1] to [4], wherein the compound (A) has a solubility in acetone at 25°C of less than 20 g / L; [6] The dental composition according to any one of [1] to [5], wherein the monomer (B) includes a monomer (B-1) having an acidic group; [7] The dental composition according to any one of [1] to [6], further comprising a filler (D); [8] The dental composition according to any one of [2] to [7], wherein the weight-average molecular weight per polymerizable group of the compound (A) is 1,250 or more and less than 20,000; [9] A dental composite resin comprising the dental composition according to any one of [1] to [8];

[10] A self-adhesive dental composite resin comprising the dental composition according to any one of [1] to [8];

[11] A dental cement comprising the dental composition according to any one of [1] to [8]; Includes. [Effects of the Invention]

[0014] The present invention provides a dental composition that exhibits low polymerization shrinkage stress and excellent mechanical strength after curing. Due to these characteristics, the dental composition is suitable for use in dental composite resins, self-adhesive dental composite resins, dental cements, and the like. [Brief explanation of the drawings]

[0015] [Figure 1]FIG. 4 is a schematic diagram for explaining how to determine the glass transition temperature when the glass transition in FIG. 3 changes stepwise in accordance with JIS K 7121-1987 "Method for determining glass transition temperature." DETAILED DESCRIPTION OF THE INVENTION

[0016] The dental composition of the present invention is a dental composition containing a compound (A) (hereinafter sometimes referred to as "compound (A)") having a weight-average molecular weight of 1,000 to 80,000, a Tg of less than 40°C, and a solubility in acetone at 25°C of less than 50 g / L, a monomer (B) (hereinafter sometimes referred to as "monomer (B)") having a solubility in acetone at 25°C of 50 g / L or more, and a polymerization initiator (C).

[0017] In this specification, "(meth)acrylic" is a general term for methacrylic and acrylic, and the same applies to similar expressions (such as "(meth)acrylic acid" and "(meth)acrylonitrile"). In this specification, the upper and lower limits of numerical ranges (such as the content of each component, values ​​calculated from each component, and physical properties) can be combined as appropriate.

[0018] The reason why the polymerization shrinkage stress generated during polymerization and curing of the dental composition of the present invention is small is unclear, but it is presumed as follows. Specifically, as the polarity difference between compound (A) and monomer (B), expressed as the difference in solubility in acetone, increases, the compatibility between the two decreases. When a composition containing compound (A) and monomer (B), which have a large polarity difference, is cured, phase separation occurs into a phase consisting of the monomer (B) component and a phase consisting of compound (A) component, similar to an island-in-a-sea structure. In the dental composition of the present invention, compound (A) is a flexible material due to its low glass transition temperature, and therefore forms a flexible phase. Therefore, it is presumed that the phase consisting of compound (A) deforms during polymerization and curing of the dental composition, thereby mitigating the polymerization shrinkage stress generated during curing.

[0019] Each component used in the dental composition of the present invention will be described below.

[0020] [Compound (A)] In the present invention, compound (A) has a weight-average molecular weight of 1,000 to 80,000, a Tg of less than 40° C., and a solubility in acetone at 25° C. (hereinafter, sometimes simply referred to as "acetone solubility") of less than 50 g / L. Compound (A) is used in the dental composition of the present invention to impart low polymerization shrinkage stress.

[0021] From the viewpoint of the mechanical strength of the cured product of the dental composition, the compound (A) preferably contains a compound having a polymerizable group. Examples of the polymerizable group include a vinyl group, a (meth)acrylic group, and a (meth)acrylamide group. The (meth)acrylic group and the (meth)acrylamide group are preferred, and the (meth)acrylic group is more preferred. Compounds having a weight-average molecular weight of 1,000 or more and not having a polymerizable group will be described later. Among the compounds (A), compounds (A) having a (meth)acrylic group as a polymerizable group will be described below. Compounds (A) having a (meth)acrylic group can be broadly classified into two types: urethane-modified (meth)acrylic compounds (A-1) having a urethane skeleton (hereinafter sometimes referred to as "urethane-modified (meth)acrylic compounds (A-1)") and (meth)acrylic compounds (A-2) not having a urethane skeleton. From the viewpoint of ease of introduction of a (meth)acrylic group and the effect of reducing polymerization shrinkage stress, urethane-modified (meth)acrylic compounds (A-1) are preferred.

[0022] The urethane-modified (meth)acrylic compound (A-1) can be easily synthesized, for example, by adding a polyol containing a polymer skeleton (described below), a compound having an isocyanate group (—NCO), and a (meth)acrylic compound having a hydroxyl group (—OH). Alternatively, the urethane-modified (meth)acrylic compound (A-1) can be easily synthesized by subjecting a (meth)acrylic compound having a hydroxyl group to a ring-opening addition reaction with a lactone or alkylene oxide, followed by an addition reaction of the resulting compound having a hydroxyl group at one end with a compound having an isocyanate group. A (meth)acrylic compound that imparts a (meth)acrylic group to a polymer can be prepared by, for example, introducing a (meth)acrylic group into a polymer of a monomer having a hydroxyl group through a dehydration condensation reaction of (meth)acrylic acid.

[0023] Urethane (meth)acrylic compound (A-1) The urethanized (meth)acrylic compound (A-1) is preferably a (meth)acrylate having, in addition to a urethane bond, a structure (polymer skeleton) selected from the group consisting of polyester, polycarbonate, polyurethane, polyether, polyconjugated diene, and hydrogenated polyconjugated diene, and more preferably a (meth)acrylate having, in the molecule, at least one polyol moiety selected from the group consisting of polyester, polycarbonate, polyurethane, polyether, polyconjugated diene, and hydrogenated polyconjugated diene, which has a structure derived from an aliphatic diol unit having 4 to 18 carbon atoms and a branched structure, and a urethane bond. These are not particularly limited as long as they have the above structure. For example, polyesters include polymers of dicarboxylic acids (aromatic dicarboxylic acids such as phthalic acid and isophthalic acid; unsaturated aliphatic dicarboxylic acids such as maleic acid) and aliphatic diols having 2 to 18 carbon atoms, polymers of dicarboxylic acids (saturated aliphatic dicarboxylic acids such as adipic acid and sebacic acid) and aliphatic diols having 2 to 18 carbon atoms, polymers of β-propiolactone, polymers of γ-butyrolactone, polymers of δ-valerolactone, polymers of ε-caprolactone, and copolymers thereof. Of these, polymers of dicarboxylic acids (aromatic dicarboxylic acids such as phthalic acid and isophthalic acid; unsaturated aliphatic dicarboxylic acids such as maleic acid) and aliphatic diols having 2 to 12 carbon atoms, and polymers of dicarboxylic acids (saturated aliphatic dicarboxylic acids such as adipic acid and sebacic acid) and aliphatic diols having 2 to 12 carbon atoms are preferred. Examples of polycarbonates include polycarbonates derived from aliphatic diols having 2 to 18 carbon atoms, polycarbonates derived from bisphenol A, and polycarbonates derived from aliphatic diols having 2 to 18 carbon atoms and bisphenol A, with preferred being polycarbonates derived from aliphatic diols having 2 to 12 carbon atoms, polycarbonates derived from bisphenol A, and polycarbonates derived from aliphatic diols having 2 to 12 carbon atoms and bisphenol A. Examples of polyurethanes include polymers of aliphatic diols having 2 to 18 carbon atoms and diisocyanates having 1 to 18 carbon atoms, with preferred being polymers of aliphatic diols having 2 to 12 carbon atoms and diisocyanates having 1 to 12 carbon atoms.Examples of polyethers include polyethylene glycol, polypropylene glycol, polybutylene glycol, and poly(1-methylbutylene glycol). Examples of polyconjugated dienes and hydrogenated polyconjugated dienes include 1,4-polybutadiene, 1,2-polybutadiene, polyisoprene, poly(butadiene-isoprene), poly(butadiene-styrene), poly(isoprene-styrene), polyfarnesene, and hydrogenated products thereof. Among these, polyester, polycarbonate, and polyconjugated diene structures are preferred because of their excellent flexibility and water resistance. The urethane-modified (meth)acrylic compound (A-1) can be produced using a polyol having the polymer skeleton described above.

[0024] Examples of compounds having an isocyanate group include hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), trimethylhexamethylene diisocyanate (TMHMDI), tricyclodecane diisocyanate (TCDDI), and adamantane diisocyanate (ADI).

[0025] Examples of the (meth)acrylic compound having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glycerin mono(meth)acrylate, and 2-hydroxy-3-acryloyloxypropyl (meth)acrylate. hydroxy(meth)acrylate compounds such as dipentaerythritol, 2,2-bis[4-[3-(meth)acryloyloxy-2-hydroxypropoxy]phenyl]propane, 1,2-bis[3-(meth)acryloyloxy-2-hydroxypropoxy]ethane, pentaerythritol tri(meth)acrylate, and dipentaerythritol tri- or tetra(meth)acrylate; and hydroxy(meth)acrylamide compounds such as N-hydroxyethyl(meth)acrylamide and N,N-bis(2-hydroxyethyl)(meth)acrylamide.

[0026] Examples of the aliphatic diol having a branched structure and 4 to 18 carbon atoms include 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,3-butanediol, 2-methyl-1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 2,7-dimethyl-1,8-octanediol, 2-methyl-1,9-nonanediol, 2,8-dimethyl-1,9-nonanediol, 2-methyl-1,10-decanediol, 2,9-dimethyl-1,10-decanediol, and 2-methyl-1,11-undeca. Examples of the methyl 1,15-pentadecanediol include 2,10-dimethyl-1,11-undecanediol, 2-methyl-1,12-dodecanediol, 2,11-dimethyl-1,12-dodecanediol, 2-methyl-1,13-tridecanediol, 2,12-dimethyl-1,13-tridecanediol, 2-methyl-1,14-tetradecanediol, 2,13-dimethyl-1,14-tetradecanediol, 2-methyl-1,15-pentadecanediol, 2,14-dimethyl-1,15-pentadecanediol, 2-methyl-1,16-hexadecanediol, and 2,15-dimethyl-1,16-hexadecanediol. Among these, from the viewpoint of excellent curability of the dental composition, it is preferable to use an aliphatic diol having 5 to 12 carbon atoms and a methyl group in the side chain, such as 2-methyl-1,4-butanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 2,7-dimethyl-1,8-octanediol, 2-methyl-1,9-nonanediol, or 2,8-dimethyl-1,9-nonanediol, as the polyol component; 2-methyl-1,4-butanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, or 2,7-dimethyl-1,8-octanediol are more preferable, and 3-methyl-1,5-pentanediol or 2-methyl-1,8-octanediol are even more preferable.

[0027] The addition reaction between a compound having an isocyanate group and a (meth)acrylic compound having a hydroxyl group can be carried out according to a known method, and there are no particular limitations.

[0028] The resulting urethane-modified (meth)acrylic compound (A-1) may be a reaction product of any combination of a polyol having at least one structure selected from the group consisting of polyester, polycarbonate, polyurethane, polyether, polyconjugated diene, and hydrogenated polyconjugated diene, a compound having an isocyanate group, and a (meth)acrylic compound having a hydroxyl group. The glass transition temperature and acetone solubility of the urethane-modified (meth)acrylic compound (A-1) can be adjusted by adjusting the skeleton and molecular weight of the structure (polymer skeleton) selected from the group consisting of polyester, polycarbonate, polyurethane, polyether, polyconjugated diene, and hydrogenated polyconjugated diene.

[0029] The weight average molecular weight per polymerizable group in the urethane-modified (meth)acrylic compound (A-1) is preferably 1,250 or more and less than 20,000, more preferably 1,500 or more and 17,500 or less, even more preferably 1,800 or more and 16,000 or less, and particularly preferably 2,500 or more and 15,000 or less. When the number of polymerizable groups in the urethane-modified (meth)acrylic compound (A-1) is within the above range, appropriate crosslinking occurs, making it possible to more effectively suppress polymerization shrinkage stress while maintaining mechanical strength.

[0030] (Meth)acrylic compounds without a urethane skeleton (A-2) The (meth)acrylic compound (A-2) without a urethane skeleton has a structure (polymer skeleton) selected from the group consisting of polyester, polycarbonate, polyurethane, polyether, polyconjugated diene, and hydrogenated polyconjugated diene. These are not particularly limited as long as they have the above structure. Examples of polyesters include polymers of phthalic acid and alkylene diols having 2 to 12 carbon atoms, polymers of adipic acid and alkylene glycols having 2 to 12 carbon atoms, polymers of maleic acid and alkylene diols having 2 to 12 carbon atoms, polymers of β-propiolactone, polymers of γ-butyrolactone, polymers of δ-valerolactone, polymers of ε-caprolactone, and copolymers thereof. Examples of polycarbonates include polycarbonates derived from aliphatic diols having 2 to 12 carbon atoms, polycarbonates derived from bisphenol A, and polycarbonates derived from aliphatic diols having 2 to 12 carbon atoms and bisphenol A. Examples of polyurethanes include polymers of aliphatic diols having 2 to 12 carbon atoms and diisocyanates having 1 to 12 carbon atoms. Examples of polyethers include polyethylene glycol, polypropylene glycol, polybutylene glycol, and poly(1-methylbutylene glycol). Examples of polyconjugated dienes and hydrogenated polyconjugated dienes include 1,4-polybutadiene, 1,2-polybutadiene, polyisoprene, poly(butadiene-isoprene), poly(butadiene-styrene), poly(isoprene-styrene), polyfarnesene, and hydrogenated products thereof. Among these, polyester, polycarbonate, and polyconjugated diene structures are preferred in terms of excellent flexibility and water resistance. The above-mentioned polyols having a polymer skeleton can be used to produce the (meth)acrylic compound (A-2) without a urethane skeleton. The glass transition temperature and acetone solubility of the (meth)acrylic compound (A-2) having no urethane skeleton can be adjusted by adjusting the skeleton and molecular weight of the structure (polymer skeleton) selected from the group consisting of polyester, polycarbonate, polyurethane, polyether, polyconjugated diene, and hydrogenated polyconjugated diene.

[0031] Examples of the (meth)acrylic compound having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glycerin mono(meth)acrylate, and 2-hydroxy-3-acryloyloxypropyl (meth)acrylate. hydroxy(meth)acrylate compounds such as dipentaerythritol, 2,2-bis[4-[3-(meth)acryloyloxy-2-hydroxypropoxy]phenyl]propane, 1,2-bis[3-(meth)acryloyloxy-2-hydroxypropoxy]ethane, pentaerythritol tri(meth)acrylate, and dipentaerythritol tri- or tetra(meth)acrylate; and hydroxy(meth)acrylamide compounds such as N-hydroxyethyl(meth)acrylamide and N,N-bis(2-hydroxyethyl)(meth)acrylamide.

[0032] The (meth)acrylic compound (A-2) obtained without a urethane skeleton may be a reaction product of any combination of the above-mentioned polyol having at least one structure selected from the group consisting of polyester, polycarbonate, polyurethane, polyether, polyconjugated diene, and hydrogenated polyconjugated diene, and a (meth)acrylic compound having a hydroxyl group.

[0033] If the number of polymerizable groups in the (meth)acrylic compound (A-2) having no urethane skeleton is too large, the crosslinking density will be high, and the polymerization shrinkage stress may not be sufficiently reduced. On the other hand, if the number of polymerizable groups is too small, the crosslinking density will be low, and the mechanical strength may be reduced. Therefore, the weight average molecular weight per polymerizable group in the (meth)acrylic compound (A-2) having no urethane skeleton is preferably 1,250 or more and less than 20,000, more preferably 1,500 or more and 17,500 or less, even more preferably 1,800 or more and 16,000 or less, and particularly preferably 2,500 or more and 15,000 or less.

[0034] Compounds with a weight-average molecular weight of 1,000 or more that do not have a polymerizable group Compounds having a weight-average molecular weight of 1,000 or more and no polymerizable group can be classified into two types: compound (A-3) having a urethane skeleton and no polymerizable group but a weight-average molecular weight of 1,000 or more (hereinafter, sometimes referred to as "compound (A-3)"), and compound (A-4) having a weight-average molecular weight of 1,000 or more and no urethane skeleton or polymerizable group (hereinafter, sometimes referred to as "compound (A-4)"), of which compound (A-3) is preferred. In one embodiment, a dental composition is provided that contains compound (A), monomer (B), and polymerization initiator (C) but does not contain compound (A-3) and / or compound (A-4).

[0035] In addition to urethane bonds, compound (A-3) has a structure (polymer skeleton) selected from the group consisting of polyester, polycarbonate, polyurethane, polyether, polyconjugated diene, and hydrogenated polyconjugated diene. These are not particularly limited as long as they have the above structure. Examples of polyesters include polymers of phthalic acid and alkylene diols having 2 to 12 carbon atoms, polymers of adipic acid and alkylene glycols having 2 to 12 carbon atoms, polymers of maleic acid and alkylene diols having 2 to 12 carbon atoms, polymers of β-propiolactone, polymers of γ-butyrolactone, polymers of δ-valerolactone, polymers of ε-caprolactone, and copolymers thereof. Examples of polycarbonates include polycarbonates derived from aliphatic diols having 2 to 12 carbon atoms, polycarbonates derived from bisphenol A, and polycarbonates derived from aliphatic diols having 2 to 12 carbon atoms and bisphenol A. Examples of polyurethanes include polymers of aliphatic diols having 2 to 12 carbon atoms and diisocyanates having 1 to 12 carbon atoms. Examples of polyethers include polyethylene glycol, polypropylene glycol, polybutylene glycol, and poly(1-methylbutylene glycol). Examples of polyconjugated dienes and hydrogenated polyconjugated dienes include 1,4-polybutadiene, 1,2-polybutadiene, polyisoprene, poly(butadiene-isoprene), poly(butadiene-styrene), poly(isoprene-styrene), polyfarnesene, and hydrogenated products thereof. Among these, polyester, polycarbonate, and polyconjugated diene structures are preferred in terms of excellent flexibility and water resistance. To produce a compound having a weight-average molecular weight of 1,000 or more and no polymerizable group, a polyol having the above-mentioned polymer skeleton can be used. The glass transition temperature and acetone solubility of the compound (A-3) can be adjusted by adjusting the skeleton and molecular weight of the structure (polymer skeleton) selected from the group consisting of polyester, polycarbonate, polyurethane, polyether, polyconjugated diene, and hydrogenated polyconjugated diene.

[0036] Examples of compounds having an isocyanate group include hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), trimethylhexamethylene diisocyanate (TMHMDI), tricyclodecane diisocyanate (TCDDI), and adamantane diisocyanate (ADI).

[0037] The compound having a hydroxyl group is not particularly limited as long as it does not have a polymerizable group, and known compounds can be used. Examples of the compound having a hydroxyl group include the above-mentioned polyols.

[0038] The addition reaction between a compound having an isocyanate group and a compound having a hydroxyl group can be carried out according to a known method, and there are no particular limitations.

[0039] The compound (A-3) obtained may be a polyol having at least one structure selected from the group consisting of polyester, polycarbonate, polyurethane, polyether, polyconjugated diene, and hydrogenated polyconjugated diene, or a reaction product of a polyol and a compound having an isocyanate group.

[0040] The weight-average molecular weight (Mw) of the compound (A) contributes to obtaining the desired solubility in acetone, and from the viewpoint of the effect of reducing viscosity and polymerization shrinkage stress, is 1,000 to 80,000, preferably 2,000 to 50,000, and more preferably 3,000 to 20,000. Note that the weight-average molecular weight (Mw) in the present invention means the weight-average molecular weight in terms of polystyrene determined by gel permeation chromatography (GPC), and can be measured by a known method.

[0041] In order to obtain the effect of reducing polymerization shrinkage stress, the polarity difference between the compound (A) and the monomer (B) is important, and the compound (A) must have low solubility in acetone compared to the monomer (B) which has high solubility in acetone. From the viewpoint of compatibility with the monomer component (B), the solubility of the compound (A) in acetone must be less than 50 g / L, preferably less than 30 g / L, more preferably less than 25 g / L, even more preferably less than 20 g / L, and particularly preferably less than 10 g / L.

[0042] The solubility parameter (SP) value may be used as a parameter for measuring the polarity difference and compatibility difference between the compound (A) and the monomer (B). The SP value is a measure of solubility, with a larger value indicating higher polarity and a smaller value indicating lower polarity. From the viewpoint of the effect of reducing polymerization shrinkage stress, the difference in the SP value between the compound (A) and the monomer (B) is 1.0 (cal / cm 3 ) 1 / 2 More than 2.0 (cal / cm 3 ) 1 / 2 More preferably, 3.0 (cal / cm 3 ) 1 / 2 More preferably, 4.0 (cal / cm 3 ) 1 / 2The above is particularly preferable. The SP value can be measured by the following method: 0.5 g of sample is weighed into a 100 mL Erlenmeyer flask and dissolved in 10 mL of acetone. While stirring with a magnetic stirrer, hexane is added dropwise to the solution, and the amount of hexane added (vh) at which the solution becomes cloudy (cloudy point) is determined. Next, when deionized water is used instead of hexane, the amount of deionized water added (vd) at the cloudy point is determined. From vh and vd, the SP value can be calculated using the formula given in Suh and Clarke, JPSA-1, 5, 1671-1681 (1967). If the SP value cannot be determined using the above method, for example, because the sample is insoluble in acetone, it can be estimated using the method proposed by Fedors et al. For details, please refer to "POLYMER ENGINEERING AND SCIENCE, February 1974, Vol. 14, No. 2, Robert F. Fedors. (pp. 147-154)." More specifically, it can be calculated using the following formula (A) by the Fedors method. SP value = (CED value) 1 / 2 =(E / V) 1 / 2 Formula (A) In the formula (A), E is the cohesive energy (cal / mol), and V is the molar volume (cm 3 / mol).

[0043] Compound (A) must have at least one glass transition temperature (hereinafter, sometimes simply referred to as "Tg") below 40°C. The Tg is not particularly limited as long as it is below 40°C. However, from the viewpoint of a more excellent effect of reducing polymerization shrinkage stress, it is preferably in the temperature range of -100°C to 30°C, more preferably in the temperature range of -75°C to 15°C, and even more preferably in the temperature range of -60°C to 10°C. If compound (A) only has a Tg of 40°C or higher, it will enter a glassy state at the temperature during polymerization, and the effect of reducing polymerization shrinkage stress will not be exhibited. As will be described later, compound (A) may have multiple Tgs. In this case, it is sufficient that one of the Tgs is below 40°C, and the other Tgs may be in the temperature range of 40°C or higher. For example, a compound having two Tgs, one of which is -42°C and the other of which is 44.6°C, is also included in compound (A). In one embodiment, among the urethane-modified (meth)acrylic compounds (A-1), a urethane-modified (meth)acrylic compound (A-1a) that does not contain an aromatic ring in its skeleton is preferred in order to prevent the glass transition temperature from becoming too high, in order to adjust the glass transition temperature to less than 40° C. In another embodiment, a urethane-modified (meth)acrylic compound (A-1b) that does not contain a cyclic structure (aromatic ring, heterocyclic ring, or alicyclic structure) in its skeleton is preferred in order to adjust the glass transition temperature to less than 40° C. In another embodiment, a polymerization initiator (C) is provided, the polymerization initiator (C) comprising: a compound (A); a monomer (B) having a solubility in acetone at 25°C of 50 g / L or more; The compound (A) has a weight-average molecular weight of 1,000 to 80,000, a Tg of less than 40°C, and a solubility in acetone at 25°C of less than 50 g / L, Examples of dental compositions include those having a Tg of less than 40°C, a solubility in acetone at 25°C of 50 g / L or more, and not containing compounds with a weight-average molecular weight of 2,000 or more (e.g., (meth)acrylic compounds, etc.).

[0044] The glass transition temperature (Tg) in the present invention is the midpoint glass transition temperature (T mgThe glass transition temperature (Tg) used in the present invention is specifically determined by measurement based on JIS K 7121-1987 (2012 supplement). In the following, the baseline means a DTA curve or DSC curve in a temperature range where no glass transition or reaction occurs in the measurement sample, as defined in JIS K 7121-1987 (2012 supplement). The midpoint glass transition temperature (T mg ) is the temperature at the point where a line equidistant from the extended line of each baseline intersects with the curve of the step-like change in the glass transition. ig ), extrapolated glass transition finish temperature (T eg ), and midpoint glass transition temperature (T mg ) indicates the extrapolated glass transition onset temperature (T ig The extrapolated glass transition end temperature (T) is the temperature at the intersection of a straight line extending from the low-temperature baseline to the high-temperature side and a tangent drawn at the point where the gradient of the curve of the step-like change in the glass transition is maximum. eg ) is the temperature at the intersection of a straight line extending the high-temperature baseline to the low-temperature side and a tangent drawn at the point where the gradient of the curve of the step-like change in the glass transition is maximum. In addition, in heat flux DSC, when a peak appears on the high-temperature side of the step-like change, the extrapolated glass transition end temperature (T eg ) is the temperature at the intersection of a straight line extending the high-temperature baseline toward the low-temperature side and a tangent drawn at the point where the slope of the curve on the high-temperature side of the peak is maximum.

[0045] The method and conditions for measuring the glass transition temperature in the present invention are as described in the Examples below using heat flux DSC.

[0046] In one embodiment, compound (A) preferably has two or more glass transition temperatures, more preferably two. The two or more Tg's preferably include at least one Tg in the lower temperature range and at least one Tg in the higher temperature range. In this embodiment, the Tg at the first point (lower temperature range) is preferably from -100°C to 20°C, more preferably from -75°C to 15°C, and even more preferably from -60°C to 10°C. In this embodiment, the Tg at the second point (higher temperature range) is preferably from 20°C to less than 80°C, more preferably from 25°C to less than 70°C, and even more preferably from 30°C to less than 65°C. One embodiment of the dental composition is one in which compound (A) has one or more glass transition temperatures in the temperature range from -100°C to 20°C and one or more glass transition temperatures in the temperature range from 20°C to less than 80°C.

[0047] Another embodiment includes a polymerizable composition comprising a compound (A), a monomer (B) having a solubility in acetone at 25°C of 50 g / L or more, and a polymerization initiator (C), The compound (A) has a weight-average molecular weight of 1,000 to 80,000, a Tg of less than 40°C, and a solubility in acetone at 25°C of less than 50 g / L, Examples of dental compositions include those that do not have two or more glass transition temperatures and do not contain a compound with a weight-average molecular weight of 2,000 or more (for example, a (meth)acrylic compound, etc.). In another embodiment, a polymerization initiator (C) is provided, the polymerization initiator (C) comprising: a compound (A); a monomer (B) having a solubility in acetone at 25°C of 50 g / L or more; The compound (A) has a weight-average molecular weight of 1,000 to 80,000, a Tg of less than 40°C, and a solubility in acetone at 25°C of less than 50 g / L, Examples of dental compositions include those that do not contain a (meth)acrylic compound that does not have two or more glass transition temperatures, has a weight average molecular weight of 5,000 to 50,000, and has a weight average molecular weight per (meth)acrylic group of 1,250 or more but less than 20,000.

[0048] The viscosity of compound (A) at 25°C is preferably 1,000 to 10,000,000 cps, more preferably 5,000 to 7,500,000 cps, and even more preferably 10,000 to 7,000,000 cps, from the viewpoints of operability and the effect of reducing polymerization shrinkage stress. The viscosity in the present invention refers to the viscosity measured at 25°C using a Brookfield viscometer. Measurement conditions such as time and rotation speed are appropriately adjusted depending on the viscosity range.

[0049] As the compound (A), commercially available products may be used. Examples of commercially available products include urethane polymers having a polymerizable group at the end, such as the "Art Resin" series (UN-7600, UN7700) manufactured by Negami Chemical Industrial Co., Ltd., and the "Kuraprene" series (LIR-30, LIR-50, LIR-390, LIR-403, LIR-410, UC-102M, UC-203M, LIR-700) having a polyisoprene skeleton or a polybutadiene skeleton manufactured by Kuraray Co., Ltd. , LBR-302, LBR-307, LBR-305, LBR-352, LBR-361, L-SBR-820, L-SBR-841), polyols manufactured by Kuraray Co., Ltd. (P-6010, P-5010, P-4010, P-3010, P-2010, P-1010, F-3010, F2010, F-1010, P-2011, P-1020, P-2020, P-530, P-2030, P-2050, C-2090), liquid polybutadiene "NISSO-PB" manufactured by Nippon Soda Co., Ltd. (B-1000, B-2000, B-3000, BI-2000, BI-3000, G-1000, G2000, G3000, GI-1000, GI-2000, GI-3000, TEAI-1000, TE-2000, TE-4000, JP-100, JP-200), etc., and UN-7600, UN770 Preferred are UN-0, LBR-302, LBR-307, LBR-305, LBR-352, LBR-361, L-SBR-820, UC-102M, UC-203M, C-2090, P-2020, P-2050, B3000, BI-2000, BI-3000, TEAI-1000, TE-2000, and TE-4000, and more preferred are UN-7600, UC-102M, TE-2000, and TE-4000.

[0050] The content of compound (A) in the dental composition of the present invention is preferably 0.1 to 50 parts by mass, based on 100 parts by mass of the total of compound (A) and monomer (B), from the viewpoints of mechanical strength, paste properties, and the effect of reducing polymerization shrinkage stress. From the viewpoints of easily causing phase separation with monomer (B) such as a sea-island structure, and from the viewpoint of mechanical strength, the content of compound (A) is more preferably 0.5 to 40 parts by mass, even more preferably 1 to 35 parts by mass, even more preferably 1 to 25 parts by mass, and particularly preferably 1 to 18 parts by mass. In one embodiment, the content of compound (A) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, based on the total amount of the dental composition, from the viewpoints of mechanical strength, paste properties, and the effect of reducing polymerization shrinkage stress. Furthermore, the content of compound (A) is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, based on the total amount of the dental composition, from the viewpoints of mechanical strength, paste properties, and the effect of reducing polymerization shrinkage stress.

[0051] [Monomer (B)] Monomer (B) is used that has high solubility in acetone. Specifically, the solubility in acetone at 25°C is 50 g / L or more, preferably 75 g / L or more, and more preferably 90 g / L or more. Monomer (B) may be used alone or in combination of two or more. Examples of monomer (B) include a monomer (B-1) having an acidic group, a hydrophobic monomer (B-2) not having an acidic group, and a hydrophilic monomer (B-3) not having an acidic group. When two or more monomers (B) are used, a mixture thereof having high solubility in acetone (a mixture having a solubility in acetone at 25°C of 50 g / L or more) may be used.

[0052] As the polarity difference between compound (A) and monomer (B) increases, their compatibility decreases, leading to a tendency for phase separation between a phase consisting of monomer (B) and a phase consisting of compound (A), similar to an islands-in-a-sea structure. Therefore, the difference between the solubility of monomer (B) in acetone and the solubility of compound (A) in acetone (solubility of monomer (B) in acetone - solubility of compound (A) in acetone) is preferably 10 g / L or more, more preferably 20 g / L or more, and even more preferably 30 g / L or more. Since the greater the polarity difference, the more likely phase separation occurs, the upper limit of the difference between the solubility of monomer (B) in acetone and the solubility of compound (A) in acetone is not particularly limited, and may be 300 g / L or less, 200 g / L or less, or 150 g / L or less. Furthermore, in such an embodiment, the low glass transition temperature of compound (A) allows compound (A) to form a more flexible phase, resulting in a dental composition with an excellent effect of reducing polymerization shrinkage stress.

[0053] Monomers with acidic groups (B-1) The monomer (B-1) having an acid group has an acid etching effect and a priming effect, and is a component that provides demineralization and penetration. The monomer (B-1) having an acid group is also polymerizable and provides a hardening effect. The inclusion of the monomer (B-1) having an acid group improves the adhesiveness and durability of the adhesive to tooth structure.

[0054] Examples of the monomer (B-1) having an acidic group include a monomer having at least one acidic group such as a phosphate group, a pyrophosphate group, a thiophosphate group, a phosphonate group, a sulfonic acid group, or a carboxylic acid group, and at least one polymerizable group such as a (meth)acryloyl group, a vinyl group, or a styrene group. From the viewpoint of adhesion to tooth structure, a phosphate group-containing monomer is preferred. Specific examples of the monomer (B-1) having an acidic group are listed below.

[0055] Examples of the phosphate group-containing 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)acryloyloxyoctyl dihydrogen phosphate, 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)acryloyl Examples of the hydrogen phosphate include acryloyloxycosyl 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[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 acid chlorides, alkali metal salts, and ammonium salts thereof.

[0056] Examples of the pyrophosphate group-containing monomer 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.

[0057] Examples of the thiophosphate group-containing monomer include 2-(meth)acryloyloxyethyl dihydrogenthiophosphate, 3-(meth)acryloyloxypropyl dihydrogenthiophosphate, 4-(meth)acryloyloxybutyl dihydrogenthiophosphate, 5-(meth)acryloyloxypentyl dihydrogenthiophosphate, 6-(meth)acryloyloxyhexyl dihydrogenthiophosphate, 7-(meth)acryloyloxyheptyl dihydrogenthiophosphate, and 8-(meth)acryloyloxyoctyl dihydrogenthiophosphate. Examples of suitable acryloyloxycarbonyl phosphates include acryloyloxycarbonyl phosphate, 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)acryloyloxyicosyl dihydrogen thiophosphate, and acid chlorides, alkali metal salts, and ammonium salts thereof.

[0058] Examples of the phosphonic acid group-containing monomer include 2-(meth)acryloyloxyethyl phenylphosphonate, 5-(meth)acryloyloxypentyl-3-phosphonopropionate, 6-(meth)acryloyloxyhexyl-3-phosphonopropionate, 10-(meth)acryloyloxydecyl-3-phosphonopropionate, 6-(meth)acryloyloxyhexyl-3-phosphonoacetate, 10-(meth)acryloyloxydecyl-3-phosphonoacetate, and acid chlorides, alkali metal salts, and ammonium salts thereof.

[0059] Examples of the sulfonic acid group-containing monomer include 2-(meth)acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid, and 2-sulfoethyl(meth)acrylate.

[0060] Carboxylic acid group-containing monomers include monomers having one carboxy group in the molecule and monomers having multiple carboxy groups in the molecule.

[0061] 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 the acryloyloxybenzoic acid include aromatic 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.

[0062] Examples of 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)acryloyloxyhexane Examples include 4-(meth)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.

[0063] Among these monomers (B-1) having an acidic group, (meth)acrylic monomers containing a phosphate group or a pyrophosphate group are preferred because they exhibit superior adhesion to tooth structure, and phosphate group-containing (meth)acrylic monomers are particularly preferred. Among these, divalent phosphate group-containing (meth)acrylic monomers having an alkyl or alkylene group with 6 to 20 carbon atoms as the main chain in the molecule are more preferred because they exhibit high decalcification properties and high adhesion in the absence of organic solvents, and divalent phosphate group-containing (meth)acrylic monomers having an alkylene group with 8 to 12 carbon atoms as the main chain in the molecule, such as 10-methacryloyloxydecyldihydrogenphosphate, are particularly preferred.

[0064] The monomer (B-1) having an acidic group may be used alone or in combination of two or more. Adhesion may be reduced when the content of the monomer (B-1) having an acidic group is either too high or too low. Therefore, the content of the monomer (B-1) having an acidic group is preferably in the range of 1 to 50 parts by mass, more preferably 3 to 40 parts by mass, and even more preferably 5 to 30 parts by mass, per 100 parts by mass of the total of the compound (A) and the monomer (B) in the dental composition.

[0065] Hydrophobic monomer without acidic group (B-2) The hydrophobic monomer (B-2) without an acidic group (hereinafter referred to as hydrophobic monomer (B-2)) improves the mechanical strength, handleability, etc. of the dental composition. The hydrophobic monomer (B-2) is preferably a radical monomer without an acidic group and having a polymerizable group. From the viewpoint of ease of radical polymerization, the polymerizable group is more preferably a (meth)acrylic group and / or a (meth)acrylamide group. The hydrophobic monomer (B-2) refers to a monomer without an acidic group and having a solubility in water at 25°C of less than 10% by mass. Examples of the hydrophobic monomer (B-2) include crosslinkable monomers such as bifunctional monomers of aromatic compounds, bifunctional monomers of aliphatic compounds, and trifunctional or higher functional monomers.

[0066] Examples of aromatic compound-based bifunctional monomers include 2,2-bis((meth)acryloyloxyphenyl)propane, 2,2-bis[4-(3-(meth)acryloyloxy-2-hydroxypropoxy)phenyl]propane, 2,2-bis(4-(meth)acryloyloxyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxypolyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxydiethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytriethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytetraethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxypentaethoxyphenyl)propane, phenyl)propane, 2,2-bis(4-(meth)acryloyloxydipropoxyphenyl)propane, 2-(4-(meth)acryloyloxydiethoxyphenyl)-2-(4-(meth)acryloyloxyethoxyphenyl)propane, 2-(4-(meth)acryloyloxydiethoxyphenyl)-2-(4-(meth)acryloyloxytriethoxyphenyl)propane, 2-(4-(meth)acryloyloxydipropoxyphenyl)-2-(4-(meth)acryloyloxytriethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxypropoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxyisopropoxyphenyl)propane, and the like. Among these, 2,2-bis[4-(3-methacryloyloxy-2-hydroxypropoxy)phenyl]propane (commonly known as "Bis-GMA"), 2,2-bis(4-(meth)acryloyloxyethoxyphenyl)propane, 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane (having an average number of moles of ethoxy groups added of 2.6, commonly known as "D-2.6E"), 2,2-bis(4-(meth)acryloyloxydiethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytriethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytetraethoxyphenyl)propane, and 2,2-bis(4-(meth)acryloyloxypentaethoxyphenyl)propane are preferred.

[0067] Examples of aliphatic compound-based bifunctional monomers include glycerol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,2-bis(3-methacryloyloxy-2-hydroxypropoxy)ethane, 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)di(meth)acrylate, N-methacryloyloxyethyl acrylamide, and N-methacryloyloxypropylamide. Among these, triethylene glycol diacrylate, triethylene glycol dimethacrylate (commonly known as "3G"), neopentyl glycol di(meth)acrylate, 1,2-bis(3-methacryloyloxy-2-hydroxypropoxy)ethane, 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate (commonly known as "UDMA"), 1,10-decanediol dimethacrylate (commonly known as "DD"), 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate, and N-methacryloyloxyethyl acrylamide (commonly known as "MAEA") are preferred.

[0068] Examples of trifunctional or higher functional monomers include trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolmethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, N,N-(2,2,4-trimethylhexamethylene)bis[2-(aminocarboxy)propane-1,3-diol]tetra(meth)acrylate, and 1,7-diacryloyloxy-2,2,6,6-tetra(meth)acryloyloxymethyl-4-oxaheptane. Among these, N,N-(2,2,4-trimethylhexamethylene)bis[2-(aminocarboxy)propane-1,3-diol]tetramethacrylate is preferred.

[0069] Among the hydrophobic monomers (B-2), aromatic bifunctional monomers and aliphatic bifunctional monomers are preferred from the viewpoints of mechanical strength and ease of handling. Bis-GMA and D-2.6E are preferred aromatic bifunctional monomers. Glycerol di(meth)acrylate, 3G, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, DD, 1,2-bis(3-methacryloyloxy-2-hydroxypropoxy)ethane, UDMA, and MAEA are preferred aliphatic bifunctional monomers.

[0070] Among the above hydrophobic monomers (B-2), Bis-GMA, D-2.6E, 3G, UDMA, DD, and MAEA are more preferred, with D-2.6E, DD, and MAEA being even more preferred, from the standpoints of initial adhesion to tooth structure, adhesion durability, and mechanical strength.

[0071] The hydrophobic monomer (B-2) may be used alone or in combination with two or more. If the content of the hydrophobic monomer (B-2) is too high, the composition may have reduced penetration into the tooth structure, resulting in reduced adhesive strength. If the content is too low, the effect of improving mechanical strength may not be sufficiently achieved. Therefore, the content of the hydrophobic monomer (B-2) is preferably in the range of 20 to 99 parts by mass, more preferably 40 to 95 parts by mass, and even more preferably 60 to 92 parts by mass, per 100 parts by mass of the total of the compound (A) and the monomer (B) in the dental composition. In some embodiments, the content of the hydrophobic monomer (B-2) is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, based on the total amount of the dental composition, from the viewpoints of mechanical strength, paste properties, and the effect of reducing polymerization shrinkage stress. Furthermore, from the viewpoints of mechanical strength, paste properties, and the effect of reducing polymerization shrinkage stress, the content of the hydrophobic monomer (B-2) is preferably 48 mass% or less, more preferably 40 mass% or less, and even more preferably 35 mass% or less, of the total amount of the dental composition.

[0072] Hydrophilic monomers without acidic groups (B-3) The dental composition of the present invention preferably further contains a hydrophilic monomer (B-3) (hereinafter referred to as hydrophilic monomer (B-3)) that does not have an acidic group. The hydrophilic monomer (B-3) not only promotes penetration of the components of the dental composition into the tooth structure, but also penetrates the tooth structure itself and adheres to the organic component (collagen) in the tooth structure. The hydrophilic monomer (B-3) is preferably a radical monomer that does not have an acidic group and has a polymerizable group. From the viewpoint of ease of radical polymerization, the polymerizable group is more preferably a (meth)acrylic group and / or a (meth)acrylamide group. The hydrophilic monomer (B-3) refers to a monomer that does not have an acidic group and has a solubility in water at 25°C of 10% by mass or more, preferably a solubility of 30% by mass or more, and more preferably a monomer that is soluble in water at any ratio at 25°C. The hydrophilic monomer (B-3) is preferably one having a hydrophilic group such as a hydroxyl group, an oxymethylene group, an oxyethylene group, an oxypropylene group, or an amide group, and examples thereof include 2-hydroxyethyl (meth)acrylate (HEMA), 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 1,3-dihydroxypropyl (meth)acrylate, 2,3-dihydroxypropyl (meth)acrylate, 2-((meth)acryloyloxy)ethyltrimethylammonium chloride, and polyethylene glycol di(meth)acrylate (containing 9 or more oxyethylene groups). hydrophilic monofunctional (meth)acrylate monomers such as N-methylol(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N,N-bis(2-hydroxyethyl)(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-ethoxymethyl(meth)acrylamide, diacetone(meth)acrylamide, 4-(meth)acryloylmorpholine, N-trihydroxymethyl-N-methyl(meth)acrylamide, N,N-dimethylacrylamide, and N,N-diethylacrylamide; and hydrophilic monofunctional (meth)acrylamide monomers such as N-methylol(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N,N-bis(2-hydroxyethyl)(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-ethoxymethyl(meth)acrylamide, diacetone(meth)acrylamide, 4-(meth)acryloylmorpholine, N-trihydroxymethyl-N-methyl(meth)acrylamide, N,N-dimethylacrylamide, and N,N-diethylacrylamide.

[0073] Among these hydrophilic monomers (B-3), from the viewpoint of adhesion to tooth structure, 2-hydroxyethyl (meth)acrylate, 2,3-dihydroxypropyl (meth)acrylate, and hydrophilic monofunctional (meth)acrylamide monomers are preferred, and 2-hydroxyethyl (meth)acrylate, N,N-dimethylacrylamide, and N,N-diethylacrylamide are more preferred. One type of hydrophilic monomer (B-3) may be blended alone, or two or more types may be blended in combination.

[0074] If the content of the hydrophilic monomer (B-3) in the present invention is too low, the effect of improving adhesive strength may not be sufficiently obtained, and if it is too high, the mechanical strength may decrease. Therefore, the content of the hydrophilic monomer (B-3) is preferably in the range of 0 to 50 parts by mass, more preferably in the range of 0 to 40 parts by mass, and even more preferably in the range of 0 to 30 parts by mass, relative to 100 parts by mass of the total of the compound (A) and the monomer (B) in the dental composition. The content of the hydrophilic monomer (B-3) may be 0 part by mass.

[0075] Since phase separation in the dental composition of the present invention is likely to become clear, the difference in solubility in acetone at 25°C between compound (A) and monomer (B) is preferably 30 g / L or more, more preferably 40 g / L or more, and even more preferably 50 g / L or more.

[0076] [Polymerization initiator (C)] Polymerization initiators (C) are broadly classified into photopolymerization initiators and chemical polymerization initiators, and photopolymerization initiators are further classified into water-soluble photopolymerization initiators (C-1) and water-insoluble photopolymerization initiators (C-2). As the polymerization initiator (C), only the water-soluble photopolymerization initiator (C-1) may be used, only the water-insoluble photopolymerization initiator (C-2) may be used, or the water-soluble photopolymerization initiator (C-1) and the water-insoluble photopolymerization initiator (C-2) may be used in combination.

[0077] Water-soluble photopolymerization initiator (C-1) The water-soluble photopolymerization initiator (C-1) improves polymerization curing at the hydrophilic tooth surface interface, achieving high adhesive strength. The water-soluble photopolymerization initiator (C-1) has a solubility in water at 25°C of 1.0% by mass or more, preferably 1.5% by mass or more, more preferably 2.0% by mass or more, and even more preferably 2.5% by mass or more. If the solubility is less than 1.0% by mass, the water-soluble photopolymerization initiator (C-1) will not dissolve sufficiently in the water in the tooth at the adhesive interface, making it difficult to promote polymerization at the adhesive interface.

[0078] Examples of the water-soluble photopolymerization initiator (C-1) include water-soluble acylphosphine oxides, water-soluble thioxanthones, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one having a (poly)ethylene glycol chain introduced to the hydroxyl group, 1-hydroxycyclohexyl phenyl ketone having a (poly)ethylene glycol chain introduced to the hydroxyl group and / or phenyl group, and 1-hydroxycyclohexyl phenyl ketone having a -OCHCOO - Na + those in which a (poly)ethylene glycol chain has been introduced into the hydroxyl group and / or phenyl group of 2-hydroxy-2-methyl-1-phenylpropan-1-one; those in which -OCH2COO has been introduced into the phenyl group of 2-hydroxy-2-methyl-1-phenylpropan-1-one - Na + and α-aminoalkylphenones in which the amino group has been converted into a quaternary ammonium salt, such as 2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1.

[0079] Examples of the water-soluble thioxanthones include 2-hydroxy-3-(9-oxo-9H-thioxanthen-4-yloxy)-N,N,N-trimethyl-1-propanaminium chloride, 2-hydroxy-3-(1-methyl-9-oxo-9H-thioxanthen-4-yloxy)-N,N,N-trimethyl-1-propanaminium chloride, 2-hydroxy-3-(9-oxo-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-propanaminium chloride, 2- Hydroxy-3-(3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-propanaminium chloride, 2-hydroxy-3-(3,4-dimethyl-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-propanaminium chloride, 2-hydroxy-3-(1,3,4-trimethyl-9-oxo-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-propanaminium chloride, and the like can be used.

[0080] Examples of the water-soluble acylphosphine oxides include acylphosphine oxides represented by the following general formula (1) or (2).

[0081] [ka]

[0082] [ka]

[0083] In the formula, R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are each independently a linear or branched alkyl group having 1 to 4 carbon atoms or a halogen atom, and M is a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, a magnesium ion, a pyridinium ion (the pyridine ring may have a substituent), or HN+ R 8 R 9 R 10 (In the formula, R 8 , R 9 , and R 10 are each independently an organic group or a hydrogen atom), n is 1 or 2, X is a linear or branched alkylene group having 1 to 4 carbon atoms, and R 7 -CH(CH3)COO(C2H4O) p It is represented by CH3, and p represents an integer of 1 to 1000.

[0084] R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 The alkyl group in R is not particularly limited as long as it is a straight or branched chain alkyl group having 1 to 4 carbon atoms, and examples thereof 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 2-methylpropyl group, and a tert-butyl group. 1 , R 2 , R 3 , R 4 , R 5 , and R 6 The alkyl group of X is preferably a linear alkyl group having 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group. Examples of the alkylene group of X include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, and an n-butylene group. The alkylene group of X is preferably a linear alkylene group having 1 to 3 carbon atoms, more preferably a methylene group or an ethylene group, and even more preferably a methylene group.

[0085] When M is a pyridinium ion, examples of the substituent on the pyridine ring include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), a carboxy group, a linear or branched acyl group having 2 to 6 carbon atoms, a linear or branched alkyl group having 1 to 6 carbon atoms, and a linear or branched alkoxy group having 1 to 6 carbon atoms. M is an alkali metal ion, an alkaline earth metal ion, a magnesium ion, a pyridinium ion (the pyridine ring may have a substituent), or HN + R 8 R 9 R 10 (wherein the symbols have the same meanings as above) is preferred. Examples of alkali metal ions include lithium ion, sodium ion, potassium ion, rubidium ion, and cesium ion. Examples of alkaline earth metal ions include calcium ion, strontium ion, barium ion, and radium ion. R 8 , R 9 , and R 10 Examples of the organic group include the same groups as the substituents on the pyridine ring (excluding halogen atoms).

[0086] Among these, R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 A compound in which all of M are methyl groups is particularly preferred from the viewpoint of storage stability and color stability in the composition. n+ An example of this is Li + , Na + , K. + , Ca 2+ , Mg 2+Examples of the amine include ammonia, trimethylamine, diethylamine, dimethylaniline, ethylenediamine, triethanolamine, N,N-dimethylamino methacrylate, N,N-dimethylaminobenzoic acid and its alkyl esters, N,N-diethylaminobenzoic acid and its alkyl esters, and N,N-bis(2-hydroxyethyl)-p-toluidine. 7 From the viewpoint of adhesiveness, p is preferably 1 or more, more preferably 2 or more, even more preferably 3 or more, particularly preferably 4 or more, and is preferably 1000 or less, more preferably 100 or less, even more preferably 75 or less, particularly preferably 50 or less.

[0087] Among these water-soluble acylphosphine oxides, the compounds represented by the general formula (1) in which M is Li and the compounds represented by the general formula (1) in which R 7 A compound represented by the general formula (2) synthesized from polyethylene glycol methyl ether methacrylate having a molecular weight of 950, which corresponds to the group represented by the formula (2), is particularly preferred.

[0088] Water-soluble acylphosphine oxides having such a structure can be synthesized according to known methods, and some are commercially available. For example, they can be synthesized by the methods disclosed in JP-A-57-197289 and WO 2014 / 095724. The water-soluble photopolymerization initiator (C-1) may be used alone or in combination of two or more.

[0089] The water-soluble photopolymerization initiator (C-1) may be dissolved in water on the surface of the tooth (wet body) and may be dispersed in the form of a powder in the dental composition, as long as it can selectively enhance the polymerization curing properties at the adhesive interface and inside the resin-impregnated layer.

[0090] When the water-soluble photopolymerization initiator (C-1) is dispersed in the composition as a powder, if the average particle size is too large, it tends to settle, so it is preferably 500 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. On the other hand, if the average particle size is too small, the specific surface area of ​​the powder becomes too large, reducing the amount that can be dispersed in the composition, so it is preferably 0.01 μm or more. That is, the average particle size of the water-soluble photopolymerization initiator (C-1) is preferably in the range of 0.01 to 500 μm, more preferably 0.01 to 100 μm, and even more preferably 0.01 to 50 μm.

[0091] The average particle size of each water-soluble photopolymerization initiator (C-1) powder can be calculated as the volume average particle size after performing image analysis using image analysis particle size distribution measurement software (Mac-View; manufactured by Mountec Co., Ltd.) based on electron microscope photographs of 100 or more particles.

[0092] When the water-soluble photopolymerization initiator (C-1) is dispersed in the composition as a powder, the shape of the initiator is not particularly limited, and various shapes such as spherical, needle-like, plate-like, crushed, etc. can be mentioned. The water-soluble photopolymerization initiator (C-1) can be prepared by a conventionally known method such as a pulverization method, a freeze-drying method, or a reprecipitation method. From the viewpoint of the average particle size of the obtained powder, the freeze-drying method and the reprecipitation method are preferred, and the freeze-drying method is more preferred.

[0093] The content of the water-soluble photopolymerization initiator (C-1) is preferably 0.01 to 20 parts by weight per 100 parts by weight of the total of the compound (A) and the monomer (B) in the dental composition, from the viewpoint of the curability of the resulting dental composition. From the viewpoint of high initial adhesive strength and adhesive durability, and reduction of polymerization shrinkage stress, the content is more preferably 0.05 to 10 parts by weight, and even more preferably 0.1 to 5 parts by weight. If the content of the water-soluble photopolymerization initiator (C-1) is less than 0.01 part by weight, polymerization at the adhesive interface may not proceed sufficiently, resulting in a decrease in adhesive strength. On the other hand, if the content of the water-soluble photopolymerization initiator (C-1) is more than 20 parts by weight, the polymerization performance of the water-soluble photopolymerization initiator (C-1) may be poor, resulting in insufficient adhesive strength and insufficient dissolution, dispersion, and diffusion in the dental composition.

[0094] Non-water-soluble photopolymerization initiator (C-2) From the viewpoint of curability, the dental composition of the present invention may contain, in addition to the water-soluble photopolymerization initiator (C-1), a water-insoluble photopolymerization initiator (C-2) (hereinafter referred to as the water-insoluble photopolymerization initiator (C-2)) having a solubility of less than 1.0 mass% in water at 25°C. The water-insoluble photopolymerization initiator (C-2) used in the present invention may be a known photopolymerization initiator. The water-insoluble photopolymerization initiator (C-2) may be used alone or in combination of two or more.

[0095] Examples of the water-insoluble photopolymerization initiator (C-2) include (bis)acylphosphine oxides, thioxanthones, ketals, α-diketones, coumarins, anthraquinones, benzoin alkyl ether compounds, and α-aminoketone compounds other than the water-soluble photopolymerization initiator (C-1).

[0096] Among the (bis)acylphosphine oxides, examples of the acylphosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylmethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, 2,3,5,6-tetramethylbenzoyldiphenylphosphine oxide, and benzoyldi(2,6-dimethylphenyl)phosphonate. Examples of bisacylphosphine oxides include bis(2,6-dichlorobenzoyl)phenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and bis(2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide.

[0097] Examples of the thioxanthones include thioxanthone and 2-chlorothioxanthen-9-one.

[0098] Examples of the ketals include benzyl dimethyl ketal and benzyl diethyl ketal.

[0099] Examples of the α-diketones include diacetyl, benzyl, dl-camphorquinone, 2,3-pentadione, 2,3-octadione, 9,10-phenanthrenequinone, 4,4′-oxybenzyl, acenaphthenequinone, etc. Among these, dl-camphorquinone is particularly preferred because it has a maximum absorption wavelength in the visible light region.

[0100] Examples of the coumarin compound include 3,3'-carbonylbis(7-diethylaminocoumarin), 3-(4-methoxybenzoyl)coumarin, 3-thienoylcoumarin, 3-benzoyl-5,7-dimethoxycoumarin, 3-benzoyl-7-methoxycoumarin, 3-benzoyl-6-methoxycoumarin, 3-benzoyl-8-methoxycoumarin, 3-benzoylcoumarin, 7-methoxy-3-(p-nitrobenzoyl)coumarin, 3-(p-nitrobenzoyl)coumarin, 3,5-carbonylbis(7-methoxycoumarin), 3-benzoyl-6-bromo Coumarin, 3,3'-carbonylbiscoumarin, 3-benzoyl-7-dimethylaminocoumarin, 3-benzoylbenzo[f]coumarin, 3-carboxycoumarin, 3-carboxy-7-methoxycoumarin, 3-ethoxycarbonyl-6-methoxycoumarin, 3-ethoxycarbonyl-8-methoxycoumarin, 3-acetylbenzo[f]coumarin, 3-benzoyl-6-nitrocoumarin, 3-benzoyl-7-diethylaminocoumarin, 7-dimethylamino-3-(4-methoxybenzoyl)coumarin, 7-diethylamino-3-(4-methoxybenzoyl)coumarin coumarin, 7-diethylamino-3-(4-diethylamino)coumarin, 7-methoxy-3-(4-methoxybenzoyl)coumarin, 3-(4-nitrobenzoyl)benzo[f]coumarin, 3-(4-ethoxycinnamoyl)-7-methoxycoumarin, 3-(4-dimethylaminocinnamoyl)coumarin, 3-(4-diphenylaminocinnamoyl)coumarin, 3-[(3-dimethylbenzothiazol-2-ylidene)acetyl]coumarin, 3-[(1-methylnaphtho[1,2-d]thiazol-2-ylidene)acetyl]coumarin, 3,3'-carbo Nylbis(6-methoxycoumarin), 3,3'-carbonylbis(7-acetoxycoumarin), 3,3'-carbonylbis(7-dimethylaminocoumarin), 3-(2-benzothiazolyl)-7-(diethylamino)coumarin, 3-(2-benzothiazolyl)-7-(dibutylamino)coumarin, 3-(2-benzimidazolyl)-7-(diethylamino)coumarin, 3-(2-benzothiazolyl)-7-(dioctylamino)coumarin, 3-acetyl-7-(dimethylamino)coumarin, 3,3'-carbonylbis(7-dibutylaminocoumarin), 3,Examples of compounds include those described in JP-A-9-3109 and JP-A-10-245525, such as 3'-carbonyl-7-diethylaminocoumarin-7'-bis(butoxyethyl)aminocoumarin, 10-[3-[4-(dimethylamino)phenyl]-1-oxo-2-propenyl]-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-11-one, and 10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-11-one.

[0101] Among the above-mentioned coumarin compounds, 3,3'-carbonylbis(7-diethylaminocoumarin) and 3,3'-carbonylbis(7-dibutylaminocoumarin) are particularly suitable.

[0102] Examples of the anthraquinones include anthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone, 1-bromoanthraquinone, 1,2-benzanthraquinone, 1-methylanthraquinone, 2-ethylanthraquinone, and 1-hydroxyanthraquinone.

[0103] Examples of the benzoin alkyl ether compounds include benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

[0104] Examples of the α-aminoketone compounds include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one.

[0105] Among these water-insoluble photopolymerization initiators (C-2), it is preferable to use at least one selected from the group consisting of (bis)acylphosphine oxides, α-diketones, and coumarin compounds, which provides a dental composition that has excellent photocurability in the visible and near-ultraviolet regions and exhibits sufficient photocurability using any of a halogen lamp, a light-emitting diode (LED), and a xenon lamp.

[0106] The content of the water-insoluble photopolymerization initiator (C-2) is not particularly limited, but from the viewpoint of the curability of the resulting composition, the content of the water-insoluble photopolymerization initiator (C-2) is preferably in the range of 0.01 to 10 parts by mass, more preferably in the range of 0.05 to 7 parts by mass, and even more preferably in the range of 0.1 to 5 parts by mass, per 100 parts by mass of the total of the compound (A) and the monomer (B) in the dental composition. If the content of the water-insoluble photopolymerization initiator (C-2) exceeds 10 parts by mass, sufficient adhesive strength may not be obtained if the polymerization performance of the polymerization initiator itself is low, and further, precipitation from the dental composition may occur.

[0107] In the present invention, the mass ratio of the water-soluble photopolymerization initiator (C-1) to the water-insoluble photopolymerization initiator (C-2) [(C-1):(C-2)] is preferably 10:1 to 1:10, more preferably 7:1 to 1:7, even more preferably 5:1 to 1:5, and particularly preferably 3:1 to 1:3. If the water-soluble photopolymerization initiator (C-1) is blended in at a mass ratio of more than 10:1, the curability of the dental composition itself may be reduced, making it difficult to achieve high adhesive strength. On the other hand, if the water-insoluble photopolymerization initiator (C-2) is blended in at a mass ratio of more than 1:10, although the curability of the dental composition itself is enhanced, the promotion of polymerization at the adhesive interface may be insufficient, making it difficult to achieve high adhesive strength.

[0108] [Chemical polymerization initiator] The dental composition of the present invention may further contain a chemical polymerization initiator, and an organic peroxide is preferably used. The organic peroxide used as the chemical polymerization initiator is not particularly limited, and known organic peroxides can be used. Representative organic peroxides include, for example, ketone peroxides, hydroperoxides, diacyl peroxides, dialkyl peroxides, peroxyketals, peroxyesters, and peroxydicarbonates. Specific examples of these organic peroxides include those described in International Publication No. 2008 / 087977.

[0109] [Filler (D)] The dental composition of the present invention may further contain a filler (D). In the present invention, the filler (D) is roughly classified into organic fillers, inorganic fillers, and organic-inorganic composite fillers.

[0110] Examples of organic filler materials include polymethyl methacrylate, polyethyl methacrylate, methyl methacrylate-ethyl methacrylate copolymer, cross-linked polymethyl methacrylate, cross-linked polyethyl methacrylate, polyamide, polyvinyl chloride, polystyrene, chloroprene rubber, nitrile rubber, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, acrylonitrile-styrene copolymer, acrylonitrile-styrene-butadiene copolymer, etc. These may be used alone or as a mixture of two or more. The shape of the organic filler is not particularly limited, and the particle size of the filler can be appropriately selected and used.

[0111] 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. These materials may be used alone or in combination. The shape of the inorganic filler is not particularly limited, and the particle size of the filler can be appropriately selected. From the viewpoint of the handleability and mechanical strength of the resulting composition, the average particle size of the inorganic filler is preferably 0.001 to 50 μm, more preferably 0.001 to 10 μm, and even more preferably 0.001 to 8 μm. 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.

[0112] Examples of the shape of the inorganic filler include amorphous fillers and spherical fillers. From the viewpoint of improving the mechanical strength of the composition, it is preferable to use a spherical filler as the inorganic filler. Furthermore, when the dental composition of the present invention is used as a self-adhesive dental composite resin, the use of the spherical filler has the advantage of producing a composite resin with excellent surface smoothness. The spherical filler used in the present invention is a filler in which, when photographed with an electron microscope, the particles observed within a unit field of view are rounded and have an average uniformity of 0.6 or more, calculated by dividing the particle diameter in a direction perpendicular to the maximum diameter by the maximum diameter. The average particle diameter of the spherical filler is preferably 0.05 to 5 μm. If the average particle diameter is less than 0.05 μm, the filling rate of the spherical filler in the composition may decrease, resulting in reduced mechanical strength. On the other hand, if the average particle diameter exceeds 5 μm, the surface area of ​​the spherical filler may decrease, resulting in a dental composition cured product with high mechanical strength.

[0113] In order to adjust the fluidity of the dental composition, the inorganic filler may be surface-treated with a known surface treatment agent such as a silane coupling agent, if necessary. Examples of such surface treatment agents include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, vinyltri(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, 8-methacryloyloxyoctyltrimethoxysilane, 11-methacryloyloxyundecyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane.

[0114] The organic-inorganic composite filler used in the present invention is obtained by adding a monomer compound to the inorganic filler described above in advance, forming a paste, polymerizing the mixture, and pulverizing it. Examples of the organic-inorganic composite filler that can be used include TMPT filler (trimethylolpropane methacrylate and silica filler mixed, polymerized, and then pulverized). The shape of the organic-inorganic composite filler is not particularly limited, and the particle size of the filler can be appropriately selected and used. From the viewpoints of the handleability and mechanical strength of the resulting composition, the average particle size of the organic-inorganic composite filler is preferably 0.001 to 50 μm, and more preferably 0.001 to 10 μm.

[0115] In this specification, the average particle size of the filler can be determined by laser diffraction scattering or electron microscope observation of the particles. Specifically, laser diffraction scattering is convenient for measuring the particle size of particles 0.1 μm or larger, while electron microscope observation is convenient for measuring the particle size of ultrafine particles less than 0.1 μm. The value of 0.1 μm is measured by laser diffraction scattering.

[0116] Specifically, the laser diffraction scattering method can be performed by, for example, measuring on a volume basis using a laser diffraction particle size distribution analyzer (SALD-2300, manufactured by Shimadzu Corporation) and a 0.2% aqueous solution of sodium hexametaphosphate as a dispersion medium.

[0117] Specifically, electron microscope observation can be performed by taking a photograph of the particles using an electron microscope (S-4000 model, manufactured by Hitachi, Ltd.) and measuring the particle sizes of particles (200 or more) observed within a unit field of view in the photograph using image analysis particle size distribution measurement software (Mac-View (Mountec Co., Ltd.)). In this case, the particle size is determined 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.

[0118] The filler (D) used in the present invention may be a mixture or combination of two or more fillers having different materials, particle size distributions, and morphologies, and may unintentionally contain particles other than the filler as impurities, as long as the effects of the present invention are not impaired.

[0119] The content of the filler (D) used in the present invention is not particularly limited, and preferably ranges from 0 to 2000 parts by mass of the filler (D) relative to 100 parts by mass of the total of the compound (A) and the monomer (B) in the dental composition. In some embodiments, the content of the filler (D) is preferably 50% by mass or more, more preferably 55% by mass, and even more preferably 60% by mass, based on the total amount of the dental composition, in order to achieve superior effects of the present invention, such as mechanical strength. Furthermore, the content of the filler (D) is preferably 98% by mass or less, more preferably 94% by mass or less, and even more preferably 88% by mass or less, based on the total amount of the dental composition, in order to achieve superior effects of the present invention, such as mechanical strength. Since the preferred content of the filler (D) varies significantly depending on the embodiment used, the preferred content of the filler (D) for each embodiment will be shown below in conjunction with the description of specific embodiments of the dental composition of the present invention.

[0120] [Polymerization accelerator (E)] In one embodiment, a polymerization accelerator (E) is used together with the water-insoluble photopolymerization initiator (C-2) and / or the chemical polymerization initiator. Examples of the polymerization accelerator (E) used in the present invention include amines, sulfinic acid and its salts, borate compounds, barbituric acid derivatives, triazine compounds, copper compounds, tin compounds, vanadium compounds, halogen compounds, aldehydes, thiol compounds, sulfites, hydrogen sulfites, and thiourea compounds.

[0121] Amines used as the polymerization accelerator (E) can be divided into aliphatic amines and aromatic amines. 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, Nn-butyldiethanolamine, N-lauryldiethanolamine, 2-(dimethylamino)ethyl methacrylate, N-methyldiethanolamine dimethacrylate, N-ethyldiethanolamine dimethacrylate, triethanolamine monomethacrylate, triethanolamine dimethacrylate, triethanolamine trimethacrylate, triethanolamine, trimethylamine, triethylamine, and tributylamine. Among these, tertiary aliphatic amines are preferred from the viewpoint of the curability and storage stability of the dental composition, and N-methyldiethanolamine and triethanolamine are more preferably used.

[0122] Examples of aromatic amines include 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, N,N-bis(2-hydroxyethyl)-4-isopropylaniline, N,N-bis(2-hydroxyethyl)-4-t-butylaniline, N,N-bis(2-hydroxyethyl)-3,5-diisopropylaniline, N,N-bis(2-hydroxyethyl)-3,5-di-t-butylaniline, N,N-dimethylaniline, N,N-dimethyl-p-toluidine, N,N-dimethyl-m-toluidine, and N,N-diethyl-p -toluidine, N,N-dimethyl-3,5-dimethylaniline, N,N-dimethyl-3,4-dimethylaniline, N,N-dimethyl-4-ethylaniline, N,N-dimethyl-4-isopropylaniline, N,N-dimethyl-4-t-butylaniline, N,N-dimethyl-3,5-di-t-butylaniline, 4-(N,N-dimethylamino)ethyl benzoate, 4-(N,N-dimethylamino)methyl benzoate, 4-(N,N-dimethylamino)propyl benzoate, 4-(N,N-dimethylamino)n-butoxyethyl benzoate, 4-(N,N-dimethylamino)2-(methacryloyloxy)ethyl benzoate, 4-(N,N-dimethylamino)benzophenone, 4-(N,N-dimethylamino)butyl benzoate, and the like. Among these, at least one selected from the group consisting of N,N-bis(2-hydroxyethyl)-p-toluidine, ethyl 4-(N,N-dimethylamino)benzoate, n-butoxyethyl 4-(N,N-dimethylamino)benzoate, and 4-(N,N-dimethylamino)benzophenone is preferably used, from the viewpoint of being able to impart excellent hardening properties to the dental composition.

[0123] Specific examples of sulfinic acids and salts thereof, borate compounds, barbituric acid derivatives, triazine compounds, copper compounds, tin compounds, vanadium compounds, halogen compounds, aldehydes, thiol compounds, sulfites, hydrogen sulfites, and thiourea compounds include those described in WO 2008 / 087977.

[0124] The polymerization accelerator (E) may be used alone or in combination with two or more. The content of the polymerization accelerator (E) used in the present invention is not particularly limited. However, from the viewpoint of the curability of the resulting dental composition, the content is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, even more preferably 0.1 parts by mass or more, and preferably 30 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, relative to 100 parts by mass of the total of the compound (A) and the monomer (B) in the dental composition. If the content of the polymerization accelerator (E) is less than 0.001 parts by mass, polymerization may not proceed sufficiently, resulting in a decrease in adhesiveness. Therefore, the content is more preferably 0.05 parts by mass or more. On the other hand, if the content of the polymerization accelerator (E) exceeds 30 parts by mass, if the polymerization performance of the polymerization initiator itself is low, sufficient adhesiveness may not be obtained and further precipitation from the dental composition may occur. Therefore, the content is more preferably 20 parts by mass or less.

[0125] [Fluoride ion-releasing substance] The dental composition of the present invention may further contain a fluoride ion-releasing substance. By incorporating a fluoride ion-releasing substance, a dental composition capable of imparting acid resistance to tooth structure can be obtained. Examples of such fluoride ion-releasing substances include metal fluorides such as sodium fluoride, potassium fluoride, sodium monofluorophosphate, lithium fluoride, and ytterbium fluoride. The above fluoride ion-releasing substances may be incorporated alone or in combination of two or more.

[0126] In addition, the dental composition may contain additives such as pH adjusters, polymerization inhibitors, thickeners, colorants, fluorescent agents, fragrances, and crosslinkers (e.g., polyvalent metal ion-releasing components) within limits that do not impair the effects of the present invention. The additives may be used alone or in combination of two or more. The dental composition of the present invention may also contain antibacterial substances such as cetylpyridinium chloride, benzalkonium chloride, (meth)acryloyloxydodecylpyridinium bromide, (meth)acryloyloxyhexadecylpyridinium chloride, (meth)acryloyloxydecylammonium chloride, and triclosan. The dental composition of the present invention may also contain known dyes and pigments as colorants.

[0127] The dental composition of the present invention may contain a solvent depending on the intended use. Examples of the solvent include water and organic solvents. Known organic solvents can be used without any limitations, including alcoholic solvents (e.g., methanol, ethanol, 1-propanol, 2-propanol), acetone, methyl ethyl ketone, tetrahydrofuran, diethyl ether, diisopropyl ether, hexane, toluene, chloroform, ethyl acetate, and butyl acetate, with alcoholic solvents being preferred. In embodiments using an organic solvent, the content of the organic solvent is preferably 1 to 2,000 parts by weight, more preferably 2 to 1,000 parts by weight, and even more preferably 3 to 500 parts by weight, per 100 parts by weight of the total of compound (A) and monomer (B). For example, when the dental composition of the present invention is used as a self-adhesive dental composite resin, dental composite resin, dental cement, or the like, it may be a solvent-free dental composition. However, as long as it does not cause problems such as poor curing or delayed curing, trace amounts of water or organic solvent (e.g., 3% by weight or less of the composition) are acceptable. Therefore, some of the ingredients to be blended are sold in a form containing water or an organic solvent (e.g., colloidal silica), but in such cases, the water or organic solvent is removed to an acceptable limit before use in preparing the dental composition of the present invention.

[0128] In the dental composition of the present invention, other components (e.g., prepolymers (oligomers) other than compound (A)), compound (A), monomer (B), polymerization initiator (C), filler (D), polymerization accelerator (E), polymerization inhibitor, and colorant) are preferably contained in an amount of less than 0.1 part by mass, more preferably less than 0.01 part by mass, and even more preferably less than 0.001 part by mass, per 100 parts by mass of the dental composition. Furthermore, the dental composition of the present invention preferably has a polymerization shrinkage stress of less than 10 MPa, more preferably less than 9.5 MPa, and even more preferably less than 9.0 MPa. The polymerization shrinkage stress can be measured as described in the Examples below.

[0129] The dental composition of the present invention can be used in dental treatments such as dental composite resins (particularly preferably self-adhesive dental composite resins), dental bonding materials, dental cements, pit and fissure sealants, loose tooth fixation materials, core buildup materials, and orthodontic bonding materials, and is particularly preferably used as a self-adhesive dental composite resin, dental composite resin, or dental cement. In this case, the dental composition of the present invention may be used in a two-bottle or two-paste form, with the components separated into two, or in a one-bottle or one-paste form. Specific embodiments of the application of the dental composition are described below.

[0130] <Self-adhesive dental composite resin> A preferred embodiment of the dental composition of the present invention is a self-adhesive dental composite resin. The self-adhesive dental composite resin made from the dental composition of the present invention contains a monomer (B-1) having an acidic group. When the dental composition of the present invention is used as a self-adhesive dental composite resin, it contains a compound (A), a monomer (B), a polymerization initiator (C), a filler (D), and a polymerization accelerator (E), and preferably the monomer (B) contains a monomer (B-1) having an acidic group, a hydrophobic monomer (B-2) not having an acidic group, and a hydrophilic monomer (B-3) not having an acidic group. Furthermore, the polymerization initiator (C) is preferably a photopolymerization initiator, and more preferably the polymerization initiator (C) contains a water-soluble photopolymerization initiator (C-1) and a water-insoluble photopolymerization initiator (C-2). When the dental composition of the present invention is used as a self-adhesive dental composite resin, a pretreatment material may be used, but since the dental composition has self-adhesive properties, a pretreatment material is not essential and the use of a pretreatment material is not necessary. A self-adhesive dental composite resin can be made by using only the dental composition of the present invention without a pretreatment material.

[0131] The content of each component in the self-adhesive dental composite resin is preferably 0.1 to 50 parts by mass of compound (A), 1 to 50 parts by mass of monomer (B-1) having an acidic group, 20 to 99 parts by mass of hydrophobic monomer (B-2) having no acidic group, and 0 to 50 parts by mass of hydrophilic monomer (B-3) having no acidic group, relative to 100 parts by mass of the total of compound (A) and monomer (B) in the dental composition. It is more preferable that the composition contains 1 to 40 parts by mass of a monomer (B-1) having an acidic group, 40 to 99 parts by mass of a hydrophobic monomer (B-2) not having an acidic group, and 0 to 40 parts by mass of a hydrophilic monomer (B-3) not having an acidic group, and it is even more preferable that the composition contains 1 to 35 parts by mass of a compound (A), 1 to 30 parts by mass of a monomer (B-1) having an acidic group, 60 to 99 parts by mass of a hydrophobic monomer (B-2) not having an acidic group, and 0 to 30 parts by mass of a hydrophilic monomer (B-3) not having an acidic group. Furthermore, the composition preferably contains 0.001 to 30 parts by mass of a polymerization initiator (C), 50 to 2000 parts by mass of a filler (D), and 0.001 to 20 parts by mass of a polymerization accelerator (E) relative to 100 parts by mass of the total of the compound (A) and the monomer (B), and more preferably contains 0.05 to 10 parts by mass of a polymerization initiator (C), 100 to 1500 parts by mass of a filler (D), and 0.05 to 10 parts by mass of a polymerization accelerator (E). The dental composition used as a self-adhesive dental composite resin does not need to contain the hydrophilic monomer (B-3).

[0132] <Dental composite resins (excluding self-adhesive dental composite resins)> A preferred embodiment of the dental composition of the present invention is a dental composite resin. The dental composite resin made from the dental composition of the present invention does not contain a monomer (B-1) having an acidic group. When the dental composition of the present invention is used as a dental composite resin, it preferably contains a compound (A), a hydrophobic monomer (B-2) having no acidic group, a hydrophilic monomer (B-3) having no acidic group, a polymerization initiator (C), a filler (D), and a polymerization accelerator (E). The polymerization initiator (C) preferably contains a photopolymerization initiator, and more preferably contains a water-soluble photopolymerization initiator (C-1) and a water-insoluble photopolymerization initiator (C-2). When the dental composition of the present invention is used as a dental composite resin, the use of a dental bonding material or a pretreatment material is essential.

[0133] The content of each component in the dental composite resin is preferably 0.1 to 50 parts by weight of compound (A), 50 to 99 parts by weight of hydrophobic monomer (B-2) not having an acidic group, and 0 to 40 parts by weight of hydrophilic monomer (B-3) not having an acidic group, per 100 parts by weight of the total of compound (A) and monomer (B) in the dental composition; more preferably 0.5 to 40 parts by weight of compound (A), 60 to 99 parts by weight of hydrophobic monomer (B-2) not having an acidic group, and 0 to 30 parts by weight of hydrophilic monomer (B-3) not having an acidic group; and even more preferably 1 to 35 parts by weight of compound (A), 70 to 99 parts by weight of hydrophobic monomer (B-2) not having an acidic group, and 0 to 20 parts by weight of hydrophilic monomer (B-3) not having an acidic group. Furthermore, the dental composition preferably contains 0.001 to 30 parts by mass of a polymerization initiator (C), 50 to 2000 parts by mass of a filler (D), and 0.001 to 20 parts by mass of a polymerization accelerator (E) relative to 100 parts by mass of the total of the compound (A) and the monomer (B), and more preferably contains 0.05 to 10 parts by mass of a polymerization initiator (C), 100 to 1500 parts by mass of a filler (D), and 0.05 to 10 parts by mass of a polymerization accelerator (E). The dental composition used as a dental composite resin does not need to contain the hydrophilic monomer (B-3).

[0134] <Dental cement> Another preferred embodiment of the dental composition of the present invention is a dental cement. Suitable examples of dental cements include resin cements, glass ionomer cements, and resin-reinforced glass ionomer cements. A self-etching primer or other pretreatment agent may be used for the dental cement. When the dental composition of the present invention is used as a dental cement, it contains a compound (A), a monomer (B), a polymerization initiator (C), a filler (D), and a polymerization accelerator (E). The monomer (B) preferably contains a monomer (B-1) having an acidic group, a hydrophobic monomer (B-2) not having an acidic group, and a hydrophilic monomer (B-3) not having an acidic group. The polymerization initiator (C) preferably contains a chemical polymerization initiator, and more preferably a combination of a chemical polymerization initiator and a photopolymerization initiator. The photopolymerization initiator preferably contains a water-soluble photopolymerization initiator (C-1) and a water-insoluble photopolymerization initiator (C-2).

[0135] The content of each component in the dental cement is preferably 0.1 to 50 parts by mass of the compound (A), 0 to 50 parts by mass of the monomer (B-1) having an acidic group, 50 to 99 parts by mass of the hydrophobic monomer (B-2) having no acidic group, and 0 to 50 parts by mass of the hydrophilic monomer (B-3) having no acidic group, relative to 100 parts by mass of the total of the compound (A) and the monomer (B) in the dental composition. It is more preferable that the composition contains 0 to 40 parts by mass of a compound (B-1), 60 to 99 parts by mass of a hydrophobic monomer (B-2) having no acidic group, and 0 to 40 parts by mass of a hydrophilic monomer (B-3) having no acidic group, and it is even more preferable that the composition contains 1 to 35 parts by mass of a compound (A), 0 to 30 parts by mass of a monomer (B-1) having an acidic group, 70 to 99 parts by mass of a hydrophobic monomer (B-2) having no acidic group, and 0 to 30 parts by mass of a hydrophilic monomer (B-3) having no acidic group. Furthermore, the dental composition preferably contains 0.001 to 30 parts by mass of a polymerization initiator (C), 50 to 2000 parts by mass of a filler (D), and 0.001 to 20 parts by mass of a polymerization accelerator (E) relative to 100 parts by mass of the total of the compound (A) and the monomer (B), and more preferably contains 0.05 to 10 parts by mass of a polymerization initiator (C), 100 to 1500 parts by mass of a filler (D), and 0.05 to 10 parts by mass of a polymerization accelerator (E). The dental composition used as a dental cement may not contain a hydrophilic monomer (B-3). When used as a dental cement of the type that uses a pretreatment agent, the dental composition may not contain a monomer (B-1) having an acidic group.

[0136] In any of the preferred embodiments of the above-mentioned self-adhesive dental composite resin, dental composite resin, and dental cement, the content of each component can be changed as appropriate based on the explanations in the above specification, and any component can be added, deleted, or otherwise modified.

[0137] The present invention includes embodiments in which the above-described configurations are combined 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. [Example]

[0138] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. Furthermore, not all of the combinations of features described in the examples are necessarily essential to the solution of the present invention. The components, their abbreviations, structures, and test methods used in the following examples and comparative examples are as follows:

[0139] [Compound (A)] UN-7600: Urethane acrylate (manufactured by Negami Chemical Industrial Co., Ltd., viscosity: 1,100,000 cps / 25°C, weight-average molecular weight (Mw): 11,500, glass transition temperature (Tg): -42°C and 44.6°C, polyester skeleton-containing urethane acrylate, number of polymerizable groups (acrylic groups): 2, weight-average molecular weight per polymerizable group: 5,750, acetone solubility: less than 10 g / L) UC-102M: Polyisoprene (manufactured by Kuraray Co., Ltd., viscosity: 30,000 cps (38°C), weight-average molecular weight (Mw): 17,000, glass transition temperature (Tg): -60°C, number of polymerizable groups (methacrylic groups): 2, weight-average molecular weight per polymerizable group: 8,500, acetone solubility: less than 10 g / L) TE-2000: Urethane methacrylate (unhydrogenated) (Nippon Soda Co., Ltd., viscosity: 1,500,000 cps / 45°C, weight-average molecular weight (Mw): approximately 2,000, glass transition temperature: -9°C, urethane methacrylate containing polybutadiene skeleton, number of polymerizable groups (methacrylic groups): approximately 1.7, weight-average molecular weight per polymerizable group: approximately 1,250 or more, acetone solubility: less than 10 g / L)

[0140] [Compounds with a weight-average molecular weight of 1,000 or more] UN-2600: Urethane acrylate (manufactured by Negami Chemical Industrial Co., Ltd., viscosity: 75,000-90,000 cps / 25°C, weight-average molecular weight (Mw): 2,500, glass transition temperature (Tg): -1°C, number of polymerizable groups (acrylic groups): 2, weight-average molecular weight per acrylic group: 1,250, acetone solubility: 50 g / L or more)

[0141] [Monomer (B)] MDP: 10-methacryloyloxydecyl dihydrogen phosphate D-2.6E: 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane (average number of moles of ethoxy groups added: 2.6) 3G: Triethylene glycol dimethacrylate DD: 1,10-decanediol dimethacrylate MAEA: N-methacryloyloxyethyl acrylamide HEMA: 2-hydroxyethyl methacrylate The acetone solubility of the entire monomer (B) component is shown in Tables 1 and 2.

[0142] [Polymerization initiator (C)] Water-soluble photopolymerization initiator (C-1) Li-TPO: phenyl(2,4,6-trimethylbenzoyl)phosphinic acid lithium salt (compound represented by the following formula (3)), average particle size: 5 μm [ka] Non-water-soluble photopolymerization initiator (C-2) CQ: dl-camphorquinone

[0143] [Filler (D)] Inorganic filler 1: fine particle silica "Aerosil (registered trademark) R 972" manufactured by Nippon Aerosil Co., Ltd., average particle size: 16 nm, refractive index: 1.46 Inorganic filler 2: silane-treated silica powder, refractive index: 1.55 Silica powder (quartz, manufactured by Nichitsu Corporation, product name "Hi-Silica") was pulverized in a ball mill to obtain pulverized silica powder. The average particle size of the obtained pulverized silica powder was measured on a volume basis using a laser diffraction particle size distribution analyzer (manufactured by Shimadzu Corporation, model "SALD-2300") and found to be 2.2 μm. 100 parts by mass of this pulverized silica powder was surface-treated with 4 parts by mass of γ-methacryloyloxypropyltrimethoxysilane by a conventional method to obtain silane-treated silica powder.

[0144] [Polymerization accelerator (E)] DABE: Ethyl 4-(N,N-dimethylamino)benzoate

[0145] 〔others〕 BHT: 2,6-di-t-butyl-4-methylphenol (stabilizer (polymerization inhibitor))

[0146] [Application of the dental composition to a self-adhesive dental composite resin or a dental composite resin] <Examples 1-1 to 1-10 and Comparative Examples 1-1 to 1-7> Using the above ingredients, the components listed in Tables 1 and 2 were mixed and kneaded at room temperature to prepare pastes (compositions) for the self-adhesive dental composite resins of Examples 1-1 to 1-9, the dental composite resin of Example 1-10, the self-adhesive dental composite resins of Comparative Examples 1-1 to 1-5, and the dental composite resins of Comparative Examples 1-6 and 1-7. These pastes were then used to measure polymerization shrinkage stress and bending properties according to the methods described below. Tables 1 and 2 show the compounding ratios (parts by mass) and test results for the dental composite resins of each Example and Comparative Example.

[0147] [Measurement of glass transition temperature] The above-mentioned compounds (A) and UN-2600 were dissolved in hexane together with CQ and DABE to obtain samples. Specifically, 1% by mass of each of CQ and DABE relative to the compound (A) and UN-2600 was dissolved in hexane, and the hexane was then distilled off to obtain a sample. The obtained sample was sandwiched between two glass slides, and the glass slides were pressed together using a metal spacer so that the sample thickness was 500 μm. Next, the front and back of the glass slides were irradiated with three beams of light each using a dental LED light irradiator (manufactured by Morita Corporation, product name "Alpha Light V") to cure the sample, obtaining a cured product. Immediately after curing, 2.3 to 2.5 mg of the resulting cured product was cut off with a razor to obtain a measurement sample. The measurement sample was loaded into the sample pan of a heat flux DSC measurement device (manufactured by NETZSCH Japan, product name "DSC 214 Polymer"), and the sample was isothermally heated at -150°C for 5 minutes before heating, and then heated to 200°C at a heating rate of 20°C / min in a nitrogen gas atmosphere of 40 mL / min, thereby measuring the glass transition temperature (n=3). The average value was taken as the glass transition temperature.

[0148] [Acetone soluble] 0.5 g of sample was weighed into a 50 mL Erlenmeyer flask equipped with a magnetic stirrer, 10 mL of acetone was added, and the mixture was stirred at room temperature for 30 minutes. The solution was deemed dissolved when no undissolved material was visible and the solution was clear. For samples that did not dissolve, the amount added was reduced and the process was repeated until the total amount reached 0.1 g.

[0149] [Measurement of polymerization shrinkage stress] A stainless steel washer (inner diameter 5.3 mm x thickness 0.8 mm) coated with a release agent was placed on a 5.0 mm thick glass plate that had been sandblasted with 50 μm alumina powder, and the dental composite resin paste of each Example and Comparative Example was filled into the washer. Next, excess paste was removed, and the dental composite resin paste was sandwiched between a separately sandblasted stainless steel jig (φ5 ​​mm) and the glass plate.

[0150] The paste was irradiated with light from the glass plate side using a dental LED light irradiator (manufactured by Morita Corporation, product name "Pencure 2000") for 10 seconds to harden the dental composite resin, and the polymerization shrinkage stress at this time was measured using a universal testing machine (Autograph AG-I 100kN, manufactured by Shimadzu Corporation) (n=3), and the average value was calculated.

[0151] [Evaluation of bending properties] Strength was evaluated by bending tests in accordance with ISO 4049:2009. Specifically, the procedure was as follows: A dental composite resin paste was filled into a stainless steel mold (2 mm long x 25 mm wide x 2 mm thick), and the top and bottom (2 mm x 25 mm surfaces) of the paste (dental composition) were pressed against a glass slide. The dental composition was then cured by irradiating the front and back of the paste through the glass slide with light for 10 seconds at five points on each side using a dental LED light irradiator (Morita Corporation, "PenCure 2000"). The resulting cured product was subjected to a bending test using a universal testing machine (Autograph AG-I 100kN, Shimadzu Corporation) with a support distance of 20 mm and a crosshead speed of 1 mm / min. The three-point bending strength and flexural modulus were measured (n = 5), and the average values ​​were calculated.

[0152] [Table 1]

[0153] [Table 2]

[0154] As shown in Tables 1 and 2, the self-adhesive dental composite resins according to the present invention (Examples 1-1 to 1-9) exhibited practically sufficient flexural strengths of 82 MPa or more and low polymerization shrinkage stresses of 8.5 MPa or less when cured. Furthermore, the dental composite resin according to the present invention (Example 1-10) exhibited a flexural strength of 100 MPa and a low polymerization shrinkage stress of 6.6 MPa when cured. In contrast, as shown in Table 2, the self-adhesive dental composite resins (Comparative Examples 1-1 to 1-5) that did not contain compound (A) or contained a compound other than (A) with a weight-average molecular weight of 1,000 or more each exhibited a polymerization shrinkage stress of 9.3 MPa or more. Furthermore, the self-adhesive dental composite resins (Comparative Examples 1-6 to 1-7) that did not contain compound (A) or contained a compound other than (A) with a weight-average molecular weight of 1,000 or more each exhibited a polymerization shrinkage stress of 9.0 MPa or more, demonstrating that the reduction in polymerization shrinkage stress was insufficient. These results suggest that the inclusion of compound (A) alleviates polymerization shrinkage stress, effectively reducing the risk of detachment and marginal leakage when restoring relatively deep cavities. [Industrial Applicability]

[0155] The dental composition according to the present invention is suitably used in the field of dentistry as a dental composite resin, a self-adhesive dental composite resin, or a dental cement.

Claims

1. Compound (A), a monomer (B) having a solubility in acetone at 25°C of 50 g / L or more ), a polymerization initiator (C), The compound (A) contains a compound having a polymerizable group and has a weight average molecular weight of 1,000 to 1,000. 80,000, with a Tg of less than 40°C and a solubility in acetone at 25°C is less than 20 g / L, The content of the compound (A) is 0.1 mass % or more and 30 mass % or less of the total amount of the dental composition. % or less by volume, The monomer (B) contains a hydrophobic monomer (B-2), and A dental composition having a content of 10 mass% or more based on the total amount of the dental composition.

2. The content of the compound (A) is 100 mass % of the total of the compound (A) and the monomer (B). The dental composition according to claim 1, wherein the amount of the dental composition is 0.1 to 50 parts by weight based on the total weight of the dental composition.

3. The compound (A) comprises a compound having a polymerizable group, and the compound having a polymerizable group is 1 or 2, comprising a urethane-modified (meth)acrylic compound (A-1) having a urethane bond.

2. The dental composition according to claim 2.

4. 4. The method according to claim 1, wherein the monomer (B) includes a monomer (B-1) having an acidic group.

2. The dental composition according to claim 1.

5. The dental composition according to any one of claims 1 to 4, further comprising a filler (D).

6. The weight average molecular weight per polymerizable group of the compound (A) is 1,250 or more and 20,000 or less. The dental composition according to any one of claims 2 to 5, wherein the solubility is less than 0.

7. A dental composite resin comprising the dental composition according to any one of claims 1 to 6. hmm.

8. A self-adhesive dental composite comprising the dental composition according to any one of claims 1 to 6. Jit resin.

9. A dental cement comprising the dental composition according to any one of claims 1 to 6.

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