Dental Composition

Abstract

The purpose of the present invention is to provide a dental composition that exhibits little polymerization shrinkage stress and that has excellent mechanical strength. The present invention relates to a dental composition comprising a compound (A) having a weight-average molecular weight of 2,000 or more, a monomer (B), and a polymerization initiator (C), wherein the glass transition region of the compound (A) having the weight-average molecular weight of 2,000 or more includes a temperature range of 20-40°C, and the monomer (B) excludes the compound (A) having the weight-average molecular weight of 2,000 or more. The weight-average molecular weight of the compound (A) having the weight-average molecular weight of 2,000 or more is preferably less than 50,000.

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 contains a large amount of a particulate composite material with a large particle size, resulting in roughness. Furthermore, since the particulate composite material is treated with polymerizable functional groups, polymerization occurs during curing, resulting in 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 have found that the above-mentioned problems can be solved by a dental composition containing a compound having a weight-average molecular weight of a certain value or more and a glass transition region including a specific temperature range. After further research, they have completed the present invention.

[0013] That is, the present invention is [1] A dental composition comprising a compound (A) having a weight-average molecular weight of 2,000 or more, a monomer (B), and a polymerization initiator (C), wherein the glass transition region of the compound (A) having a weight-average molecular weight of 2,000 or more includes a temperature range of 20 to 40°C, and the monomer (B) excludes the compound (A) having a weight-average molecular weight of 2,000 or more; [2] The dental composition according to [1], wherein the weight-average molecular weight of the compound (A) having a weight-average molecular weight of 2,000 or more is less than 50,000; [3] The dental composition according to [1] or [2], wherein the compound (A) having a weight-average molecular weight of 2,000 or more has a urethane bond; [4] The dental composition according to [3], wherein the compound (A) having a weight-average molecular weight of 2,000 or more is a urethane-modified (meth)acrylic compound (A-1); [5] The dental composition according to any one of [1] to [4], wherein the compound (A) having a weight-average molecular weight of 2,000 or more has a glass transition temperature of 20°C or less; [6] The dental composition according to any one of [1] to [5], wherein the compound (A) having a weight-average molecular weight of 2,000 or more is present in an amount of 0.1 to 50 parts by mass per 100 parts by mass of the total of the compound (A) having a weight-average molecular weight of 2,000 or more and the monomer (B); [7] The dental composition according to any one of [1] to [6], wherein the compound (A) having a weight-average molecular weight of 2,000 or more has two or more glass transition temperatures; [8] The dental composition according to [7], wherein the compound (A) having a weight-average molecular weight of 2,000 or more has one or more glass transition temperatures in a temperature range of -100°C or more and 20°C or less, and one or more glass transition temperatures in a temperature range of 20°C or more and less than 80°C; [9] The dental composition according to any one of [1] to [8], wherein the monomer (B) includes a monomer (B-1) having an acidic group;

[10] The dental composition according to any one of [1] to [9], further containing a filler (D);

[11] The dental composition according to any one of [1] to

[10] , wherein the compound (A) having a weight-average molecular weight of 2,000 or more has a polymerizable group, and the weight-average molecular weight per polymerizable group is 1,250 or more but less than 20,000;

[12] A dental composite resin comprising the dental composition according to any one of [1] to

[11] ;

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

[11] ;

[14] A dental cement comprising the dental composition according to any one of [1] to

[11] ; 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. 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." [Figure 2] 1 shows the results of DSC measurement of UN-7600 used in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0016] The dental composition of the present invention comprises a compound (A) having a weight-average molecular weight of 2,000 or more, a monomer (B), and a polymerization initiator (C), wherein the glass transition region of the compound (A) having a weight-average molecular weight of 2,000 or more covers the entire temperature range of 20 to 40°C, and the monomer (B) excludes the compound (A) having a weight-average molecular weight of 2,000 or more. The glass transition region used in the present invention is defined as the temperature range from the first change point (the lowest temperature change point) of an endothermic peak to the last change point (the highest temperature change point) where the endothermic peak terminates, as measured using a heat flux differential scanning calorimeter (DSC). Specifically, the glass transition region used in the present invention is determined by measurement based on JIS K 7121-1987 (2012 supplement). In the following, the "baseline" refers to the DTA curve or DSC curve in the temperature range where no glass transition or reaction occurs in the measurement sample, as defined in JIS K 7121-1987 (2012 supplement). ig ) to obtain the extrapolated glass transition end temperature (T eg ) means the temperature range up to the extrapolated glass transition onset temperature (Tig 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 drawn from 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. ig ), extrapolated glass transition finish temperature (T eg ), and midpoint glass transition temperature (T mg When the compound (A) having a weight-average molecular weight of 2,000 or more has two or more glass transition temperatures, the glass transition region is the lowest T ig from the highest temperature T eg In addition, the extrapolated glass transition end temperature (T eg The glass transition temperature (Tg) in the present invention is the temperature at the intersection of a straight line extending the high-temperature side baseline to the low-temperature side and a tangent drawn at the point where the gradient of the curve on the high-temperature side of the peak is maximum. mg ) means the midpoint glass transition temperature (T mg ) is the temperature at the point where a line equidistant along the vertical axis from the extension of each baseline intersects with the curve of the step-like change in the glass transition.

[0017] The method and conditions for measuring the glass transition temperature and glass transition region of the present invention are as described in the Examples below using heat flux DSC.

[0018] 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.

[0019] 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, if the dental composition contains a compound (A) with a weight-average molecular weight of 2,000 or more and the glass transition region of the compound (A) covers the entire temperature range from 20 to 40°C, it is presumed that the kinetic energy generated during shrinkage is converted into thermal energy, thereby attenuating the shrinkage stress generated during curing of the dental composition. This is explained in more detail below. When a dental composition is polymerized and cured, curing begins from the direction of light exposure in the case of photopolymerization, and from the center in the case of chemical polymerization. During this process, shrinkage stress acts toward the curing source, causing stress at the adhesive interface, resulting in reduced adhesion and contraction gaps. In the case of a dental composition of the present invention containing a compound (A) with a weight-average molecular weight of 2,000 or more, the compound (A) with a weight-average molecular weight of 2,000 or more is in the glass transition region at polymerization temperatures (room temperature to the oral cavity, 20 to 40°C). This results in active micro-Brownian motion of the molecular main chain, resulting in a high loss tangent (Tan δ). When polymerization shrinkage stress is applied to the dental composition in this glass transition region, the state of the molecular chain segments changes, but at the same time, the molecular chain segments try to return to their original state. During this process, friction occurs between or within molecules, and kinetic energy is converted into thermal energy, which is thought to result in a reduction in polymerization shrinkage stress.

[0020] Each component used in the dental composition of the present invention will be described below.

[0021] [Compound (A) having a weight-average molecular weight of 2,000 or more] The compound (A) having a weight-average molecular weight of 2,000 or more (hereinafter, sometimes referred to as "compound (A)") has a glass transition region that encompasses the entire temperature range of 20 to 40°C. The compound (A) is used in the dental composition of the present invention to impart an effect of reducing polymerization shrinkage stress. One type of compound (A) may be used alone, or two or more types may be used in combination. One preferred embodiment is a dental composition in which the compound (A) is a compound having a urethane bond.

[0022] 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 compound (A) include compounds having a polymerizable group and a urethane bond. Examples of the polymerizable group include a vinyl group, a (meth)acrylic group, and a (meth)acrylamide group. A (meth)acrylic group or a (meth)acrylamide group is preferred, with a (meth)acrylic group being more preferred. Compounds having a weight-average molecular weight of 2,000 or more and no 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 bond (hereinafter sometimes referred to as "urethane-modified (meth)acrylic compounds (A-1)") and (meth)acrylic compounds (A-2) not having a urethane bond. In terms 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.

[0023] Urethane (meth)acrylic compound (A-1) 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.

[0024] 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 due to their excellent flexibility and water resistance. Polyols having the above-mentioned polymer skeleton can be used to produce the urethane-modified (meth)acrylic compound (A-1). By adjusting the skeleton and molecular weight of a structure (polymer skeleton) selected from the group consisting of polyester, polycarbonate, polyurethane, polyether, polyconjugated diene, and hydrogenated polyconjugated diene, it becomes easier to set the glass transition region within a desired range and to prepare a compound having two or more glass transition temperatures in a specific temperature range.

[0025] 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).

[0026] 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.

[0027] 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.

[0028] 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 is not particularly limited. Furthermore, by using a catalyst in the production method, it becomes easier to set the glass transition region within a desired range, and it also becomes easier to prepare a compound having two or more glass transition temperatures within a specific temperature range. The catalyst is not particularly limited, but examples thereof include dibutyltin compounds such as di-n-butyltin dilaurate, dibutyltin dichloride, dibutyltin maleate, dibutyltin oxide, and dibutyldiacetate.

[0029] 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. In one embodiment, in order to adjust the glass transition temperature to 20 to 40°C, 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 to prevent the glass transition temperature from becoming too high. 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 to adjust the glass transition temperature to less than 40°C. In another embodiment, the composition comprises a compound (A) having a weight-average molecular weight of 2,000 or more, a monomer (B), and a polymerization initiator (C), wherein the glass transition region of the compound (A) having a weight-average molecular weight of 2,000 or more includes a temperature range of 20 to 40°C, and the monomer (B) is a compound other than the compound (A) having a weight-average molecular weight of 2,000 or more, Examples of dental compositions include those that do not have a glass transition region that includes a temperature range of 20 to 40° C. and do not contain compounds with a weight-average molecular weight of 2,000 or more (for example, (meth)acrylic compounds, etc.).

[0030] (Meth)acrylic compounds without urethane bonds (A-2) The (meth)acrylic compound (A-2) without a urethane bond 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 the (meth)acrylic compound (A-2) without a urethane bond, a polyol having the above-mentioned polymer skeleton can be used.

[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 bond 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] Compounds with a weight-average molecular weight of 2,000 or more that do not have polymerizable groups Compounds having a weight-average molecular weight of 2,000 or more and no polymerizable group can be classified into two types: compound (A-3) having a urethane bond and no polymerizable group but a weight-average molecular weight of 2,000 or more (hereinafter, sometimes referred to as "compound (A-3)"), and compound (A-4) having a weight-average molecular weight of 2,000 or more and no urethane bond 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).

[0034] 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. The aforementioned polyols having a polymer skeleton can be used to produce the compound (A-3) having no polymerizable group and a weight-average molecular weight of 2,000 or more.

[0035] 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).

[0036] 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.

[0037] 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.

[0038] The compound (A-3) obtained may be a reaction product of a polyol having at least one structure selected from the group consisting of polyester, polycarbonate, polyurethane, polyether, polyconjugated diene, and hydrogenated polyconjugated diene, and a compound having an isocyanate group.

[0039] From the viewpoint of the effect of reducing polymerization shrinkage stress, the compound (A) having a weight-average molecular weight of 2,000 or more is preferably hydrophobic. Also, from the viewpoint of the effect of reducing polymerization shrinkage stress, the compound (A) having a weight-average molecular weight of 2,000 or more is preferably incompatible with other monomer components.

[0040] The weight-average molecular weight (Mw) of compound (A) is a factor in obtaining a desired glass transition region and glass transition temperature, and from the viewpoint of the effect of reducing viscosity and polymerization shrinkage stress, is 2,000 or more, preferably 3,000 to 50,000, and more preferably 5,000 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] To achieve the effect of reducing polymerization shrinkage stress, the glass transition region of compound (A) must include the entire temperature range of 20 to 40°C. Although the temperature of the dental composition may rise during polymerization, it is believed that the effect of reducing polymerization shrinkage stress can also be achieved during polymerization and curing if the glass transition region includes the temperature during polymerization. From the above perspective, the wider the temperature range of the glass transition region, the more preferable it is. It is preferable that the glass transition region extends to 25°C or higher (e.g., the glass transition region includes 20 to 45°C), more preferably to 30°C or higher (e.g., the glass transition region includes 20 to 50°C), even more preferably to 35°C or higher (e.g., the glass transition region includes 20 to 55°C), and particularly preferably to 40°C or higher (e.g., the glass transition region includes 20 to 60°C). In some embodiments, the glass transition region may be 25°C or higher.

[0042] The weight average molecular weight per polymerizable group in the compound (A) having a weight average molecular weight of 2,000 or more (suitably 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.

[0043] From the viewpoint of the effect of reducing polymerization shrinkage stress, the compound (A) having a weight-average molecular weight of 2,000 or more preferably has a glass transition temperature (hereinafter sometimes simply abbreviated as "Tg") of 20°C or less. The Tg of the compound (A) 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.

[0044] In one embodiment, compound (A) preferably has two or more glass transition temperatures, more preferably two. With respect to the two or more Tg's, it is preferable that at least one Tg exists in the lower temperature range and at least one Tg exists 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 includes a dental composition in which compound (A) having a weight-average molecular weight of 2,000 or more has one or more glass transition temperatures in the temperature range of from -100°C to 20°C and one or more glass transition temperatures in the temperature range of from 20°C to less than 80°C.

[0045] In another embodiment, the composition comprises a compound (A) having a weight-average molecular weight of 2,000 or more, a monomer (B), and a polymerization initiator (C), wherein the glass transition region of the compound (A) having a weight-average molecular weight of 2,000 or more includes a temperature range of 20 to 40°C, and the monomer (B) is a compound other than the compound (A) having a weight-average molecular weight of 2,000 or more; 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, the composition comprises a compound (A) having a weight-average molecular weight of 2,000 or more, a monomer (B), and a polymerization initiator (C), wherein the glass transition region of the compound (A) having a weight-average molecular weight of 2,000 or more includes a temperature range of 20 to 40°C, and the monomer (B) is a compound other than the compound (A) having a weight-average molecular weight of 2,000 or more, Examples of dental compositions include those that do not have a glass transition region that includes a temperature range of 20 to 40°C, do not have two or more glass transition temperatures, and do not contain compounds with a weight-average molecular weight of 2,000 or more (for example, (meth)acrylic compounds, etc.).

[0046] The viscosity of the compound (A) having a weight-average molecular weight of 2,000 or more at 25°C is preferably 5,000 to 10,000,000 cps, more preferably 10,000 to 7,500,000 cps, and even more preferably 20,000 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.

[0047] The compound (A) having a weight-average molecular weight of 2,000 or more may be a commercially available product, such as the "Art Resin" series (UN-7600 (viscosity: 1,100,000 cps / 25°C, weight-average molecular weight (Mw): 11,500)) manufactured by Negami Chemical Industrial Co., Ltd., the "Kuraprene" series (UC-102M, UC-203M) having a polyisoprene skeleton or a polybutadiene skeleton manufactured by Kuraray Co., Ltd., and the liquid polybutadiene "NISSO-PB" manufactured by Nippon Soda Co., Ltd.

[0048] The content of the compound (A) having a weight-average molecular weight of 2,000 or more in the dental composition of the present invention is preferably 0.1 to 50 parts by mass, 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, per 100 parts by mass of the total of the compound (A) having a weight-average molecular weight of 2,000 or more and the monomer (B), from the viewpoints of mechanical strength, paste properties, and the effect of reducing polymerization shrinkage stress. In one embodiment, the content of the compound (A) having a weight-average molecular weight of 2,000 or more 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, from the viewpoints of mechanical strength, paste properties, and the effect of reducing polymerization shrinkage stress, the content of compound (A) having a weight-average molecular weight of 2,000 or more is preferably 30 mass% or less, more preferably 25 mass% or less, and even more preferably 20 mass% or less, of the total amount of the dental composition.

[0049] [Monomer (B)] Examples of the 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. The monomer (B) may be used singly or in combination of two or more. The monomer (B) excludes compounds (A) having a weight-average molecular weight of 2,000 or more. When a compound belongs to both a compound (A) having a weight-average molecular weight of 2,000 or more and a monomer (B), it is considered to be a compound (A) having a weight-average molecular weight of 2,000 or more. Furthermore, when the monomer (B) contains a polymer backbone, the weight-average molecular weight of the monomer (B) is preferably less than 2,000. When the monomer (B) does not contain a polymer backbone, the concept of weight-average molecular weight does not exist, so the molecular weight is used instead of the weight-average molecular weight. The molecular weight of the monomer (B) is preferably less than 2,000.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Examples of the sulfonic acid group-containing monomer include 2-(meth)acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid, and 2-sulfoethyl(meth)acrylate.

[0057] Carboxylic acid group-containing monomers include monomers having one carboxy group in the molecule and monomers having multiple carboxy groups in the molecule.

[0058] 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.

[0059] 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.

[0060] 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 (meth)acrylic monomers containing a phosphate group are more preferred. Among these, divalent (meth)acrylic monomers containing a phosphate group and having an alkyl or alkylene group with 6 to 20 carbon atoms as the main chain in the molecule are even more preferred because they exhibit high decalcification properties and high adhesion in the absence of organic solvents, and divalent (meth)acrylic monomers containing a phosphate group and having an alkylene group with 8 to 12 carbon atoms as the main chain in the molecule, such as 10-methacryloyloxydecyldihydrogenphosphate, are particularly preferred.

[0061] 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) having a weight-average molecular weight of 2,000 or more and the monomer (B) in the dental composition.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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 and 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) having a weight-average molecular weight of 2,000 or more 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.

[0069] 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 (number of oxyethylene groups: 9 or more). and 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.

[0070] 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.

[0071] The inclusion of the hydrophilic monomer (B-3) in the present invention is expected to improve the penetration into tooth structure, but if it is present in excess, 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) having a weight-average molecular weight of 2,000 or more and the monomer (B) in the dental composition. The content of the hydrophilic monomer (B-3) may be 0 part by mass.

[0072] [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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] Examples of the water-soluble acylphosphine oxides include acylphosphine oxides represented by the following general formula (1) or (2).

[0077] [ka]

[0078] [ka]

[0079] 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.

[0080] 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.

[0081] 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).

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] When the water-soluble photopolymerization initiator (C-1) is dispersed in the composition as a powder, the shape thereof 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.

[0089] 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) having a weight-average molecular weight of 2,000 or more and the monomer (B) in the dental composition, from the viewpoint of 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 reduced 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.

[0090] 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.

[0091] 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).

[0092] 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.

[0093] Examples of the thioxanthones include thioxanthone and 2-chlorothioxanthen-9-one.

[0094] Examples of the ketals include benzyl dimethyl ketal and benzyl diethyl ketal.

[0095] 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.

[0096] 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.

[0097] Among the above-mentioned coumarin compounds, 3,3'-carbonylbis(7-diethylaminocoumarin) and 3,3'-carbonylbis(7-dibutylaminocoumarin) are particularly suitable.

[0098] Examples of the anthraquinones include anthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone, 1-bromoanthraquinone, 1,2-benzanthraquinone, 1-methylanthraquinone, 2-ethylanthraquinone, and 1-hydroxyanthraquinone.

[0099] Examples of the benzoin alkyl ether compounds include benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

[0100] Examples of the α-aminoketone compounds include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one.

[0101] 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.

[0102] 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 weight, more preferably 0.05 to 7 parts by weight, and even more preferably 0.1 to 5 parts by weight, per 100 parts by weight of the total of the compound (A) having a weight-average molecular weight of 2,000 or more and the monomer (B) in the dental composition. Note that if the content of the water-insoluble photopolymerization initiator (C-2) exceeds 10 parts by weight, 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.

[0103] 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.

[0104] [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.

[0105] [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.

[0106] 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.

[0107] 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 addition, when the inorganic filler is surface-treated with a surface treatment agent, the average particle size of the inorganic filler means the average particle size before the surface treatment.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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, manufactured by 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.

[0114] 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.

[0115] The content of the filler (D) used in the present invention is not particularly limited, but preferably ranges from 0 to 2,000 parts by mass of the filler (D) relative to 100 parts by mass of the total of the compound (A) and the monomer (B) having a weight-average molecular weight of 2,000 or more 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 or more, and even more preferably 60% by mass or more, based on the total amount of the dental composition, from the viewpoint of achieving 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, from the viewpoint of achieving 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 is shown below in conjunction with the description of specific embodiments of the dental composition of the present invention.

[0116] [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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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, and even more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the total of the compound (A) having a weight-average molecular weight of 2,000 or more and the monomer (B) in the dental composition. It is also 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. 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, and if the polymerization performance of the polymerization initiator itself is low, sufficient adhesion may not be obtained, and furthermore, precipitation from the dental composition may occur. Therefore, the content is more preferably 20 parts by mass or less.

[0121] [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.

[0122] 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.

[0123] 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 mass, more preferably 2 to 1,000 parts by mass, and even more preferably 3 to 500 parts by mass, per 100 parts by mass of the total of the compound (A) having a weight-average molecular weight of 2,000 or more and the monomer (B). For example, when the dental composition of the present invention is used as a dental composite resin (particularly preferably a self-adhesive dental composite resin), dental cement, or the like, the dental composition may be solvent-free. However, as long as it does not cause inconvenience such as poor curing or delayed curing, the inclusion of trace amounts of water or organic solvents (for example, 3% by mass or less of the composition) is acceptable. Therefore, although some of the components to be blended are sold in a form containing water or organic solvents (for example, colloidal silica), in such cases, the dental composition of the present invention can be prepared by removing the water or organic solvent to the acceptable limit.

[0124] In the dental composition of the present invention, other components (e.g., prepolymers (oligomers) other than the compound (A) having a weight-average molecular weight of 2,000 or more, the monomer (B), the polymerization initiator (C), the filler (D), the polymerization accelerator (E), the polymerization inhibitor, and the 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.

[0125] 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 suitable for use as dental composite resins including self-adhesive dental composite resins or dental cements. 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.

[0126] <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 preferably contains a compound (A) having a weight-average molecular weight of 2,000 or more, a monomer (B), a polymerization initiator (C), a filler (D), and a polymerization accelerator (E), and 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. 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.

[0127] The content of each component in the self-adhesive dental composite resin is preferably 0.1 to 50 parts by mass of the compound (A) having a weight-average molecular weight of 2,000 or more, 1 to 50 parts by mass of the monomer (B-1) having an acidic group, 20 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) having a weight-average molecular weight of 2,000 or more and the monomer (B) in the dental composition. (B-1) having an acidic group, 1 to 40 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 more preferably, the composition contains 1 to 35 parts by mass of a compound (A) having a weight-average molecular weight of 2,000 or more, 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) having no acidic group, and 0 to 30 parts by mass of a hydrophilic monomer (B-3) having no acidic group. Furthermore, the composition preferably contains 0.001 to 30 parts by mass of a polymerization initiator (C), 50 to 2,000 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) having a weight-average molecular weight of 2,000 or more and the monomer (B), and more preferably contains 0.05 to 10 parts by mass of a polymerization initiator (C), 100 to 1,500 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).

[0128] <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) having a weight-average molecular weight of 2,000 or more, 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.

[0129] The content of each component in the dental composite resin is preferably 0.1 to 50 parts by mass of the compound (A) having a weight-average molecular weight of 2,000 or more, 50 to 99 parts by mass of the hydrophobic monomer (B-2) having no acidic group, and 0 to 40 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) having a weight-average molecular weight of 2,000 or more and the monomer (B) in the dental composition. It is more preferable that the composition contains 0.5 to 40 parts by mass of a compound (A) having a weight-average molecular weight of 2,000 or more, 60 to 99 parts by mass of a hydrophobic monomer (B-2) having no acidic groups, and 0 to 30 parts by mass of a hydrophilic monomer (B-3) having no acidic groups, and it is even more preferable that the composition contains 1 to 35 parts by mass of a compound (A) having a weight-average molecular weight of 2,000 or more, 70 to 99 parts by mass of a hydrophobic monomer (B-2) having no acidic groups, and 0 to 20 parts by mass of a hydrophilic monomer (B-3) having no acidic groups. Furthermore, the dental composition preferably contains 0.001 to 30 parts by mass of a polymerization initiator (C), 50 to 2,000 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) having a weight-average molecular weight of 2,000 or more and the monomer (B), and more preferably contains 0.05 to 10 parts by mass of a polymerization initiator (C), 100 to 1,500 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).

[0130] <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 the like may be used as a pretreatment agent for the dental cement. When the dental composition of the present invention is used as a dental cement, it contains a compound (A) having a weight-average molecular weight of 2,000 or more, a monomer (B), a polymerization initiator (C), a filler (D), and a polymerization accelerator (E). 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. The polymerization initiator (C) preferably contains a chemical polymerization initiator, and more preferably, a chemical polymerization initiator and a photopolymerization initiator are used in combination. Preferably, a water-soluble photopolymerization initiator (C-1) and a water-insoluble photopolymerization initiator (C-2) are used in combination.

[0131] The content of each component in the dental cement is preferably 0.1 to 50 parts by mass of the compound (A) having a weight-average molecular weight of 2,000 or more, 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) having a weight-average molecular weight of 2,000 or more and the monomer (B) in the dental composition, and 0.5 to 50 parts by mass of the compound (A) having a weight-average molecular weight of 2,000 or more. It is more preferable that the composition contains 40 parts by mass of a compound (A) having a weight-average molecular weight of 2,000 or more, 0 to 40 parts by mass of a monomer (B-1) having an acidic group, 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) having a weight-average molecular weight of 2,000 or more, 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 composition preferably contains 0.001 to 30 parts by mass of a polymerization initiator (C), 50 to 2,000 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) having a weight-average molecular weight of 2,000 or more and the monomer (B), and more preferably contains 0.05 to 10 parts by mass of a polymerization initiator (C), 100 to 1,500 parts by mass of a filler (D), and 0.05 to 10 parts by mass of a polymerization accelerator (E).The composition may not contain a hydrophilic monomer (B-3), and in the case of a type that uses a pretreatment material, the composition may not contain a monomer (B-1) having an acidic group.

[0132] 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.

[0133] 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]

[0134] 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:

[0135] [Compound (A) having a weight-average molecular weight of 2,000 or more] 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 region: -51°C to 60°C, 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)

[0136] <Synthesis Example 1> [Production of Compound 1] (1) 125 g of isophorone diisocyanate and 0.4 g of di-n-butyltin dilaurate were added to a 5 L four-neck flask equipped with a stirrer, a temperature controller, a thermometer, and a condenser, and the mixture was heated to 70°C with stirring. (2) On the other hand, 850 g of polyester polyol ("Kuraray Polyol (registered trademark) P-5010" manufactured by Kuraray Co., Ltd.; a polymer composed of adipic acid and 3-methyl-1,5-pentanediol, weight average molecular weight Mw: 5,000) was added to a dropping funnel equipped with a side tube, and the liquid in this dropping funnel was added dropwise to the flask (1) above. The solution in the flask (1) above was stirred while the internal temperature of the flask was maintained at 65 to 75°C, and the solution was added dropwise at a constant rate over 4 hours. After the addition was completed, the mixture was stirred at the same temperature for 24 hours to allow the reaction to proceed. (3) Next, a solution prepared by uniformly dissolving 75 g of 2-hydroxyethyl acrylate and 0.4 g of hydroquinone monomethyl ether in another dropping funnel was added dropwise at a constant rate over 2 hours while maintaining the internal temperature of the flask at 55 to 65°C, and then the reaction was carried out for 4 hours while maintaining the temperature of the solution in the flask at 70 to 80°C, thereby obtaining Compound 1. Compound 1: (Viscosity: 900,000 cps / 25°C, Weight-average molecular weight (Mw): 13,000, Glass transition region: -35°C to 55°C, Glass transition temperature: -25°C and 35°C, Number of polymerizable groups (acrylic groups): 2, Weight-average molecular weight per polymerizable group: 6,500)

[0137] <Synthesis Example 2> [Production of Compound 2] (1) Into a 5 L four-neck flask equipped with a stirrer, a temperature controller, a thermometer, and a condenser, 882 g of polyester polyol ("Kuraray Polyol (registered trademark) P-2010, manufactured by Kuraray Co., Ltd.; a polymer composed of adipic acid and 3-methyl-1,5-pentanediol, weight average molecular weight Mw: 2,000)", 212 g of a monoadduct obtained by reacting isophorone diisocyanate and 2-hydroxyethyl acrylate in a molar ratio of 1:1 (VESTANATEP-DC1241, manufactured by Evonik), and 0.4 g of di-n-butyltin dilaurate were added, and the mixture was stirred and reacted at 70°C for approximately 24 hours to obtain Compound 2. Compound 2: (Viscosity: 650,000 cps / 25°C, Weight-average molecular weight (Mw): 8,800, Glass transition region: -15°C to 62°C, Glass transition temperature: -10°C and 48°C, Number of polymerizable groups (acrylic groups): 2, Weight-average molecular weight per polymerizable group: 4,400)

[0138] [Compounds other than compound (A) with a weight-average molecular weight of 2,000 or more] UN-2600: Urethane acrylate (manufactured by Negami Chemical Industrial Co., Ltd., viscosity: 75,000 to 90,000 cps / 25°C, weight average molecular weight (Mw): 2,500, glass transition region: -10°C to 8°C, glass transition temperature (Tg): -1°C, number of polymerizable groups (acrylic groups): 2, weight average molecular weight per polymerizable group: 1,250)

[0139] [Monomer (B)] Monomers with acidic groups (B-1) MDP: 10-methacryloyloxydecyl dihydrogen phosphate Hydrophobic monomer without acidic group (B-2) 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 Hydrophilic monomers without acidic groups (B-3) HEMA: 2-hydroxyethyl methacrylate

[0140] [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

[0141] [Filler (D)] Inorganic filler 1: Aerosil (registered trademark) R 972 fine particle silica 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 in a conventional manner to obtain silane-treated silica powder.

[0142] [Polymerization accelerator (E)] DABE: Ethyl 4-(N,N-dimethylamino)benzoate

[0143] 〔others〕 BHT: 2,6-di-t-butyl-4-methylphenol (stabilizer (polymerization inhibitor))

[0144] [Application of the dental composition to a self-adhesive dental composite resin or a dental composite resin] <Examples 1-1 to 1-12 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 1-11, the dental composite resin of Example 1-12, 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 each Example and Comparative Example.

[0145] [Viscosity measurement] Each of the compounds (A) having a weight average molecular weight of 2,000 or more and UN-2600 was subjected to dynamic viscoelasticity measurement using a rotational rheometer (AR2000 manufactured by TA Instruments Co., Ltd.) at 25°C, plate diameter: 25 mm, plate gap: 0.50 mm, and shear rate: 1.0 s -1 The viscosity was measured (n=3) under the above measurement conditions, and the average value was calculated.

[0146] [Measurement of weight-average molecular weight] Tetrahydrofuran was used as the eluent, and the column consisted of two TSKgel SuperMultipore HZM-M columns and one TSKgel SuperHZ4000 column connected in series (Tosoh Corporation). The GPC system used was a Tosoh HLC-8320 equipped with a differential refractive index detector (RI detector). For the measurements, 4 mg of each of the compounds (A) and UN-2600 with a weight-average molecular weight of 2,000 or greater was dissolved in 5 mL of tetrahydrofuran to prepare a sample solution. The column oven temperature was then set to 40°C, and 20 μL of the sample solution was injected at an eluent flow rate of 0.35 mL / min. The chromatogram of the sample solution was then measured. Ten standard polystyrene samples with molecular weights ranging from 400 to 5,000,000 were also measured by GPC, and a calibration curve showing the relationship between retention time and molecular weight was created. Based on this calibration curve, the weight-average molecular weights of the compound (A) having a weight-average molecular weight of 2,000 or more and the compound having a weight-average molecular weight of 2,000 or more were determined from the chromatogram measured as described above (n=1).

[0147] [Calculation of the number of polymerizable groups] The number of polymerizable groups in each of the above-mentioned compounds (A) having a weight average molecular weight of 2,000 or more and UN-2600 is 1 The number of polymerizable groups was calculated based on the results of H-NMR measurements. Compound (A) and UN-2600, each with a weight-average molecular weight of 2,000 or more, dissolved in deuterated chloroform, were measured at room temperature with a nuclear magnetic resonance spectrometer (ULTRA SHIELD 400 PLUS, manufactured by Bruker Japan Co., Ltd.) with 16 accumulations. The approximate number of polymerizable groups was calculated from the ratio of the integral value of the proton peak derived from the methacryloyl group (5.7 to 6.6 ppm) to the integral value of the proton peak derived from the urethane bond (4.5 to 5.2 ppm).

[0148] [Measurement of glass transition temperature and glass transition region] The above-mentioned compounds (A) with a weight-average molecular weight of 2,000 or more and UN-2600 were dissolved in acetone together with CQ and DABE to obtain samples. Specifically, 1% by mass of each of CQ and DABE relative to the weight-average molecular weight of each compound (A) with a weight-average molecular weight of 2,000 or more and UN-2600 was dissolved in acetone, and the acetone 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 plate to obtain a sample thickness of 500 μm. The front and back of the glass slides were then 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. 2.3 to 2.5 mg of the cured product was cut off with a razor to obtain a measurement sample. The measurement sample was filled 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 and glass transition region (n=3). mg The average value of the glass transition temperature was taken as the glass transition temperature. ig The average value of the glass transition temperature T eg The measurement results for UN-7600 are shown in Figure 2. In this measurement, the baseline shift was detected as Tg.

[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 1-11) 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 1-12) exhibited a flexural strength of 100 MPa and low polymerization shrinkage stresses 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 the compound (A) having a weight-average molecular weight of 2,000 or more or that contained a compound other than (A) having a weight-average molecular weight of 2,000 or more each exhibited a polymerization shrinkage stress of 9.3 MPa or more. Furthermore, the dental composite resins (Comparative Examples 1-6 to 1-7) that did not contain compound (A) with a weight-average molecular weight of 2,000 or more, or that contained a compound other than (A) with a weight-average molecular weight of 2,000 or more, each had a polymerization shrinkage stress of 9.0 MPa or more, demonstrating that the reduction in polymerization shrinkage stress was insufficient in any of them. These results suggest that the inclusion of compound (A) with a weight-average molecular weight of 2,000 or more alleviates the 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 (particularly suitably a self-adhesive dental composite resin) or a dental cement. [Explanation of symbols]

[0156] 1: Glass transition temperature 1 2: Glass transition temperature 2 3: Glass transition region

Claims

1. a compound (A) having a weight-average molecular weight of 2,000 or more, a monomer (B), a polymerization initiator (C), and a filler (D), wherein the glass transition region of the compound (A) having a weight-average molecular weight of 2,000 or more includes a temperature range of 20 to 40°C; the compound (A) having a weight average molecular weight of 2,000 or more has a glass transition temperature of 20°C or less, the compound (A) having a weight average molecular weight of 2,000 or more is a urethanized (meth)acrylic compound (A-1) having a (meth)acrylic group as a polymerizable group and a urethane bond, the urethane-modified (meth)acrylic compound (A-1) is a (meth)acrylate having, in addition to a urethane bond, a structure selected from the group consisting of polyester, polycarbonate, polyurethane, polyether, polyconjugated diene, and hydrogenated polyconjugated diene; the monomer (B) contains a hydrophobic monomer (B-2) which does not have an acidic group and has a solubility in water at 25°C of less than 10% by mass, the hydrophobic monomer (B-2) is at least one selected from the group consisting of aromatic bifunctional monomers, aliphatic bifunctional monomers, and trifunctional or higher functional monomers; The content of the filler (D) is 50% by mass or more and 98% by mass or less based on the total amount of the dental composition, A dental composition, wherein the monomer (B) does not include the compound (A) having a weight average molecular weight of 2,000 or more.

2. 2. The dental composition according to claim 1, wherein the compound (A) having a weight-average molecular weight of 2,000 or more has a weight-average molecular weight of less than 50,000.

3. 3. The dental composition according to claim 1, wherein the compound (A) having a weight-average molecular weight of 2,000 or more is present in an amount of 0.1 to 50 parts by mass per 100 parts by mass of the total of the compound (A) having a weight-average molecular weight of 2,000 or more and the monomer (B).

4. The dental composition according to any one of claims 1 to 3, wherein the compound (A) having a weight-average molecular weight of 2,000 or more has two or more glass transition temperatures.

5. 5. The dental composition according to claim 4, wherein the compound (A) having a weight-average molecular weight of 2,000 or more has one or more glass transition temperatures in a temperature range of −100° C. or higher and 20° C. or lower, and one or more glass transition temperatures in a temperature range of 20° C. or higher and lower than 80° C.

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

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

9. A self-adhesive dental composite resin comprising the dental composition according to any one of claims 1 to 7.

10. A dental cement comprising the dental composition according to any one of claims 1 to 7.

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