JP5731807B2 - Dental curable composition - Google Patents

Description

  The present invention relates to a dental curable composition.

  In the restoration of a tooth damaged by caries, fracture or the like, a photocurable filling / restoration material called a composite resin is generally used because the restoration work is easy and aesthetic. Such a composite resin is usually a material composed of a polymerizable monomer, a filler (filler) and a polymerization initiator. As the polymerizable monomer, a (meth) acrylate radical polymerizable monomer is used because of its good photopolymerizability.

  However, the (meth) acrylate-based radical polymerizable monomer is of an addition polymerization type. For this reason, the composite resin using the addition polymerization type radical polymerizable monomer has a problem that the polymerization shrinkage is essentially large due to its curing mechanism, and further, it is susceptible to polymerization inhibition by oxygen. Yes. In addition, when filling and hardening the composite resin after filling the cavity of the tooth requiring restoration, it is necessary to irradiate light from the surface of the filled composite resin, that is, from a position far from the tooth. For this reason, when shrinkage occurs due to the polymerization of the composite resin, a gap is likely to be formed at the interface between the composite resin filled in the cavity and the tooth.

  In order to solve such problems, a dental curable composition using an oxetane compound having a functional group containing an oxetane ring has been proposed by the present applicant (see Patent Documents 1 and 2). Here, the functional group containing an oxetane ring shown in Patent Document 1 is composed of an oxetane ring and a monovalent group and a divalent group bonded to the 3-position of the oxetane ring. The monovalent group is composed of a monovalent alkyl group having 1 to 10 carbon atoms, and the divalent group is a methylene group bonded to the 3-position of the oxetane ring and an ether bond bonded to the methylene group. And a divalent aromatic carbon group bonded to the oxygen atom. Moreover, the polymerization shrinkage rate of the dental curable composition using the oxetane compound shown in Patent Documents 1 and 2 is about 0.4% to 3%, and the shrinkage due to polymerization is very small. .

JP 2007-15946 A (Claims 1-3, Table 3, Table 4) JP 2007-31288 A (Claim 1, paragraph 0031, Table 2, Table 3, etc.)

  In the dental curable compositions shown in Patent Documents 1 and 2, shrinkage due to polymerization is suppressed to be considerably small as described above. However, even if the polymerization shrinkage rate is improved to about 0.4%, a force to peel off acts between the cured product of the dental curable composition filled in the cavity and the inner wall surface of the cavity. However, it is inevitable that the adhesiveness is lowered. Therefore, there is a possibility that a gap is formed at the interface between the cured product and the cavity and the cured product may fall out of the cavity even though the improvement is made compared with the conventional dental curable composition. Remain. In addition to this, when a gap is formed at the interface between the cured product and the cavity, bacteria may enter through this gap and cause bacterial infection.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the dental curable composition which the shrinkage | contraction accompanying superposition | polymerization is further improved and the volume expansion accompanying superposition | polymerization is also possible.

The above-mentioned subject is achieved by the following present invention. That is,
The dental curable composition of the present invention comprises (I) an oxetane compound having at least one functional group containing an oxetane ring in the molecule, and (II) a cationic polymerization initiator, and (I) an oxetane compound. As described above, at least an oxetane compound having at least one functional group represented by the following general formula (i) in the molecule as the functional group containing the oxetane ring is used.

[In the general formula (i), Ar ¹ is a monovalent aromatic group which may have a substituent. ]

In one embodiment of the dental curable composition of the present invention, (II) the cationic polymerization initiator is preferably a photoacid generator.

It is preferable that the other embodiment of the dental curable composition of the present invention further includes (III) an epoxy compound.

  In another embodiment of the dental curable composition of the present invention, (III) the epoxy compound preferably has an alicyclic epoxy group.

In another embodiment of the dental curable composition of the present invention, (III) the epoxy compound is (1) a carbon atom at the 3-position or 4-position of the cyclohexene oxide group which may have a substituent, An epoxy compound to which a group represented by the general formula (ii) is bonded, and (2) a 5- to 8-membered ring at the 3- or 4-position carbon atom of the cyclohexene oxide group which may have a substituent. It consists of at least one epoxy compound selected from epoxy compounds having at least two cyclohexene oxide ring-containing units to which carbon atoms constituting the hydrocarbon ring are bonded, and satisfying the following formula (1) Is preferred.
Formula (1) 90/1 ≧ (a × A) / (b × B) ≧ 45/55
[In the formula (1), a represents the average number of functional groups containing the oxetane ring contained in one molecule of (I) oxetane compound, and A is contained in the dental curable composition (I ) Represents the molar ratio (mol%) of the oxetane compound, b represents the average number of epoxy groups contained in one molecule of (III) epoxy compound, and B is contained in the dental curable composition (III ) Represents the molar ratio (mol%) of the epoxy compound. ]

[In General Formula (II), R ⁵ and R ⁶ are each a hydrogen atom or a hydrocarbon group having 1 to 13 carbon atoms which may have a substituent, and the total carbon number of R ⁵ and R ⁶ is 2 That's it. ]

  ADVANTAGE OF THE INVENTION According to this invention, the shrinkage | contraction accompanying superposition | polymerization can further be improved, and the dental curable composition which can also carry out the volume expansion accompanying superposition | polymerization can be provided.

It is a schematic explanatory drawing explaining an example of the steric hindrance of the functional group shown by general formula (i). It is a schematic explanatory drawing explaining the state after the oxetane ring which comprises the functional group shown by general formula (i) opens.

The dental curable composition of the present embodiment includes (I) an oxetane compound having at least one functional group containing an oxetane ring in the molecule, and (II) a cationic polymerization initiator, and (I) oxetane. As the compound, at least an oxetane compound having a functional group containing an oxetane ring represented by the following general formula (i) in the molecule is used. Here, in the following general formula (i), Ar ¹ is a monovalent aromatic group which may have a substituent.

  In the dental curable composition of this embodiment, as the cationic polymerizable monomer, (I) one or more oxetane compounds having in the molecule at least one functional group containing an oxetane ring are used. At least one of the one or more oxetane compounds has at least one functional group represented by the general formula (i) in the molecule. The oxetane compound having at least one functional group represented by the general formula (i) in the molecule has the specificity of volume expansion when polymerized using this compound alone. For this reason, when polymerizing the dental curable composition of this embodiment and obtaining hardened | cured material, compared with the case where the dental curable composition shown by patent document 1, 2 is used, the shrinkage | contraction accompanying superposition | polymerization is. Generation | occurrence | production can be suppressed further. Therefore, the adhesion between the cured product of the dental curable composition filled in the cavity and the inner wall surface of the cavity is further increased, and the cured product falls out of the cavity, or the cured product and the cavity The problem of gaps at the interface can be greatly improved.

  Moreover, in the dental curable composition of this embodiment, the compounding ratio of the oxetane compound having at least one functional group represented by the general formula (i) in the molecule with respect to all the polymerizable monomers to be used. In many cases, volume expansion is possible with polymerization. Thus, if volume expansion occurs when the dental curable composition filled in the cavity becomes a cured product by polymerization, the cured product presses the inner wall surface of the cavity. Therefore, in this case, the mechanical fitting force between the cured product of the dental curable composition and the cavity is increased, and the cured product has an effect of preventing dropping from the cavity and the gap between the interface between the cured product and the cavity. The generation prevention effect can be further enhanced.

  In addition, in the oxetane compound having at least one functional group represented by the general formula (i) in the molecule, the reason why the volume expansion accompanying the polymerization occurs is estimated as follows. First, usually, when a polymerizable compound is polymerized, a negative volume change called polymerization shrinkage occurs. This is because the molecules (polymerizable monomers) before polymerization are adjacent to each other so that they can be polymerized (intermolecular distance). This is because the distance is closer to the distance (coupling distance). On the other hand, the oxetane compound having a functional group represented by the general formula (i) used as an essential component in the dental curable composition of the present embodiment has the following characteristics in terms of molecular structure.

  That is, in the oxetane compound having the functional group represented by the general formula (i), a benzene ring or a heterocyclic ring constituting an aromatic group having a low degree of molecular motion is located at the 3-position of the oxetane ring having a low degree of molecular motion. It has a directly bonded molecular structure. Here, a case where a benzene ring is directly bonded to the 3-position of the oxetane ring will be described as an example. A hydrogen atom (or substituent) bonded to a carbon atom at the 2-position (or 6-position) of the benzene ring, and an oxetane The hydrogen atom bonded to the two carbon atoms adjacent to the ring oxygen atom is very close to each other, and steric hindrance occurs in this portion (see FIG. 1). FIG. 1 is a schematic explanatory view illustrating an example of the steric hindrance of the functional group represented by the general formula (i). Specifically, the functional group represented by the general formula (i) is an oxetane ring 3. It is a figure explaining the steric hindrance in the case where it has the molecular structure which the phenyl group which does not have a substituent as an aromatic group directly couple | bonded in position.

  For this reason, rotation of the carbon-carbon bond between the oxetane ring and the benzene ring constituting the aromatic group is inhibited. That is, in the example shown in FIG. 1, the rotation of the carbon-carbon bond indicated by the symbol B in the direction of the arrow R is inhibited. Therefore, before the oxetane ring is opened, the degree of freedom of molecular movement of the functional group represented by the general formula (i) is significantly limited.

  On the other hand, when the oxetane ring is opened by the polymerization reaction, the degree of freedom of rotation of the carbon-carbon bond and the carbon-oxygen bond derived from the oxetane ring is significantly improved. For this reason, as illustrated in FIG. 2, the rotational movement of the bond between the carbon atom at the 3-position of the oxetane ring and the carbon atom of the benzene ring constituting the aromatic group (the bond indicated by B in the figure) In other words, the steric hindrance hindering the rotational movement of the benzene ring that was directly bonded to the 3-position of the oxetane ring is eliminated. In addition to this, by opening the oxetane ring, the degree of rotational freedom of the interatomic bond constituting the oxetane ring is also significantly improved. FIG. 2 is a schematic explanatory view for explaining a state after the oxetane ring constituting the functional group represented by the general formula (i) is opened, and specifically has the molecular structure shown in FIG. It is a figure which shows the state after the oxetane ring of a functional group opened.

  Therefore, when the polymerization reaction is performed using the oxetane compound having the functional group represented by the general formula (i), the molecules are polymerized and changed from the intermolecular distance to the bond distance. Compared with the oxetane compound, the unit structure of the polymer after polymerization (part corresponding to the oxetane compound before polymerization) significantly improves the degree of freedom of molecular motion as a whole. In other words, when compared per molecule, the steric bulk of the polymer unit structure after polymerization is greater than the steric bulk of the oxetane compound before polymerization. Therefore, when polymerization is performed using an oxetane compound having a functional group represented by the general formula (i), it is considered that volume expansion accompanying the polymerization appears.

  In addition, the shrinkage | polymerization shrinkage | contraction rate of the dental curable composition using the oxetane compound which has an oxetane ring shown by patent document 1, 2 is about 0.4%-3%, and the shrinkage accompanying superposition | polymerization is very small. It has the characteristics. However, the polymerization shrinkage shown in Patent Documents 1 and 2 is larger than that in the case where volume shrinkage occurs when the dental curable composition of the present embodiment is cured (polymerized), and the volume associated with the polymerization is further increased. Expansion has not been realized. This is because the molecular structure of the functional group having an oxetane ring is not a structure in which an aromatic group is directly bonded to the 3-position of the oxetane ring. That is, the atom bonded to the carbon atom at the 3-position of the oxetane ring is not an atom constituting a part of the benzene ring, such as a carbon atom constituting an alkyl group or an alkylene group. That is, there is no room for significant steric hindrance as illustrated in FIG. For this reason, the degree of freedom of molecular motion of the group bonded to the 3-position of the oxetane ring is higher than when the 3-position group bonded to the oxetane ring is an aromatic group.

  Therefore, the increase in the degree of freedom of molecular motion due to the opening of the oxetane ring during polymerization is such that (A) the aromatic due to the elimination of steric hindrance as illustrated in FIG. This is the sum of a significant increase in the degree of freedom of molecular motion of the group and an increase in the degree of freedom of molecular motion derived from the opening of the (B) oxetane ring, including the oxetane ring shown in Patent Documents 1 and 2. In the functional group, (B) the degree of freedom of molecular motion derived from the opening of the oxetane ring is only increased. For this reason, when only the oxetane compound having an oxetane ring shown in Patent Documents 1 and 2 is used, it is presumed that volume expansion due to polymerization can be very small, but volume expansion cannot be obtained. The

  The dental curable composition of the present embodiment described above includes at least an oxetane compound having at least one functional group represented by the general formula (i) in the molecule and a cationic polymerization initiator. However, if necessary, an epoxy compound and other additives can be used. Below, each component which comprises the dental curable composition of this embodiment is demonstrated in detail.

-(I) Oxetane compound-
The oxetane compound used in the dental curable composition of this embodiment has at least one functional group containing an oxetane ring in the molecule. And when the oxetane compound to be used is only one kind, the oxetane compound in which the functional group containing the oxetane ring has the functional group represented by the general formula (i) is necessarily used.

  On the other hand, when two or more oxetane compounds are used, at least one oxetane compound is an oxetane compound in which a functional group containing an oxetane ring has a functional group represented by the general formula (i). In this case, the content A of all oxetane compounds contained in the dental curable composition, and the content of polymerizable monomers other than the oxetane compounds used as necessary, such as epoxy compounds described later The ratio (C / (A + B)) of the content C of the oxetane compound having the functional group represented by the general formula (i) with respect to the total amount of the amount B is a dental curable composition having a smaller polymerization shrinkage than conventional. From the viewpoint of obtaining, it is preferably 20% by mass or more. Furthermore, the ratio (C / (A + B)) is 40% by mass or more in order to make it easy to control the dental curable composition so that the volume expansion coefficient during polymerization exceeds 0%. It is preferably 70% by mass or more. Further, by using two or more oxetane compounds in combination and / or using a polymerizable monomer other than an oxetane compound such as an epoxy compound, the viscosity of the dental curable composition and the polymerization time It is easy to adjust the polymerization shrinkage rate and volume expansion rate of the resin to a desired range, and to adjust various physical properties such as the refractive index of the cured product obtained by polymerization to a desired range.

  In addition, the polymerization shrinkage rate at the time of superposition | polymerization is so preferable that it is small, and specifically, it is preferable that it is 0.25% or less. Further, as described above, the volume expansion may be performed, that is, the volume expansion coefficient may exceed 0%. In this case, the volume expansion coefficient is particularly preferably 0.02% or more. Moreover, the upper limit of the volume expansion coefficient at the time of superposition | polymerization is although it does not specifically limit, 3% or less is preferable and 1% or less is more preferable. By setting the volume expansion rate to 3% or less, it is possible to prevent the hardened material volume-expanded in the cavity from being easily damaged by pressing the tooth strongly from the inside.

  Further, regardless of whether the functional group containing an oxetane ring is a functional group represented by the general formula (i), the oxetane compound has two or more functional groups containing an oxetane ring in its molecule. There may be two and it is preferable to have two. In this case, it becomes easy to ensure the strength of the cured product obtained by polymerization. Moreover, when the oxetane compound has two or more functional groups containing an oxetane ring in the molecule, the functional groups containing all oxetane rings are preferably functional groups represented by the general formula (i). Moreover, in the dental curable composition of this embodiment, the oxetane compound to be used is volatile and has a composition regardless of whether the functional group containing an oxetane ring is a functional group represented by the general formula (i). From the viewpoint of the operability of the product, the functional group equivalent of the functional group containing an oxetane ring is preferably 150 to 500 g / mol, and more preferably liquid at normal temperature.

In general formula (i), Ar ¹ is a monovalent aromatic group which may have a substituent. Here, the monovalent aromatic group can be selected from an aromatic hydrocarbon group such as a phenyl group and a naphthyl group, and an aromatic heterocyclic group such as a pyridinyl group and a quinolinyl group. Of these, an aromatic hydrocarbon group is preferred. The aromatic hydrocarbon group can be used without particular limitation as long as it contains one or more benzene rings. The number of benzene rings is preferably 1 to 6, preferably 1 to 2, and preferably 1 Is most preferred. Here, as the aromatic hydrocarbon group, a monovalent monocyclic aromatic hydrocarbon group (that is, a phenyl group) and a monovalent condensation in which all benzene rings constituting the aromatic hydrocarbon group are condensed with each other. A polycyclic aromatic hydrocarbon group. Examples of the monovalent condensed polycyclic aromatic hydrocarbon group include a naphthyl group. In addition, when the monovalent aromatic group is an aromatic heterocyclic group and the hetero atom constituting the heterocyclic ring does not have a hydrogen atom or a substituent, the heterocyclic group directly bonded to the 3-position of the oxetane ring The atoms constituting the ring are preferably atoms other than the atoms adjacent to the hetero atom. For example, when the heterocyclic ring is pyridine, the carbon atom at any position selected from the 3-position, 4-position, and 5-position is preferably directly bonded to the 3-position of the oxetane ring.

  Moreover, as a substituent, it is C1-C10 alkyl, such as a methyl group, an ethyl group, a propyl group, iso-propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group. Group: a cyclohexyl group having 3 to 8 carbon atoms such as cyclohexyl group and cyclopentyl; a halogen atom such as chlorine atom, bromine atom, fluorine atom and iodine atom; alkoxy having 1 to 10 carbon atoms such as methoxy group, ethoxy group and butoxy group Group; aryl group such as phenyl group and naphthyl group; aralkyl group such as benzyl group, etc., among which alkyl group having 1 to 3 carbon atoms such as methyl group and ethyl group; 3 alkoxy groups; halogen atoms such as fluorine and chlorine are preferred. The number of these substituents substituted on the aromatic hydrocarbon group is preferably 4 or less, more preferably 2 or less.

  In addition, an aromatic group and another atomic group are bonded to the 3-position of the oxetane ring represented by the general formula (i). Here, the structure of the other atomic group bonded to the 3rd position of the oxetane ring is not particularly limited, but the atomic group bonded to the 3rd position of the oxetane ring has at least one of two hydrogen atoms constituting the methylene group as an organic group. Or a group containing a methylene group bonded to the 3-position of the oxetane ring and an oxygen atom bonded to the methylene group so as to form an ether bond. Here, as a molecular structure containing a functional group containing an oxetane ring represented by the general formula (i) and an atomic group bonded to the 3-position of the oxetane ring, a molecular structure represented by the following general formula (iii) is: The molecular structure represented by the following structural formula 1 is more preferable. Specifically, the oxetane compound having one functional group represented by the general formula (i) in the molecule, exemplified below, or two or more functional groups represented by the general formula (i) in the molecule, The oxetane compound having 2 to 8 is preferable.

In General Formula (iii), Ar ¹ is the same aromatic group as Ar ¹ shown in General Formula (i), and R ¹ and R ² are a hydrogen atom or an organic group having 1 to 10 carbon atoms. . Here, examples of the organic group having 1 to 10 carbon atoms that can be selected as R ¹ and R ² include alkyl groups such as methyl group, ethyl group, propyl group, hexyl group, octyl group, decyl group, benzyl group, and phenethyl group. Or substituted alkyl group, alkoxy group such as methoxy group and ethoxy group, acyloxy group such as acetyloxy group and propionyloxy group, etc. Among them, hydrogen atom or alkyl group is more preferable, and hydrogen is most preferable among them It is. R ¹ and R ² may be the same or different from each other.

  Here, the oxetane compound having one functional group represented by the general formula (i) in the molecule can be selected, for example, from the group of compounds exemplified below. In the structural formula shown below, the numerical range shown as “0-10” means that any value among integers of 0 to 10 can be taken.

  Moreover, as an oxetane compound which has 2 or more of functional groups shown by general formula (i) in a molecule | numerator, it can select from the compound group illustrated below, for example. In the structural formula shown below, the numerical range indicated as “1-20” means that any value among the integers of 1 to 20 can be taken. Note that it is more preferable to use an oxetane compound having two or more functional groups represented by the general formula (i) than using an oxetane compound having one or more functional groups represented by the general formula (i).

  Moreover, the dental curable composition of this embodiment can use together oxetane compounds other than the oxetane compound which has a functional group shown in general formula (i) as needed. As such an oxetane compound, a known oxetane compound can be used. For example, an oxetane compound having a functional group represented by the following general formula (iv) can be used.

Here, in General Formula (iv), Ar ² is a divalent aromatic hydrocarbon group which may have a substituent, and R ³ is a hydrogen atom or an aromatic having 1 to 10 carbon atoms. Organic group other than the group hydrocarbon group.

In the functional group represented by the general formula (iv), an oxetane ring is present as an (oxetane-3-yl) group, and this group is bonded to a methylene group. Further, this methylene group is an aromatic hydrocarbon group Ar ^2. And an ether bond. Here, the oxetane compound having the functional group represented by the general formula (iv) may have at least one functional group represented by the general formula (iv) in the molecule. From the standpoint of securing the mechanical strength, it is preferable to have two or more, more preferably within the range of 2 to 8.

Here, as the organic group having 1 to 10 carbon atoms represented by R ³ , an organic group other than the known aromatic hydrocarbon group having the above-mentioned carbon number can be adopted without limitation, but preferably has 1 to 10 carbon atoms. Are preferably an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, an alkyloxyalkyl group having 1 to 10 carbon atoms, and a phenyloxyalkyl group. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an iso-propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Moreover, as a C1-C10 hydroxyalkyl group, a hydroxymethyl group, 2-hydroxyethyl group, 6-hydroxyhexyl group, 10-hydroxydecyl group, etc. are mentioned. Examples of the alkyloxyalkyl group include methoxymethyl group, ethyloxymethyl group, propyloxymethyl group, nonyloxymethyl group, 6-methyloxyhexyl group, 6-ethyloxyhexyl group, and 3-propyloxyhexyl group. Can be mentioned. Moreover, as a C1-C10 phenyloxyalkyl group, a phenyloxymethyl group, 2-phenyloxyethyl group, 3-phenyloxypropyl group, 3- (4-methylphenyl) oxypropyl group, etc. are mentioned. Among these, an alkyl group having 1 to 10 carbon atoms is more preferable, particularly an alkyl group having 1 to 10 carbon atoms, and an ethyl group is most preferable among them.

The divalent aromatic hydrocarbon group represented by Ar ² is preferably an aromatic ring having 6 to 14 carbon atoms, specifically, a monocyclic aromatic ring such as a benzene ring or naphthalene. Examples thereof include condensed polycyclic aromatic rings such as a ring, a phenanthrene ring, and an anthracene ring.

  Examples of the substituent of the aromatic hydrocarbon group include carbon number such as methyl group, ethyl group, propyl group, iso-propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, and decyl group. An alkyl group having 1 to 10; a cyclohexyl group having 3 to 8 carbon atoms such as a cyclohexyl group and cyclopentyl; a halogen atom such as a chlorine atom, a bromine atom, a fluorine atom and an iodine atom; a carbon number such as a methoxy group, an ethoxy group and a butoxy group 1-10 alkoxy groups; aryl groups such as phenyl groups and naphthyl groups; aralkyl groups such as benzyl groups, etc., among which alkyl groups having 1 to 3 carbon atoms such as methyl groups and ethyl groups; methoxy, ethoxy and the like A C 1-3 alkoxy group; a halogen atom such as fluorine or chlorine is preferred. The number of these substituents substituted on the aromatic hydrocarbon group is preferably 4 or less, more preferably 2 or less.

  In addition, when the oxetane compound having a functional group represented by the general formula (iv) has an ester bond in the molecule, the dental curable composition obtained using the oxetane compound is in a wet condition during the cationic curing. When exposed, there is a possibility that the ester bond is hydrolyzed by the action of the acid used as the cationic polymerization initiator and the physical properties of the cured product are lowered. Therefore, it is preferable that the oxetane compound having a functional group represented by the general formula (iv) does not have the above-described ester bond in the molecule. As such an oxetane compound, it can select from the compound group illustrated below, for example.

Moreover, as an oxetane compound having the functional group represented by the general formula (iv), two or more groups represented by the following general formula (v) are bonded to the Ar ² group constituting the functional group represented by the general formula (iv). Oxetane compounds having a functional group can also be used. In this case, the Ar ² group has a valence of 2 or more.

In general formula (v), R ³ is the same as that shown in general formula (iv).

  Here, as an oxetane compound which has a functional group shown by general formula (v), it can select from the compound group illustrated below, for example.

  Moreover, as an oxetane compound other than the oxetane compound having a functional group represented by the general formula (i), an oxetane compound represented by the following general formula (vi) is most preferable.

Here, in the general formula (vi), R ⁴ is oxygen or a divalent hydrocarbon group having 1 to 13 carbon atoms, and u is 0 or 1. When u is 0, the two benzene rings represented by the general formula (vi) are directly bonded by a single bond. Here, as a C1-C13 bivalent hydrocarbon group, what was illustrated as a functional group shown in general formula (iv) has a bivalent aliphatic hydrocarbon group, an alicyclic hydrocarbon group, An aromatic hydrocarbon group etc. are mentioned. R ⁴ is preferably an oxygen atom or an alkylene group having 1 to 13 carbon atoms, and most preferably an oxygen atom or an alkylene group having 1 to 5 carbon atoms.

  Further, as an oxetane compound other than the oxetane compound having the functional group represented by the general formula (i), an oxetane compound having two or more functional groups represented by the general formula (v) other than those exemplified above in the molecule is used. You can also. Examples of such oxetane compounds include bis [1-ethyl (3-oxetanyl)] methyl ether, 1,2-bis [(3-ethyloxetane-3-yl) methyloxy] ethane, and 1,3-bis. [(3-ethyloxetane-3-yl) methyloxy] propane, 1,4-bis [(3-ethyloxetane-3-yl) methyloxy] butane, 1,5-bis [(3-ethyloxetane-3 -Yl) methyloxy] pentane, 1,6-bis [(3-ethyloxetane-3-yl) methyloxy] hexane, 1,7-bis [(3-ethyloxetane-3-yl) methyloxy] heptane, 1,8-bis [(3-ethyloxetane-3-yl) methyloxy] octane, 1,4-bis [(3-ethyloxetane-3-yl) methyloxymethyl] benzene, 4,4′-bi [(3-Ethyloxetane-3-yl) methyloxymethyl] biphenyl, 2,2′-bis [(3-ethyloxetane-3-yl) methyloxymethyl] biphenyl, diethylene glycol bis [(3-ethyloxetane-3 -Yl) methyl] ether, tritylene glycol bis [(3-ethyloxetane-3-yl) methyl] ether, tetraethylene glycol bis [(3-ethyloxetane-3-yl) methyl] ether, trimethylolpropane tris [ (3-Ethyloxetane-3-yl) methyl] ether, pentaerythritol tetrakis [(3-ethyloxetane-3-yl) methyl] ether, or the following group of compounds may be mentioned.

-(III) Epoxy compound-
It is preferable to add an epoxy compound to the dental curable composition of this embodiment as needed from the viewpoint of controlling the polymerization rate (curing rate) during polymerization. When an epoxy compound is used in combination with the oxetane compound as the cationic polymerizable monomer, the curing rate can be further improved as compared with the case where the oxetane compound is used alone as the cationic polymerizable monomer.

  Here, as the epoxy compound, a known compound can be used as long as it is a compound having an epoxy ring in the molecule, but a compound having an alicyclic epoxy group such as a cyclohexene oxide group is preferable because of its high cationic polymerization activity. . Here, as an epoxy compound which has an alicyclic epoxy group, the epoxy compound shown to the following (1)-(3) is mentioned. The epoxy compound shown in (1) and (2) is described in detail below, and then the epoxy compound shown in (3) is described in detail.

(1) An epoxy compound in which a group represented by the following general formula (ii) is bonded to a carbon atom at the 3-position or the 4-position of a cyclohexene oxide group which may have a substituent.
(2) A cyclohexene oxide ring-containing unit in which a carbon atom constituting a 5- to 8-membered hydrocarbon ring is bonded to the 3- or 4-position carbon atom of the optionally substituted cyclohexene oxide group An epoxy compound having at least 2 units. In addition, in this epoxy compound, it is preferable that the cyclohexene oxide ring containing unit contained in a molecule | numerator is 2-8 units.
(3) An epoxy compound having an alicyclic epoxy group other than the epoxy compounds shown in the above (1) and (2).

Here, in general formula (ii), R ⁵ and R ⁶ are a hydrogen atom or a hydrocarbon group having 1 to 13 carbon atoms which may have a substituent, and the total carbon number of R ⁵ and R ⁶ Is 2 or more.

  The central carbon atom (tetravalent carbon atom) of the group represented by the general formula (ii) and the individual carbon atoms constituting the 5-membered to 8-membered hydrocarbon ring are bonded to these carbon atoms. The surrounding atomic groups are in a very bulky and dense state. For this reason, the conformation of the cyclohexene oxide ring is fixed by bonding one of the bonds of these carbon atoms to the 3- or 4-position carbon atom of the cyclohexene oxide group. Therefore, the volume of the cyclohexene oxide group and surrounding atomic groups in the epoxy compounds shown in the above (1) and (2) is smaller than the volume of the normal cyclohexene oxide group and surrounding atomic groups.

  On the other hand, in the epoxy compounds shown in the above (1) and (2), when the epoxy ring constituting the cyclohexene oxide ring is opened, the cyclohexene oxide ring can take a relatively free conformation. The volume of surrounding atomic groups increases. The dental curable composition obtained by combining the epoxy compound represented by the above (1) and (2) with at least the oxetane compound having the functional group represented by the general formula (i) has a small functional group equivalent of the epoxy group. Even in this case, cationic curing can be carried out very quickly. In addition to this, it is easy to increase the amount of the epoxy compound that can be used from the viewpoint of controlling the curing rate within a range in which polymerization shrinkage is further suppressed. In addition, in the case where the number of cyclohexene oxide rings contained in the epoxy compound shown in (1) is 2 or more and the epoxy compound containing 2 or more cyclohexene oxide rings in the molecule shown in (2) above, The mechanical strength of the object can be further improved.

In the epoxy compounds shown in the above (1) and (2), as other substituents that the cyclohexene oxide group may have, substitution of a divalent aromatic hydrocarbon group Ar ² shown in the general formula (iv) What was illustrated as group is mentioned, Especially C1-C3 alkyl groups, such as a methyl group, are preferable. In addition, the number of these substituents bonded to the cyclohexene oxide group is preferably 4 or less, and more preferably 2 or less.

Moreover, as a C1-C13 hydrocarbon group shown as R < ⁵ > and R < ⁶ > in general formula (ii), a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, Examples thereof include alkyl groups such as octyl group, nonyl group and decyl group; cyclohexyl groups such as cyclohexyl group and cyclopentyl; aryl groups such as phenyl group and naphthyl group; and aralkyl groups such as benzyl group. As a substituent of a C1-C13 hydrocarbon group, halogen atoms and oxygen atoms, such as a chlorine atom, a bromine atom, a fluorine atom, and an iodine atom, are mentioned. Moreover, the C1-C13 hydrocarbon group may be a cyclohexene oxide group.

The total number of carbon atoms of R ⁵ and R ⁶ makes the group represented by the general formula (ii) bulky, and fixes the conformation of the cyclohexene oxide ring in the state before the opening of the epoxy ring constituting the cyclohexene oxide ring In order to exhibit the curing to be performed, it is preferably 2 or more, and more preferably in the range of 2 to 10. Moreover, when either one of R ⁵ and R ⁶ is a hydrogen atom, from the same viewpoint, the total carbon number of R ⁵ and R ⁶ is preferably in the range of 3 to 10.

Note that the two hydrocarbon groups represented as R ⁵ and R ⁶ may be bonded to each other to form a ring.

  Here, the compound having 2 or more cyclohexene oxide rings contained in the epoxy compound shown in the above (1) can be selected, for example, from the compound group exemplified below.

  In the epoxy compound shown in (2) above, the hydrocarbon ring having a carbon atom bonded to the 3-position or 4-position carbon atom of the cyclohexene oxide group is preferably a 5-membered ring to a 8-membered ring. Or a 6-membered ring is more preferable. Further, the hydrocarbon ring may be a condensed ring having two or more rings having the same carbon number constituting the ring, or two condensed rings having the same carbon number constituting the ring. It is preferable. Examples of the hydrocarbon ring include cycloaliphatic hydrocarbons such as cyclopentane ring, cyclopentene ring, cyclopentene oxide ring, cyclohexane ring, cyclohexene ring, and cyclohexene oxide ring, and aromatic hydrocarbons such as benzene ring and naphthalene ring. It is done.

  As an epoxy compound shown to said (2), it can select from the compound group illustrated below, for example.

  It is more preferable that the carbon atom of the cyclohexene oxide group to which the surrounding carbon atoms are bonded is the 4-position of the cyclohexene oxide group from the viewpoint of ease of production. Furthermore, it is preferable that these epoxy compounds also have no ester bond in the molecule, like the above-mentioned oxetane compound, from the viewpoint of suppressing a decrease in physical properties of the cured product due to moisture absorption during curing.

  Among the epoxy compounds shown in the above (1) and (2), those having a small volumetric expansion rate and a volume expansion coefficient exceeding 0% even when used in a large amount for the purpose of availability and improvement of the curing rate From the viewpoint of easy control, it is particularly preferable to use an epoxy compound represented by the following general formula (vii).

Here, in the general formula (vii), R ^{7 to} R ²⁴ are a hydrogen atom, a halogen atom, an alkoxy group, or an alkyl group, and each group may be the same or different. R ²⁵ and R ²⁶ are a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and the total carbon number of R ²⁵ and R ²⁶ is 2 or more. M is an integer of 0 or 1.

  For the same reason, the epoxy compounds shown in the above (1) and (2) are particularly preferably those selected from the compound group exemplified below.

  The epoxy compounds shown in the above (1) and (2) exemplified above may be used alone or in combination of two or more.

Moreover, when using at least one epoxy compound selected from the epoxy compound shown in the above (1) and the epoxy compound shown in the above (2), the blending ratio of the oxetane compound and the epoxy compound is not particularly limited. From the viewpoint of being able to significantly reduce the influence of moisture and facilitating curing even under high humidity conditions such as in the oral cavity, it is preferable to satisfy the following formula (1).
Formula (1) 45/55 ≦ (a × A) / (b × B) ≦ 90/10

  In the formula (1), a represents the average number of functional groups containing the oxetane ring contained in one molecule of the oxetane compound, and A represents the molar ratio (moles) of the oxetane compound contained in the dental curable composition. B) represents the average number of epoxy groups contained in one molecule of the epoxy compound, and B represents the molar ratio (mol%) of the epoxy compound contained in the dental curable composition.

  Here, when it is desired to increase the curing rate, the value of (a × A) / (b × B) may be increased within the range shown in the equation (1). Further, from the viewpoint of sufficiently suppressing polymerization shrinkage during polymerization when using an epoxy compound in combination, (a × A) / (b × B) is more preferably within the range of 45/55 to 80/20, More preferably within the range of 45/55 to 70/30.

  Next, the epoxy compound shown in the above (3) will be described. To the dental curable composition of this embodiment, the epoxy compound shown in the above (3) can be added as necessary within a range in which the purpose of the present invention for further suppressing polymerization shrinkage can be ensured. . In this case, from the viewpoint of suppressing the shrinkage during polymerization, the amount of the epoxy compound shown in the above (3) is 100 as the total of all cationic polymerizable functional groups contained in the dental curable composition. In the case of mass parts, it is preferably 30 parts by mass or less.

  As the epoxy compound shown in (3) above, an epoxy compound having two or more alicyclic epoxy groups is preferable because of its high curing activity. Examples of such an epoxy compound include 1,2,5,6-diepoxycyclooctane, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and bis (3,4-epoxycyclohexylmethyl). Glutarate, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxycyclohexylmethyl) pimelate, bis (3,4-epoxycyclohexylmethyl) suberate, bis (3,4-epoxycyclohexylmethyl) zelate, Bis (3,4-epoxycyclohexylmethyl) sebacate, 1,4-bis (3,4-epoxycyclohexylmethyloxymethyl) benzene, 1,4-bis (3,4-epoxycyclohexylmethyloxymethyl) biphenyl, methylbiphenyl [2- (7-oxabicyclo [4.1.0] hept-3-yl) ethyl] phenylsilane, dimethylbis [(7-oxabicyclo [4.1.0] hept-3-yl) methyl] silane Methyl [(7-oxabicyclo [4.1.0] hept-3-yl) methyl] [2- (7-oxabicyclo [4.1.0] hept-3-yl) ethyl] silane, 1, 4-phenylenebis [dimethyl [2- (7-oxabicyclo [4.1.0] hept-3-yl) ethyl]] silane, 1,2-ethylenebis [dimethyl [2- (7-oxabicyclo [4 .1.0] Hept-3-yl) ethyl]] silane, dimethyl [2- (7-oxabicyclo [4.1.0] hept-3-yl) ethyl] silane, 1,3-bis [2- (7-Oxabicyclo [4.1.0] hept-3 Yl) ethyl] -1,1,3,3-tetramethyldisiloxane, 2,5-bicyclo [2.2.1] heptylenebis [dimethyl [2- (7-oxabicyclo [4.1.0] hept- 3-yl) ethyl]] silane, 1,6-hexylenebis [dimethyl [2- (7-oxabicyclo [4.1.0] hept-3-yl) ethyl]] silane, or a compound shown below Groups can be exemplified.

  The epoxy compound shown to said (3) illustrated above may use only 1 type, and may use 2 or more types together.

-Other polymerizable monomers-
In the dental curable composition of the present embodiment, in addition to the cationically polymerizable monomers such as the oxetane compound and the epoxy compound described above, an addition polymerization type such as a (meth) acrylate monomer as necessary. It is also possible to mix the radically polymerizable monomer. However, addition polymerization type radical polymerizability is inhibited by polymerization due to oxygen, so it is not preferable to add too much. When the radical polymerizable monomer is blended, the blending amount is 30% by mass or less with respect to the total amount (100% by mass) of the blending amount of the cationic polymerizable monomer and the radical polymerizable monomer. Preferably, the content is 10% by mass or less.

  Specific examples of such radical polymerizable monomers include methyl (meth) acrylate, glycidyl (meth) acrylate, 2-cyanomethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, and allyl (meth) acrylate. 2-hydroxyethyl mono (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, propylene glycol di (meth) Acrylate, dipropylene glycol di (meth) acrylate, 2,2-bis [4- (meth) acryloyloxyethoxyphenyl] propane, 2,2-bis [4- (meth) acryloyloxyethoxye Xylphenyl] propane, 2,2-bis {4- [3- (meth) acryloyloxy-2-hydroxypropoxy] phenyl} propane, 1,4-butanediol di (meth) acrylate, 1,3-hexanediol di ( And (meth) acrylate monomers such as (meth) acrylate, urethane di (meth) acrylate, and trimethylolpropane di (meth) acrylate.

-(II) Cationic polymerization initiator-
The cationic polymerization initiator used in the dental curable composition of the present embodiment is not particularly limited, and any known cationic polymerization initiator may be used. As such cationic polymerization initiators, Lewis acids or Bronsted acids, or compounds that produce Lewis acids or Bronsted acids by heating or light irradiation are known. It is particularly preferable to employ a so-called photoacid generator that generates a Lewis acid or a Bronsted acid by light irradiation because it is easy to polymerize rapidly in an environment such as the oral cavity. It is also preferable to use a so-called thermal acid generator that generates an acid by heating.

  Examples of the photoacid generator include diaryliodonium salt compounds, sulfonium salt compounds, sulfonic acid ester compounds, pyridinium salt compounds, and halomethyl-substituted S-triazine conductors.

  Among these, diaryliodonium salt compounds and sulfonium salt compounds are excellent in that the polymerization activity is particularly high. Specific examples of diaryliodonium salt compounds include diphenyliodonium, bis (p-chlorophenyl) iodonium, ditolyliodonium, bis (p-tert-butylphenyl) iodonium, p-isopropylphenyl-p-methylphenyliodonium, Bis (m-nitrophenyl) iodonium, p-tert-butylphenylphenyliodonium, p-methoxyphenylphenyliodonium, bis (p-methoxyphenyl) iodonium, p-octyloxyphenylphenyliodonium, p-phenoxyphenylphenyliodonium, bis Cations such as (p-dodecylphenyl) iodonium, chloride, bromide, p-toluenesulfonate, trifluoromethanesulfonate, tetrafluoroborate And diaryl iodonium salt compounds comprising anions such as tetrakispentafluorophenylborate, tetrakispentafluorophenyl gallate, hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate.

  Among these, p-toluene sulfonate, trifluoromethane sulfonate, tetrafluoroborate, tetrakispentafluorophenylborate, tetrakispentafluorophenyl gallate, hexafluorophosphate, hexagonal from the viewpoint of solubility in polymerizable monomers. A compound having fluoroarsenate or hexafluoroantimonate as an anion can be preferably used. In addition, it has hexafluoroantimonate, tetrakispentafluorophenylborate, tetrakispentafluorophenylgallate as an anion in that it is low in nucleophilicity and can be stably stored as a mixture with a polymerizable monomer if it is not irradiated with light. A compound can be used conveniently.

  Examples of sulfonium salt compounds include dimethylphenacylsulfonium, dimethylbenzylsulfonium, dimethyl-4-hydroxyphenylsulfonium, dimethyl-4-hydroxynaphthylsulfonium, dimethyl-4,7-dihydroxynaphthylsulfonium, dimethyl-4,8- Cations such as dihydroxynaphthylsulfonium, triphenylsulfonium, p-tolyldiphenylsulfonium, p-tert-butylphenyldiphenylsulfonium, diphenyl-4-phenylthiophenylsulfonium, chloride, bromide, p-toluenesulfonate, trifluoromethanesulfonate , Tetrafluoroborate, tetrakispentafluorophenylborate, tetrakispentafluorophenylgallate, hexaful Examples thereof include sulfonium salt compounds composed of anions such as orophosphate, hexafluoroarsenate and hexafluoroantimonate.

  These photoacid generators may be used singly or in combination as needed. The amount of these photoacid generators used is not particularly limited as long as the polymerization can be initiated by light irradiation, but an appropriate polymerization rate and various physical properties of the resulting cured product (for example, weather resistance). In general, it is preferably used within a range of 0.001 to 10 parts by mass with respect to 100 parts by mass of the cationic polymerizable monomer, More preferably, it is used within the range of 5 parts by mass.

  The photoacid generators as described above are usually many compounds that do not absorb at wavelengths in the near ultraviolet region to wavelengths in the visible region. For this reason, a special light source is often required to excite the polymerization reaction. Therefore, it is preferable that a compound having absorption in the near-ultraviolet wavelength to visible wavelength is used as a sensitizer in addition to the photoacid generator.

  Examples of compounds used as such sensitizers include acridine dyes, benzoflavine dyes, condensed polycyclic aromatic compounds such as anthracene and perylene, and phenothiazine.

  Among these sensitizers, a condensed polycyclic aromatic compound is preferable in terms of good polymerization activity, and a structure in which a saturated carbon atom having at least one hydrogen atom is bonded to the condensed polycyclic aromatic ring. Condensed polycyclic aromatic compounds having are preferred.

  Specific examples of such condensed polycyclic aromatic compounds having a structure in which a saturated carbon atom having at least one hydrogen atom is bonded to a condensed polycyclic aromatic ring include 1-methylnaphthalene and 1-ethylnaphthalene. 1,4-dimethylnaphthalene, acenaphthene, 1,2,3,4-tetrahydrophenanthrene, 1,2,3,4-tetrahydroanthracene, benzo [f] phthalane, benzo [g] chroman, benzo [g] isochroman, N-methylbenzo [f] indoline, N-methylbenzo [f] isoindoline, phenalene, 4,5-dimethylphenanthrene, 1,8-dimethylphenanthrene, acephenanthrene, 1-methylanthracene, 9-methylanthracene, 9-ethylanthracene , 9-cyclohexylanthracene, 9,10-dimethyl Luanthracene, 9,10-diethylanthracene, 9,10-dicyclohexylanthracene, 9-methoxymethylanthracene, 9- (1-methoxyethyl) anthracene, 9-hexyloxymethylanthracene, 9,10-dimethoxymethylanthracene, 9- Dimethoxymethylanthracene, 9-phenylmethylanthracene, 9- (1-naphthyl) methylanthracene, 9-hydroxymethylanthracene, 9- (1-hydroxyethyl) anthracene, 9,10-dihydroxymethylanthracene, 9-acetoxymethylanthracene 9- (1-acetoxyethyl) anthracene, 9,10-diacetoxymethylanthracene, 9-benzoyloxymethylanthracene, 9,10-dibenzoyloxymethylanthracene, 9 -Ethylthiomethylanthracene, 9- (1-ethylthioethyl) anthracene, 9,10-bis (ethylthiomethyl) anthracene, 9-mercaptomethylanthracene, 9- (1-mercaptoethyl) anthracene, 9,10-bis (Mercaptomethyl) anthracene, 9-ethylthiomethyl-10-methylanthracene, 9-methyl-10-phenylanthracene, 9-methyl-10-vinylanthracene, 9-allylanthracene, 9,10-diallylanthracene, 9-chloro Methyl anthracene, 9-bromomethylanthracene, 9-iodomethylanthracene, 9- (1-chloroethyl) anthracene, 9- (1-bromoethyl) anthracene, 9- (1-iodoethyl) anthracene, 9,10-dichloromethylanthracene 9,10-dibromomethylanthracene, 9,10-diiodomethylanthracene, 9-chloro-10-methylanthracene, 9-chloro-10-ethylanthracene, 9-bromo-10-methylanthracene, 9-bromo-10 -Ethylanthracene, 9-iodo-10-methylanthracene, 9-iodo-10-ethylanthracene, 9-methyl-10-dimethylaminoanthracene, acanthrene, 7,12-dimethylbenz (a) anthracene, 7,12- Dimethoxymethylbenz (a) anthracene, 5,12-dimethylnaphthacene, collanthrene, 3-methylcholanthrene, 7-methylbenzo (a) pyrene, 3,4,9,10-tetramethylperylene, 3,4,9, 10-tetrakis (hydroxymethyl) perylene, bio Nsuren, Isoviolanthrone Ren, 5,12-dimethyl-naphthacene, 6,13-dimethyl pentacene, 8,13- dimethyl penta Fen, 5,16- dimethyl hexamethylene Sen, 9,14- dimethyl hexa Fen and the like.

  As the condensed polycyclic aromatic compound other than the above, naphthalene, phenanthrene, anthracene, naphthacene, benz [a] anthracene, pyrene, perylene and the like are preferably used.

  Among these condensed polycyclic aromatic compounds, a compound having absorption at a wavelength in the visible range, which can excite polymerization with visible light in consideration of harm to the living body, is preferable, and has a maximum absorption in the visible range. The compound which has is more preferable. Further, these condensed polycyclic aromatic compounds may be used in combination with a plurality of compounds as necessary.

  Although the addition amount of the condensed polycyclic aromatic compound also varies depending on the other components to be combined and the kind of the polymerizable monomer, the amount of the condensed polycyclic aromatic compound is usually 0 with respect to 1 mol of the photoacid generator. It is preferable to add within a range of 0.001 mol to 20 mol, and it is more preferable to add within a range of 0.005 mol to 10 mol.

  Furthermore, from the viewpoint of further improving the polymerization activity, it is preferable to add an oxidized photoradical generator in addition to the condensed polycyclic aromatic compound. An oxidized photoradical generator is a compound in which the mechanism for generating active radical species by excitation by light irradiation has an oxidant action (it is reduced itself). As such an oxidized photo radical generator, a type that generates a radical by extracting hydrogen from a hydrogen donor by excitation (hydrogen abstraction type radical generator), a radical is generated by self-cleavage by excitation, Next, there are a type in which this radical extracts an electron from an electron donor (self-cleaving radical generator) and a type in which the radical is excited by light irradiation to directly extract an electron to form a radical. These oxidized photoradical generators are not particularly limited, and known compounds may be used. However, in terms of higher polymerization activity when irradiated with light than other compounds, hydrogen abstraction type photoradicals are used. A generator is preferred, and among them, a diaryl ketone compound, an α-diketone compound or a ketocoumarin compound is particularly preferred.

  Specific examples of the diaryl ketone compound include 4,4-bis (dimethylamino) benzophenone, 9-fluorenone, 3,4-benzo-9-fluorenone, 2-dimethylamino-9-fluorenone, and 2-methoxy-9-fluorenone. 2-chloro-9-fluorenone, 2,7-dichloro-9-fluorenone, 2-bromo-9-fluorenone, 2,7-dibromo-9-fluorenone, 2-nitro-9-fluorenone, 2-acetoxy-9 -Fluorenone, benzanthrone, anthraquinone, 1,2-benzanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 1-dimethylaminoanthraquinone, 2,3-dimethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone 1,5-dichloroanthraquinone, 1,2-dimethoxyanthraquinone, 1,2-diacetoxy-anthraquinone, 5,12-naphthacenequinone, 6,13-pentacenequinone, xanthone, thioxanthone, 2,4-dimethylthioxanthone, 2,4 -Diethylthioxanthone, 2-chlorothioxanthone, 9 (10H) -acridone, 9-methyl-9 (10H) -acridone, dibenzosuberenone and the like can be mentioned.

  Specific examples of α-diketone compounds include camphorquinone, benzyl, diacetyl, acetylbenzoyl, 2,3-pentadione, 2,3-octadione, 4,4′-dimethoxybenzyl, 4,4′-oxybenzyl, 9,10-phenanthrenequinone, acenaphthenequinone, etc. are mentioned.

  The ketocoumarin compounds include 3-benzoylcoumarin, 3- (4-methoxybenzoyl) coumarin, 3-benzoyl-7-methoxycoumarin, 3- (4-methoxybenzoyl) 7-methoxy-3-coumarin, and 3-acetyl. -7-dimethylaminocoumarin, 3-benzoyl-7-dimethylaminocoumarin, 3,3′-coumarinoketone, 3,3′-bis (7-diethylaminocoumarino) ketone, and the like.

  These oxidized photoradical generators can be used alone or in admixture of two or more. Moreover, although the amount of addition varies depending on the other components to be combined and the kind of the polymerizable monomer, the photo radical generator is usually within a range of 0.001 mol to 20 mol with respect to 1 mol of the photo acid generator described above. It is preferable to add, and it is more preferable to add within the range of 0.005 to 10 mol.

On the other hand, as the thermal acid generator, for example, the cation moiety is quaternary ammonium, sulfonium, phosphonium, iodonium, and the anion moiety is BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SbF ₄ ⁻ , AsF ₆ ^−. A quaternary ammonium salt, a sulfonium salt, a phosphonium salt, an iodonium salt, or the like constituted by the above can be used alone or in combination of two or more.

Examples of the quaternary ammonium salt include N, N-dimethyl-N-benzylanilinium hexafluoroantimonate, N, N-diethyl-N-benzylanilinium tetrafluoroborate, N, N-dimethyl-N-benzylpyridinium. Hexafluoroantimonate, N, N-diethyl-N-benzylpyridinium trifluoromethanesulfonic acid, N, N-dimethyl-N- (4-methoxybenzyl) pyridinium hexafluoroantimonate, N, N-diethyl-N- (4 -Methoxybenzyl) pyridinium hexafluoroantimonate, N, N-diethyl-N- (4-methoxybenzyl) toluidinium hexafluoroantimonate, N, N-dimethyl-N- (4-methoxybenzyl) toluidinium hexafluoroantimonate And the like can be used.

Examples of the sulfonium salt include triphenylsulfonium tetrafluoroborate, 2-butenyltetramethylenesulfonium hexafluoroantimonate, 3-methyl-2-butenyltetramethylenesulfonium hexafluoroantimonate, triphenylsulfonium hexafluoroantimonate, Triphenylsulfonium hexafluoroarsenate, tri (4-methoxyphenyl) sulfonium hexafluoroarsenate, diphenyl (4-phenylthiophenyl) sulfonium hexafluoroarsenate, and the like can be used.

As the phosphonium salt, for example, ethyltriphenylphosphonium tetrafluoroborate, tetrabutylphosphonium tetrafluoroborate and the like can be used.

Examples of the iodonium salt include diphenyliodonium hexafluoroarsenate, di-4-chlorophenyliodonium hexafluoroarsenate, di-4-bromophenyliodonium hexafluoroarsenate, di-p-tolyliodonium hexafluoroarsenate, phenyl ( 4-methoxyphenyl) iodonium hexafluoroarsenate and the like can be used.

  Commercially available products that can be used as thermal acid generators include, for example, Adeka Opton CP-66, Adeka Opton CP-77 (above, manufactured by Asahi Denka Kogyo Co., Ltd.), CI-2855 (above, made by Nippon Soda Co., Ltd.), Sun Aid SI -60L, sun aid SI-80L, sun aid SI-100L, sun aid SI-110L, sun aid SI-180L, sun aid SI-110, sun aid SI-145, sun aid SI-150, sun aid SI-160, sun aid SI-180 (or more, Sanshin Chemical Co., Ltd.).

  In addition, CI-2855 (above, Nippon Soda Co., Ltd. product), Sun-Aid SI-60L, Sun-Aid SI-80L, Sun-Aid SI-100L, Sun-Aid SI-110L, Sun-Aid SI-180L, Sun-Aid SI-110, Sun-Aid SI-145, Sun-Aid SI-150, Sun-Aid SI-160, and Sun-Aid SI-180 (manufactured by Sanshin Chemical Industry Co., Ltd.) can generate an acid by irradiation with light in addition to heating.

  These thermal acid generators can be used alone or in admixture of two or more. In addition, the amount of addition varies depending on the other components to be combined and the type of polymerizable monomer, but generally within a range of 0.001 to 10 parts by mass with respect to 100 parts by mass of the cationic polymerizable monomer. It is preferable to use, and it is more preferable to use within the range of 0.05 part by mass to 5 parts by mass.

-Various additives-
In the dental curable composition of the present embodiment, various additives can be further blended as necessary.

  A typical example of such an additive is a filler (filler). In the case where volume shrinkage occurs at the time of polymerization when no filler is added, the effect of suppressing the volume shrinkage at the time of polymerization can be further increased by adding the filler to the dental curable composition of the present embodiment. . Further, by using the filler, the operability of the dental curable composition before curing can be improved, or the mechanical properties after curing can be improved.

  When a filler is blended with the dental curable composition of this embodiment, the type and blending amount of the filler may be appropriately set according to the use of the dental curable composition. For example, when the dental curable composition of the present embodiment is used as a filling restorative material, a known filler may be blended as a filler for the dental filling restorative material.

  Examples of the filler include inorganic fillers made of particles of inorganic oxides such as amorphous silica, silica-titania, silica-zirconia, silica-titania-barium oxide, quartz, and alumina. Furthermore, for the purpose of easily obtaining dense inorganic oxide particles when these inorganic oxide particles are fired at a high temperature, the inorganic oxide particles and a small amount of Group I metal oxides are used. It is also possible to use composite oxide particles. The filler used in the dental curable composition of the present embodiment is particularly preferably a composite oxide inorganic filler mainly composed of silica and zirconia because it has X-ray contrast properties.

  The particle size and shape of these inorganic fillers are not particularly limited, and spherical or amorphous particles having an average particle diameter of 0.01 μm to 100 μm, which are generally used as dental materials, are used appropriately depending on the purpose. do it. Further, the refractive index of these inorganic fillers is not particularly limited, and those having a refractive index of 1.4 to 1.7 which the fillers used for general dental materials have can be used without limitation. Further, as the inorganic filler, in order to obtain higher surface smoothness and abrasion resistance, it is preferable to use a spherical or substantially spherical inorganic powder and / or an aggregate thereof. The term “substantially spherical” as used herein refers to taking a picture of the inorganic filler with a scanning electron microscope and gradually increasing the particle diameter in the direction perpendicular to the maximum particle diameter observed in the unit field of view at the maximum diameter. Means that the average uniformity is 0.6 or more.

  The particle diameter and the like of the inorganic spherical filler are not particularly limited, but in order to obtain higher surface smoothness and wear resistance, the inorganic particles having an average particle diameter of 0.01 μm to 1 μm and / or this It is preferable to use an inorganic spherical filler made of an aggregate of inorganic particles. These inorganic spherical fillers may be any mode selected from a single particle system and a mixed particle system composed of two or more kinds of particles having different average particle diameters.

  Moreover, it is preferable to treat the inorganic filler with a surface treatment agent typified by a silane coupling agent from the viewpoint of improving compatibility with the polymerizable monomer and improving mechanical strength and water resistance. A known method can be adopted as the surface treatment method. Here, as a silane coupling agent, methyltrimethoxysilane, methyltriethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, vinyltriacetoxysilane, Vinyltris (2-methoxyethoxy) silane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltris (2-methoxyethoxy) silane, 3-chloropropyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3- Glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxy Silane, 5,6-epoxyhexyltriethoxysilane, 3-ethyl-3- [3- (triethoxysilyl) propoxymethyl] oxetane, N-phenyl-γ-aminopropyltrimethoxysilane, hexamethyldisilazane, etc. are preferable. Used for. Particularly when the polymerizable monomer is a cationic polymerizable monomer, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, which is a silane coupling agent having a cationic polymerizable functional group, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 5,6-epoxyhexyltriethoxysilane, 3-ethyl-3- [3- (triethoxysilyl) propoxymethyl] oxetane and the like are desirable. Only one kind of the silane coupling agent can be used, or two or more kinds can be mixed and used.

  Moreover, an organic-inorganic composite filler can also be suitably used for the purpose of achieving both a higher filler filling rate and good operability. The organic-inorganic composite filler is obtained by polymerizing and curing a polymerization curable composition mainly composed of a polymerizable monomer and an inorganic filler, and is pulverized by a known production method. The organic-inorganic composite filler produced is used without any limitation.

  The blending amount when the filler is blended with the dental curable composition of the present embodiment is not particularly limited, but when used as a dental filling restorative material, it is 50 with respect to 100 parts by mass of the polymerizable monomer. It is preferably within the range of ˜1500 parts by mass, and more preferably within the range of 70 to 1000 parts by mass. Furthermore, these fillers such as inorganic fillers and organic-inorganic composite fillers may be used alone, or a plurality of fillers having different materials, particle sizes, shapes, etc. may be used in combination. However, it is particularly preferable to use an inorganic filler alone or a mixture of an inorganic filler and an organic-inorganic composite filler in terms of excellent mechanical properties after curing.

  Furthermore, in the dental curable composition of the present embodiment, if necessary, a stabilizer such as a polymerization inhibitor, an antioxidant and an ultraviolet absorber, an antistatic agent, a coloring material such as a dye and a pigment, a fragrance, Known additives such as organic solvents and thickeners may be blended.

  In particular, when an iodonium salt-based initiator is blended as a cationic polymerization initiator in the dental curable composition of the present embodiment, the dental curable composition is used in a high temperature environment of about 50 ° C. or a room temperature environment. From the viewpoint of suppressing gelation of the dental curable composition when stored for a long period of time, it is preferable that a binderd phenol and a hindered amine are blended. Here, the hindered phenols are those in which at least one of the two aromatic carbons adjacent to the aromatic carbon to which the phenolic hydroxyl group is bonded is substituted with a secondary alkyl group or a tertiary alkyl group. Indicates. Among them, the one in which both of the two aromatic carbons adjacent to the aromatic carbon to which the phenolic hydroxyl group is bonded is substituted with a tertiary alkyl group is most preferably used. Such compounds include 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-methylphenol, 2,4,6-tri-t-butylphenol, n-octadecyl-3- ( 3,5-di-t-butyl-4-hydroxyphenyl) propionate, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, tris (3,5-di -T-butyl-4-hydroxybenzyl) isocyanurate and the like. These hindered phenols may be used in combination with a plurality of compounds as necessary. The amount of these hindered phenols to be added varies depending on the other components to be combined, but usually the hindered phenol group may be added within a range of 0.001 mol to 1 mol with respect to 1 mol of the diaryl iodonium salt described above. Preferably, it is added in the range of 0.005 mol to 0.8 mol.

  The hindered amine is a secondary or tertiary aliphatic amine compound, and at least two of the alkyl groups bonded to the nitrogen atom constituting the amine compound are secondary or tertiary alkyl groups. Indicates something. As such hindered amines, known compounds can be used without particular limitation, and for example, hindered amines known as light stabilizers for resins can be used. Among these, pyrrolidines, piperidines, and piperazines that are chemically stable cyclic amines are preferable, and piperidines are more preferable from the viewpoint of easy availability. Specific examples of such hindered amines include 2,6-dimethylpiperidine, N-methyl-2,6-dimethylpiperidine, N-methyl-2,6-dimethylpiperidin-4-one, and N-methyl-4. -Hydroxy-2,6-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, N-methyl-2,2,6,6-tetramethylpiperidine, N-methyl-2,2,6,6- Tetramethylpiperidin-4-one, N-methyl-4-hydroxy-2,2,6,6-tetramethylpiperidine, bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis (N -Methyl-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidinyl) -1,2,3,4- Tantetracarboxylate, tetrakis (N-methyl-2,2,6,6-tetramethyl-4-piperidinyl) -1,2,3,4-butanetetracarboxylate, tetrakis (2,2,6,6- Tetramethyl-4-piperidinyl) -1,2,3,4-butanetetracarboxylate, poly [(6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazi / 2 , 4-diyl] [(2,2,6,6-tetramethyl-4-piperidinyl) imino] hexamethyllene (2,2,6,6-tetramethyl-4-piperidinyl) iminol, dimethyl succinate-1 -(2-hydroxyethyl) 4-hydroxy-2,2,6,6-tetramethyl-4-piperidine polycondensate, etc. These hindered amines may be used as required. These compounds may be used in combination.

  Although the amount of hindered amines to be added varies depending on other components to be combined, the hindered amino group is usually added in an amount of 0.001 mol to 1 mol of the above-mentioned iodonium salt in that it hardly affects the physical properties of the cured product after curing. It is preferably within the range of 1 mol, and more preferably within the range of 0.005 mol to 0.8 mol.

  The dental curable composition of the present embodiment is particularly preferably used as a dental restoration material as described above, but is not limited thereto, and other uses such as a dental adhesive and a denture base material. Can also be used.

-Manufacturing method, packaging form and curing method of dental curable composition-
The manufacturing method of the dental curable composition of this embodiment is not particularly limited, and a known manufacturing method may be adopted as appropriate. Specifically, in addition to the oxetane compound having a functional group represented by the general formula (i) and the cationic polymerization initiator, which are essential components constituting the dental curable composition of the present embodiment, further, if necessary What is necessary is just to weigh a predetermined amount and mix these other compounding components mix | blended.

  The packaging form of the dental curable composition of the present embodiment is not particularly limited, and may be appropriately determined in consideration of its purpose and storage stability. For example, when a photocationic polymerization initiator is blended as a cationic polymerization initiator, all components constituting the dental curable composition of the present embodiment can be packaged in a light-shielded state. On the other hand, when a component that can initiate cationic polymerization at room temperature without light irradiation is used as a polymerization initiator, the dental curable composition of this embodiment is not polymerized or cured during storage. A packaging form in which an object is divided into two or more packages and both are mixed immediately before use is preferable.

  As a means for curing the dental curable composition of the present embodiment, a known polymerization means may be appropriately employed according to the polymerization initiation mechanism of the used cationic polymerization initiator. As a polymerization means, a light irradiation means by a light source such as a carbon arc, a xenon lamp, a metal halide lamp, a tungsten lamp, a fluorescent lamp, sunlight, a helium cadmium laser, an argon laser, a heating means using a heating polymerizer, or the like A polymerization means combining these can be used without limitation. In the case of polymerization by light irradiation, the irradiation time varies depending on the wavelength of the light source, the intensity, the shape and material of the cured body, and therefore may be determined in advance through preliminary experiments. However, generally, it is preferable to adjust the blending ratio of various components constituting the dental curable composition so that the irradiation time is in the range of about 5 seconds to 60 seconds. Similarly, the heating time and heating temperature may be determined in advance by preliminary experiments.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited only to the examples shown below.

(1) Compounds used in Examples and Comparative Examples and their abbreviations Oxetane compound having a functional group represented by general formula (i) Oxetane compounds having a functional group represented by general formula (i) were synthesized by Synthesis Examples 1 to 6 below.

<Synthesis Example 1>
The following oxetane compound (PXOH, molecular weight 164.20) was synthesized by the method described in Tetrahedron, 2002, 58, 7065-7074.

<Synthesis Example 2>
The following oxetane compound (PX-E, molecular weight 192.25) was synthesized by the following procedure. First, 32.84 g (0.2 mol) PXOH and 34.4 g (0.22 mol) iodoethane were ice-cooled in 100 ml tetrahydrofuran solvent in the presence of 5.28 g (0.22 mol) sodium hydride. The reaction was continued for 1 hour. Then, it was made to react at room temperature for further 4 hours. Subsequently, 50 ml of water was added to the solution obtained by the reaction, and the mixture was vigorously stirred to obtain an emulsion. This emulsion was extracted three times with diethyl ether, and the organic layer was separated with a separatory funnel. The separated organic component was concentrated by a rotary evaporator, and the concentrated solution was purified and isolated by silica gel column chromatography to obtain PX-E (20 g, yield 51%). The results of ¹ H NMR measurement of PX-E are as follows: 1H NMR δ1.11 (t, 3H), 3.42 (q, 2H), 3.64 (s, 2H), 5.05 ( s, 4H), 7.02-7.38 (m, 5H).

<Synthesis Example 3>
The following oxetane compound (PX2-B, molecular weight 382.49) was synthesized by the following procedure. First, 65.68 g (0.4 mol) PXOH and 38.86 g (0.18 mol) 1.4-dibromo in the presence of 10.56 g (0.44 mol) sodium hydride in 150 ml tetrahydrofuran solvent. Butane was reacted in the same manner as in Synthesis Example 2 and purified and isolated. This gave PX2-B (20 g, 30% yield). The results of ¹ H NMR measurement of PX2-B are as follows: 1H NMR δ 1.46 (m, 4H), 3.37 (t, 4H), 3.64 (s, 4H), 5.05 ( s, 8H), 7.02-7.38 (m, 10H).

<Synthesis Example 4>
The following oxetane compound (PX2-H, molecular weight 410.55) was synthesized by the following procedure. First, 65.68 g (0.4 mol) PXOH and 43.91 g (0.18 mol) 1.6-dibromo in the presence of 10.56 g (0.44 mol) sodium hydride in 150 ml tetrahydrofuran solvent. Hexane was reacted in the same manner as in Synthesis Example 2 and purified and isolated. This gave PX2-H (23 g, 31% yield). The results of ¹ H NMR measurement of PX2-H are as follows: 1H NMR δ 1.29 (m, 4H), 1.46 (m, 4H), 3.37 (t, 4H), 3.64 ( s, 4H), 5.05 (s, 8H), 7.02-7.38 (m, 10H).

<Synthesis Example 5>
The following oxetane compound (PX2-X, molecular weight 430.54) was synthesized by the following procedure. First, 65.68 g (0.4 mol) PXOH and 31.51 g (0.18 mol) 1.4-bis in the presence of 10.56 g (0.44 mol) sodium hydride in 150 ml tetrahydrofuran solvent. (Chloromethyl) benzene was reacted in the same manner as in Synthesis Example 2 and purified and isolated. Thereby, PX2-X (62 g, yield 80%) was obtained. The results of ¹ H NMR measurement of PX2-X are as follows: 1H NMR δ 3.64 (s, 4H), 4.60 (s, 4H), 5.05 (s, 8H), 7.02- 7.38 (m, 14H).

<Synthesis Example 6>
The following oxetane compound (PXO2-X, molecular weight 382.49) was synthesized by the following procedure. First, 32.84 g (0.2 mol) PXOH, 23.23 g (0.2 mol) 2-ethyl-2 in the presence of 10.56 g (0.44 mol) sodium hydride in 150 ml tetrahydrofuran solvent. -Hydroxymethyloxetane and 31.51 g (0.18 mol) of 1.4-bis (chloromethyl) benzene were reacted in the same manner as in Synthesis Example 2 and purified and isolated. This gave PXO2-X (21 g, 30% yield). The results of ¹ H NMR measurement of PXO2-X are as follows: 1H NMR δ1.11 (t, 3H), 3.42 (q, 2H), 3.61 (s, 2H), 3.64 ( s, 2H), 4.43 (dd, 4H), 4.60 (s, 4H), 5.05 (s, 4H), 7.02-7.38 (m, 9H).

2. An oxetane compound having a functional group containing an oxetane ring other than the functional group represented by the general formula (i), as an oxetane compound having a functional group containing an oxetane ring other than the functional group represented by the general formula (i); OX-P (molecular weight 192.25), OX-2 (molecular weight 382.49), OX-3 (molecular weight 410.55) and OX-4 (molecular weight 482.61) were prepared.

3. Epoxy compound
DEP-B (molecular weight 236.35) and DEP-D (molecular weight 194.27) shown below were prepared as epoxy compounds.

4). Photoacid generator The following IMDPI was prepared as a photoacid generator.

5. Condensed polycyclic aromatic compound The following DMAn was prepared as a condensed polycyclic aromatic compound.

6). Oxidized photoradical generator The following CQ (camphorquinone) was prepared as an oxidized photoradical generator.

7). Other polymerizable monomers other than oxetane compounds and epoxy compounds Bis-GMA and TEGDMA shown below were prepared as other polymerizable monomers other than oxetane compounds and epoxy compounds.

(2) Preparation of curable composition In the dark, a polymerization initiator was added to the polymerizable monomer and stirred and dissolved until uniform to prepare curable compositions A to R. Table 1 shows the composition.

(3) Surface treatment of inorganic filler 20 g of spherical silica-zirconia (particle size 0.2 μm) was suspended in 80 ml of hydrochloric acid adjusted to pH 4.0, and 3-ethyl-3-ethyl silane coupling agent was stirred while stirring. 1.2 g of (3-triethoxysilylpropoxy) methyloxetane was added dropwise. After stirring for 1 hour, water was distilled off with an evaporator, and the obtained solid was pulverized with a mortar and then dried at 80 ° C. under reduced pressure for 15 hours. After drying, the obtained powder was stored in a desiccator using inorganic filler PF1 and silica gel as the drying agent. In the preparation of the inorganic filler PF1, an inorganic filler obtained by treating with 1 g of 3-methacryloxypropyltrimethoxysilane instead of 3-ethyl-3- (3-triethoxysilylpropoxy) methyloxetane as a silane coupling agent It was set to PF2.

(4) Preparation of organic-inorganic composite filler 0.5 parts by mass of azobisisobutyronitrile as a polymerization initiator in advance for 100 parts by mass of a mixture of 60 parts by mass of Bis-GMA and 40 parts by weight of TEGDMA 25 parts by mass (hereinafter abbreviated as “AIBN”) and 75 parts by mass of PF2 were mixed in an agate mortar to form a paste. This was polymerized by heating at 95 ° C. under a nitrogen atmosphere for 1 hour. The obtained polymerized cured product was pulverized using a vibration ball mill. The obtained pulverized product was used as an organic-inorganic composite filler HF1 (average particle size: 20 μm).

(5) Preparation of paste It mixed so that mass ratio of inorganic filler PF1 and organic-inorganic composite filler HF1 might be 40:60. Next, 82 parts by mass of this mixture and 18 parts by mass of curable composition C were mixed in an agate mortar, and the resulting mixture was degassed under vacuum to remove bubbles and obtain paste C. Further, in the same manner as in the case of preparing paste C, pastes D, M, and N were also prepared using curable compositions D, M, and N.

(6) Evaluation Table 2 shows the curing time and volume change rate of the curable compositions A to R. Table 3 shows the curing time, volume change rate, bending strength, and cavity compatibility test of pastes C, D, M, and N.

  The curing time of the curable composition shown in Table 2 and the volume change rate before and after curing of the curable composition, and the curing time of the paste shown in Table 3, the volume change rate before and after curing of the paste, and the paste were cured. The bending strength of the cured product was determined by the following procedure. The test methods and evaluation criteria for the cavity compatibility test shown in Table 3 are as follows.

-Curing time of the curable composition shown in Table 2-
In a polypropylene container having an inner diameter of 1.6 cm and a depth of 1.1 cm, 0.9 g of the curable composition was placed, and the cured thick film was 4 mm. Next, from a distance of 0.5 cm, a dental light irradiator (TOKUSO
Light irradiation was performed for 2 minutes using POWER LITE (manufactured by Tokuyama Corporation). At this time, the time from the start of irradiation until the tweezer tip was not pierced by the polymer even if the polymer surface was strongly pushed vertically with a sharp tweezer tip was defined as the curing time.

-Volume change rate before and after hardening of curable composition shown in Table 2-
The curable composition in a liquid state before curing was placed in a 10 ml volumetric flask with a known weight, the liquid level was adjusted to the marked line, and then stored overnight in a 23 ° C. incubator. After storage, the liquid level was confirmed to match the marked line, and the weight was measured. The density of the curable composition was calculated by subtracting the weight of the volumetric flask before putting the curable composition from the measured weight and further dividing by the volume. The above operation was performed on three or more samples, and the average value was defined as the composition density d1.

The same kind of curable composition as that used for the measurement of the composition density d1 and the same curable composition as that used for the evaluation of the curing time was placed in a polypropylene resin container having a diameter of 3 cm and a depth of 1 cm. It put to 0.5 cm, was irradiated with light with a dental light irradiator α light for 10 minutes, and was cured. After curing, the mixture was allowed to stand at room temperature for 30 minutes, and the density was measured using a digital hydrometer (manufactured by Sartorius) with the buoyancy-generating liquid as water (water temperature 23-24 ° C.). The same operation was performed on three or more samples, and the average value was taken as the cured body density d2. From the obtained d1 and d2, the volume change rate (%) was calculated based on the following formula (2). In the formula (2), when the value of the volume change rate is positive, volume expansion occurs with polymerization, and when the value of the volume change rate is negative, volume shrinkage occurs with polymerization.
Formula (2) Volume change rate = {(d1−d2) / d2} × 100

-Curing time of paste shown in Table 3-
A paste is placed on a glass plate so that the diameter is about 6 mm and the height is 3 mm. From the height of about 5 mm above the accumulated paste, a light irradiator (TOKUSO
Light was irradiated by POWER LITE, manufactured by Tokuyama Corporation. At this time, in order not to block the irradiation light with a needle having a thickness of about 0.4 mm, the hardness of the top surface and the side surface of the accumulated paste is examined, and the time from the start of irradiation until the needle stops sticking to the entire accumulated paste Was set as the curing time.

-Volume change rate before and after curing of paste shown in Table 3-
Using a digital hydrometer (manufactured by Sartorius), the density of the paste was measured with the buoyancy generating liquid as water (water temperature 23-24 ° C.). The same measurement was performed on three or more samples, and the average value was defined as the paste density d1.

  Next, a PTFE (polytetrafluoroethylene) mold having a diameter of 1 cm × 1 cm and a depth of 3 cm is filled with a paste so that bubbles do not enter, pressed with a PP (polypropylene) sheet, and 10 minutes with a dental light irradiator α light. Irradiated with light to obtain a cured product. After the cured product was allowed to stand at room temperature for 30 minutes, the density of the cured product was measured using a digital hydrometer (manufactured by Sartorius) in the same manner as the paste density measurement. The same measurement was performed on three or more samples, and the average value was taken as the cured body density d2. From the obtained d1 and d2, the volume change rate (%) was calculated based on the above formula (2). In the formula (2), when the value of the volume change rate is positive, volume expansion occurs with polymerization, and when the value of the volume change rate is negative, volume shrinkage occurs with polymerization.

-Flexural strength of cured products obtained by curing the paste shown in Table 3-
The paste was filled in the mold holes (length 2 mm, width 2 mm, depth 25 mm), and then the openings of the holes were covered with a polypropylene film. Next, the paste was cured by irradiating light on the polypropylene film for 1.5 minutes with a light irradiator (TOKUSO POWER LITE, manufactured by Tokuyama Corporation). After the obtained bar-shaped cured product was stored at 37 ° C. overnight, an autograph (manufactured by Shimadzu Corporation) was used, and the three-point bending strength was 5 for each at a fulcrum distance of 20 mm and a crosshead speed of 0.5 mm / min. Each cured product was measured, and the average value was calculated as the bending strength shown in Table 3. At this time, the standard deviation of bending strength was also calculated.

-Cavity compatibility test shown in Table 3-
The cavity compatibility test was performed according to the following procedure. First, a 4 mm diameter and 2 mm deep hole was drilled in a 5 mm thick polytetrafluoroethylene plate to form a simulated cavity. Next, the simulated cavity was filled with paste, and the opening of the simulated cavity was covered with a polypropylene film. Then, the paste was hardened by irradiating light for 1.5 minutes with a light irradiator (TOKUSO POWER LITE, manufactured by Tokuyama Corporation) from above the polypropylene film. After the polytetrafluoroethylene plate having a cured product formed in the simulated cavity was stored at 37 ° C. overnight, the surface of the polytetrafluoroethylene plate opposite to the surface on which the simulated cavity was formed was hit with a hammer. At this time, whether or not the cured product in the simulated cavity was dropped and the number of hammer strikes required until the cured product was dropped were evaluated according to the following criteria.
A: Even if the number of strikes is 6, the cured product does not fall out of the simulated cavity.
B: Hardened material falls out of the simulated cavity in the range where the number of strikes is 2 times or more and 5 times or less.
C: The number of strikes is one, and the cured product falls out of the simulated cavity.

Claims (5)

(I) an oxetane compound having at least one functional group containing an oxetane ring in the molecule, and (II) a cationic polymerization initiator,
(I) A dental curable composition characterized in that at least one oxetane compound having in the molecule at least one functional group represented by the following general formula (i) is used as the oxetane compound. object.

[In the general formula (i), Ar ¹ is a monovalent aromatic group which may have a substituent. ] The dental curable composition according to claim 1,
(II) A dental curable composition wherein the cationic polymerization initiator is a photoacid generator. The dental curable composition according to claim 1 or 2,
(III) A dental curable composition further comprising an epoxy compound. The dental curable composition according to claim 3,
(III) A dental curable composition, wherein the epoxy compound has an alicyclic epoxy group. The dental curable composition according to claim 3 or 4,
(III) The epoxy compound is (1) an epoxy compound in which a group represented by the following general formula (ii) is bonded to a carbon atom at the 3-position or 4-position of the cyclohexene oxide group which may have a substituent, and (2) A cyclohexene oxide ring containing a carbon atom constituting a 5- to 8-membered hydrocarbon ring bonded to the 3- or 4-position carbon atom of the optionally substituted cyclohexene oxide group A dental curable composition comprising at least one epoxy compound selected from an epoxy compound having at least two units and satisfying the following formula (1).
Formula (1) 90/10 ≧ (a × A) / (b × B) ≧ 45/55
[In the formula (1), a represents the average number of functional groups containing the oxetane ring contained in one molecule of (I) oxetane compound, and A is contained in the dental curable composition (I ) Represents the molar ratio (mol%) of the oxetane compound, b represents the average number of epoxy groups contained in one molecule of (III) epoxy compound, and B is contained in the dental curable composition (III ) Represents the molar ratio (mol%) of the epoxy compound. ]

[In General Formula (ii), R ⁵ and R ⁶ are each a hydrogen atom or a hydrocarbon group having 1 to 13 carbon atoms which may have a substituent, and the total carbon number of R ⁵ and R ⁶ is 2 That's it. ]

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