JP2021084865A - Dental curable composition - Google Patents

Abstract

To provide a dental curable composition that can be suitably used as a dental composite resin with high color compatibility even when used for the restoration of class III and IV cavities, without using a pigment material or dye material.SOLUTION: Provided is a dental curable composition containing: a polymerizable monomer component; an inorganic spherical filler that has an average primary particle size in the range of 100-1,000 nm and in which 90% or more of the total number of particles in the number-based particle size distribution exists in the range of 5% before and after the average primary particle size; an amorphous inorganic filler in the range above 1,000 nm and below 3,000 nm; and a polymerization initiator, wherein nFB>nP and 0.000≤nFC-nP≤0.002 when the refractive index of the cured product of the polymerizable monomer component at 25°C is nP, the refractive index of the inorganic spherical filler at 25°C is nFB, and the refractive index of the amorphous inorganic filler at 25°C is nFC.SELECTED DRAWING: None

Description

The present invention relates to a dental curable composition. More specifically, the present invention relates to a dental curable composition suitable as a dental filling restoration material having high convenience of use and excellent aesthetics.

Dental composite resin (hereinafter, also simply referred to as "CR") is a type of material for repairing teeth damaged by caries, fracture, etc., and is a type of material for repairing teeth that have been damaged by caries, fracture, etc. / Or consists of a curable composition containing an organic filler. Restoration using dental composite resin (CR) (CR restoration) is rapidly becoming widespread because it can reduce the amount of cutting of the tooth substance, give a color tone equivalent to that of natural tooth color, and is easy to operate. .. Further, in recent years, it has been used not only for restoration of the anterior tooth portion but also for the molar tooth portion to which a high occlusal pressure is applied because of the improvement of mechanical strength and the improvement of the adhesive force with the tooth.

As mentioned above, one of the excellent features of CR restoration is that it can be restored with high aesthetics. Natural teeth are composed of dentin and enamel, and each part has a color tone (hue, saturation, etc.). Since the brightness) is different, in order to perform highly aesthetic restoration, it is necessary to take detailed measures according to the condition of the tooth to be restored (tooth to be restored). For example, even if the repaired tooth is lightly damaged and the tooth cavity is shallow, a plurality of CRs having different color tones are prepared, and the actual repaired tooth and its adjacent tooth (hereinafter, also referred to as "around the repaired tooth"). ) And the one with the best color tone are generally selected and used (see Non-Patent Document 1). In addition, when the tooth cavity is deep, the color tone of the tooth is not only the color tone of the tooth surface (enamel part) but also the color tone of the deep part (dentin part) that can be seen through, and it is viewed in a state rich in gradation. Therefore, the color tone of the curable paste to be filled is changed for each constant depth, and this delicate color tone is reproduced by laminating and filling (see Non-Patent Document 1 and Non-Patent Document 2).

In order to meet such demands, many CRs whose color tone is prepared by adding pigment substances and dye substances in different types and blending amounts are provided. However, in CR whose color tone has been adjusted using a pigment substance or a dye substance, these substances in the CR cured product fade or discolor due to aged deterioration, so that the color changes as time passes after the restoration, and the repaired portion. The appearance of the tooth may not match the natural tooth.

On the other hand, as a technique for coloring without using a pigment substance or a dye substance, coloring is performed by coloring light (hereinafter, also simply referred to as "interference light") using reflection, interference, scattering, transmission, etc. of light by fine particles in a medium. There is a technique to generate it (hereinafter, the color expressed by such a principle is also referred to as "structural color"), and by applying these techniques, a composite material in which inorganic particles are dispersed in a medium such as a resin is the desired color. A technique for developing a color is also known (see Patent Document 1).

That is, Patent Document 1 includes, for example, "a polymerizable monomer component (A), an inorganic spherical filler (B) having an average particle size in the range of 230 nm to 1000 nm, and a polymerization initiator (C). more than 90% of the individual particles constituting the spherical filler (B) is present in the range of 5% before and after the average particle diameter, refractive index n _F in the 25 ° C. of inorganic spherical filler (B) is a polymer consists sex monomer component curable composition which satisfies the condition that is greater than the refractive index n _P at 25 ° C. of the polymer obtained by polymerizing (a) ", to form a cured body of the" thickness 1mm In the state, the brightness (V) of the colorimetric value measured by the Mansell color system of the colored light under the black background measured using the color difference meter is less than 5, and the saturation (C) is 0.05 or more. There is disclosed a curable composition in which the lightness (V) of the colorimetric value measured by the Mansell color system of the colored light under a white background is 6 or more and the saturation (C) is less than 2. .. Further, in Patent Document 1, since the CR composed of the curable composition does not use (1) a dye substance or a pigment substance, the problem of discoloration with time is unlikely to occur, and (2) (the average of the inorganic spherical fillers used). It can be colored yellow to red, which is the same color as ivory color (depending on the particle size), and (3) the cured product easily matches the color of the tooth to be restored, and it is a complicated shade-taking or composite resin. It is described that one type of composite resin has an excellent feature that it is possible to restore the appearance of a wide range of colors of teeth to be restored, which is close to that of natural teeth, without performing shade selection. The curable composition disclosed in Patent Document 1 is designed to emit yellow to red colored light mainly for the purpose of repairing the tooth cavity in which dentin is located in the deep layer. As the inorganic spherical filler (B), one having an average particle diameter of 230 nm or more is used, but if the color tone is not particular, including the bluish color, the structural color itself may be one having an average particle diameter of 100 nm or more. it can.

Patent No. 6250245

Hideo Matsumura, Junji Tagami, "Adhesive YEARBOOK 2006", 1st Edition, Kuintessensu Publishing Co., Ltd., August 2006, p. 129-137 Shinji Miyazaki, "Science & Techniques for Composite Resin Restoration", 1st Edition, Kuintessensu Publishing Co., Ltd., January 2010, p. 48-49

The curable composition disclosed in Patent Document 1 exhibits the above-mentioned excellent characteristics when used as a CR. However, the curable composition was designed mainly for the purpose of repairing the tooth cavity in which dentin is located in the deep layer as described above, and is a class III cavity (anterior tooth) in which dentin is not present in the deep layer. Color compatibility has not been investigated when used to repair (adjacent dentin without dentin) or class IV dentin (adjacent dentin of anterior teeth with dentin).

Therefore, when the present inventors examined the color tone compatibility in the restoration of the anterior tooth portion (class III cavity and class IV cavity) of the curable composition disclosed in Patent Document 1, the structural color was changed by the interference light. Although it appears, it is probably because the cured product is too transparent and it is difficult for reflected light and scattered light to reach the observer, but the repaired part looks blackish (the developed structural color is visible). It became clear that there are some cases that cannot be recognized. In such a phenomenon, a layered structure is introduced in the restoration part, a cured body of CR with low transparency is placed in the base part (the part corresponding to the vicinity of the back side of the restoration tooth), and the surface layer part (the front side of the restoration tooth). It is considered that the problem can be solved by arranging the CR made of the curable composition in the above, but it is inevitable that the operation becomes complicated.

The present invention solves the above-mentioned problems peculiar to CR that adjusts the color tone by structural color, which has not been recognized so far, and is class III without using a pigment substance or a dye substance. It is an object of the present invention to provide a dental curable composition which can obtain high color compatibility even when used for repairing a cavity or a class IV cavity and can be used as a CR.

The present inventors can solve the above-mentioned problems with respect to the curable composition disclosed in Cited Document 1 if the transparency of the obtained cured product can be reduced while maintaining the structural color expression function. I thought that I could do it, and conducted a diligent study. As a result, (1) the average primary particle size is in the range of more than 1000 nm and less than 3000 nm, which has the same or slightly higher refractive index as the refractive index of the polymer obtained by polymerizing the polymerizable monomer contained in CR. The transparency of the cured product can be lowered by blending the amorphous inorganic filler in (2), and the transparency at that time can be adjusted by the blending amount of the amorphous inorganic filler in (3). When the transparency is lowered by the addition of the amorphous filler, the structural color to be developed becomes difficult to recognize as the degree of the reduction becomes stronger, and (4) it is opaque based on the findings of (2) above. We have found that when the sex is appropriately adjusted, the visibility of the expressed structural color can be maintained and the above-mentioned problems can be solved, and the present invention has been completed.

That is, in the first invention, the polymerizable monomer component (A) has an average primary particle diameter in the range of 100 nm or more and 1000 nm or less, and 90% or more of the total number of particles in the number-based particle size distribution is the average primary particle. Dental curing comprising an inorganic spherical filler (B) present in a range of 5% before and after the particle size, an amorphous inorganic filler (C) in a range of more than 1000 nm and less than 3000 nm, and a polymerization initiator (D). The refractive index of the polymer obtained by polymerizing the polymerizable monomer component (A) in the sex composition at 25 ° C. is n _P, and the refractive index of the inorganic spherical filler (B) at 25 ° C. is defined as nP. When n _FB and the refractive index of the amorphous inorganic filler (C) at 25 ° C. are n _FC , n _FB > n _P and 0.000 ≦ n _FC −n _P ≦ 0.002. , A dental curable composition.

In the above-mentioned dental curable composition of the present invention, a cured product having a thickness of 1 mm obtained by curing the dental curable composition of the present invention from the viewpoint of maintaining effective visibility of the developed structural color. In the spectral reflectance curve under a black background measured using a color difference meter, the maximum value of the spectral reflectance in the wavelength region (yellow to red region) of 600 nm or more and 750 nm or less: SR ₁ is 400 nm or more and 500 nm or less. Maximum value of spectral reflectance in the wavelength region (blue region) of: The spectral reflectance ratio defined as the value divided by _{SR 2 : SR 1} / SR ₂ is in the range of 0.8 or more and 2.0 or less, especially 0. It is preferably in the range of 0.9 or more and 1.5 or less. Further, from the viewpoint of developing a structural color from yellow to red with high intensity, the average primary particle size of the inorganic spherical filler (B) is preferably 230 nm or more and 350 nm or less, particularly preferably 245 nm or more and 300 nm or less. The total blending amount of the inorganic spherical filler (B) and the amorphous inorganic filler (C) with respect to 100 parts by mass of the polymerizable monomer (A) is 100 parts by mass or more and 1500 parts by mass or less. The proportion of the amount of the amorphous inorganic filler (C) to be blended is preferably 5% or more and 30% or less. Further, from the viewpoint that the color tone compatibility of the repaired portion is higher when the III-class cavity and the IV-class cavity are repaired by the cured product of the dental curable composition of the present invention, the background of the cured product having a thickness of 1 mm is used. The ratio of the Y stimulus values determined by the tristimulus value measurement by the color difference meter with black and white as Y _b (black background) and Y _w (white background), respectively: defined by _{Y b} / Y _w. It is preferable to give a cured product having a contrast ratio of 0.30 to 0.70, particularly 0.4 to 0.6.

The second invention is a dental filling restoration material for repairing a class III tooth cavity and / or a class IV tooth cavity composed of the dental curable composition of the present invention, and the third invention is the present invention. A dental material for class III and / or class IV tooth cavity restoration, which comprises a cured product of a dental curable composition.

The patent document states that the dental curable composition of the present invention can have a color tone that is in harmony with the surroundings by a structural color with only one type without using a dye substance or a pigment substance that causes a problem of fading. Not only does it have the same effect as the curable composition disclosed in 1, but it also has moderate opacity, so it is also used in the repair of anterior tooth defects, especially in the repair of class III and IV cavities. It is possible to perform restoration with high color compatibility with natural teeth with one type without using.

The greatest feature of the present invention is an amorphous inorganic filler having an average particle size of more than 1000 nm and less than 3000 nm in a curable composition that expresses a structural color as disclosed in Patent Document 1. The refractive index of the amorphous inorganic filler (C) at 25 ° C. is n _FC, and the refractive index of the polymer obtained by polymerizing the polymerizable monomer component (A) at 25 ° C. is n _P. By blending the amorphous inorganic filler (C) satisfying the relationship of 0.000 ≦ n _FC −n _P ≦ 0.002 in the obtained cured product, the visibility of the structural color to be developed can be maintained. The point is that it gives appropriate opacity. As a result, appropriate opacity is imparted to the cured product, and for example, for a cured product having a thickness of 1 mm, the Y stimulation value determined by the tristimulus value measurement with a color difference meter with a black and white background is set to Y _b (each). Ratio of both when it is defined as (black background) and Y _w (white background): The _{contrast ratio defined by Y b} / Y _w is in the range of 0.3 to 0.7, more preferably 0.4 to 0.6. Can be. Moreover, since the opacity at this time is such that the effect of the interference light as described above can be maintained, it is possible to perform aesthetic restoration that exhibits a natural color tone even for restoration of class III and IV tooth cavities. ..

As described above, the present invention is based on a curable composition that expresses a structural color, and expresses the basic composition (each component, its blending amount, etc.) and the structural color of the curable composition that is the base thereof. The conditions and the like to be satisfied are basically the same as those of the curable composition disclosed in Patent Document 1. That is, the dental curable composition of the present invention has the polymerizable monomer component (A), the average primary particle size in the range of 100 nm or more and 1000 nm or less, and 90% or more of the total number of particles in the number-based particle size distribution. Contains the inorganic spherical filler (B) and the polymerization initiator (D) present in the range of 5% before and after the average primary particle size, and further, the refractive index of the inorganic spherical filler (B) at 25 ° C.: n _{The FB} is larger than the refractive index at 25 ° C. of the polymer obtained by polymerizing the polymerizable monomer component (A): n _P. By satisfying such conditions, the interference light and the structural color based on the interference light can be clearly confirmed without using a dye substance or a pigment substance, and it is close to a natural tooth regardless of the depth of the tooth cavity. It is a dental curable composition capable of restoration with good color compatibility, particularly a curable composition for a dental filling restoration material.

Here, the relationship between the particle size of the inorganic spherical filler (B) and the light interference phenomenon is considered to be in accordance with Bragg diffraction conditions, and interference light having a color tone corresponding to the average primary particle size of the inorganic spherical filler (B) is generated. (Structural color appears). Then, the generation of interference light (expression of structural color) can be confirmed by measuring the spectral reflectance using a color difference meter. However, when measured under a white background, it is difficult to observe colored light due to interference because the diffusely reflected light of external light (for example, C light source and D65 light source) is strong, so it is necessary to perform the measurement under a black background. .. When measured under a black background, the reflection spectrum corresponding to the wavelength of the interference light generated by absorbing or blocking external light can be clearly confirmed. In addition, when the structural color of a specific color does not appear due to reasons such as not satisfying the above-mentioned reflectance condition, or reasons such as adding only an amorphous filler and not adding an inorganic spherical filler (B), under a black background. When the spectral reflectance is measured, a relatively strong bluish reflection tends to be observed ( _{see the spectral reflectance ratio of Comparative Examples 4 to 9: SR 1} / SR ₂ ), and the reflection spectrum is also blue. The intensity of the wavelength region of the system is usually significantly higher than the intensity of the wavelength region of the yellow to red system. On the other hand, the curable composition disclosed in Patent Document 1 has a maximum in the wavelength region from yellow to red. In the present invention, although the expression of the structural color decreases due to the decrease in transparency (increase in opacity), the opacity is appropriately controlled, so that the intensity in the yellow to red wavelength region is in the blue wavelength region. The level is equal to or higher than the intensity, and it is possible to obtain high color compatibility.

Hereinafter, each component of the dental curable composition of the present invention will be described.

<Polymerizable monomer component (A)>
As the polymerizable monomer component (A), known ones can be used without particular limitation. When viewed for dental use, radically polymerizable or cationically polymerizable monomers are preferable from the viewpoint of polymerization rate. Particularly preferable radically polymerizable monomers include (meth) acrylates exemplified below, which are (meth) acrylic compounds, and particularly preferable cationically polymerizable monomers include epoxies and oxetans. .. In general, as the (meth) acrylic compound preferably used, examples of (meth) acrylates include those shown in the following (a) to (d).

(A) Monofunctional polymerizable monomer (i) Those having no acidic group or hydroxyl group Methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) Acrylate, n-lauryl (meth) acrylate, n-stearyl (meth) acrylate, tetraflufuryl (meth) acrylate, glycidyl (meth) acrylate, methoxyethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene Glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, ethoxyethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, ethoxytriethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, phenoxyethylene glycol ( Meta) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxytriethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobolonyl (meth) acrylate, trifluoroethyl (meth) Meta) Acrylate etc.

(Ii) Those having an acidic group (meth) acrylic acid, N- (meth) acryloyl glycine, N- (meth) acryloyl aspartic acid, N- (meth) acryloyl-5-aminosalicylic acid, 2- (meth) Acryloyloxyethyl Hydrogen Succinate, 2- (Meta) Acryloyloxyethyl Hydrogenphthalate, 2- (Meta) Acryloyloxyethyl Hydrogenmalate, 6- (Meta) Acryloyloxyethyl Naphthalene-1,2,6-Tricarboxylic Acid , O- (meth) acryloyl tyrosine, N- (meth) acryloyl tyrosine, N- (meth) acryloylphenylalanine, N- (meth) acryloyl-p-aminobenzoic acid, N- (meth) acryloyl-o-aminobenzoic acid , P-vinyl benzoic acid, 2- (meth) acryloyloxy benzoic acid, 3- (meth) acryloyloxy benzoic acid, 4- (meth) acryloyloxy benzoic acid, N- (meth) acryloyl-5-aminosalicylic acid, N -(Meta) acryloyl-4-aminosalicylic acid and other compounds in which the carboxyl group of these compounds is acid anhydride-based, 11- (meth) acryloyloxyundecane-1,1-dicarboxylic acid, 10- (meth) acryloyloxy Decane-1,1-dicarboxylic acid, 12- (meth) acryloyl oxide Decane-1,1-dicarboxylic acid, 6- (meth) acryloyloxyhexane-1,1-dicarboxylic acid, 2- (meth) acryloyloxyethyl- 3'-methacryloyloxy-2'-(3,4-dicarboxybenzoyloxy) propylsuccinate, 4- (2- (meth) acryloyloxyethyl) trimellitate anhydride, 4- (2- (meth) acryloyl) Oxyethyl) trimerite, 4- (meth) acryloyloxyethyl trimerite, 4- (meth) acryloyloxybutyl trimerite, 4- (meth) acryloyloxyhexyl trimerite, 4- (meth) acryloyloxydecyltri Meritate, 4- (meth) acryloyloxybutyl trimerite, 6- (meth) acryloyloxyethylnaphthalene-1,2,6-tricarboxylic acid anhydride, 6- (meth) acryloyloxyethylnaphthalene-2,3 6-Tricarboxylic acid anhydride, 4- (meth) acryloyloxyethylcarbonylpropionoyl-1,8-naphthalic acid anhydride, 4- (meth) acryloyl oki Siethylnaphthalene-1,8-tricarboxylic acid anhydride, 9- (meth) acryloyloxynonane-1,1-dicarboxylic acid, 13- (meth) acryloyloxytridecane-1,1-dicarboxylic acid, 11- (meth) ) Acryloyl undecane-1,1-dicarboxylic acid, 2- (meth) acryloyloxyethyl dihydrogen phosphate, 2- (meth) acryloyloxyethylphenylhydrogen phosphate, 10- (meth) acryloyloxydecyldihydrogen Phosphate, 6- (meth) acryloyloxyhexyl dihydrogen phosphate, 2- (meth) acryloyloxyethyl-2-bromoethyl hydrogen phosphate, 2- (meth) acrylamide ethyldihydrogen phosphate, 2- (Meta) acrylamide-2-methylpropanesulfonic acid, 10-sulfodecyl (meth) acrylate, 3- (meth) acryloxypropyl-3-phosphonopropionate, 3- (meth) acryloxypropylphosphonoacetate, 4 -(Meta) acryloyloxybutyl-3-phosphonopropionate, 4- (meth) acryloyloxybutylphosphonoacetate, 5- (meth) acryloyloxypentyl-3-phosphonopropionate, 5- (meth) Acryloyloxypentylphosphonoacetate, 6- (meth) acryloylhexyl-3-phosphonopropionate, 6- (meth) acryloylhexylphosphonoacetate, 10- (meth) acryloyloxydecyl-3-phosphonopro Pionate, 10- (meth) acryloyloxydecylphosphonoacetate, 2- (meth) acryloyloxyethyl-phenylphosphonate, 2- (meth) acryloyloxyethylphosphonic acid, 10- (meth) acryloyloxydecylphosphonic acid, N -(Meta) acryloyl-ω-aminopropylphosphonic acid, 2- (meth) acryloyloxyethylphenylhydrogen phosphate, 2- (meth) acryloyloxyethyl 2'-bromoethylhydrogen phosphate, 2- (meth) acryloyloxy Ethylphenylphosphonate etc.

(Iii) Those having a hydroxyl group 2-Hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 10-hydroxydecyl ( Meta) acrylate, propylene glycol mono (meth) acrylate, glycerol mono (meth) acrylate, erythritol mono (meth) acrylate, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N, N- (dihydroxyethyl) ) (Meta) acrylamide, etc.

(B) Bifunctional polymerizable monomer (ro-i) Aromatic compound type 2,2-bis (methacryloyloxyphenyl) propane, 2,2-bis [(3-methacryloyloxy-2-hydroxypropyloxy) ) Phenyl] propane, 2,2-bis (4-methacryloyloxyphenyl) propane, 2,2-bis (4-methacryloyloxypolyethoxyphenyl) propane, 2,2-bis (4-methacryloyloxydiethoxyphenyl) propane , 2,2-Bis (4-methacryloyloxytetraethoxyphenyl) propane, 2,2-bis (4-methacryloyloxypentaethoxyphenyl) propane, 2,2-bis (4-methacryloyloxydipropoxyphenyl) propane, 2 (4-methacryloyloxydiethoxyphenyl) -2 (4-methacryloyloxytriethoxyphenyl) propane, 2 (4-methacryloyloxydipropoxyphenyl) -2- (4-methacryloyloxytriethoxyphenyl) propane, 2,2- Bis (4-methacryloyloxypropoxyphenyl) propane, 2,2-bis (4-methacryloyloxyisopropoxyphenyl) propane and acrylates corresponding to these methacrylates; 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-chloro A vinyl monomer having a -OH group such as methacrylate such as -2-hydroxypropyl methacrylate or an acrylate corresponding to these methacrylates, and a diisocyanate compound having an aromatic group such as diisocyanate methylbenzene and 4,4'-diphenylmethane diisocyanate. Diadect obtained from the addition of di (methacrylloxyethyl) diphenylmethanediurethane and the like.

(Ro-iii) Aliphatic compounds Ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,4 -Butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, and acrylates corresponding to these methacrylates; 2-hydroxyethyl methacrylate, 2-hydroxy such as 1,6-bis (methacrylethyloxycarbonylamino) trimethylhexane. Vinyl monomers having a -OH group such as methacrylates such as propyl methacrylate and 3-chloro-2-hydroxypropyl methacrylate or acrylates corresponding to these methacrylates, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diisocyanatemethylcyclohexane, and isophorone. Diisocyanate, diastacts obtained from adducts with diisocyanate compounds such as methylenebis (4-cyclohexylisocyanate); 1,2-bis (3-methacryloyloxy-2-hydroxypropoxy) ethyl and the like.

(C) Trifunctional polymerizable monomer Trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, pentaerythritol trimethacrylate, trimethylolmethane trimethacrylate and other methacrylates, and acrylates corresponding to these methacrylates.

(D) tetrafunctional polymerizable monomer pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate; diisocyanate methylbenzene, diisocyanate methylcyclohexane, isophorone diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, methylenebis (4-cyclohexylisocyanate), 4 , 4-Diphenylmethane Diisocyanate, Trilene-2,4-Diisocyanate and other diisocyanates and diisducts obtained from adducts of glycidole dimethacrylate and the like.

A plurality of types of these polyfunctional (meth) acrylate-based polymerizable monomers may be used in combination, if necessary. Further, if necessary, methacrylates such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, hydroxyethyl methacrylate, tetrahydrofurfuryl methacrylate, and glycidyl methacrylate, and monofunctional (meth) acrylate-based singles such as acrylates corresponding to these methacrylates. A metric or a polymerizable monomer other than the above (meth) acrylate-based monomer may be used.

In the present invention, as the polymerizable monomer component (A), a plurality of types of polymerizable monomers are generally used for adjusting the physical properties (mechanical properties and adhesiveness to the dentin) of the cured product. At this time, it is desirable to set the type and amount of the polymerizable monomer so that the refractive index of the component (A) at 25 ° C. is in the range of 1.38 to 1.55. That is, by setting the refractive index in the range of 1.38 to 1.55, the refractive index n _P of the polymer obtained from the polymerizable monomer component (A) is approximately 1.40 to 1.57. The range can be set, and it becomes easy to satisfy the condition of _{n P} <n _FB. In addition, a plurality of types of polymerizable monomers may be used as the polymerizable monomer component (A), and the refractive index of the polymerizable monomer component (A) in this case is a plurality of types of polymerizable single amounts. The refractive index of the mixture of the bodies may be within the above range, and the individual polymerizable monomers may not necessarily be within the above range. The refractive index of the polymerizable monomer or the cured product of the polymerizable monomer can be determined at 25 ° C. using an Abbe refractive index meter.

<Inorganic spherical filler (B)>
The dental curable composition contains various fillers such as inorganic powder and organic powder, but the dental curable composition of the present invention has the purpose of expressing colored light due to interference. An inorganic spherical filler (B) having an average primary particle size in the range of 100 nm or more and 1000 nm or less and having a specific particle size distribution and a specific refractive index is blended.

The inorganic spherical filler (B) is spherical, and 90% or more of the number of individual particles constituting the inorganic spherical filler (B) is narrow such that 90% or more is present in the range of 5% before and after the average primary particle size. By having the particle size distribution, the particles can be dispersed so as to have short-range regularity, and interference light having a specific wavelength corresponding to the average primary particle size can be generated. Here, for the average primary particle size of the inorganic spherical filler (B), a photograph of the powder is taken with a scanning electron microscope, and 30 or more particles observed within the unit field of view of the photograph are selected and each of them is selected. The average value obtained by determining the primary particle size (maximum size). The spherical shape may be a substantially spherical shape, and does not necessarily have to be a perfect true sphere. Take a picture of the particles with a scanning electron microscope, measure the maximum diameter of each particle (30 or more) within the unit field of view, and divide the particle diameter in the direction orthogonal to the maximum diameter by the maximum diameter. The degree of uniformity may be 0.6 or more, more preferably 0.8 or more.

The number-based particle size distribution of the inorganic spherical filler (B) may be such that the ratio of the number of particles existing in the range of 5% before and after the average primary particle size to the total number of particles is 90% or more. The ratio is preferably 91% or more, and more preferably 93% or more.

The expression of colored light due to light diffraction and interference is due to the fact that diffraction and interference occur according to Bragg conditions and light of a specific wavelength is emphasized. When particles of the above particle size are blended, the dental hardening thereof is performed. Colored light (interference light) is generated in the cured product of the sex composition, and a structural color corresponding to the particle size thereof is developed.

The average primary particle size of the inorganic spherical filler (B) may be in the range of 100 nm or more and 1000 nm or less. When spherical particles having an average primary particle diameter of less than 100 nm are used, the interference phenomenon of visible light is unlikely to occur. On the other hand, when an inorganic spherical filler having an average primary particle size of more than 1000 nm is used, the appearance of light interference phenomenon can be expected, but when used as a restoration material for dental filling, the inorganic spherical filler is settled and has polishability. There is a drop.

According to the study by the present inventors, the color tone of the structural color developed when the inorganic spherical filler (B) is used is in the range of 100 nm to 1000 nm depending on the average primary particle size of the inorganic spherical filler used. It was found that the color changed in a repeating cycle of bluish-yellowish-red diameter with the increase, and the intensity tended to decrease in the cycle with a large average primary particle diameter. Therefore, from the viewpoint of developing a high-strength structural color, the average primary particle size is preferably 100 nm or more and 500 nm or less. Further, from the viewpoint of strongly expressing the structural color of yellow to red, the average primary particle size is preferably 230 nm or more and 350 nm or less, and particularly preferably 245 nm or more and 300 nm or less.

For example, when spherical particles having an average primary particle diameter in the range of 230 nm to 260 nm are used, the obtained colored light is yellowish and falls into the category of B-based (red-yellow) in the shade guide (“VITAClasical”, manufactured by VITA). It is useful for repairing certain teeth, especially for the tooth cavity formed from enamel to dentin. When spherical particles with an average primary particle diameter in the range of 260 nm to 350 nm are used, the obtained colored light is red-based, and the teeth are in the A-based (reddish-brown) category in the shade guide (“VITAClasical”, manufactured by VITA). It is useful for repairing dentin, especially for the repair of cavities formed from enamel to dentin. Since most of the hues of dentin are reddish, by using an inorganic spherical filler (B) having an average primary particle size in the above-mentioned suitable range, it is widely compatible with restoration teeth of various color tones. Can be improved.

As the inorganic spherical filler (B), those used as components of ordinary dental curable compositions can be used without limitation. Specifically, amorphous silica, silica / titanium group element oxide-based composite oxide particles (silica / zirconia, silica / titania, etc.), quartz, alumina, barium glass, strontium glass, lantern glass, fluoroaluminosilicate glass. , Inorganic powders such as itterbium fluoride, zirconia, titania, colloidal silica and the like. Of these, silica-titanium group element oxide-based composite oxide particles are preferable because the refractive index of the filler can be easily adjusted.

Here, the silica-titanium group element oxide-based composite oxide particles are composite oxides of silica and titanium group element (group 4 element of the periodic table) oxide, and are silica titania, silica zirconia, and the like. Examples include silica, titania, and zirconia. Of these, silica zirconia is preferable because the refractive index of the filler can be adjusted and high X-ray impermeable property can be imparted. The composite ratio is not particularly limited, but from the viewpoint of imparting sufficient X-ray impermeableness and setting the refractive index within a suitable range described later, the silica content is 70 to 95 mol%, and the titanium group. Those having an element oxide content of 5 to 30 mol% are preferable. In the case of silica zirconia, the refractive index can be freely changed by changing each composite ratio in this way.

It should be noted that these silica-titanium group element oxide-based composite oxide particles may be composited with a metal oxide other than silica and the titanium group element oxide in a small amount. Specifically, an alkali metal oxide such as sodium oxide and lithium oxide may be contained in an amount of 10 mol% or less.

The method for producing such a silica-titanium group element oxide-based composite oxide particle is not particularly limited. For example, a mixed solution containing a hydrolyzable organic silicon compound and a hydrolyzable organic titanium group metal compound is alkaline. The so-called sol-gel method, in which the reaction product is precipitated by adding it to a solvent and hydrolyzing it, is preferably adopted.

These silica-titanium group oxide-based composite oxide particles may be surface-treated with a silane coupling agent. By surface treatment with a silane coupling agent, the interfacial strength of the polymerizable monomer (A) with the cured product portion becomes excellent. Typical silane coupling agents include organosilicon compounds such as γ-methacryloyloxyalkyltrimethoxysilane and hexamethyldisilazane. The amount of the surface treatment of these silane coupling agents is not particularly limited, and the optimum value may be determined after confirming the mechanical properties of the obtained dental curable composition in advance by experiments. If so, it is in the range of 0.1 parts by mass to 15 parts by mass with respect to 100 parts by mass of the particles.

In the dental curable composition of the present invention, in order to generate interference light or develop a structural color, the refractive index of the inorganic spherical filler (B) at 25 ° C.: n _FB is the polymerizable monomer. The refractive index of the polymer obtained by polymerizing the component (A) at 25 ° C. must be larger than _{n P.} That is, it is necessary to satisfy the relationship of _{n P} <n _FB. Difference between n _FB and n _{P : n FB} −n _P is preferably 0.001 or more, more preferably 0.002 or more, and most preferably 0.005 or more.

In the dental curable composition of the present invention, the inorganic spherical filler (B) may be blended as it is, but it is obtained by mixing it with a polymerizable monomer (A) or the like in advance and polymerizing it. It may be blended in the form of an organic-inorganic composite filler composed of the composite.

The method for producing the organic-inorganic composite filler is not particularly limited, and for example, a method of mixing predetermined amounts of each component of the inorganic spherical filler (B), the polymerizable monomer, and the polymerization initiator, heating, light irradiation, and the like. A general production method of pulverizing after polymerizing in the above can be adopted. Alternatively, the manufacturing method described in International Publication No. 2011/115007 or International Publication No. 2013/039169 can be adopted. In this production method, inorganic agglomerated particles formed by agglomerating spherical inorganic fillers are immersed in a polymerizable monomer solvent containing a polymerizable monomer, a polymerization initiator, and an organic solvent, and then the organic solvent is removed. The polymerizable monomer is polymerized and cured by a method such as heating or light irradiation. According to the production method described in International Publication No. 2011/115007 or International Publication No. 2013/039169, the surface of each inorganic primary particle of the inorganic agglomerated particles in which the inorganic primary particles are aggregated is covered, and each inorganic primary particle is covered. An organic-inorganic composite filler having an organic resin phase bonded to each other and having a cohesive gap formed between the organic resin phases covering the surface of each inorganic primary particle can be obtained.

<Atypical Inorganic Filler (C)>
The dental curable composition of the present invention is an amorphous inorganic filler having an average particle size in the range of more than 1000 nm and less than 3000 nm for the purpose of imparting appropriate opacity to the cured product, and is a specific refractive index. An amorphous inorganic filler (C) having a refractive index is blended. Here, the irregular shape means that the shape of the primary particles observed by SEM or the like has a large number of irregular corners and surfaces, and the amorphous inorganic filler (C) is usually referred to as an irregular shape. It means a filler composed of particles obtained by crushing or crushing. The average particle size of the amorphous filler (C) is 50% particle size (for example, LS230 manufactured by Beckman Coulter is used as a measuring device and ethanol is used as a dispersion medium) by a laser scattering method (for example, LS230 manufactured by Beckman Coulter is used as a measuring device). It means D50). Specifically, first, 0.01 to 1 g of the measurement sample was added to 5 ml of ethanol as a dispersion medium, and then the solution in which the sample was suspended was dispersed with an ultrasonic disperser for about 1 to 5 minutes, and 0.04. The particle size distribution of particles with a particle size in the range of ~ 2000 μm is measured. Then, a cumulative distribution is drawn from the small diameter side for each volume with respect to the particle size range divided based on the obtained particle size distribution, and the particle size with a cumulative total of 50% is defined as the average particle size (D50).

In order to exhibit the effect of the present invention, as an amorphous inorganic filler, the average particle size is in the range of more than 1000 nm and less than 3000 nm, and the refractive index of the amorphous inorganic filler at 25 ° C.: n _FC and the polymerizable property. refractive index at 25 ° C. of the polymer obtained by polymerizing a monomer component (a): relationship between _{n P is, 0.000 ≦ n FC -n P ≦} 0.002 relation satisfying amorphous inorganic filler ( It is necessary to mix C).

When the average particle size of the amorphous inorganic filler is 1000 nm or less, it is not possible to impart appropriate opacity to the cured product. On the other hand, in the case of 3000 nm or more, the opacity of the cured product becomes too high, so that the structural color caused by the interference light is not generated or even if it is generated, it becomes impossible to visually recognize the structural color. The average particle size of the amorphous inorganic filler (C) is preferably more than 1000 nm and less than 2500 nm, preferably more than 1000 nm, in that it is possible to impart appropriate opacity to the cured product while ensuring the visibility of the structural color. More preferably, it is less than 2000 nm.

As an index of "opacity" given to the cured product of the dental curable composition of the present invention, the contrast ratio (Y _b / Y _w ) measured in the state of the cured product having a thickness of 1 mm is used. Can be done. Here, Y _b means a Y stimulus value determined by tristimulus value measurement with a color difference meter with a black background for a cured product having a thickness of 1 mm, and Y _w means a Y stimulus value when the background is white and similarly measured. It means the Y stimulation value. When the contrast ratio (Y _b / Y _w ) is less than 0.3, the brightness (shade of color) of the cured product at the repair site (filling site) when used for repairing a class III or IV cavity, for example. Is low, the transmitted light at the site is strong, and the colored light from the cured product is weakened, so that it is difficult to obtain good color tone compatibility. Further, when the contrast ratio exceeds 0.7, the brightness of the cured product is high, the reflected light on the surface of the repaired portion (filled portion) is strong, and the colored light from the cured product is weakened, which is also good. It becomes difficult to obtain color tone compatibility. Therefore, when the contrast ratio (Y _b / Y _w ) is in the range of 0.30 or more and 0.70 or less, it can be said that the above-mentioned "appropriate opacity" is obtained. In order to have excellent color compatibility in the repair of class III and IV cavities, the contrast ratio (Y _b / Y _w ) is preferably in the range of 0.35 or more and 0.65 or less, and is 0. More preferably, it is in the range of .40 or more and 0.60 or less.

Further, in the cured product of the dental curable composition of the present invention, although the opacity is increased by adding the amorphous inorganic filler (C), the visibility of the structural color is maintained. That is, the interference light generated in the cured product or the structural color developed in the cured product can be confirmed by the spectral reflectance curve under a black background measured with a color difference meter for the cured product having a thickness of 1 mm. it can. As described above, the structural color is selected according to the purpose from a wide color tone range (usually, bluish to yellow to red) according to the size of the average primary particle size of the inorganic spherical filler (B). The structural color of the desired color tone) is developed, and in the reflection reflectance measurement using a color difference meter under a black background, the reflection in the wavelength region corresponding to the color tone is significantly increased.

When the dental curable composition of the present invention is used for repairing, for example, a class III or IV cavity, the cured product can be confirmed to be yellow to red in addition to having appropriate opacity as described above. It is preferable to develop a (visible) structural color in order to perform aesthetic restoration with high color tone compatibility. From this point of view, it is preferable that the dental curable composition of the present invention provides a cured product having a spectral reflectance ratio: SR ₁ / SR _{2 in} the range of 0.8 or more and 2.0 or less. Here, SR ₁ and SR ₂ are spectral reflectances under a black background measured by using a color difference meter for a cured product having a thickness of 1 mm obtained by curing the dental curable composition of the present invention. _{In the curve, the maximum value of spectral reflectance (SR 1} ) in the wavelength region of 600 nm or more and 750 nm or less (yellow to red region) and the maximum value of spectral reflectance in the wavelength region of 400 nm or more and 500 nm or less (blue region) (SR). ₂ ) means. When the spectral reflectance ratio is less than 0.8, the yellow to red colored light is weak, and it tends to be difficult to obtain color tone compatibility with yellowish or reddish natural teeth. Further, when the spectral reflectance ratio exceeds 2.0, the yellow to red colored light is too strong, so that it is difficult to obtain good color tone compatibility. In order to have excellent color compatibility when used for repairing a class III or IV cavity, the spectral reflectance ratio is more preferably in the range of 0.9 or more and 1.5 or less.

The material of the amorphous inorganic filler (C) is not particularly limited, and known materials can be used. Specifically, borosilicate glass, soda glass, glass containing heavy metals (for example, barium, strontium, zirconium), aluminosilicate glass, fluoroaluminosilicate glass, glass ceramics, itterbium fluoride, yttrium fluoride and other metal fluorides, Suitable are silica, composite inorganic oxides such as silica-zirconia, silica-titania, and silica-alumina. A particularly preferable example is a composite oxide containing silica and zirconia as main components because a cured product having X-ray contrast property and more excellent wear resistance can be obtained.

The amorphous inorganic filler (C) is preferably used after its surface is treated with an appropriate surface treatment agent for the purpose of improving the dispersibility in the polymerizable monomer as a matrix. As the method of the treatment, the surface treatment method of the substantially spherical inorganic filler can be used without any limitation as in the above-mentioned method.

The total amount of the inorganic spherical filler (B) and the amorphous inorganic filler (C) in the present invention is 100 parts by mass or more and 1500 parts by mass or less, particularly 100 parts by mass with respect to 100 parts by mass of the polymerizable monomer (A). It is preferably parts by mass or more and 1000 parts by mass or less. From the viewpoint of good structural color expression, the proportion of the amorphous inorganic filler (C) is 5% or more and 30% or less of the total amount of the inorganic spherical filler (B) and the amorphous inorganic filler (C). It is preferable to mix them in such a manner. With such a blending amount and blending ratio, a natural color tone is exhibited with respect to the repair of the III-class or IV-class cavity, and more aesthetic repair is possible.

<Polymerization initiator (D)>
The polymerization initiator (D) is not particularly limited as long as it has a function of polymerizing the polymerizable monomer (A), but is used for direct filling and restoration of dentistry, which is often cured in the oral cavity. It is preferable to use a polymerization initiator or a chemical polymerization initiator, and it is more preferable to use a photopolymerization initiator (composition) from the viewpoint of simplicity without the need for a mixing operation.

Examples of the polymerization initiator used for photopolymerization include benzoin alkyl ethers such as benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether, benzyl ketals such as benzyl dimethyl ketal and benzyl diethyl ketal, benzophenone and 4,4'-dimethylbenzophenone. , Benzoyl compounds such as 4-methacryloxybenzophenone, diacetyl, 2,3-pentadionebenzyl, camphorquinone, 9,10-phenanthraquinone, α-diketones such as 9,10-anthraquinone, 2,4-di Thioxanson compounds such as ethoxythioxanthone, 2-chlorothioxanthone, methylthioxanthone, bis- (2,6-dichlorobenzoyl) phenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -2,5-dimethyl Phenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -4-propylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -1-naphthylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -Bisacylphosphine oxides such as phenylphosphine oxide can be used.

A reducing agent is often added to the photopolymerization initiator, and examples thereof include tertiary amines such as 2- (dimethylamino) ethyl methacrylate, ethyl 4-dimethylaminobenzoate, and N-methyldiethanolamine. Examples include aldehydes such as lauryl aldehyde, dimethylaminobenzaldehyde and terephthalaldehyde, and sulfur-containing compounds such as 2-mercaptobenzoxazole, 1-decanthyl, thiosartyl acid and thiobenzoic acid.

Further, there are often examples of using a photoacid generator in addition to the above photopolymerization initiator and reducing compound. Examples of such a photoacid generator include diaryliodonium salt compounds, sulfonium salt compounds, sulfonic acid ester compounds, halomethyl-substituted-S-triazine derivatives, pyridinium salt compounds and the like.

These polymerization initiators may be used alone, but two or more of them may be mixed and used. The amount of the polymerization initiator to be blended may be selected as an effective amount according to the purpose, but is usually 0.01 to 10 parts by mass, more preferably 0.1, based on 100 parts by mass of the polymerizable monomer. It is used in a proportion of ~ 5 parts by mass.

<Other additives>
In addition to the above components (A) to (D), other known additives can be added to the dental composite restoration material of the present invention as long as the effect is not impaired. Specific examples thereof include a polymerization inhibitor and an ultraviolet absorber. Further, for the purpose of adjusting the viscosity or the like, a filler having a particle size that is sufficiently smaller than the wavelength of light and does not easily affect the color tone and transparency can be blended.

In the present invention, as described above, restoration with good color compatibility with natural teeth can be performed with a single paste (dental curable composition) without using a coloring substance such as a pigment. Therefore, it is preferable not to blend a pigment that may change color with time. However, in the present invention, the blending of the pigment itself is not denied, and a pigment that does not interfere with the colored light due to the interference of the inorganic spherical filler may be blended. Specifically, any pigment of about 0.0005 to 0.5 parts by mass, preferably about 0.001 to 0.3 parts by mass with respect to 100 parts by mass of the polymerizable monomer may be blended. ..

The dental curable composition of the present invention can be prepared by weighing and mixing a predetermined amount of the above components (A) to (D). At this time, it is preferable to mix the inorganic spherical filler (B) and the amorphous inorganic filler (C) under the condition that they are dispersed in the polymerizable monomer (A). In addition, the dental curable composition of the present invention defoams under reduced pressure conditions from the viewpoint that good color tone compatibility, which is the effect of the present invention, can be easily obtained without deteriorating the visibility of the developed structural color. Therefore, it is preferable to prepare so that bubbles of 1000 nm or more are not substantially contained.

The dental curable composition of the present invention is particularly preferably used as a dental filling restoration material typified by a photocurable composite resin as described above, but is not limited thereto, and may be used for other purposes as well. Can be preferably used. Examples of its use include dental cement, restoration materials for abutment construction, and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

First, various physical property measurement methods in Examples and Comparative Examples will be described.
(1) Average particle size of inorganic spherical filler A scanning electron microscope (“XL-30S” manufactured by Philips) takes a picture of the powder, and the number of particles observed in the unit field of view of the picture (30 or more). ) And the primary particle size (maximum size) were measured, and the average particle size was calculated by the following formula based on the measured values.

(2) Percentage of particles present in the range of 5% before and after the average primary particle size in the inorganic spherical filler (B) First, regarding individual particles (30 or more) observed in the unit field of view of the above-mentioned photograph. , The number of particles whose primary particle size is less than 95% of the average primary particle size obtained in (1) above, and the primary particle size exceeds 105% of the average primary particle size. The number of particles was measured and the total number was calculated. Next, by subtracting the total number of particles from the total number of particles (30 or more) observed in the unit field of view of the photograph, the number of particles existing in the range of 5% before and after the average primary particle size in the number-based particle size distribution is determined. Finally, the ratio (%) of the number of the particles to the total number of particles was determined, and the ratio (%) of the particles existing in the range of 5% before and after the average primary particle size was used.

(3) Uniformity Take a picture of the powder with a scanning electron microscope (“XL-30S” manufactured by Philips), and set the maximum diameter of each particle (30 or more) within the unit field of view of the picture. The average of the values obtained by dividing the particle diameters in the orthogonal directions by the maximum diameter was defined as the uniformity.

(4) Measurement of refractive index <Refractive index of polymerizable monomer component (A)>
The refractive index of the polymerizable monomer (or a mixture of the polymerizable monomers) used was measured in a constant temperature room at 25 ° C. using an Abbe refractive index meter (manufactured by Atago Co., Ltd.).
_{<Refractive index n P} of the polymer of the polymerizable monomer component (A)>
An Abbe Refractive Index Meter was obtained from a polymer sample obtained by polymerizing the polymerizable monomer component (polymerizable monomer or a mixture of polymerizable monomers) used under substantially the same conditions as the polymerization conditions in the cavity. _{The refractive index n P} was determined by measuring in a constant temperature room at 25 ° C. using (manufactured by Atago).
That is, a uniform composition obtained by mixing the polymerizable monomer component (A) with CQ 0.3% by mass, DMBE 1.0% by mass, and HQME 0.15% by mass based on the mass of the component is obtained. , A mold having a hole of φ7 mm × 0.5 mm was placed, and polyester films were pressure-welded on both sides. Then, it was cured by irradiating it with light for 30 seconds using a halogen type dental light irradiator (Demetron LC, manufactured by Cybron) having a light intensity of 500 mW / cm ^{2, and then it was taken out from the mold to prepare a polymer sample.} In the refractive index measurement, when the sample was set in the device, bromonaphthalene (a solvent that does not dissolve the sample and has a higher refractive index than the sample) was added dropwise to the sample for the purpose of bringing the polymer into close contact with the measurement surface. ..
<Refractive index of inorganic spherical filler n _FB and refractive index of amorphous inorganic filler>
The refractive index of the inorganic spherical filler and the amorphous inorganic filler used was measured by an immersion method using an Abbe refractive index meter (manufactured by Atago Co., Ltd.).
That is, in a constant temperature room at 25 ° C., 1 g of an inorganic spherical filler or a surface-treated product thereof is dispersed in 50 ml of anhydrous toluene in a 100 ml sample bottle. While stirring this dispersion with a stirrer, 1-bromotoluene is added dropwise little by little, the refractive index of the dispersion at the time when the dispersion becomes the most transparent is measured, and the obtained values are used as an inorganic spherical filler and an amorphous inorganic. The refractive index of the filler was used.

(5) Evaluation of Contrast Ratio (Y _b / Y _w ) of Curable Composition Put the paste of the curable composition prepared in Examples and Comparative Examples into a mold having a through hole of 7 mmφ × 1 mm, and put it on both sides. The polyester film was pressure welded. After irradiating both sides with a visible light irradiator (manufactured by Tokuyama, power light) for 30 seconds each to cure, remove from the mold and use a color difference meter (manufactured by Tokyo Denshoku, "TC-1800MKII") to cure the above. The Y value (background color black and white) of the tristimulus values of the body was measured. The contrast ratio (Y _b / Y _w ) was calculated based on the Y value (Y _b ) of the obtained background color black and the Y value (Y _{w) of the background color white.}

(6) Visual Evaluation of Colored Light (Interference Light) The paste of the dental curable composition prepared in Examples and Comparative Examples was placed in a mold having a hole of 7 mmφ × 1 mm, and both sides were pressure-welded with a polyester film. After irradiating both sides with a visible light irradiator (manufactured by Tokuyama, power light) for 30 seconds each to cure, take it out of the mold, place it on the adhesive surface of black tape (carbon tape) of about 10 mm square, and visually color it. I checked the color tone of the light.

(7) Spectral reflectance ratio (SR ₁ / SR _{2 on a} black background)
The paste of the curable composition prepared in Examples and Comparative Examples was placed in a mold having a through hole of 7 mmφ × 1 mm, and polyester films were pressure-welded on both sides. After irradiating both sides with a visible light irradiator (manufactured by Tokuyama, power light) for 30 seconds each to cure, remove from the mold and use a color difference meter (manufactured by Tokyo Denshoku, "TC-1800MKII") to black background. The spectral reflectance is measured below, and the maximum reflectance in the yellow to red region (600-750 _{nm): SR 1} and the maximum reflectance in the blue region (400-500 nm): SR ₂ are obtained, and SR ₁ is obtained. The spectral reflectance ratio was calculated by dividing by _{SR 2.}

(8) Evaluation of Colored Light (Interference Light) by Spectral Reflectance on a White Background The paste of the curable composition prepared in Examples and Comparative Examples was placed in a mold having a through hole of 7 mmφ × 1 mm, and polyester was placed on both sides. The film was pressed. After irradiating both sides with a visible light irradiator (manufactured by Tokuyama, power light) for 30 seconds each to cure, remove from the mold and use a color difference meter (manufactured by Tokyo Denshoku, "TC-1800MKII") to create a white background. The spectral reflectance was measured below.

(9) Flexural strength The paste of the dental curable composition was filled in a stainless steel mold using a filler, pressed with polypropylene, and then used with a visible light irradiator Power Light (manufactured by Tokuyama Corporation). Light irradiation was performed for 30 seconds x 3 times from one surface in close contact with polypropylene at different locations so that the entire surface was exposed to light. Next, the opposite surface was similarly brought into close contact with polypropylene and irradiated with light for 30 seconds × 3 times to obtain a cured product. The cured product was prepared into a 2 × 2 × 25 mm prismatic shape with # 1500 water-resistant abrasive paper to prepare a sample piece. The obtained test piece was mounted on a testing machine (manufactured by Shimadzu Corporation, Autograph AG5000D), and the bending fracture strength at three points was measured at a distance between fulcrums of 20 mm and a crosshead speed of 1 mm / min to obtain a load-deflection curve. It is shown by the equation, bending strength: sigma _B (Pa) and flexural modulus: was determined E _B (Pa). Five test pieces were evaluated, and the average value was taken as the bending strength.

However, the meaning and unit of each symbol in the above formula are as shown below.
P: Load at the time of breaking the test piece (N)
S: Distance between fulcrums (m)
W: Width of test piece (m)
B: Specimen thickness (m)
F / Y: Gradient (N / m) of the straight part of the load-deflection curve.

(10) Evaluation of color tone compatibility Using a model tooth for tooth restoration that reproduces the No. 1 IV-class tooth cavity (width 3 mm, height 3 mm) on the upper right, fill the defect with a curable paste, cure, polish, and color tone. The compatibility was visually confirmed. The model teeth for tooth restoration are in the category of A system (reddish brown) in the shade guide "VITAPAN Classical", and have high hue and high saturation high hue model teeth (equivalent to A4) and low hue and low hue. Low-saturation model teeth (equivalent to A1) and high-hue and high-saturation high-saturation model teeth (equivalent to B4) in the category of B system (red-yellow) in the shade guide "VITAPAN Classical". Low hue and low saturation model teeth (equivalent to B1) were used.
⊚: The color tone of the restoration matches well with the model tooth for tooth restoration.
◯: The color tone of the restoration is similar to that of the model tooth for tooth restoration.
Δ: The color tone of the restoration is similar to that of the model tooth for tooth restoration, but the compatibility is not good.
X: The color tone of the restoration does not match the model tooth for tooth restoration.

Next, the abbreviations and substance names of the polymerizable monomers, polymerization initiators, etc. used in Examples and Comparative Examples are shown below.
[Polymerizable monomer]
-UDM: 1,6-bis (methacrylicethyloxycarbonylamino) trimethylhexane-3G: triethylene glycol dimethacrylate-bis-GMA: 2,2-bis [(3-methacryloyloxy-2-hydroxypropyloxy) phenyl] Propane [polymerization initiator]
-CQ: camphorquinone-DMBE: N, N-dimethylp-ethyl benzoate.
[Polymerization inhibitor]
-HQME: Hydroquinone monomethyl ether.

The polymerizable monomers shown in Table 1 were mixed to prepare matrices M1 and M2.

[Inorganic spherical filler]
The inorganic spherical filler is prepared by a method described in JP-A-58-110414, JP-A-58-156524, etc., to prepare a hydrolyzable organic silicon compound (tetraethyl silicate or the like) and a hydrolyzable organic titanium. A mixed solution containing a group metal compound (tetrabutyl zirconeate, tetrabutyl titanate, etc.) is added to an ammoniacal alcohol (for example, methanol, ethanol, isopropyl alcohol, isobutyl alcohol, etc.) solution introduced with aqueous ammonia. It was prepared using the so-called sol-gel method, in which the reaction product is precipitated by hydrolysis.

[Amorphous inorganic filler]
Atypical silica-zirconia is prepared by dissolving an alkoxysilane compound in an organic solvent by the method described in JP-A-2-132102, JP-A-3-197311, etc., and adding water to the solution to partially hydrolyze the alkoxysilane compound. After decomposition, Alkoxyside and an alkali metal compound of other metals to be further compounded are added and hydrolyzed to form a gel-like substance, and then the gel-like substance is dried, crushed as necessary, and fired. Prepared. The amorphous barium glass was prepared by crushing commercially available barium glass (manufactured by Schott AG) as necessary and classifying it. Amorphous ytterbium fluoride was prepared by pulverizing commercially available ytterbium trifluoride (manufactured by Tribach) as necessary and classifying it.
Table 2 shows the inorganic spherical fillers used in Examples and Comparative Examples, and Table 3 shows the amorphous inorganic fillers.

Examples 1-17
To 100 g of the polymerizable monomer M1 or M2, 0.3% by mass of CQ, 1.0% by mass of DMBE, and 0.15% by mass of HQME were added and mixed, and a uniform polymerizable monomer was added. The composition was prepared. Next, each of the fillers shown in Tables 2 and 3 is measured in a mortar, the above-mentioned polymerizable monomer composition is gradually added under red light, and the mixture is sufficiently kneaded in a dark place to be uniform. It was a curable paste. Further, this paste was defoamed under reduced pressure to remove air bubbles, and a dental curable composition was produced. The physical characteristics of the obtained dental curable composition were evaluated based on the above method. The composition and results are shown in Tables 4 and 5. The numerical values in parentheses in Table 4 represent the blending amount (unit: parts by mass) of each component.

Comparative Examples 1-9
To 100 g of the polymerizable monomer M1, 0.3% by mass of CQ, 1.0% by mass of DMBE, and 0.15% by mass of HQME were added and mixed to form a uniform polymerizable monomer composition. Was prepared. Next, each of the fillers shown in Table 4 is measured in a mortar, the above-mentioned polymerizable monomer composition is gradually added under red light, and the paste is sufficiently kneaded in a dark place to provide a uniform curable paste. And said. Further, this paste was defoamed under reduced pressure to remove air bubbles, and a dental curable composition was produced. The physical characteristics of the obtained dental curable composition were evaluated based on the above method. The composition and results are shown in Tables 4 and 5.

Comparative Example 10
To 100 g of the polymerizable monomer M2, 0.3% by mass of CQ, 1.0% by mass of DMBE, and 0.15% by mass of HQME were added and mixed to form a uniform polymerizable monomer composition. Was prepared. Next, the inorganic spherical filler shown in Table 4 was weighed into a dairy pot, the above polymerizable monomer composition was gradually added under red light, and 0.070 g of titanium dioxide (white pigment) was added to the pigment. 0.002 g of yellow (yellow pigment), 0.0006 g of pigment red (red pigment), and 0.0002 g of pigment blue (blue pigment) were added and sufficiently kneaded in a dark place to obtain a uniform curable paste. Further, this paste was defoamed under reduced pressure to remove air bubbles, and a dental composite restoration material was produced. By visual evaluation, the color tone (equivalent to A4) was suitable for the A system of the high chromaticity model tooth. Subsequently, each physical property was evaluated based on the above method. The composition and results are shown in Tables 4 and 5.

As can be seen from the results of Examples 1-17, when the conditions specified in the present invention are met, the dental curable composition exhibits a yellow to red colored light due to light interference under a black background. It can be seen that the color tone compatibility is good and the bending strength is high.

As can be understood from the results of Comparative Examples 1 and 2, when only the inorganic spherical filler having an average particle diameter of 230 nm or 280 nm is blended as the filler, the yellow and red colored lights due to the interference of light under the black background are clear. However, due to the low contrast ratio of the cured product, good color compatibility cannot be obtained for class IV cavities.

As can be understood from the results of Comparative Example 3, when only an inorganic spherical filler having an average particle diameter of 178 nm is blended as a filler, the colored light due to light interference under a black background is blue and the contrast of the cured product is high. Due to the low ratio, good color compatibility is not obtained for class IV cavities.

As shown in the results of Comparative Examples 4 to 8, when the amorphous filler was used instead of the spherical filler, the dental curable composition did not show colored light under a black background, and Comparative Examples As shown in the result of 9, the average particle size of the amorphous inorganic filler does not satisfy the range of more than 1000 nm and less than 3000 nm, and the refractive index of the amorphous inorganic filler and the polymerizable monomer component are polymerized. When the difference from the refractive index with the obtained polymer is large, the color tone compatibility is inferior.

As can be understood from the results of Comparative Example 10, the dental curable composition in which the color tone was adjusted by adding a pigment (color tone suitable for the A system of the high-chromaticity model tooth (equivalent to A4)) was a color difference meter (a color difference meter (equivalent to A4)). When the spectral reflectance was measured with a black background color and a white background color using "TC-1800MKII" manufactured by Tokyo Denshoku Co., Ltd., the spectral reflectance characteristics according to the pigment added to both the black background color and the white background color were obtained. It was observed to show. The color tone compatibility of the high-chromaticity model tooth with the color tone (equivalent to A4) suitable for the A system was relatively good, but the color tone compatibility with other model teeth was low.

Claims (7)

The polymerizable monomer component (A) has an average primary particle size in the range of 100 nm or more and 1000 nm or less, and 90% or more of the total number of particles in the number-based particle size distribution is in the range of 5% before and after the average primary particle size. A dental curable composition comprising an inorganic spherical filler (B) present in, an amorphous inorganic filler (C) in the range of more than 1000 nm and less than 3000 nm, and a polymerization initiator (D).
The refractive index of the polymer obtained by polymerizing the polymerizable monomer component (A) at 25 ° C. is n _P, and the refractive index of the inorganic spherical filler (B) at 25 ° C. is n _FB. refractive index at 25 ° C. of the inorganic filler (C) a when a _{n FC,}
n _FB > n _P and 0.000 ≦ n _FC −n _P ≦ 0.002.
A dental curable composition characterized by that. In the spectral reflectance curve under a black background measured with a color difference meter for a cured product having a thickness of 1 mm, the maximum value of the spectral reflectance in the wavelength region of 600 nm or more and 750 nm or less: SR ₁ is 400 nm or more and 500 nm or less. Maximum value of spectral reflectance in the wavelength region of: The spectral reflectance ratio defined as the value divided by _{SR 2 : SR 1} / SR ₂ is given as a cured product in the range of 0.8 or more and 2.0 or less. The dental curable composition according to claim 1. The total blending amount of the inorganic spherical filler (B) and the amorphous inorganic filler (C) with respect to 100 parts by mass of the polymerizable monomer (A) is 100 parts by mass or more and 1500 parts by mass or less, and the total blending amount. The dental curable composition according to claim 1 or 2, wherein the proportion of the amount of the amorphous inorganic filler (C) to be blended is 5% or more and 30% or less. For a cured product with a thickness of 1 mm, both when the Y stimulus values determined by the tristimulus value measurement with a color difference meter with a black and white background are Y _b (black background) and Y _w (white background), respectively. Ratio: The dental curability according to any one of claims 1 to 3, wherein a cured product having a contrast ratio of 0.3 to 0.7 defined by _{Y b} / Y _{w is provided.} Composition. The dental curable composition according to any one of claims 1 to 4, wherein the inorganic spherical filler (B) has an average primary particle size of 230 nm or more and 350 nm or less. A dental filling restoration material for repairing a class III tooth cavity and / or a class IV tooth cavity comprising the dental curable composition according to any one of claims 1 to 5. A dental material for repairing a class III tooth cavity and / or a class IV tooth cavity, which comprises a cured product of the dental curable composition according to any one of claims 1 to 5.