JP7422994B2 - Dental curable composition - Google Patents

Description

The present invention relates to dental curable compositions. Specifically, the present invention relates to a dental curable composition suitable as a dental filling and restorative material that is easy to use and has excellent aesthetics.

Dental composite resin (hereinafter also simply referred to as "CR") is a type of material used to repair teeth damaged by caries, fracture, etc. and/or an organic filler. Restorations using dental composite resin (CR) (CR restorations) are rapidly becoming popular because they can reduce the amount of tooth material removed, provide a color similar to natural tooth color, and are easy to operate. . Furthermore, in recent years, due to its improved mechanical strength and adhesive strength with teeth, it has been used not only for the restoration of anterior teeth but also for molars where high occlusal pressure is applied.

As mentioned above, one of the excellent features of CR restoration is that it is possible to perform highly aesthetic restorations.Natural teeth are made up of dentin and enamel, and each part has different color tones (hue, saturation, In order to perform a highly aesthetic restoration, careful treatment is required depending on the condition of the tooth to be restored (tooth to be restored). For example, even if the restored tooth is lightly damaged and the cavity is shallow, a plurality of CRs with different colors are prepared, and from among these, the actual restored tooth and its adjacent teeth (hereinafter also referred to as "surroundings of the restored tooth") are prepared. ) and the one that best matches the color tone is generally selected and used (see Non-Patent Document 1). In addition, when the 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 layer (dentin part) that can be seen through it, and the color tone is rich in gradation. Therefore, this delicate color tone is reproduced by changing the color tone of the curable paste filled at a certain depth and filling the paste in layers (see Non-Patent Document 1 and Non-Patent Document 2).

In order to meet such demands, many CRs have been provided in which color tones are adjusted by adding pigments and dyes in varying types and amounts. However, with CR whose color tone has been adjusted using pigments or dyes, these substances in the cured CR material fade or change color over time, causing the color to change over time after the repair, causing the repaired area to fade. The appearance of the teeth may no longer match your natural teeth.

On the other hand, as a technology for coloring without using pigments or dyes, coloring is achieved using colored light (hereinafter also simply referred to as "interference light") that utilizes reflection, interference, scattering, and transmission of light by fine particles in a medium. There are technologies to produce the desired color (hereinafter, colors developed based on this principle are also referred to as "structural colors"), and these technologies can be applied to create the desired color in composite materials in which inorganic particles are dispersed in a medium such as resin. A technique for causing color development is also known (see Patent Document 1).

That is, Patent Document 1 states, for example, that ``a polymerizable monomer component (A), an inorganic spherical filler (B) having an average particle diameter within the range of 230 nm to 1000 nm, and a polymerization initiator (C); 90% or more of the individual particles constituting the spherical filler (B) exist within a range of 5% before and after the average particle diameter, and the refractive index n _F of the inorganic spherical filler (B) at 25° C. A curable composition that satisfies the condition that the refractive index at 25°C of the polymer obtained by polymerizing the monomer component (A) is larger than _the The lightness (V) of the colorimetric value according to the Munsell color system of colored light against a black background, measured using a color difference meter, is less than 5, and the chroma (C) is 0.05 or more. and a curable composition having a colorimetric value (V) of 6 or more and a chroma (C) of less than 2 in the Munsell color system of colored light under a white background. . According to Patent Document 1, CR made of the above-mentioned curable composition (1) does not use dyes or pigments, so the problem of discoloration over time is unlikely to occur, and (2) (the average of the inorganic spherical filler used) (Depending on the particle size), it can be colored yellow to red, which is the same color as dentine, and (3) the cured product can be easily harmonized with the color of the tooth to be restored, eliminating the need for complicated shade taking and composite resin. It is described that the method has an excellent feature in that it is possible to restore teeth with a wide range of colors with an appearance close to that of natural teeth using one type of composite resin without having to select a shade. Note that the curable composition disclosed in Patent Document 1 is designed to emit yellow to red colored light with the main purpose of repairing cavities in which dentin is located in the deep layer. , an inorganic spherical filler (B) with an average particle diameter of 230 nm or more is used, but if you are not particular about the color tone, including blue, it is possible to use a structural color with an average particle diameter of 100 nm or more. can.

Patent No. 6250245

Supervised by Hideo Matsumura and Junji Tagami, "Adhesive YEARBOOK 2006", 1st edition, Quintessence Publishing Co., Ltd., August 2006, p. 129-137 Masashi Miyazaki, “Science and Techniques of Composite Resin Restoration”, 1st edition, Quintessence Publishing Co., Ltd., January 2010, p. 48-49

The curable composition disclosed in Patent Document 1 exhibits the excellent characteristics described above when used as a CR. However, as mentioned above, this curable composition is designed primarily for the purpose of repairing cavities in which dentin is located in the deep layer, and is designed for the purpose of restoring class III cavities (front teeth, etc.) in which dentin is not present in the deep layer. The color compatibility has not been investigated when used to repair class IV cavities (proximal cavities of anterior teeth that do not include the incisal angle) or class IV cavities (proximal cavities of anterior teeth that include the incisal angle).

Therefore, when the present inventors investigated the color tone compatibility of the curable composition disclosed in Patent Document 1 in the restoration of anterior teeth (class III cavities and class IV cavities), it was found that the structural color was However, this is probably because the cured product is too transparent, making it difficult for reflected light and scattered light to reach the observer, but the repaired area appears black (the developed structural color is not visible to the naked eye). It has become clear that there are some cases where it cannot be recognized. This phenomenon can be solved by introducing a layered structure into the restoration part, placing a hardened CR material with low transparency in the base part (corresponding to the back side of the restored tooth), and placing a hardened CR material with low transparency in the surface part (the front side of the restored tooth). It is thought that this problem can be solved by disposing a CR made of the above-mentioned curable composition, but the operation becomes complicated.

The present invention solves the problems that have not been recognized hitherto, which are unique to CR that performs color tone adjustment using structural colors, as described above. The object of the present invention is to provide a dental curable composition that can be used as a CR and can provide high color compatibility even when used for the repair of cavities and class IV cavities.

The present inventors believe that the above problem can be solved if the curable composition disclosed in Cited Document 1 can reduce the transparency of the resulting cured product while retaining its structural color expression function. I thought it was possible and did some serious research. As a result, (1) the average primary particle diameter is within the range of more than 1000 nm and less than 3000 nm, which has a refractive index that is the same as or slightly higher than the refractive index of the polymer obtained by polymerizing the polymerizable monomer contained in CR. (2) The transparency of the cured product can be lowered by blending the amorphous inorganic filler, (2) the transparency at that time can be adjusted by the amount of the amorphous inorganic filler, (3) When the transparency is reduced by adding the amorphous filler, the stronger the degree of the reduction, the more difficult it becomes to recognize the developed structural color, and (4) based on the findings in (2) above, the transparency is reduced. The inventors have discovered that when the properties are appropriately adjusted, the visibility of the developed structural color can be maintained and the above-mentioned problems can be solved, and the present invention has been completed.

That is, the first invention is characterized in that 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 in the number-based particle size distribution, 90% or more of the total number of particles is the average primary particle size. Dental hardening comprising an inorganic spherical filler (B) existing in a range of 5% before and after the particle size, an amorphous inorganic filler (C) having a particle size of more than 1000 nm and less than 3000 nm, and a polymerization initiator (D) The refractive index at 25° C. of the polymer obtained by polymerizing the polymerizable monomer component (A) is n _P , and the refractive index at 25° C. of the inorganic spherical filler (B) is When n _FB is the refractive index at 25 _{° C. of the amorphous inorganic filler (C), n FB >} n _P and 0.000≦n _FC −n _P ≦0.002. For a cured product with a thickness of 1 mm, the Y stimulus values determined by tristimulus value measurement using a color difference meter with black and white backgrounds are Y _b (black background) and Y _w (white background), respectively. This dental curable composition is characterized in that it provides a cured product having a contrast ratio defined by the ratio of both: Y _b /Y _w of 0.3 to 0.7.

In the dental curable composition of the present invention, from the viewpoint of maintaining effective visibility of the developed structural color, a 1 mm thick cured product obtained by curing the dental curable composition of the present invention is preferred. In the spectral reflectance curve under a black background measured using a color difference meter, the maximum value of spectral reflectance in the wavelength range of 600 nm or more and 750 nm or less (yellow to red region): SR ₁ is set as SR 1 for 400 nm or more and 500 nm or less The maximum value of spectral reflectance within the wavelength range (blue region): 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 .9 or more and 1.5 or less. Further, from the viewpoint of expressing a yellow to red structural color with high intensity, it is preferable that the average primary particle diameter of the inorganic spherical filler (B) is 230 nm or more and 350 nm or less, particularly 245 nm or more and 300 nm or less; The total amount of the inorganic spherical filler (B) and the amorphous inorganic filler (C) relative 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 It is preferable that the blended amount of the amorphous inorganic filler (C) is 5% or more and 30% or less. Furthermore, from the viewpoint of improving the color tone compatibility of the repaired portion when a class III cavity or class IV cavity is repaired using the cured product of the dental curable composition of the present invention, the contrast ratio is 0.4 to 0.4. It is preferable that the cured product has a hardness of 0.6.

A second aspect of the present invention is a dental filling and restorative material for repairing class III cavities and/or class IV cavities, which is made of the curable dental composition of the present invention, and a third aspect of the present invention is This is a dental material for repairing class III cavities and/or class IV cavities, which is made of a cured product of a dental curable composition.

The dental curable composition of the present invention does not use dyes or pigments that cause problems with discoloration, and uses only one type of structural color to achieve a color tone that harmonizes with the surroundings, as described in the above patent document. Not only does it have the same effect as the curable composition disclosed in No. 1, but it also has appropriate opacity, so it can be used as a base material for the restoration of anterior tooth defects, especially for the restoration of class III and class IV cavities. It is possible to perform restorations with high color compatibility with natural teeth using one type of tooth without using any.

The greatest feature of the present invention is that in the curable composition that exhibits a structural color as disclosed in Patent Document 1, an amorphous inorganic filler having an average particle diameter of more than 1000 nm and less than 3000 nm is used. , when the refractive index at 25°C of the amorphous inorganic filler (C) is n _FC , and the refractive index at 25°C of the polymer obtained by polymerizing the polymerizable monomer component (A) is n _P. By blending an amorphous inorganic filler (C) that satisfies the relationship of 0.000≦n _FC -n _P ≦0.002 into the resulting cured product, it is possible to maintain the visibility of the developed structural color. The point is that it provides appropriate opacity. By doing this, appropriate opacity is imparted to the cured product, and for example, for a cured product with a thickness of 1 mm, the Y stimulus value determined by tristimulus value measurement using a color difference meter with a black and white background, respectively, is Y _b ( The contrast ratio defined by Y _b /Y _{w (black background) and Y w (} white background) is in the range of 0.3 to 0.7, more preferably 0.4 to 0.6. It can be done. Furthermore, since the opacity at this time is sufficient to maintain the effect of interference light as described above, it is possible to perform aesthetic restorations that exhibit a natural color tone even for the restoration of class III or class IV cavities. .

As described above, the present invention is based on a curable composition that expresses structural color, and the basic composition (each component and its blending amount, etc.) of the curable composition that is the base and the composition that expresses structural color. The conditions that must be met in order to achieve this are basically the same as those for the curable composition disclosed in Patent Document 1. That is, in the dental curable composition of the present 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. contains an inorganic spherical filler (B) and a polymerization initiator (D), which are present in a range of 5% before and after the average primary particle diameter, and further includes a refractive index at 25 ° C. of the inorganic spherical filler (B): n _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 these conditions, interference light and the structural color based on this can be clearly confirmed without using dyes or pigments, and regardless of the depth of the cavity, it is possible to clearly see the interference light and the structural color, which is close to that of natural teeth, regardless of the depth of the cavity. The present invention provides a dental curable composition that enables restoration with good color compatibility, particularly a curable composition for dental filling and restorative materials.

Here, the relationship between the particle size of the inorganic spherical filler (B) and the light interference phenomenon is considered to follow the Bragg diffraction conditions, and interference light with a color tone corresponding to the average primary particle size of the inorganic spherical filler (B) is generated. (Structural color appears). The generation of interference light (expression of structural color) can be confirmed by measuring spectral reflectance using a color difference meter. However, when measuring against a white background, it is difficult to observe colored light due to interference due to the strong scattered reflection of external light (e.g. C light source, D65 light source), so it is necessary to perform the measurement against a black background. . When measuring against a black background, it is possible to clearly see the reflection spectrum corresponding to the wavelength of interference light generated by absorption or blocking of external light. In addition, if a specific structural color does not appear due to reasons such as not satisfying the above refractive index conditions or adding only an amorphous filler and not adding an inorganic spherical filler (B), When performing spectral reflectance measurements, there is a tendency for relatively strong blue reflections to be observed (see the spectral reflectance ratios of Comparative Examples 4 to 9: SR ₁ / SR ₂ ), and even when looking at the reflection spectra, there is a tendency for relatively strong blue reflection to be observed. Usually, the intensity in the yellow to red wavelength range is significantly higher than the intensity in the yellow to red wavelength range. On the other hand, the curable composition disclosed in Patent Document 1 has a maximum in the wavelength range from yellow to red. In the present invention, although the expression of structural color decreases due to the decrease in transparency (increase in opacity), the opacity is appropriately controlled, so the intensity in the yellow to red wavelength region is lower than that in the blue wavelength region. The level is equal to or higher than the strength, making it possible to obtain high color tone compatibility.

Each component of the dental curable composition of the present invention will be explained below.

<Polymerizable monomer component (A)>
As the polymerizable monomer component (A), known ones can be used without particular limitation. From the viewpoint of polymerization rate, radically polymerizable or cationically polymerizable monomers are preferred for dental applications. Particularly preferred radically polymerizable monomers include (meth)acrylates, which are (meth)acrylic compounds, as exemplified below, and particularly preferred cationically polymerizable monomers include epoxies and oxetanes. . Generally, examples of (meth)acrylates that are preferably used as (meth)acrylic compounds include those shown in (a) to (d) below.

(i) Monofunctional polymerizable monomer (i-i) Those that do not have acidic groups or hydroxyl groups Methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth) Acrylate, n-lauryl (meth)acrylate, n-stearyl (meth)acrylate, tetrafurfuryl (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 ( meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytriethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, trifluoroethyl ( (meth)acrylate, etc.

(I-ii) Those having an acidic group (meth)acrylic acid, N-(meth)acryloylglycine, N-(meth)acryloyl aspartic acid, N-(meth)acryloyl-5-aminosalicylic acid, 2-(meth)acryloylglycine Acryloyloxyethyl hydrogen succinate, 2-(meth)acryloyloxyethyl hydrogen phthalate, 2-(meth)acryloyloxyethyl hydrogen malate, 6-(meth)acryloyloxyethylnaphthalene-1,2,6-tricarboxylic acid , O-(meth)acryloyltyrosine, N-(meth)acryloyltyrosine, N-(meth)acryloylphenylalanine, N-(meth)acryloyl-p-aminobenzoic acid, N-(meth)acryloyl-o-aminobenzoic acid , p-vinylbenzoic acid, 2-(meth)acryloyloxybenzoic acid, 3-(meth)acryloyloxybenzoic acid, 4-(meth)acryloyloxybenzoic acid, N-(meth)acryloyl-5-aminosalicylic acid, N -(meth)acryloyl-4-aminosalicylic acid, etc. and compounds obtained by converting the carboxyl group of these compounds into acid anhydride groups, 11-(meth)acryloyloxyundecane-1,1-dicarboxylic acid, 10-(meth)acryloyloxy Decane-1,1-dicarboxylic acid, 12-(meth)acryloyloxydodecane-1,1-dicarboxylic acid, 6-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 2-(meth)acryloyloxyethyl- 3'-methacryloyloxy-2'-(3,4-dicarboxybenzoyloxy)propyl succinate, 4-(2-(meth)acryloyloxyethyl) trimellitate anhydride, 4-(2-(meth)acryloyl) oxyethyl) trimellitate, 4-(meth)acryloyloxyethyl trimellitate, 4-(meth)acryloyloxybutyl trimellitate, 4-(meth)acryloyloxyhexyl trimellitate, 4-(meth)acryloyloxydecyl trimellitate Melitate, 4-(meth)acryloyloxybutyl trimellitate, 6-(meth)acryloyloxyethylnaphthalene-1,2,6-tricarboxylic anhydride, 6-(meth)acryloyloxyethylnaphthalene-2,3, 6-tricarboxylic anhydride, 4-(meth)acryloyloxyethylcarbonylpropionoyl-1,8-naphthalic anhydride, 4-(meth)acryloyloxyethylnaphthalene-1,8-tricarboxylic anhydride, 9- (meth)acryloyloxynonane-1,1-dicarboxylic acid, 13-(meth)acryloyloxytridecane-1,1-dicarboxylic acid, 11-(meth)acrylamidoundecane-1,1-dicarboxylic acid, 2-(meth)acryloyloxytridecane-1,1-dicarboxylic acid, ) Acryloyloxyethyl dihydrogen phosphate, 2-(meth)acryloyloxyethyl phenyl hydrogen phosphate, 10-(meth)acryloyloxydecyl dihydrogen phosphate, 6-(meth)acryloyloxyhexyl dihydrogen phosphate Phate, 2-(meth)acryloyloxyethyl-2-bromoethyl hydrogen phosphate, 2-(meth)acrylamidoethyl dihydrogen phosphate, 2-(meth)acrylamido-2-methylpropanesulfonic acid, 10-sulfodecyl (meth)acrylate, 3-(meth)acryloxypropyl-3-phosphonopropionate, 3-(meth)acryloxypropylphosphonoacetate, 4-(meth)acryloxybutyl-3-phosphonopropionate , 4-(meth)acryloxybutylphosphonoacetate, 5-(meth)acryloxypentyl-3-phosphonopropionate, 5-(meth)acryloxypentylphosphonoacetate, 6-(meth)acryloxyhexyl -3-phosphonopropionate, 6-(meth)acryloxyhexylphosphonoacetate, 10-(meth)acryloxydecyl-3-phosphonopropionate, 10-(meth)acryloxydecylphosphonoacetate, 2-(meth)acryloyloxyethyl-phenylphosphonate, 2-(meth)acryloyloxyethylphosphonic acid, 10-(meth)acryloyloxydecylphosphonic acid, N-(meth)acryloyl-ω-aminopropylphosphonic acid, 2- (meth)acryloyloxyethylphenyl hydrogen phosphate, 2-(meth)acryloyloxyethyl 2'-bromoethyl hydrogen phosphate, 2-(meth)acryloyloxyethylphenylphosphonate, etc.

(I-iii) Those having a hydroxyl group 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 10-hydroxydecyl ( meth)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) ) (meth)acrylamide, etc.

(b) Bifunctional polymerizable monomer (b-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- Acrylates corresponding to bis(4-methacryloyloxypropoxyphenyl)propane, 2,2-bis(4-methacryloyloxyisopropoxyphenyl)propane and their methacrylates; 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-chloro Vinyl monomers having an -OH group such as methacrylates such as -2-hydroxypropyl methacrylate or acrylates corresponding to these methacrylates, and diisocyanate compounds having aromatic groups such as diisocyanate methylbenzene and 4,4'-diphenylmethane diisocyanate. diaduct obtained from the addition of; di(methacryloxyethyl)diphenylmethane diurethane, etc.

(Ro-ii) 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 -OH group-containing vinyl monomers such as methacrylates such as propyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, or acrylates corresponding to these methacrylates, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diisocyanate methylcyclohexane, and isophorone. diisocyanates, diadducts obtained from adducts with diisocyanate compounds such as methylenebis(4-cyclohexylisocyanate); 1,2-bis(3-methacryloyloxy-2-hydroxypropoxy)ethyl, etc.

(c) Trifunctional polymerizable monomer Methacrylates such as trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, pentaerythritol trimethacrylate, trimethylolmethane trimethacrylate, and acrylates corresponding to these methacrylates.

(d) Tetrafunctional polymerizable monomer Pentaerythritol tetramethacrylate, pentaerythritol tetraacrylate; diisocyanate methylbenzene, diisocyanate methylcyclohexane, isophorone diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, methylene bis(4-cyclohexyl isocyanate), 4 , 4-diphenylmethane diisocyanate, tolylene-2,4-diisocyanate, and other diisocyanate compounds and glycidol dimethacrylate.

A plurality of types of these polyfunctional (meth)acrylate polymerizable monomers may be used in combination as necessary. Furthermore, if necessary, methacrylates such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, hydroxyethyl methacrylate, tetrahydrofurfuryl methacrylate, glycidyl methacrylate, and monofunctional (meth)acrylate units such as acrylates corresponding to these methacrylates may be added. Polymerizable monomers other than the above-mentioned (meth)acrylate monomers may also be used.

In the present invention, multiple types of polymerizable monomers are generally used as the polymerizable monomer component (A) in order to adjust the physical properties (mechanical properties and adhesiveness to tooth substance) of the cured product. In this case, it is desirable to set the type and amount of the polymerizable monomer so that the refractive index of 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. This makes it easy to satisfy the condition n _P < n _FB . In addition, there are cases where multiple types of polymerizable monomers are used as the polymerizable monomer component (A), and in this case, the refractive index of the polymerizable monomer component (A) It is sufficient that the refractive index of the mixture of the polymerizable monomers falls within the above range, and the individual polymerizable monomers do not necessarily need to fall within the above range. Note that the refractive index of the polymerizable monomer or the cured product of the polymerizable monomer can be determined at 25° C. using an Abbe refractometer.

<Inorganic spherical filler (B)>
Dental curable compositions contain various fillers such as inorganic powders and organic powders, but the dental curable compositions of the present invention contain fillers for the purpose of producing colored light due to interference. , an inorganic spherical filler (B) having an average primary particle diameter within 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 in a narrow range of 5% before and after the average primary particle diameter. By having a particle size distribution, the particles are dispersed with short-range regularity, and it becomes possible to generate interference light of a specific wavelength depending on the average primary particle size. Here, the average primary particle diameter of the inorganic spherical filler (B) is determined by taking a photograph of the powder using a scanning electron microscope, selecting 30 or more particles observed within a unit field of view of the photograph, and It refers to the average value of the primary particle diameter (maximum diameter). The spherical shape may be any approximately spherical shape, and does not necessarily have to be a perfect sphere. Take a photo of particles with a scanning electron microscope, measure the maximum diameter of each particle (30 or more) within the unit field of view, and calculate the average particle diameter in the direction perpendicular to the maximum diameter divided by the maximum diameter. It is sufficient if the degree of symmetry is 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 diameter to the total number of particles is 90% or more, but the above-mentioned The ratio is preferably 91% or more, more preferably 93% or more.

The appearance of colored light due to light diffraction and interference is due to the fact that diffraction and interference occur in accordance with the Bragg condition, and light of a specific wavelength is emphasized.When particles of the above particle size are blended, the dental hardening Colored light (interference light) is generated in the cured product of the sexual composition, and a structural color corresponding to the particle size is developed.

The average primary particle diameter of the inorganic spherical filler (B) may be within 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, visible light interference phenomenon is less likely to occur. On the other hand, when an inorganic spherical filler with an average primary particle size exceeding 1000 nm is used, it can be expected that light interference will occur, but when used as a restorative material for dental fillings, sedimentation and abrasiveness of the inorganic spherical filler may occur. A decline occurs.

In addition, according to studies by the present inventors, the tone of the structural color developed when using the inorganic spherical filler (B) varies in the range of 100 nm to 1000 nm, depending on the average primary particle diameter of the inorganic spherical filler used. It was found that as the particle size increases, the diameter changes through repeated cycles of blue to yellow to red, and the intensity tends to decrease in cycles where the average primary particle size is large. Therefore, from the viewpoint of expressing a strong structural color, the average primary particle diameter is preferably 100 nm or more and 500 nm or less. Furthermore, from the viewpoint of strongly expressing a yellow to red structural color, the average primary particle diameter is preferably 230 nm or more and 350 nm or less, particularly 245 nm or more and 300 nm or less.

For example, when using spherical particles with an average primary particle diameter in the range of 230 nm to 260 nm, the colored light obtained is yellowish and falls into the category of B type (red-yellow) in the shade guide ("VITA Classic", manufactured by VITA). It is useful for restoring certain teeth, especially cavities that have formed from the enamel to the dentin. When spherical particles with an average primary particle size in the range of 260 nm to 350 nm are used, the colored light obtained is reddish and falls within the category of A type (reddish brown) in the shade guide (“VITA Classical”, manufactured by VITA). It is particularly useful for repairing cavities formed from enamel to dentin. Since the hue of dentin is often reddish, by using the inorganic spherical filler (B) having an average primary particle diameter within the above-mentioned preferred range, it is widely compatible with restored teeth of various tones. can be made better.

As the inorganic spherical filler (B), those used as a component of ordinary dental curable compositions can be used without limitation. Specifically, amorphous silica, silica/titanium group element oxide composite oxide particles (silica/zirconia, silica/titania, etc.), quartz, alumina, barium glass, strontium glass, lanthanum glass, fluoroaluminosilicate glass , ytterbium fluoride, zirconia, titania, colloidal silica, and other inorganic powders. Among these, silica/titanium group element oxide composite oxide particles are preferred 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, such as silica-titania, silica-zirconia, Examples include silica, titania, and zirconia. Among these, silica-zirconia is preferred because it is possible to adjust the refractive index of the filler and also provide high X-ray opacity. The composite ratio is not particularly limited, but from the viewpoint of imparting sufficient X-ray opacity and setting the refractive index within the preferred range described below, the silica content is 70 to 95 mol%, and the titanium group Preferably, the content of elemental oxides is 5 to 30 mol%. In the case of silica-zirconia, by changing each composite ratio in this way, the refractive index can be changed freely.

In addition, in these silica/titanium group element oxide-based composite oxide particles, a composite of metal oxides other than silica and titanium group element oxides is also allowed as long as the amount is small. Specifically, an alkali metal oxide such as sodium oxide or lithium oxide may be contained within 10 mol%.

The method for producing such silica/titanium group element oxide composite oxide particles is not particularly limited. For example, a mixed solution containing a hydrolyzable organosilicon compound and a hydrolyzable organotitanium group metal compound is A so-called sol-gel method, in which the reaction product is precipitated by adding it to a solvent and performing hydrolysis, is preferably employed.

These silica/titanium group oxide composite oxide particles may be surface-treated with a silane coupling agent. The surface treatment with the silane coupling agent provides excellent interfacial strength with the cured portion of the polymerizable monomer (A). Typical silane coupling agents include organosilicon compounds such as γ-methacryloyloxyalkyltrimethoxysilane and hexamethyldisilazane. There is no particular limit to the amount of surface treatment with these silane coupling agents, and the optimum value may be determined after confirming the mechanical properties, etc. of the resulting dental curable composition in advance through experiments, but the preferred ranges are shown below. In this case, the amount is in the range of 0.1 parts by mass to 15 parts by mass based on 100 parts by mass of particles.

In the dental curable composition of the present invention, in order to generate interference light or develop a structural color, the refractive index at 25°C of the inorganic spherical filler (B): n _FB is the polymerizable monomer. The refractive index at 25° C. of the polymer obtained by polymerizing component (A) must be larger than n _P. That is, it is necessary to satisfy the relationship n _P < n _FB . The 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 is, but may be obtained by mixing it with the polymerizable monomer (A) etc. in advance and polymerizing it. It may be blended in the form of an organic-inorganic composite filler consisting of a composite.

The method for producing the above-mentioned organic-inorganic composite filler is not particularly limited, and for example, a method such as mixing predetermined amounts of each component of the inorganic spherical filler (B), a polymerizable monomer, and a polymerization initiator, heating, light irradiation, etc. A general manufacturing method can be adopted in which the polymer is polymerized and then pulverized. Alternatively, the manufacturing method described in International Publication No. 2011/115007 or International Publication No. 2013/039169 can also be adopted. In this production method, inorganic aggregated 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 methods such as heating and light irradiation. According to the manufacturing method described in International Publication No. 2011/115007 or International Publication No. 2013/039169, inorganic primary particles cover the surface of each inorganic primary particle of inorganic aggregated particles, and each inorganic primary particle is An organic-inorganic composite filler is obtained which has organic resin phases that are bonded to each other and in which cohesive gaps are formed between the organic resin phases that cover the surface of each inorganic primary particle.

<Amorphous inorganic filler (C)>
The dental curable composition of the present invention contains an amorphous inorganic filler having an average particle diameter of more than 1,000 nm and less than 3,000 nm for the purpose of imparting appropriate opacity to the cured product, and which has a specific refractive index. An amorphous inorganic filler (C) having a certain ratio is blended. Here, amorphous means that the shape of the primary particle observed by SEM etc. has many irregular corners and faces, and the amorphous inorganic filler (C) is usually A filler consisting of particles obtained by crushing or grinding. In addition, the average particle diameter of the amorphous filler (C) is the 50% particle diameter ( 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 sample suspension was dispersed for about 1 to 5 minutes using an ultrasonic disperser. The particle size distribution of particles with a particle size in the range of ~2000 μm is determined. Then, based on the obtained particle size distribution, a cumulative volume distribution is drawn for each of the divided particle size ranges from the small diameter side, and the particle size that gives a cumulative 50% is defined as the average particle size (D50).

In order to exhibit the effects of the present invention, the average particle diameter of the amorphous inorganic filler is within the range of more than 1000 nm and less than 3000 nm, and the refractive index at 25°C of the amorphous inorganic filler is n _FC and the polymerizability. An amorphous inorganic filler whose relationship with the refractive index n _P at 25° C. of the polymer obtained by polymerizing the monomer component (A) satisfies the relationship 0.000≦n _FC −n _P ≦0.002. C) must be added.

When the average particle diameter of the amorphous inorganic filler is 1000 nm or less, appropriate opacity cannot be imparted 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 no interference light is generated, or even if interference light is generated, the structural color caused by it cannot be visually recognized. The average particle diameter of the amorphous inorganic filler (C) is preferably more than 1000 nm and less than 2500 nm, and more than 1000 nm, in that it can 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" imparted 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 with a thickness of 1 mm is used. Can be done. Here, Y _b means the Y stimulus value determined by tristimulus value measurement using a color difference meter with a black background on a cured product with a thickness of 1 mm, and Y _w means the Y stimulus value determined in the same manner with a white background. Y means stimulus value. When the contrast ratio (Y _b /Y _w ) is less than 0.3, the brightness (color shading) of the cured body at the repair site (filling site) when used for repairing, for example, a class III cavity or a class IV cavity. As a result, the transmitted light at the site is strong and the colored light from the cured product is weak, making it difficult to obtain good color tone compatibility. In addition, when the contrast ratio exceeds 0.7, the brightness of the cured product becomes high, the reflected light on the surface of the repair site (filling site) is strong, and the colored light from the cured product becomes weak, which also results in a good result. 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 achieved. In order to have excellent color tone compatibility in the repair of class III cavities and class 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 0. More preferably, it is in the range of .40 or more and 0.60 or less.

Furthermore, in the cured product of the dental curable composition of the present invention, although the opacity increases 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 a spectral reflectance curve against a black background, which is measured using a color difference meter on a 1 mm thick cured product. can. As mentioned above, the structural color is a color tone depending on the average primary particle size of the inorganic spherical filler (B) (usually selected from a wide color range of blue to yellow to red depending on the purpose). A structural color of a preferable color tone) is expressed, and in reflection emissivity measurement using a color difference meter against a black background, the reflection in the wavelength range corresponding to the color tone becomes significantly high.

When the dental curable composition of the present invention is used, for example, to repair a class III cavity or a class IV cavity, the cured product has appropriate opacity as described above and can be confirmed as yellow to red. It is preferable to develop a (visible) structural color in order to perform aesthetic restoration with high color tone compatibility. From this viewpoint, the dental curable composition of the present invention preferably provides a cured product having a spectral reflectance ratio: SR ₁ /SR ₂ of 0.8 or more and 2.0 or less. Here, the above SR ₁ and SR ₂ refer to the spectral reflectance on a black background measured using a color difference meter on a 1 mm thick cured product 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 (SR ₁ ) in the wavelength region of 400 nm or more and 500 nm or less (blue region) 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. Furthermore, if the spectral reflectance ratio exceeds 2.0, the yellow to red colored light is too strong, making it difficult to obtain good color tone compatibility. In order to have excellent color compatibility when used for repairing class III cavities and class IV cavities, 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 (e.g. barium, strontium, zirconium), aluminosilicate glass, fluoroaluminosilicate glass, glass ceramics, metal fluorides such as ytterbium fluoride, yttrium fluoride, Silica and composite inorganic oxides such as silica/zirconia, silica/titania, silica/alumina, etc. are suitable. Particularly preferred examples include composite oxides containing silica and zirconia as main components because they have X-ray contrast properties and can yield cured products with better abrasion resistance.

The amorphous inorganic filler (C) is preferably used after its surface is treated with a suitable surface treatment agent in order to improve its dispersibility in the polymerizable monomer as a matrix. As the method for this treatment, similar to the method described above as the surface treatment method for the substantially spherical inorganic filler, it can be used without any restrictions.

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 or less, based on 100 parts by mass of the polymerizable monomer (A). It is preferably at least 1000 parts by mass. 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 so that With such a blending amount and blending ratio, a natural color tone will be exhibited for the repair of class III cavities and class IV cavities, and more aesthetic repair will be possible.

<Polymerization initiator (D)>
The polymerization initiator (D) is not particularly limited as long as it has the function of polymerizing the polymerizable monomer (A), but the light used in dental direct filling restoration applications, which are often hardened in the oral cavity, may be used. It is preferable to use a polymerization initiator or a chemical polymerization initiator, and it is more preferable to use a photopolymerization initiator (composition) because it is simple and does not require a mixing operation.

Polymerization initiators used in 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. , benzophenones such as 4-methacryloxybenzophenone, α-diketones such as diacetyl, 2,3-pentadionebenzyl, camphorquinone, 9,10-phenanthraquinone, 9,10-anthraquinone, 2,4-di Thioxanthone 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.

Note that a reducing agent is often added to the photopolymerization initiator, examples of which 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-decanethiol, thiosalcylic acid, and thiobenzoic acid.

Furthermore, in addition to the above-mentioned photopolymerization initiator and reducing compound, a photoacid generator is often used in addition. Examples of such photoacid generators 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, or two or more types may be used in combination. The amount of the polymerization initiator to be blended may be selected as an effective amount depending on the purpose, but the ratio is usually 0.01 to 10 parts by weight, more preferably 0.1 parts by weight, based on 100 parts by weight of the polymerizable monomer. It is used in a proportion of ~5 parts by mass.

<Other additives>
In addition to the above-mentioned components (A) to (D), other known additives may be added to the dental composite restorative material of the present invention within a range that does not impede its effects. Specific examples include polymerization inhibitors and ultraviolet absorbers. Further, for the purpose of adjusting viscosity, etc., filler having a particle size that is sufficiently smaller than the wavelength of light and does not easily affect color tone or transparency can be blended.

As described above, the present invention enables restoration with good color compatibility with natural teeth with a single paste (dental curable composition) without using a coloring substance such as a pigment. Therefore, it is preferable that pigments that may change color over time are not added. However, in the present invention, the blending of pigments itself is not denied, and pigments may be blended to the extent that they do not interfere with colored light due to interference with the inorganic spherical filler. Specifically, the pigment may be blended in an amount of about 0.0005 to 0.5 parts by mass, preferably about 0.001 to 0.3 parts by mass, per 100 parts by mass of the polymerizable monomer. .

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

The dental curable composition of the present invention is particularly suitable for use as a dental filling and restorative material, typified by the above-mentioned photocurable composite resin, but is not limited thereto, and can also be used for other purposes. It can be used suitably. Its uses include, for example, dental cement and restorative materials for building abutments.

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

First, methods for measuring various physical properties in Examples and Comparative Examples will be explained.
(1) Average particle diameter of inorganic spherical filler Take a photograph of the powder with a scanning electron microscope (manufactured by Philips, "XL-30S"), and the number of particles observed within the unit field of view of the photograph (30 or more ) and the primary particle diameter (maximum diameter) were measured, and the average particle diameter was calculated from the following formula based on the measured values.

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

(3) Uniformity A photograph of the powder is taken using a scanning electron microscope (manufactured by Philips, "XL-30S"), and the maximum diameter of each particle (30 or more) within the unit field of view of the photograph is The average value obtained by dividing the particle diameter in the orthogonal direction by its maximum diameter was defined as the degree of symmetry.

(4) Measurement of refractive index <Refractive index of polymerizable monomer component (A)>
The refractive index of the polymerizable monomer (or mixture of polymerizable monomers) used was measured in a thermostatic chamber at 25° C. using an Abbe refractometer (manufactured by Atago).
<Refractive index n _P of polymer of polymerizable monomer component (A)>
The polymer sample obtained by polymerizing the used polymerizable monomer component (polymerizable monomer or mixture of polymerizable monomers) under almost the same conditions as the polymerization conditions in the cavity was measured using an Abbe refractometer. (manufactured by Atago Corporation) in a constant temperature room at 25° C. to determine the refractive index _nP .
That is, a homogeneous composition obtained by mixing the polymerizable monomer component (A) with 0.3% by mass of CQ, 1.0% by mass of DMBE, and 0.15% by mass of HQME based on the mass of the component. The sample was placed in a mold having holes of φ7 mm x 0.5 mm, and polyester films were pressed on both sides. Thereafter, it was irradiated with light for 30 seconds using a halogen-type dental light irradiator (Demetron LC, manufactured by Cyblon) with a light intensity of 500 mW/cm ² to cure it, and then taken out from the mold to prepare a polymer sample. In addition, when measuring the refractive index, when setting the sample in the device, bromonaphthalene (a solvent that does not dissolve the sample and has a higher refractive index than the sample) was dropped onto the sample in order to bring the polymer into close contact with the measurement surface. .
<The refractive index of the inorganic spherical filler is n _FB and the refractive index of the 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 refractometer (manufactured by Atago).
That is, in a thermostatic chamber at 25° C., 1 g of the inorganic spherical filler or its surface-treated material is dispersed in 50 ml of anhydrous toluene in a 100 ml sample bottle. While stirring this dispersion with a stirrer, 1-bromotoluene was added dropwise little by little, and the refractive index of the dispersion was measured at the point when the dispersion became most transparent. It was taken as the refractive index of the filler.

(5) Evaluation of contrast ratio (Y _b /Y _w ) of curable compositions The pastes of the curable compositions prepared in the examples and comparative examples were put into a mold with a 7 mmφ x 1 mm through hole, and the pastes were placed on both sides. A polyester film was pressed. After curing by irradiating both sides with visible light irradiator (manufactured by Tokuyama, Power Light) for 30 seconds each, remove from the mold and use a color difference meter (manufactured by Tokyo Denshoku, "TC-1800MKII") to cure the above. The tristimulus Y values of the body (background colors black and white) were measured. The contrast ratio (Y _b /Y _w ) was calculated based on the obtained Y value (Y _b ) for the black background and Y value (Y _w ) for the white background.

(6) Visual evaluation of colored light (interference light) Pastes of the dental curable compositions prepared in Examples and Comparative Examples were placed in a mold with a hole of 7 mmφ x 1 mm, and both sides were pressed together with a polyester film. After curing by irradiating both sides with visible light irradiator (manufactured by Tokuyama, Power Light) for 30 seconds each, remove from the mold, place on the adhesive side of black tape (carbon tape) about 10 mm square, and visually color it. I checked the color of the light.

(7) Spectral reflectance ratio (SR ₁ /SR ₂ on black background)
The pastes of the curable compositions prepared in the Examples and Comparative Examples were put into a mold having a through hole of 7 mmφ x 1 mm, and polyester films were pressed on both sides. After curing by irradiating both sides with visible light irradiator (manufactured by Tokuyama, Power Light) for 30 seconds each, remove from the mold and use a color difference meter (manufactured by Tokyo Denshoku, "TC-1800MKII") to cure the black background. Measure the spectral reflectance below, find the maximum value of reflectance in the yellow to red region (600-750 nm): SR ₁ and the maximum value of reflectance in the blue region (400-500 nm): SR ₂ , and calculate SR ₁ . The spectral reflectance ratio was calculated by dividing by _SR2 .

(8) Evaluation of colored light (interference light) based on spectral reflectance on a white background The paste of the curable composition prepared in the Examples and Comparative Examples was put into a mold with a through hole of 7 mmφ x 1 mm, and both sides were covered with polyester. The film was pressed. After curing by irradiating both sides with visible light irradiator (manufactured by Tokuyama, Power Light) for 30 seconds each, remove from the mold and use a color difference meter (manufactured by Tokyo Denshoku, ``TC-1800MKII'') to measure against a white background. The spectral reflectance was measured below.

(9) Bending strength The paste of the dental curable composition was filled into a stainless steel mold using a filling device, and pressed with polypropylene, using a visible light irradiator Powerlight (manufactured by Tokuyama). Light was irradiated from one side for 30 seconds x 3 times, changing the location so that the entire surface was exposed to light, and was placed in close contact with the polypropylene. Next, from the opposite side, the polypropylene was similarly brought into close contact with light irradiation for 30 seconds x 3 times to obtain a cured product. The cured product was prepared into a prismatic shape of 2×2×25 mm using #1500 water-resistant abrasive paper and used as a sample piece. The obtained test piece was mounted on a testing machine (manufactured by Shimadzu Corporation, Autograph AG5000D), and the three-point bending fracture strength was measured at a distance between fulcrums of 20 mm and a crosshead speed of 1 mm/min, and a load-deflection curve was obtained. Bending strength: σ _B (Pa) and bending modulus of elasticity: E _B (Pa) were determined using the formulas shown below. Note that 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 test piece fracture (N)
S: Distance between fulcrums (m)
W: Width of test piece (m)
B: Thickness of test piece (m)
F/Y: Slope of the straight part of the load-deflection curve (N/m).

(10) Evaluation of color tone compatibility Using a tooth restoration model tooth that reproduces the IV class cavity (width 3 mm, height 3 mm) shown in the upper right corner, the defect is filled with hardening paste, hardened and polished, and the color tone Compatibility was visually confirmed. In addition, the model teeth for tooth restoration are in the category of A series (reddish brown) in the shade guide "VITAPAN Classic", and there are two types: high hue and high chroma model teeth (equivalent to A4) and low hue and low chromaticity model teeth (equivalent to A4). A model tooth with low chroma (equivalent to A1) and a tooth model with high chroma (equivalent to B4) with high hue and saturation, which is in the category of B series (red-yellow) in the shade guide "VITAPAN Classic". A low chromaticity model tooth (equivalent to B1) with low hue and low saturation was used.
◎: The color tone of the restoration material matches well with the model tooth for tooth restoration.
○: The color tone of the restoration is similar to the tooth model for tooth restoration.
Δ: The color tone of the restoration is similar to that of the tooth restoration model, but the compatibility is not good.
×: The color tone of the restoration does not match the tooth model for tooth restoration.

Next, the abbreviations and substance names of polymerizable monomers, polymerization initiators, etc. used in Examples and Comparative Examples are shown below.
[Polymerizable monomer]
・UDMA: 1,6-bis(methacrylethyloxycarbonylamino)trimethylhexane ・3G: Triethylene glycol dimethacrylate ・bis-GMA: 2,2-bis[(3-methacryloyloxy-2-hydroxypropyloxy)phenyl] Propane [Polymerization initiator]
- CQ: Camphorquinone - DMBE: Ethyl N,N-dimethyl p-benzoate.
[Polymerization inhibitor]
- HQME: Hydroquinone monomethyl ether.

Polymerizable monomers as shown in Table 1 were mixed to prepare matrices M1 and M2.

[Inorganic spherical filler]
The inorganic spherical filler is prepared by the method described in JP-A-58-110414, JP-A-58-156524, etc., using a hydrolyzable organosilicon compound (such as tetraethyl silicate) and a hydrolyzable organotitanium. A mixed solution containing a group metal compound (tetrabutyl zirconate, tetrabutyl titanate, etc.) is added to an ammoniacal alcohol (e.g., methanol, ethanol, isopropyl alcohol, isobutyl alcohol, etc.) solution into which ammonia water has been introduced, It was prepared using a so-called sol-gel method in which a reaction product is precipitated by hydrolysis.

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

Examples 1 to 17
To 100 g of polymerizable monomer M1 or M2, 0.3% by mass of CQ, 1.0% by mass of DMBE, and 0.15% by mass of HQME are added and mixed to form a homogeneous polymerizable monomer. A composition was prepared. Next, measure each filler shown in Tables 2 and 3 into a mortar, gradually add the above polymerizable monomer composition under red light, and thoroughly knead in the dark to obtain a uniform mixture. It was made into a curable paste. Furthermore, this paste was degassed under reduced pressure to remove air bubbles to produce a dental curable composition. The physical properties of the obtained dental curable composition were evaluated based on the methods described above. 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 to 9
To 100 g of 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, measure each filler shown in Table 4 into a mortar, gradually add the above polymerizable monomer composition under red light, and thoroughly knead in a dark place to form a uniform hardening paste. And so. Furthermore, this paste was degassed under reduced pressure to remove air bubbles to produce a dental curable composition. The physical properties of the obtained dental curable composition were evaluated based on the methods described above. The composition and results are shown in Tables 4 and 5.

Comparative example 10
To 100 g of 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 out in a mortar, and the above polymerizable monomer composition was gradually added under red light. 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 form a uniform hardenable paste. Furthermore, this paste was degassed under reduced pressure to remove air bubbles to produce a dental composite restorative material. Visual evaluation showed that the color tone was compatible with the A-series of high-chromatic model teeth (equivalent to A4). Subsequently, each physical property was evaluated based on the above method. The composition and results are shown in Tables 4 and 5.

As understood from the results of Examples 1 to 17, when the conditions specified in the present invention are met, the dental curable composition exhibits 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 high bending strength is exhibited.

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

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

As shown in the results of Comparative Examples 4 to 8, when an amorphous filler was used without using a spherical filler, the dental curable composition did not show colored light under a black background; As shown in the results of 9, the average particle diameter 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. If the difference in refractive index from the obtained polymer is large, the color tone compatibility is poor.

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 compatible with the A series of high-chromatic model teeth (equivalent to A4)) was evaluated using a color difference meter ( When we measured the spectral reflectance with a black background and a white background using a TC-1800MKII (manufactured by Tokyo Denshoku Co., Ltd.), we found that both the black background and the white background showed spectral reflection characteristics depending on the added pigment. It was observed that Although the color compatibility of the high-chromatic model tooth with the color matching the A system (equivalent to A4) was relatively good, the color compatibility with other model teeth was low.

Claims (6)

Polymerizable monomer component (A), the average primary particle size is within the range of 100 nm or more and 1000 nm or less, and in the number-based particle size distribution, 90% or more of the total number of particles 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
The refractive index at 25° C. of the polymer obtained by polymerizing the polymerizable monomer component (A) is n _P , the refractive index at 25° C. of the inorganic spherical filler (B) is n _FB , and the amorphous When the refractive index at 25°C of the inorganic filler (C) is _nFC ,
n _FB > n _P , and 0.000≦n _FC −n _P ≦ 0.002,
For a cured product with a thickness of 1 mm, the Y stimulus values determined by tristimulus value measurement using a color difference meter with black and white backgrounds are Y _b (black background) and Y _w (white background), respectively. Providing a cured product having a contrast ratio defined by ratio: Y _b /Y _w of 0.3 to 0.7,
A dental curable composition characterized by: In the spectral reflectance curve under a black background measured using a color difference meter on a cured product with a thickness of 1 mm, the maximum value of spectral reflectance in the wavelength range of 600 nm or more and 750 nm or less: SR 1 is set as SR ₁ in the 400 nm or more and 500 nm or less To provide a cured product in which the spectral reflectance ratio: SR ₁ /SR ₂ defined as the value divided by the maximum value of spectral reflectance within the wavelength range: SR ₂ is in the range of 0.8 or more and 2.0 or less. The dental curable composition according to claim 1, characterized in that: The total amount of the inorganic spherical filler (B) and the amorphous inorganic filler (C) relative 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 amount contained is 100 parts by mass or more and 1500 parts by mass or less. The dental curable composition according to claim 1 or 2, wherein the proportion of the amorphous inorganic filler (C) in the dental curable composition is 5% or more and 30% or less. The dental curable composition according to any one of claims 1 to 3 , wherein the inorganic spherical filler (B) has an average primary particle diameter of 230 nm or more and 350 nm or less. A dental filling and restorative material for repairing class III cavities and/or class IV cavities, comprising the dental curable composition according to any one of claims 1 to 4 . A dental material for restoring class III cavities and/or class IV cavities, comprising a cured product of the dental curable composition according to any one of claims 1 to 4 .