Material kit for tooth restoration

Abstract

[Problem] To provide a material kit for tooth restoration that, when a cavity formed in a tooth that has been subjected to whitening treatment using a medicine is restored by a layered filling method using a plurality of kinds of polymerization-curable compositions (pastes), enables highly aesthetic restoration of a tooth to be restored having various whiteness. [Solution] A material kit for tooth restoration according to the present invention contains at least one upper layer paste and at least one lower layer paste. The composition and the amount of a colorant to be added to each paste are adjusted so that the transparency of a cured body of the upper layer paste falls within a certain relatively low range, the transparency of a cured body of the lower layer paste falls within a certain range lower than the transparency of the upper layer cured body, the lightness of a lower layer is higher than the lightness of an upper layer, and the value of the difference between the chroma of the lower layer cured body and the chroma of the upper layer cured body falls within a certain small range, thereby adjusting the lightness, chromaticity and chroma, and contrast ratio of the cured body of each paste fall within specific ranges.

Description

Tooth restoration material kit

[0001] The present invention relates to a tooth restoration material kit. More specifically, it relates to a tooth restoration material kit used for restoring cavities in teeth, and in particular for aesthetically restoring teeth that have become whiter than natural teeth due to treatments such as whitening.

[0002] Composite resin (sometimes abbreviated as "CR") is a paste-like, polymerizable dental composition containing polymerizable monomers, inorganic fillers made of inorganic powders and granules, and polymerization initiators as its main components. It is one of the most widely used materials in dental treatment for restoring tooth defects and cavities after the removal of caries. To accommodate the diverse color variations of the teeth being restored, CR is available in various shades, and typically, 16 shades, such as those represented by VITA's shade guide "VITAPAN Classical," or several shades selected from those, are available. The 16 shades mentioned above are comprised of five types with different saturations: A1, A2, A3, A3.5, A4 (reddish-brown hue), four types with different saturations: B1, B2, B3, B4 (reddish-yellow hue), four types with different saturations: C1, C2, C3, C4 (gray hue), and three types with different saturations: D2, D3, D4 (reddish-gray hue).

[0003] In restorations using composite resin (CR), if the damage or cavity of the tooth to be restored is very small, it is often restored by filling with a single type of CR (also called the single-layer restoration method). On the other hand, if the damage or cavity of the tooth to be restored is deep, or if a higher aesthetic level is desired, a layered restoration method is employed in which a lower layer of CR consisting of one or more shades corresponding to dentin and an upper layer of CR consisting of one or more shades corresponding to enamel are used in combination to reproduce the tooth structure consisting of dentin and enamel, and these are sequentially filled and hardened to form a layer, or sequentially filled and layered and then hardened (see Patent Document 1). In particular, in layered restorations of anterior teeth, brightness control is considered important, and a more aesthetically pleasing restoration is possible by improving the compatibility of the brightness of the restored tooth with the brightness of the adjacent teeth (Non-Patent Document 1). Thus, since brightness control is important in layered restorations of anterior teeth, kits containing CR with matching brightness are also known (see Patent Document 1).

[0004] Incidentally, in recent years, there has been a growing demand for teeth whitening treatments aimed at improving aesthetics. Three methods are known for teeth whitening: those using prosthetics, those using composite resin (CR), and those using medication. Teeth whitening treatments are often performed on the upper front teeth or on both the upper and lower front teeth.

[0005] The prosthetic method involves creating and attaching prostheses that are whiter than natural teeth. This method is expensive because it requires a large amount of tooth reduction and the creation of many prostheses. Furthermore, the skill of selecting appropriate materials is required to ensure the aesthetic finish (Non-Patent Literature 2). The composite resin (CR) method involves covering the tooth surface with CR that is whiter than the original natural tooth, using a technique (direct veneer method) (Non-Patent Literature 1) to thinly fill the surface layer of the tooth with CR. This method makes it possible to avoid cutting the natural tooth, or to cut only a small amount, and is often less expensive than the prosthetic method. This method is also often performed using a layered filling method, but if the original tooth structure is dark (low brightness, high saturation), it is necessary to fill it with CR as a base to increase the brightness and reduce the saturation of the original tooth structure, which can result in a thick filling layer and a large, unnatural change in tooth morphology. Both the prosthetic method and the CR method are effective in improving the aesthetics of teeth that are difficult to whiten with (chemical) whitening (discolored teeth). On the other hand, while prosthetic materials and composite resins are usually available in multiple shades, currently only one or two shades whiter than natural teeth are available. As a result, there are cases where the teeth do not achieve the desired level of whiteness for the patient, or become too white.

[0006] One example of a chemical method involves applying a chemical containing a peroxide, such as hydrogen peroxide, to the tooth surface and activating the chemical with heat or light to bleach the teeth. This method is generally known as (narrowly defined) whitening (or bleaching) (Patent Document 2). This method allows teeth to be whitened without damaging natural teeth and is relatively cheaper than the aforementioned methods. However, the whitening effect varies depending on the original natural tooth color and enamel thickness, so multiple treatments may be necessary. Also, because the teeth are bleached in stages, it is easier to achieve the level of whiteness desired by the patient.

[0007] For these reasons, the demand for teeth whitening using peroxides is increasing, and consequently, there is a need for composite resins with colors suitable for restoring teeth after whitening (also called whitened teeth). For this reason, composite resins corresponding to so-called bleach shades, which are brighter and less saturated than the 16 shades used for normal natural teeth, and have an emphasized whiteness, are now being offered. Against this backdrop, in recent years, additional bleach shade guides have been released for VITA's shade guide "VITAPAN Classical," as well as a dedicated shade guide "VITA Bleachedguide 3D-MASTER" to facilitate matching the level of whitening desired by the patient. The bleach shades mentioned above are lighter than B1, the lightest shade in the "VITAPAN Classical" range, and come in three shades in order of increasing saturation: 0M1, 0M2, and 0M3.

[0008] Japanese Patent Publication No. 5436723, Japanese Unexamined Patent Publication No. 2009-062397, International Publication No. 2024 / 190027, Japanese Unexamined Patent Publication No. 2025-73716

[0009] Miyazaki, Masashi, "Improving the Efficiency of Composite Resin Restorations: Achieving Aesthetics in a Short Time, Without Waste, and Without Mistakes!" Ishiyaku Publishers, April 10, 2020, pp. 42-44, pp. 116-119. Kohama, Tadakazu, "Rules for Anterior Aesthetic Treatment: Understanding the Criteria and Steps for Success," Interaction Co., Ltd., March 28, 2022, pp. 32-37.

[0010] Even when performing filling treatment on teeth that have undergone whitening and have deep cavities, a layered filling method is employed to achieve a high level of aesthetic restoration. However, in reality, dentists and other users perform layered filling by combining bleach shade composite resins that are available to them, or by combining a bleach shade composite resin with a composite resin of another available shade. It has been found that this method makes it difficult to aesthetically reproduce the subtle differences in color tone of teeth that have undergone whitening from patient to patient (see Comparative Examples 1 and 2 described below).

[0011] Therefore, an object of the present invention is to provide a dental restorative material kit consisting of a combination of a lower layer CR and an upper layer CR that facilitates matching of the color tone to the tooth to be restored and harmonization of the color tone with adjacent teeth in the restoration of whitening teeth by the layered filling method.

[0012] The present invention solves the above problem, and an embodiment of the present invention is a dental restorative material kit comprising at least one polymerizable curable composition for an upper layer and at least one polymerizable curable composition for a lower layer. Both the upper-layer polymerizable curable composition and the lower-layer polymerizable curable composition contain a polymerizable monomer component, an inorganic powder, a polymerization initiator, and a colorant. A cured product of the upper-layer polymerizable curable composition has a contrast ratio within a range of 0.55 or more and less than 0.70, and has a lightness L ＊ is within the range of 62.5 or more and less than 74.0. A cured product of the lower-layer polymerizable curable composition has a contrast ratio within a range of 0.70 or more and 0.80 or less, and has a lightness L ＊ is within the range of 74.0 or more and 80.0 or less. The cured products of the upper-layer polymerizable curable composition and the lower-layer polymerizable curable composition have chromaticity a ＊ is within the range of -4.0 or more and 1.0 or less, and chromaticity b ＊ is within the range of -2.0 or more and 3.0 or less, and chroma C ＊ is within the range of 2.0 or more and 4.0 or less. Among the chroma C ＊ of cured products of all the included upper-layer polymerizable curable compositions and lower-layer polymerizable curable compositions, the maximum chroma C ＊ and the minimum chroma C ＊ has a difference of 1.5 or less. The contrast ratio of each cured product is the ratio of the Y value on a black background to the Y value on a white background in the XYZ color system, obtained by measuring the reflected light when auxiliary illuminant C is irradiated in the thickness direction onto a 1 mm-thick plate-shaped cured product under a black background and a white background using a spectrophotometer, respectively. The lightness L of each cured product ＊ , chromaticity a ＊ , and chromaticity b ＊This is a CIE Lab color system value obtained by measuring the reflected light when an auxiliary illuminant C is irradiated in the thickness direction onto a 3 mm thick plate-shaped hardened body using a spectrophotometer under a black background. The chrominance C of each hardened body is... ＊ The above chromaticity a ＊ and chromaticity b ＊ Using the formula { (a ＊ ) ２ + (b ＊ ) ２} １／２ This is the value obtained by [the method described].

[0013] In the above-described form of tooth restoration material kit (hereinafter also referred to as "the kit of the present invention"), it is preferable that the tooth restoration material kit is for filling and restoring cavities formed in teeth bleached with a peroxide-containing agent by a layered filling method.

[0014] According to the present invention, in the restoration of whitened teeth by the layered filling method, it is possible to reproduce whitened teeth that exhibit subtly different shades depending on the patient, and to achieve aesthetically harmonious restorations with the color of adjacent teeth.

[0015] 1. Overview of the Kit of the Present Invention The kit of the present invention, like conventional dental restoration material kits, comprises a plurality of polymerizable curable compositions that yield cured bodies of different shades. Here, each of the plurality of polymerizable curable compositions is a paste-like curable composition (hereinafter also referred to as "curable paste") containing polymerizable monomer components, inorganic fillers consisting of inorganic powders and granules, polymerization initiators, and colorants, and corresponds to CR for dental restoration. In conventional dental restoration material kits, each of the plurality of curable pastes contained in the kit is in the form of a product housed in a container, and these are set together. It is preferable that the kit of the present invention also takes such a form. That is, it is preferable that each of the plurality of polymerizable curable compositions is housed in a different container.

[0016] Conventional dental restorative materials generally focus on matching the hardened material's color to the 16 shades of the "VITA Classical" shade guide (manufactured by VITA Corporation), emphasizing differences in hue and saturation. Bleach shades are formulated to have a stronger whiteness in the hardened material, and using them can sometimes reproduce the color of whitened teeth in small cavities or single-layer fillings. However, as mentioned above, it is difficult to reproduce a wide range of whitened tooth shades in layered fillings such as those for deep cavities. For example, when using a bleach shade with a strong whiteness or high transparency to reproduce the enamel of whitened teeth as a hardened paste for the upper layer, the saturation of the restored tooth often becomes higher than that of the surrounding whitened teeth when layered.

[0017] To investigate the cause of high saturation, the inventors examined the color tones of hardened CR in various bleach shades of commercially available CR. In addition, considering layered filling restorations of whitened teeth with a strong white tint, they investigated (i) the color tones of hardened CR in white or highly transparent bleach shades, which are often used for upper layer formation with an emphasis on enamel texture; and (ii) the color tones of hardened CR in relatively strong bleach shades and relatively white (non-bleach shade) CR, which are often used for lower layer formation to correspond to dentin. Surprisingly, the results showed that the saturation of hardened CR in bleach shades was high. ＊ The variation is large, and in both the CR hardened bodies of the bleach shades for upper and lower layer formation, the chromium C is relatively high. ＊ It was confirmed that this is the case. Furthermore, it was confirmed that the phenomenon of the restored area having a higher saturation than the surrounding whitened teeth is often observed when the lower layer has high saturation and the upper layer has high transparency.

[0018] Based on these findings, we prepared upper and lower layer curable pastes with varying brightness, saturation, and contrast ratios of the hardened bodies. Using these, we performed layered fillings in deep cavities in artificial teeth with different shades depending on the degree of whitening. We found that good color harmony could be obtained by using upper and lower layer curable pastes that met the following conditions. Specifically, we found that when the transparency of the upper layer was set to a relatively low range, the transparency of the lower layer to be even lower than that of the upper layer, the brightness of the upper layer was set to a relatively high range, the brightness of the lower layer was set to be higher than that of the upper layer, and its saturation was adjusted to be similar to that of the upper layer, good color harmony could be obtained simply by selecting the shade taking for the upper layer bleach shade curable paste.

[0019] In other words, the present invention is a dental restoration material kit comprising a plurality of polymerizable curable compositions (curable pastes), each including at least one polymerizable curable composition (curable paste) for the upper layer and at least one polymerizable curable composition (curable paste) for the lower layer, characterized in that the plurality of curable pastes comprising this kit are specified from the viewpoint of the color tone of the cured body provided by these pastes. With such a kit of the present invention, by simply selecting one or more from at least one upper layer curable paste and at least one lower layer curable paste (stored in different containers), the restored tooth can be easily adapted to the color tone of a whitened tooth. Furthermore, as described above, the components of each curable paste are no different from the components of curable pastes used in conventional dental restoration material kits.

[0020] First, we will explain the components of the curable paste, including those that are not particularly different from conventional products. Next, we will explain the values ​​of various indicators such as chromaticity, which are characteristic features of the present invention, and then we will explain in detail the characteristic features of the kit of the present invention.

[0021] In this specification, unless otherwise specified, the notation "x to y" using numerical values ​​x and y means "greater than or equal to x and less than or equal to y". If a unit is attached only to the numerical value y in such notation, that unit shall also apply to the numerical value x. Furthermore, in this specification, the term "(meth)acrylic" means both "acrylic" and "methacrylic". Similarly, the term "(meth)acrylate" means both "acrylate" and "methacrylate", and the term "(meth)acryloyl" means both "acryloyl" and "methacryloyl".

[0022] 2. Components of the curable paste The multiple polymerizable compositions that constitute the kit of the present invention, namely the upper layer polymerizable composition and the lower layer polymerizable composition, each contain polymerizable monomer components, inorganic powders and granules, polymerization initiators, and colorants. These components are described below.

[0023] <Polymerizable Monomer Components> As polymerizable monomer components, polymerizable monomers such as radical polymerizable monomers and cationic polymerizable monomers used in conventional dental curable compositions can be used without particular limitation. In particular, it is preferable to use commonly used (meth)acrylic compounds, and from the viewpoint of providing appropriate moldability in the paste state before curing while suppressing dryness, it is especially preferable to use polyfunctional (meth)acrylic compounds that do not have acidic groups and hydroxyl groups, mixed with monofunctional (meth)acrylic compounds that do not have acidic groups and hydroxyl groups, hydroxyl group-containing (meth)acrylic compounds, etc., as needed.

[0024] Examples of polyfunctional (meth)acrylic compounds that do not have acidic or hydroxyl groups and are preferably used include methyl (meth)acrylate, ethyl (meth)acrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, and 1,6-bis(methacrylateethyloxycarbonylamino)trimethylhexane.

[0025] Examples of acidic group-containing (meth)acrylic compounds include (meth)acrylic acid, N-(meth)acryloyl-p-aminobenzoic acid, 2-(meth)acryloyloxybenzoic acid, 2-(meth)acryloyloxyethylphenylhydrogenphosphate, and 2-(meth)acryloyloxyethylphosphonic acid. Examples of hydroxyl group-containing (meth)acrylic compounds include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 2,2-bis[(3-methacryloyloxy-2-hydroxypropyloxy)phenyl]propane, and 2,2-bis[4-(4-methacryloyloxy)-3-hydroxybutoxyphenyl]propane.

[0026] <Inorganic Powders and Granules> Inorganic powders and granules used in the dental field as filling materials for composite resins can be used without limitation. Specifically, examples include amorphous silica, silica-zirconia, silica-titania, quartz, alumina, barium glass, zirconia, titania, lanthanides, colloidal silica, and ytterbium fluoride. Among these, it is preferable to use powders and granules made of silica-based composite oxides such as silica-zirconia and silica-titania, blended with inorganic powders and granules that function as X-ray contrast agents, such as ytterbium fluoride, as needed, because they improve mechanical strength.

[0027] The average primary particle diameter of these inorganic powders and granules is not particularly limited, and those with an average primary particle diameter of 0.01 μm to 100 μm, which are commonly used as dental materials, can be used as appropriate depending on the purpose. In the present invention, it is preferable to use spherical inorganic fillers with an average primary particle diameter of 100 to 500 nm as the inorganic filler, as this improves the surface smoothness of the resulting hardened body. The term "average primary particle diameter" refers to the average value obtained by taking a photograph of the particles with a scanning electron microscope, selecting 30 or more particles observed within the unit field of view of the photograph, and determining the particle diameter (maximum diameter) of each particle. Hereafter, when "average primary particle diameter" is mentioned in this specification, it refers to the average primary particle diameter measured by the same method.

[0028] Furthermore, the refractive index of the inorganic powder (for light at 25°C and a wavelength of 589 nm) is not particularly limited, and those in the range of 1.4 to 1.7, which are common in dental filling materials, can be used without restriction.

[0029] These inorganic powders and granules are preferably treated with surface treatment agents, such as silane coupling agents, to improve their compatibility with polymerizable monomers and enhance their mechanical strength and water resistance. The surface treatment method can be any known method, and suitable silane coupling agents include methyltrimethoxysilane, methyltriethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and hexamethyldisilazane.

[0030] Furthermore, these inorganic powders can also be used as organic-inorganic composite powders, which are composed of particles of an organic-inorganic composite material obtained by first adding polymerizable monomers to them to form a paste, then polymerizing and pulverizing it.

[0031] The amount of inorganic powder in each curable paste is preferably 200 to 1900 parts by mass, more preferably 300 to 900 parts by mass, per 100 parts by mass of polymerizable monomer components. It is used in an amount within this range and that does not adversely affect the desired color tone of the curable paste.

[0032] <Polymerization Initiator> As a polymerization initiator, photopolymerization initiators or chemical polymerization initiators used in direct dental fillings and restorations, which are often cured in the oral cavity, can be used without particular restriction. It is more preferable to use a photopolymerization initiator because it does not require mixing and is simpler.

[0033] Examples of photopolymerization initiators 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; benzophenones such as benzophenone, 4,4'-dimethylbenzophenone, and 4-methacryloxybenzophenone; α-diketones such as diacetyl, 2,3-pentadione benzyl, camphorquinone, 9,10-phenanthraquinone, and 9,10-anthraquinone; and 2,4-diethoxythioxanthone, 2- Examples include thioxanthone compounds such as chlorothioxanthone and methylthioxanthone; and bisacylphosphine oxides such as bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

[0034] Photopolymerization initiators are often used in combination with reducing agents. Examples of reducing agents include tertiary amines such as 2-(dimethylamino)ethyl methacrylate, 4-dimethylaminobenzoate ethyl, 4'-dimethylaminoacetophenone, and N-methyldiethanolamine; aldehydes such as lauryl aldehyde, dimethylaminobenzaldehyde, and terephthalaldehyde; and sulfur-containing compounds such as 2-mercaptobenzoxazole, 1-decanethiol, thiosalicylic acid, and thiobenzoic acid.

[0035] Furthermore, in addition to the photopolymerization initiator and reducing agent, a photoacid generator may also be used. Examples of such photoacid generators include diaryliodonium salt compounds, sulfonium salt compounds, sulfonic acid ester compounds, halomethyl-substituted S-triazine derivatives, and pyridinium salt compounds.

[0036] The amount of polymerization initiator in each curable paste can be selected according to the purpose, but it is usually 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass, per 100 parts by mass of polymerizable monomer components.

[0037] <Colorants> The color tone of the cured body of each curable paste is adjusted by finally incorporating a colorant. Examples of colorants used include pigments and dyes, but the use of pigments is preferred.

[0038] Suitable pigments include white pigments such as titanium dioxide, zinc oxide, and zirconium oxide; red pigments such as red iron oxide, molybdenum red, and chromophthalate red; yellow pigments such as yellow iron oxide, titanium yellow, chromium oxide, and chromophthalate yellow; blue pigments such as cobalt blue, ultramarine, Prussian blue, chromophthalate blue, and phthalocyanine blue; and black pigments such as black iron oxide and carbon black.

[0039] By combining several of these colorants and adjusting the respective proportions, the brightness L of the cured paste can be adjusted. ＊ , chromaticity a ＊ , chromaticity b ＊ The contrast ratio can be adjusted.

[0040] Generally, when using a pigment as a coloring agent, the total amount of the pigment is preferably 0.0005 to 0.3 parts by mass per 100 parts by mass of polymerizable monomer.

[0041] <Other Ingredients> Each curable paste may contain other additives such as polymerization inhibitors and ultraviolet absorbers, to the extent that they do not inhibit its effect. Natural teeth are fluorescent, and it is good practice to add a fluorescent agent to reproduce this fluorescence. The amount added should be determined so that the fluorescence when exposed to light with a wavelength of around 400 nm is comparable to that of natural teeth. When a fluorescent agent is added, the total amount is preferably 0.0005 to 0.01 parts by mass, and more preferably 0.001 to 0.005 parts by mass, per 100 parts by mass of polymerizable monomer components.

[0042] 3. Regarding the values ​​of various indicators related to color tone, in the kit of the present invention, the lightness L in the CIE Lab color system of the curable paste cured body is... ＊ , chromaticity a ＊ , chromaticity b ＊ , and saturation C ＊ The curable paste is identified by the contrast ratio, which is defined as the ratio of the Y values ​​of a black background and a white background in the XYZ color system. This is because, although the appearance color of the cured paste is basically determined by the composition and amount of various colorants blended into the curable paste, it is also affected by the type and composition of polymerizable monomer components, the type and blending ratio of inorganic powders and granules, etc., making it practically impossible to highly specify the color of the cured paste obtained by the raw materials and composition of the cured paste. Furthermore, the appearance color of the cured paste is affected not only by the color of the cured paste itself, but also by transparency, ambient colors such as the substrate, and the thickness of the cured paste. Therefore, in this invention, the curable paste is identified using the values ​​of various indicators measured under the measurement conditions described below.

[0043] <chromaticity a ＊ , chromaticity b ＊ , brightness L ＊ and saturation C ＊ > Chromaticity a ＊ and chromaticity b ＊ This is an index that represents hue, and lightness L ＊a is a measure of brightness, and each is a value measured according to the provisions of JIS Z8729. Specifically, using a spectrophotometer (e.g., a colorimeter), an auxiliary illuminant C is irradiated along the thickness direction of a plate-shaped sample (hardened body) with a thickness of 3 mm (preferably 3.0 ± 0.1 mm, particularly preferably 3.00 ± 0.02 mm) under black background conditions, and the reflected light is measured, and the a is expressed in the CIE Lab color system. ＊ value, b ＊ Value and L ＊ Read the value. a ＊ and b ＊ The symbol indicates the direction of the color, a ＊ The red direction, -a ＊ The direction is green, b ＊ Yellow direction, -b ＊ The blue direction is indicated. Also, a larger number indicates a stronger color. On the other hand, L ＊ The value closer to 100 indicates brightness, and the value closer to 0 indicates darkness. In other words, it represents the brightness L of each cured material. ＊ , chromaticity a ＊ , and chromaticity b ＊ This value is obtained by measuring the reflected light when an auxiliary illuminant C is irradiated in the thickness direction onto a 3 mm thick plate-shaped hardened body using a spectrophotometer under a black background, and is in the CIE Lab color system.

[0044] Saturation C ＊ This is a scale that represents vividness, and the above chromaticity a ＊ , b ＊ Based on this, formula: C ＊ = {(a ＊ ) ２ + (b ＊ ) ２} １／２ It can be obtained from C. ＊ The higher the value, the more vivid it is. ＊ A lower value indicates that the color is closer to achromatic (white or black).

[0045] <Contrast ratio Y ｂ / Y ｗ > Contrast ratio Y ｂ / Y ｗThis is a measure of transparency. It is calculated using the Y value, which relates to brightness, from the tristimulus values ​​of the XYZ color system specified in JIS Z8729. Specifically, a plate-shaped sample (hardened body) with a thickness of 1 mm (preferably 1.00 ± 0.02 mm) is set in a spectrophotometer (e.g., a colorimeter) with a black or white background in contact with its back surface. An auxiliary illuminant C is shone from the surface along the thickness direction of the plate-shaped sample as standard light C, and the Y value of the reflected light is measured. Y value in the case of a black background: Y ｂ Y value when the background is white: Y ｗ The ratio of the two obtained from this: Y ｂ / Y ｗ This represents the contrast ratio. A contrast ratio closer to 1 means it is opaque, and a contrast ratio closer to 0 means it is transparent. That is, the contrast ratio Y of each cured material. ｂ / Y ｗ This is the ratio of the Y value on a black background to the Y value on a white background in the XYZ color system, obtained by measuring the reflected light when an auxiliary illuminant C is irradiated in the thickness direction of a 1 mm thick plate-shaped hardened body, using a spectrophotometer under a black background and a white background, respectively.

[0046] <Relationship between the color tone of curable paste and the color tone of cured product> Generally, the refractive index of monomer components in curable paste changes upon polymerization and curing. Therefore, the difference in refractive index between the inorganic powder and matrix (the monomer or the resin which is the cured monomer) changes before and after curing, which alters the internal light scattering state. As a result, the values ​​of various indexes related to color tone will differ when measuring reflected light. However, the color tone of the cured product is uniquely determined by the composition of the curable paste.

[0047] Therefore, in order to adjust the various index values ​​related to the color tone of the curable paste (and its cured form) to the desired values, one should measure the various index values ​​of the cured form each time while making fine adjustments to the composition and amount of colorant, based on the color tone of the curable paste (before curing). In order to understand the relationship between the curable paste composition and the various index values ​​of the cured form in advance, the composition and amount of colorant should be determined based on that relationship.

[0048] 3. Regarding the multiple curable compositions (curable pastes) constituting the kit of the present invention, the kit of the present invention includes, similar to conventional dental restoration material kits used in the layered filling method, an upper layer curable paste used to form the uppermost layer, and a lower layer curable paste for forming a lower layer consisting of a single layer or a laminate that serves as the base. Furthermore, since the intended use is the restoration of whitened teeth by the layered filling method, each curable paste is a so-called bleach shade. As described above, in the kit of the present invention, the upper layer curable paste is made to have a whiteness corresponding to the bleach shade while having relatively low transparency, and the lower layer curable paste is made to have lower transparency than the upper layer and is adjusted to reduce the difference in saturation with the upper layer (cured body). As a result, when used for the restoration of whitened teeth by the layered filling method, it is possible to reproduce whitened teeth that exhibit subtly different shades depending on the patient, and to achieve aesthetically harmonious restoration with the color tone of adjacent teeth.

[0049] In other words, the kit of the present invention comprises at least one curable paste for the upper layer and at least one curable paste for the lower layer, and these multiple curable pastes satisfy the conditions shown in (1) to (3) below. In the conditions below, based on the fact that the color tone of the cured body is uniquely determined by the composition of the curable paste, (for the sake of simplicity of explanation,) various indices relating to the color tone of the cured body according to the above definition are referred to as various indices of the curable paste, for example, the chromaticity a of the curable paste. ＊ (or chromaticity b) ＊ , brightness L ＊ or saturation C ＊ It is expressed as follows:

[0050] (1) The curable paste for the upper layer is 0.55 ≤ Y ｂ / Y ｗ The relationship <0.70 is satisfied, and the curable paste for the lower layer is 0.70 ≤ Y ｂ / Y ｗ It satisfies the relationship ≤ 0.80.

[0051] (2) The hardening paste for the upper layer is 62.5 ≤ L ＊The relationship <74.0 is satisfied, and the curable paste for the lower layer is 74.0 ≤ L ＊ It satisfies the relationship ≤ 80.0.

[0052] (3) All of the upper layer curable paste and lower layer curable paste satisfy all of the following relationships 1) to 4): 1) -4.0 ≤ a ＊ ≤ 1.0 2) -2.0 ≤ b ＊ ≤3.0 3) 2.0 ≤C ＊ ≤4.0 4) C in the fully curable paste ＊ The difference between the maximum and minimum values ​​is within 1.5. That is, the chrominance C of the cured products of all the polymerizable compositions for the upper layer and the lower layer is within 1.5. ＊ The highest saturation C ＊ The minimum saturation C ＊ The difference is within 1.5.

[0053] Regarding the number of upper and lower hardening pastes that make up the kit of the present invention, the kit of the present invention only needs to have at least one upper hardening paste and at least one lower hardening paste, but from the viewpoint of being able to accommodate the diversity of shades of the whitened teeth to be restored, it is preferable to include 1 to 3 upper hardening pastes and 1 to 3 lower hardening pastes. Furthermore, from the viewpoint of improving the efficiency of shade taking for the lower hardening paste, it is more preferable to include 1 or 2 lower hardening pastes. Note that it is not necessary to prepare many shades for the lower hardening paste, and aesthetic restoration is possible even with just one type by matching the shade of the upper hardening paste with the whitened tooth.

[0054] Regarding the above condition (1), when the contrast ratio of the curable paste for the upper layer is less than 0.55, the high transparency causes the paste to appear dark under the influence of the intraoral background, which may make it difficult to match the color tone of whitened teeth; when the contrast ratio is 0.70 or more, the transparency characteristic of enamel cannot be reproduced, making it difficult to confirm the characteristic structure of the underlying dentin. In addition, when the contrast ratio of the curable paste for the lower layer is less than 0.70, it cannot be distinguished from enamel, making it difficult to confirm the characteristic structure of dentin; when the contrast ratio exceeds 0.80, it is too opaque compared to natural dentin, making it difficult to achieve a natural restoration. For the reason that it can accommodate the color tone of whitened teeth and enable a restoration in which the characteristic structure of dentin is reproduced by layered filling, the contrast ratio of the curable paste for the upper layer satisfies 0.60≦Y ｂ / Y ｗ <0.70 is preferable, and the contrast ratio of the curable paste for the lower layer satisfies 0.70≦Y ｂ / Y ｗ ≦0.78 is preferable.

[0055] Regarding the above condition (2), when the lightness L ＊ of the contained curable paste is less than 62.5, the restoration site becomes darker relative to the color tone of whitened teeth when the curable paste is used, making it difficult to obtain good color matching. Conversely, when the lightness L ＊ of the contained curable paste exceeds 80.0, the restoration site becomes unnaturally white relative to the color tone of whitened teeth when the curable paste is used, making it difficult to achieve color matching. In the kit of the present invention, for the reason that the reproduction of the characteristic structure of dentin during layered filling is improved, the lightness of the curable paste for the upper layer is set to 62.5≦L ＊ <74.0, and the lightness of the curable paste for the lower layer is set to 74.0≦L ＊ ≦80.0.

[0056] Regarding 1) to 3) of the above condition (3), a ＊ = curable pastes outside the range of -4.0 to 1.0, or b ＊ = curable pastes outside the range of -2.0 to 3.0, have difficulty matching the color tone of whitened teeth. Specifically, when a ＊ is less than -4.0, the green tone is too strong, and when a＊ When it exceeds 1.0, the redness is strong, b ＊ When it is less than -2.0, the blue tint is strong, b ＊ When it exceeds 3.0, the yellow color becomes stronger. Also, a * When C is less than -4.0, ＊ This makes it difficult to obtain a cured product with a saturation of 2.0 to 4.0. Furthermore, if a curable paste with a saturation of less than 2.0 is included, the filled area will appear unnaturally white and stand out when the paste is used, and if it exceeds 4.0, the vividness of the hue will be noticeable, making it difficult to perceive whiteness.

[0057] Regarding condition (3) 4) above, even if conditions 1) to 3) are satisfied, the saturation C of multiple curable pastes ＊ If the difference between the maximum and minimum values ​​exceeds 1.5, that is, saturation C ＊ When using a combination of upper and lower hardening pastes with a difference of more than 1.5, the saturation contrast effect can make the saturation appear higher or lower than the actual saturation of the hardening paste, making shade taking difficult or creating a gap where the hue of the dentin or enamel restoration appears more vivid and saturated than it actually is. To facilitate shade taking and prevent a gap in color tone after restoration, saturation C ＊ The difference between the maximum and minimum values ​​is preferably within 1.3, and more preferably within 1.0. As described above, in each combination of upper and lower layer curable pastes (between upper layers, between lower layers, and between upper and lower layers), the saturation C of the cured body is ＊ The difference between them is preferably within 1.5, more preferably within 1.3, and more preferably within 1.0.

[0058] As mentioned above, various index values ​​related to the color tone of the curable paste (or its cured form) can be controlled by the composition of the colorant. For example, if the composition of components other than the colorant is the same, the lightness L can be increased by adding a white colorant. ＊ The value can be increased by incorporating red and blue colorants. ＊It can be made lower. Similarly, chromaticity a, which represents the chromaticity from green to red. ＊ The positive value can be increased by adding a red coloring agent, and the negative value can be increased by adding a coloring agent with a strong green tint, i.e., a combination of yellow and blue coloring agents. Also, chromaticity b represents the chromaticity from blue to yellow. ＊ The positive value can be increased by adding a yellow coloring agent, and the negative value can be increased by adding a blue coloring agent. Saturation C ＊ As is clear from its definition formula, this can be controlled by controlling the values ​​of both chromaticity. Furthermore, the contrast ratio can be increased by incorporating white and red colorants, and decreased by reducing the amounts of white and red colorants.

[0059] 4. Regarding the form and use of the kit of the present invention, as described above, each of the multiple curable pastes included in the kit of the present invention is usually in the form of a product contained in a container. As a container for containing the curable paste, a syringe-type container is preferable from the viewpoint of convenience during use and reduction of the risk of foreign matter contamination. As a syringe-type container, depending on the viscosity of the curable paste, etc., 1) a syringe-type container equipped with a syringe body, a nut member, a screw member, an extrusion member and a closure member (see Patent Document 3); 2) a syringe-type container having a cylindrical barrel with a nozzle at the tip to which a needle tip can be attached, a cap detachably attached to the nozzle to seal the nozzle, or a needle tip attached to the nozzle and a cap detachably attached to the tip region of the needle of the needle tip to seal the needle, and a plunger having a gasket at the tip and an operating part at the rear end, wherein a fluid containment space is formed in the barrel on the tip side of the gasket by slidably inserting the gasket from the rear end of the barrel (see Patent Document 4); etc. can be used as appropriate. Furthermore, in the kit of the present invention, the brightness L ＊ The more curable the paste, the higher the contrast ratio (lower transparency) and the lighter the L ＊The curable paste with a lower contrast ratio is controlled to have a lower contrast ratio (higher transparency). Therefore, in layered filling, where a paste with a higher contrast ratio is used as the lower layer to restore the dentin portion and a paste with a lower contrast ratio is used as the upper layer to restore the enamel portion, the tooth structure can be well reproduced by controlling the thickness of each layered curable paste according to the shade of the whitened tooth being restored. Accordingly, the kit of the present invention can be suitably used as a kit for filling and restoring cavities formed in teeth bleached with a peroxide-containing agent using the layered filling method. The kit of the present invention can be used on its own, but curable pastes not included in the kit of the present invention can also be used in combination as upper or lower layer curable pastes, as long as they satisfy the conditions of the present invention. For example, when restoring a whitened tooth that is difficult to match with the upper layer curable paste included in the kit of the present invention, it is also possible to use a commercially available CR that has a shade that matches the whitened tooth and satisfies the conditions that the upper layer curable paste in the kit of the present invention must satisfy, in combination with the lower layer curable paste in the kit of the present invention.

[0060] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0061] First, we will explain the substances used as raw materials for the compositions prepared in the examples and comparative examples, their abbreviations, and the methods for evaluating the above raw materials and the prepared compositions.

[0062] 1. Raw materials and their abbreviations / codes (1) Polymerizable monomers: bis-GMA: 2,2-bis[(3-methacryloyloxy-2-hydroxypropyloxy)phenyl]propane; 3G: triethylene glycol dimethacrylate.

[0063] (2) Polymerization initiators: CQ: Camphorquinone, DMBE: 4-dimethylaminobenzoate ethyl, DMA: 4'-dimethylaminoacetophenone, MDEOA: N-methyldiethanolamine, DPIC: Diphenyliodonium-2-carboxylate monohydrate, TAZ: 2,4,6-tris(trichloromethyl)-1,3,5-triazine

[0064] (3) Inorganic powders and organic inorganic powders (fillers) - Spherical silica zirconia filler: Average particle size of primary particles 0.2 μm, γ-methacryloyloxypropyltrimethoxysilane surface treated product - Organic inorganic composite filler: Prepared by the following method. 15 parts by mass of bis-GMA and 10 parts by mass of 3G were mixed. 0.5% by mass of a polymerization initiator (azobisisobutyronitrile) was dissolved in this mixture. Next, 75 parts by mass of spherical silica zirconia filler was added and mixed to obtain a paste. This paste was polymerized and cured by heating at 95°C for one hour under nitrogen pressure (0.5 MPa) atmosphere. The obtained cured body was pulverized using a vibrating ball mill. 0.02% by mass of γ-methacryloyloxypropyltrimethoxysilane was added to the pulverized cured body, and the mixture was reduced in ethanol at 90°C for 5 hours to perform surface treatment. This resulted in obtaining an organic-inorganic composite filler with an average particle size of 30 μm.

[0065] (4) Colorants: White pigment: Titanium dioxide; Yellow pigment: Pigment yellow; Red pigment: Pigment red; Blue pigment: Pigment blue

[0066] (5) Other ingredients / fluorescent agent: Diethyl 2,5-dihydroxyterephthalate

[0067] 2. Evaluation Methods The physical properties and evaluations described in the examples and comparative examples were measured by the following methods.

[0068] (1) A polyacetal mold with a thickness of 1 mm or 3 mm and a through hole with a diameter of 7 mm was filled with a curable paste, and both sides were pressed together with polyester film. Both sides were irradiated with visible light (Tokuyama Powerlight) for 10 seconds each to cure, and then the cured body was removed from the mold. The obtained cured body was color-measured using a colorimeter (Nippon Denshoku Industries Ltd., SE7700) with auxiliary illuminant C under black background conditions and white background conditions. From the color measurement results of the 1 mm cured body, the Y value in the XYZ color system was determined, and the Y value under a white background (Y ｗ ) Y value under a black background (Y ｂ ) ratio (Y ｂ / Y ｗ A contrast ratio defined as ) was obtained. From the color measurement results of the 3 mm hardened material, the lightness L expressed in the CIE Lab color system was obtained. ＊ Value, chromaticity a ＊ and chromaticity b ＊ , and chromaticity a ＊ and chromaticity b ＊ The required saturation C ＊ The value was obtained.

[0069] (2) Visual evaluation of color match during tooth restoration A Class IV cavity (width 3 mm, height 5 mm, depth 4 mm) was reproduced on the distal side of the upper left incisor (1) of VITA's hard resin tooth "VITA EXCELL Anteria" T51 in bleach shades (0M1 shade, 0M2 shade, 0M3 shade, 0M1 being the whitest) and used for evaluation. The artificial tooth prepared in the cavity was restored using the layered filling method, and the color match was visually confirmed. Criteria for visual evaluation of color match: A+: The color of the restored area matches the color of the restoration well. A: The color of the restored area matches the color of the restoration. B: The color of the restored area is close to the color of the restoration. C: The color of the restored area does not match the color of the restoration.

[0070] Example 1 A dental restoration material kit K1 consisting of three types of curable pastes K1-1, K1-2, and K1-3, whose various physical properties related to color tone are within the scope of the present invention, was manufactured by the method described below. K1-1 and K1-2 are curable pastes for the upper layer, and K1-3 is a curable paste for the lower layer.

[0071] First, a polymerizable substrate paste was prepared. The polymerizable substrate paste was prepared by blending polymerizable monomers (10.80 parts by mass of bis-GMA and 7.20 parts by mass of 3G), polymerization initiators (0.04 parts by mass of CQ, 0.04 parts by mass of DMBE, 0.02 parts by mass of MDEOA, and 0.02 parts by mass of TAZ), fillers (32.80 parts by mass of spherical silica-zirconia filler and 49.20 parts by mass of organic-inorganic composite filler), and other components (0.002 parts by mass of fluorescent agent per 100 parts by mass of polymerizable monomer components). Next, a coloring agent was added to the polymerizable substrate paste prepared by the above method to color it. The color tone and contrast ratio of each curable paste prepared are shown in Table 1. Note that "ΔC" in Table 1 refers to... ＊ "This refers to the saturation C of the cured body in all combinations of the upper layer curable paste and lower layer curable paste for each kit (between upper layers, between lower layers, and between upper and lower layers). ＊ The maximum value (absolute value) of the difference is shown. Table 2 also shows the type and amount of colorant blended into each curable paste (parts by mass per 100 parts by mass of polymerizable base paste).

[0072] Using the manufactured dental restoration material kit K1, we restored Grade IV cavities with three types of bleach-shade artificial teeth. We selected a hardening paste from the kit to match the color of each artificial tooth, and performed layered filling with lower and upper layers of paste, adjusting the thickness and shape of the filling. For each layered filling, we used a dental light curing unit to light-cure each layer before applying the next layer.

[0073] After filling, the color matching of the restored area and the reproducibility of the tooth structure were visually evaluated. The results are shown in Table 3. Paste saturation C ＊ Because the difference in values ​​was small, the saturation did not increase when layered filling was performed, and it was possible to perform restorations that matched the color tone of bleached-shade artificial teeth.

[0074]

[0075]

[0076]

[0077] Example 2 A tooth restoration material kit K2 was manufactured in the same manner as in Example 1, except that the polymerization initiator (0.04 parts by mass of CQ, 0.03 parts by mass of DMA, 0.04 parts by mass of MDEOA, and 0.08 parts by mass of DPIC) was changed, and the colorant formulation was changed as shown in Table 2. The kit consisted of four types of curable pastes K2-1, K2-2, K2-3, and K2-4, in which various physical properties related to color tone were within the scope of the present invention. Using the tooth restoration material kit K2, restoration of artificial teeth by layered filling and its visual evaluation were performed. The color tone and contrast ratio of each curable paste are shown in Table 1, and the results of artificial tooth restoration are shown in Table 3. Curable pastes K2-1 and K2-2 are curable pastes for the upper layer, and curable pastes K2-3 and K2-4 are curable pastes for the lower layer.

[0078] Paste saturation C ＊ Because the difference in values ​​was small, the saturation did not increase when layered filling was performed, and it was possible to perform restorations that matched the color tone of bleached-shade artificial teeth. In addition, because there were more shades than in Kit K1, the reproduction of the color tone of each bleached-shade artificial tooth was better.

[0079] Comparative Example 1 A commercially available dental restoration material kit (Esterite Asteria, manufactured by Tokuyama Dental) containing bleach shade CR was used to restore a Class IV cavity in an artificial tooth in the same manner as in Example 1. The kit includes two types of bleach shade CR: a lower layer CR and a relatively white upper layer CR, both of which were used. The color tone and contrast ratio of each curable paste are shown in Table 1. The various physical properties related to the color tone of the upper layer CR, curable paste S1-1, are as follows: Lightness L ＊ , chromaticity b ＊ , saturation C ＊ Contrast ratio Y ｂ / Y ｗ This deviated from the scope of the present invention. Various physical properties relating to the color tone of the curable paste S1-2, which is the lower layer CR, are chromatic b ＊ , saturation C ＊ Contrast ratio Y ｂ / Y ｗ This deviated from the scope of the present invention.

[0080] The results of artificial tooth restorations using these composite resins are shown in Table 3. The layered filling increased the saturation of the filling site, resulting in a poor match with the bleach shade of the artificial tooth.

[0081] Comparative Example 2 A commercially available dental restorative material kit (WHITE DENTAL BEAUTY's "Professional Composite System") containing only bleach shade CR was used to restore a Class IV cavity in an artificial tooth in the same manner as in Example 1. The color tone and contrast ratio of each curable paste are shown in Table 1. Various physical properties related to the color tone of curable paste S2-1, which is the upper layer CR, are as follows: ＊ and Y ｂ / Y ｗ This deviated from the scope of the present invention. The various physical properties related to the color tone of the curable paste S2-2, which is the lower layer CR, were within the range of the lower layer paste of the present invention. However, for the other lower layer CR curable pastes S2-3 and S2-4, the chromaticity b ＊ and saturation C ＊ For the curable paste S2-5, the brightness is L ＊ , chromaticity b ＊ , saturation C ＊ This deviated from the scope of the present invention.

[0082] Table 3 shows the results of artificial tooth restorations using these composite resins. When hardening paste S2-1 was used for the upper layer and hardening paste S2-2 for the lower layer, the resulting color was close to the whitest 0M1 shade artificial tooth, but the brightness of hardening paste S2-1 was insufficient, resulting in a slightly darker color. In other cases, the saturation of the filled area increased due to the layered filling, making it difficult to match the color of the bleach shade artificial tooth, and thus aesthetic reproduction of the diverse shades of bleach within the kit was difficult.

[0083] Example 3 Kit K3 was used to repair a Class IV cavity in an artificial tooth. The curable pastes K2-1 and K2-2 contained in the kit K2 of the present invention, which was used in Example 2, were used as the upper layer, and the curable paste S2-2 contained in the commercially available kit S2, which was used in Comparative Example 2, was used as the lower layer. The results are shown in Table 3. As shown in the table, it was possible to repair artificial teeth with a color match that matched any bleach shade.

[0084] Comparative Example 3 Kit S3 was used to repair a Class IV cavity in an artificial tooth. Kit S3 used the commercially available kit S1 used in Comparative Example 1 as the upper layer, and the kit K1 of the present invention used in Example 1 as the lower layer. The results are shown in Table 3. As shown in the table, in all cases, the saturation of the filling area increased due to the layered filling, and a match with the bleach shade of the artificial tooth could not be obtained.

[0085] Comparative Example 4 Kit S4 was used to repair a Class IV cavity in an artificial tooth. The curable pastes K2-1 and K2-2 contained in Kit K2 of the present invention, which was used in Example 2 above, were used as the upper layer, and the curable pastes K2-3, K2-4, and K2-5 contained in the commercially available Kit S2 used in Comparative Example 1 were used as the lower layer. The results are shown in Table 3. As shown in the table, in all cases, the saturation of the filling area increased due to the layered filling, and a match with the color tone of the bleached artificial tooth could not be obtained.

Claims

1. A dental restoration material kit comprising at least one polymerizable curable composition for an upper layer and at least one polymerizable curable composition for a lower layer, wherein both the polymerizable curable composition for the upper layer and the polymerizable curable composition for the lower layer comprise a polymerizable monomer component, an inorganic powder, a polymerization initiator and a colorant, a cured product of the polymerizable curable composition for the upper layer has a contrast ratio within a range of 0.55 or more and less than 0.70, and a lightness L ＊ is within a range of 62.5 or more and less than 74.0, a cured product of the polymerizable curable composition for the lower layer has a contrast ratio within a range of 0.70 or more and 0.80 or less, and a lightness L ＊ is within a range of 74.0 or more and 80.0 or less, cured products of the polymerizable curable composition for the upper layer and the polymerizable curable composition for the lower layer have a chromaticity a ＊ within a range of -4.0 or more and 1.0 or less, a chromaticity b ＊ within a range of -2.0 or more and 3.0 or less, and a chroma C ＊ within a range of 2.0 or more and 4.0 or less, the difference between the maximum chroma C ＊ and the minimum chroma C ＊ among the chroma C ＊ of cured products of all of the included polymerizable curable composition for the upper layer and polymerizable curable composition for the lower layer is 1.5 or less, the contrast ratio of each cured product is a ratio of a Y value on a black background to a Y value on a white background in the XYZ color system, obtained by measuring reflected light when auxiliary illuminant C is irradiated in the thickness direction onto a plate-shaped cured product having a thickness of 1 mm under a black background and a white background, respectively, using a spectrophotometer, the lightness L ＊ , chromaticity a ＊ , and chromaticity b ＊ of each cured product are values in the CIE Lab color system, obtained by measuring reflected light when auxiliary illuminant C is irradiated in the thickness direction onto a plate-shaped cured product having a thickness of 3 mm under a black background using a spectrophotometer, the chroma C ＊ of each cured product is obtained using said chromaticity a ＊ and chromaticity b ＊ by the formula {(a ＊ ) ２ + (b ＊ ) ２} １／２ .

2. A dental restoration material kit according to claim 1, for filling and restoring cavities formed in teeth bleached with a peroxide-containing agent by a layered filling method.

Images