Dental cement preparation kit

Abstract

To provide a kit that can prepare dental cement having appropriate dripping and ejection properties even after long-term storage, even when using a general inorganic filler.SOLUTION: A dental cement preparation kit includes: the above first agent containing a predetermined amount of a first polymerizable monomer (A1), a first thickener (B1), a first inorganic filler (C1), and an organic peroxide (D); and the above second agent containing 100 pts.mass of a second polymerizable monomer (A2), and a predetermined amount of a second thickener (B2), a second inorganic filler (C2), a thiourea compound (E), and a copper compound (F). The M value indicating the hydrophobicity of the (A1) and (A2) is 14 to 18. The average particle size of the first and second inorganic fillers (C2) is 0.1 μm or more and 10 μm or less, and the MR color value (Δa*m) is more than 0 and less than 10. The average particle size of the first and second thickeners (B2) is 0.003 μm or more and less than 0.1 μm.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a kit for preparing dental cement.

Background Art

[0002] When bonding restorations such as inlays, onlays, laminate veneers, and crowns in dental treatment, dental resin cement (hereinafter simply referred to as "dental cement") is used. Dental cement generally contains a polymerizable monomer, a filler, and a chemical polymerization initiator. The chemical polymerization initiator contains an oxidizing agent and a reducing agent, and by bringing them into contact with each other and reacting during use, the hardening of the dental cement is advanced. For this reason, usually, they are stored in two packages so that they do not react with each other before use.

[0003] From the viewpoint of convenience that such dental cement can be kneaded and used in the required amounts when using the two packaged agents at the time of use, it is often provided in the form of a kit filled in a container called a so-called double syringe. The above container has a structure in which two syringes capable of extruding the contents from the nozzle by pushing a plunger are arranged in parallel and integrated, and further, the two plungers can be operated simultaneously. With a kneading tool called a mixing tip attached to the nozzle, by simultaneously pushing the two plungers, a mixture (kneaded paste) of the two agents can be extruded from the tip of the mixing tip.

[0004] When clinically using the above kit to bond dental cement to bond dentin and a crown restoration (prosthesis), an excess amount of dental cement (hereinafter also referred to as "excess cement") protruding from the joint between the dentin and the crown restoration, called the margin part, needs to be scraped off and removed using a dental short needle or the like.

[0005] Clinically, from the perspective of operability when packing after extruding the kneaded paste, it is desired that the "extrudability", which is evaluated by the pressure required to discharge the paste, is appropriate. Also, when removing excess cement, if the "flowability" evaluated by the flow distance (due to its own weight) when the kneaded paste is placed on a vertical surface and left standing is too high, the excess cement spreads over a wide area, making its removal difficult, or it becomes necessary to remove the excess cement before it drips and spreads, resulting in a shorter time for the removal operation and a higher difficulty level of the operation. Therefore, from the perspective of excess cement removability, it is also desired that the "flowability" evaluated by the flow distance due to the weight of the kneaded paste placed on a vertical surface is appropriate. To meet such requirements, in the above kit, for the two agents to be sub-packaged, it is common to adjust the type and blending amount of the inorganic filler or blend a thickener so that both the extrudability and the flowability are within an appropriate range.

[0006] By the way, as combinations of an oxidizing agent and a reducing agent used in a chemical polymerization initiator for dental cement, initiator systems composed of combinations of organic peroxides and amines, organic peroxides and borate compounds, and organic peroxides and transition metal compounds are known. Among them, an initiator system composed of a combination of a hydroperoxide (organic peroxide) and a thiourea compound exhibits excellent polymerization activity, has little discoloration of the paste, is excellent in aesthetics, and also has good storage stability.

[0007] Patent Document 1 discloses a two-paste type dental curable composition suitable for dental cement, which consists of a first and a second paste, each containing a hydroperoxide and a specific substituted cyclic thiourea compound.

[0008] In addition, Patent Document 2 discloses that in a self-adhesive dental curable composition used for dental cement, it is important that the paste properties change little even after long-term storage. By using a filler having a specific average particle size that has been subjected to a specific hydrophobization treatment as the inorganic filler, it is possible to suppress the change in paste properties over time. And as one specific example of a two-paste type dental composition using such a technique, a two-paste type dental composition using a chemical polymerization initiator composed of a combination of an organic peroxide (oxidizing agent) and a thiourea compound (reducing agent) is also disclosed.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0010] In the dental cement preparation kit including the two-paste type dental composition using a double syringe as described above, the fluidity of each paste before kneading is adjusted so as to have appropriate fluidity from immediately after kneading to pressing. However, as also pointed out in Patent Document 2, even when such adjustment is made, it is conceivable that the paste properties may change during the storage period. For such reasons, the present inventors examined the storage stability of a two-paste type dental composition using a thiourea compound as a reducing agent as disclosed in Patent Document 1. As a result, it became clear that when each paste was stored for a long period of time, the fluidity of the paste increased over time, the properties of the kneaded paste changed, and the "operability" and "dripping property" often deviated from the initial set range.

[0011] If the technology disclosed in Patent Document 2 is used, it is considered that the occurrence of the above problems can be suppressed. However, in that case, since it is necessary to perform a specific hydrophobization treatment on the inorganic filler, the process becomes numerous and complicated, and restrictions on the materials that can be used occur.

[0012] In view of the above circumstances, an object of the present invention is to perform surface treatment using a general silane coupling agent or the like that is used as a general-purpose surface treatment agent, such as an alkylalkoxysilane, without being restricted by the type of surface treatment agent, and to provide a hydrophobized inorganic filler. Even in the case of using, it is an object of the present invention to provide a kit capable of preparing a dental cement (kneaded paste) having appropriate sagging properties and extrudability after long-term storage.

Means for Solving the Problems

[0013] In order to achieve the above object, a kit for preparing a dental cement according to one embodiment of the present invention comprises a first agent and a second agent that are separately packaged, and is a kit for preparing a dental cement for preparing a dental cement by mixing both agents. The first agent contains 100 parts by mass of a first polymerizable monomer (A1) having an M value indicating a degree of hydrophobicity of 14 to 18, 3.5 to 5.5 parts by mass of a first thickener (B1) having an average particle diameter of 0.003 μm or more and less than 0.1 μm, and an average particle diameter of 0.1 μm or more and 10 μm or less. 181.5 to 295 parts by mass of a first inorganic filler (C1), and 0.5 to 10 parts by mass of an organic peroxide (D). The second agent contains 100 parts by mass of a second polymerizable monomer (A2) having the above M value of 14 to 18, 3.5 to 5.5 parts by mass of a second thickener (B2) having an average particle diameter of 0.003 μm or more and less than 0.1 μm, and an average particle diameter of 0.1 μm or more and 10 μm or less. 181.5 to 295 parts by mass of a second inorganic filler (C2), 0.5 to 2.5 parts by mass of a thiourea compound (E), and 0.001 to 0.05 parts by mass of a copper compound (F). The above M value represents the minimum value (parts by mass) of the content of methanol in a mixed solution consisting of 1 part by mass of the above first polymerizable monomer (A1) or the above second polymerizable monomer (A2), 2 parts by mass of water, and methanol, which becomes a homogeneous solution at 25°C. The change in color difference a of the above first inorganic filler (C1) and the above second inorganic filler (C2) before and after addition of methyl red, measured in anhydrous toluene * Δa * m is each greater than 0 and less than 10.

[0014] Each of the above first polymerizable monomer (A1) and the above second polymerizable monomer (A2) preferably consists of 0 mass% or more and less than 1 mass% of a polymerizable monomer having the above M value of 0 or more and less than 2, 35 to 55 mass% of a polymerizable monomer having the above M value of 2 or more and less than 15, and the balance of a polymerizable monomer having the above M value of 15 or more and less than 35.

[0015] Each of the above first inorganic filler (C1) and the above second inorganic filler (C2) is preferably silica-based composite oxide particles surface-treated with at least one surface treatment agent selected from vinyltriethoxysilane, vinyltrimethoxysilane, vinyl-tris(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, κ-methacryloyloxydodecyltrimethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, γ-glycidoxypropyl-trimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl-trimethoxysilane, γ-ureidopropyl-triethoxysilane, γ-chloropropyltrimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, and methyltriethoxysilane. [[Effect of the Invention]]

[0016] According to the present invention, even when using a hydrophobized inorganic filler treated with a general surface treatment agent without particularly using a special surface treatment agent, a kit for preparing a dental cement capable of maintaining appropriate sagging properties and discharge properties over a long period can be provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] 1. Overview of dental cement preparation kit As described above, it has become clear that in a two-paste type dental hardenable composition using a chemical polymerization initiator having excellent characteristics, such as a combination of an organic peroxide such as a hydroperoxide and a thiourea compound, as disclosed in Patent Document 1, when the individual components are stored for a long period of time and then kneaded to prepare a mixed paste (dental cement), the properties of the mixed paste change.

[0018] It is known that even in general hydrophobic inorganic fillers that have been treated with a surface treatment agent such as a general-purpose silane coupling agent such as alkylalkoxysilane, acid sites such as surface hydroxyl groups remain to a certain extent (see Patent Document 3). From this, the inventors presume that the cause of such a phenomenon is that the liquid components (components other than thickeners and inorganic fillers) in the paste containing a hydrophilic thiourea compound and the inorganic filler gradually become familiar with each other over time via the hydrophilic hydroxyl groups remaining on the surface of the inorganic filler, and when methyl red was dropped onto the hydrophobic inorganic filler according to the method described in Patent Document 3, the presence of hydroxyl groups was confirmed. Therefore, the inventors thought that if the hydrophobicity of the liquid components was increased, the change in fluidity over time could be suppressed, and further investigations were carried out.

[0019] As a result, with respect to the (one) paste (the second agent) containing the hydrophilic thiourea compound, by increasing the degree of hydrophobicity of the polymerizable monomer and keeping it within a certain range, the compatibility with the polymerizable monomer is moderately worsened, and it was confirmed that the increase in fluidity (dripping property) over time can be suppressed to some extent without reducing the ejection property. If the hydrophobicity of the polymerizable monomer is increased too much, in relation to the hydrophilic groups of the inorganic filler remaining even after the hydrophobization treatment, the compatibility with the polymerizable monomer becomes too poor and the ejection property deteriorates. Since the effect of suppressing the change in fluidity (dripping property) was not sufficient only by adjusting the hydrophobicity of the polymerizable monomer, when a small amount of a viscosity modifier (thickener) was blended within a range that does not adversely affect the ejection property, the expected effect was obtained. From this, by blending approximately the same amount of thickener also in the other paste (the first agent) containing an organic peroxide (not containing a thiourea compound) to make the fluidity (dripping property) of the two pastes uniform, a dental cement preparation kit capable of preparing a dental cement having appropriate dripping property and ejection property even when stored for a long time was successfully obtained.

[0020] Hereinafter, the dental cement preparation kit of the present invention will be described in detail, including points that are not particularly different from conventional products. However, the present invention is not limited to the following embodiments. In this specification, unless otherwise specified, the notation "x to y" using numerical values x and y means "x or more and y or less". In such notation, when a unit is attached only to the numerical value y, the unit is also applied to the numerical value x. Further, in this specification, the term "(meth)acrylic" means both "acrylic" and "methacrylic".

[0021] 2. Details of the dental cement preparation kit (1) Overall configuration In the dental cement preparation kit of the present invention, by mixing the first agent and the second agent, which are separately packaged and each contain an oxidizing agent and a reducing agent, radicals are generated by a redox reaction, and polymerization curing proceeds to obtain a dental cement. In the kit for preparing dental cement of the present invention, typically, using a dedicated instrument having a double syringe container filled with the first and second agents respectively, kneading of the first and second agents and extrusion from the syringe container are performed simultaneously to prepare dental cement.

[0022] The first agent of the present invention contains: 100 parts by mass of a first polymerizable monomer (A1) having an M value of 14 to 18; 3.5 to 5.5 parts by mass of a first thickener (B1) having an average particle diameter of 0.003 μm or more and less than 0.1 μm; 181.5 to 295 parts by mass of a first inorganic filler (C1) having an average particle diameter of 0.1 μm or more and 10 μm or less; and 0.5 to 10 parts by mass of an organic peroxide (D).

[0023] The second agent of the present invention contains: 100 parts by mass of a second polymerizable monomer (A2) having an M value of 14 to 18; 3.5 to 5.5 parts by mass of a second thickener (B2) having an average particle diameter of 0.003 μm or more and less than 0.1 μm; 181.5 to 295 parts by mass of a second inorganic filler (C2) having an average particle diameter of 0.1 μm or more and 10 μm or less; 0.5 to 2.5 parts by mass of a thiourea compound (E); and 0.001 to 0.05 parts by mass of a copper compound (F).

[0024] The M value of the present invention is an index indicating the degree of hydrophobicity. Specifically, the M value of the present invention represents the minimum value of the content (parts by mass) of methanol in a mixed solution consisting of 1 part by mass of the first polymerizable monomer (A1) or the second polymerizable monomer (A2), 2 parts by mass of water, and methanol, which becomes a homogeneous solution at 25°C. The higher the M value, the higher the hydrophobicity.

[0025] In the present invention, the change amount Δa * of the color difference a * m before and after adding methyl red to the above-mentioned first and second inorganic fillers (C2), measured in anhydrous toluene, is respectively more than 0 and less than 10. Δa * m is an index of the amount of hydrophilic groups (acid points) remaining on the surface of the inorganic filler. The change amount Δa * of the color difference a * mExceeding 0 and less than 10 means the range shown by a general inorganic filler subjected to ordinary hydrophobization treatment.

[0026] In the present invention, in the second agent, in order to balance the hydrophilicity and hydrophobicity of the second polymerizable monomer (A2), the second inorganic filler (C2), and the thiourea compound (E), the blending amounts of the respective components and the hydrophobicity degree of the second polymerizable monomer (A2) are adjusted. Thereby, in the second agent, a good paste property in which appropriate sagging property and discharge property are maintained over a long period can be obtained.

[0027] Here, since the first agent does not contain the hydrophilic thiourea compound (E), in the first agent, the change in the paste property over time is not as large as that of the second agent, but after long-term storage, the paste property changes more or less. For this reason, also in the first agent, from the viewpoint of maintaining appropriate sagging property and discharge property, the hydrophilicity and hydrophobicity of the first polymerizable monomer (A1) and the first inorganic filler (C1) are balanced, and the blending amounts of the respective components and the hydrophobicity degree of the first polymerizable monomer (A1) are adjusted.

[0028] Thus, in the dental cement preparation kit of the present invention, in both the first agent and the second agent, by adjusting the level of the hydrophobicity degree of the polymerizable monomer (A), a good paste property can be easily maintained over a long period. Hereinafter, the constitution and action of each component will be described.

[0029] (2) Details of each component (a) First and second polymerizable monomers (A1), (A2) The first and second polymerizable monomers (A1) and (A2) of the present invention may each be a single polymerizable monomer or a mixture of a plurality of polymerizable monomers. However, from the viewpoint of adjusting to a predetermined M value described later, it is preferably a mixture of two or more polymerizable monomers. Here, as the first and second polymerizable monomers (A1) and (A2) of the present invention, from the viewpoint of ease of handling and physical properties (mechanical properties and adhesiveness to dentin in dental applications) when used as a dental filling and restorative material, it is preferable to use a radical polymerizable monomer or a cationic polymerizable monomer. From the viewpoint of easy control of the polymerization rate, it is preferable to use a radical polymerizable monomer, particularly a (meth)acrylic-based polymerizable monomer.

[0030] The above-mentioned first polymerizable monomer (A1) and the above-mentioned second polymerizable monomer (A2) may have the same composition or different compositions, but from a practical viewpoint such as productivity, it is preferably the same composition.

[0031] In the present invention, the M values of the first and second polymerizable monomers (A1) and (A2) are each 14 to 18. When the M value is 14 or more and the degree of hydrophobicity is at a certain level or more, even when the second agent contains the hydrophilic thiourea compound (E), the compatibility with a general hydrophobic inorganic filler becomes moderately poor, so that the increase in sagging over time can be suppressed to a certain extent. Also, the sagging property does not change with time in the first agent, and the sagging property of the kneaded paste (dental cement) at the initial stage of kneading obtained by kneading the first agent and the second agent also becomes stable. Furthermore, when the M value is 18 or less and the degree of hydrophobicity is at a certain level or less, good dispersibility of the inorganic filler can be maintained in the first agent and the second agent, and deterioration of the dischargeability can be prevented. As a result, a stable paste property with appropriate sagging and dischargeability maintained over a long period can be obtained. From the viewpoint of obtaining such an effect, the M values of the first and second polymerizable monomers (A1) and (A2) are preferably 15 to 17.

[0032] The above M value can be measured by a method similar to the following titration method. That is, first, 1 part by mass of the polymerizable monomer to be measured for the M value and 2 parts by mass of water are mixed to obtain a mixed solution at a liquid temperature of 25°C. Next, in a constant temperature room at 25°C, methanol is dropped into the mixed solution under stirring. At this time, the dropping of methanol is carried out slowly so that the state of the mixed solution after the dropping of methanol can be confirmed (so that it can be determined whether it becomes a homogeneous solution or not), and it is carried out until the polymerizable monomer dissolves and becomes a homogeneous solution. Then, at this time, the total dropping amount (parts by mass) of the dropped methanol may be measured (or the parts by mass may be obtained by converting the dropping volume into mass). That value becomes the M value of the polymerizable monomer.

[0033] The M value of the first polymerizable monomer (A1) in the first agent of the present invention and the M value of the second polymerizable monomer (A2) in the second agent may be different from each other or may be the same.

[0034] In order to make the M values of the first and second polymerizable monomers (A1) and (A2) 14 to 18, the polymerizable monomer can be used alone or in a mixture of a plurality. As can be easily understood since the M value is an index of the hydrophobicity degree, in the molecular structure of the polymerizable monomer, the M value of the polymerizable monomer containing many hydrophilic groups such as a hydroxyl group becomes low, and conversely, the M value of the polymerizable monomer having a high content ratio of highly hydrophobic groups such as a phenyl group, an alkyl group, and an alkylene group becomes high. Also, in a mixture of polymerizable monomers, an approximate M value can also be predicted by obtaining a weighted average weighted by the content ratio based on the M values of the respective polymerizable monomers as components. Therefore, after determining the mixture composition based on such a prediction, the M value can be measured to confirm the M value of the mixture.

[0035] In order to make the M values of the first and second polymerizable monomers (A1) and (A2) of the present invention be 14 to 18, the first and second polymerizable monomers (A1) and (A2) are each preferably composed of a polymerizable monomer having an M value of 0 or more and less than 2: 0% by mass or more and less than 1% by mass, a polymerizable monomer having an M value of 2 or more and less than 15: 35 to 55% by mass, and a highly hydrophobic polymerizable monomer having an M value of 15 or more and less than 35: the balance. The polymerizable monomer having an M value of 0 or more and less than 2 may not be particularly included. Thus, the M values of the first and second polymerizable monomers (A1) and (A2) can be set within the desired range of M values by combining a low-hydrophobic polymerizable monomer, a medium-hydrophobic polymerizable monomer, and a highly hydrophobic polymerizable monomer.

[0036] Examples of polymerizable monomers having an M value of 0 or more and less than 2 that can be preferably used as the polymerizable monomers of the present invention include 2-hydroxyethyl methacrylate (HEMA), 10-methacryloyloxydecyl dihydrogen phosphate (MDP), mono(2-methacryloxyethyl) acid phosphate, bis(2-methacryloxyethyl) acid phosphate, glycerol dimethacrylate, and the like.

[0037] Examples of polymerizable monomers having an M value of 2 or more and less than 15 that can be preferably used as the polymerizable monomers of the present invention include triethylene glycol dimethacrylate (3G), 1,6-bis(methacryloylethyloxycarbonylamino)trimethylhexane (UDMA), nonamethylene diol dimethacrylate (ND), 2,2-bis[4-(3-methacryloyloxy)-2-hydroxypropoxyphenyl]propane (Bis-GMA), and the like.

[0038] Examples of polymerizable monomers having an M value of 15 or more and less than 35 that can be preferably used as the polymerizable monomers of the present invention include 2,2'-bis(4-methacryloxypolyethoxyphenyl)propane (M value: 25.2) (D-2.6E), and the like.

[0039] (b) First and second thickeners (B1), (B2) The thickener (B2) of the present invention is incorporated in a small amount to supplement the effect of preventing the change in sagging property over time by adjusting the M value of the second polymerizable monomer (A2) in the second agent. Further, the thickener (B1) of the present invention is incorporated in a small amount to adjust the sagging property in the first agent to the same level as that of the second agent and to prevent the change in sagging property over time that may slightly occur (when this is not incorporated). By incorporating this, the fluidity of the dental cement of the present invention can be adjusted, and a good paste property having appropriate sagging property and discharge property excellent in workability can be obtained. As the thickener of the present invention, a general thickener used as a thixotropy-imparting agent in the field of dental materials, specifically, a thickener composed of particulate matter having an average particle diameter of 0.003 μm or more and less than 0.1 μm can be used without particular limitation. The above average particle diameter means the average particle of primary particles, and the thickener may be incorporated as agglomerated particles in which primary particles are agglomerated.

[0040] The materials of the particulate matter serving as the first and second thickeners (B1) and (B2) of the present invention can be those made of materials known to be generally usable as thickeners without particular limitation. Examples of such thickeners include inorganic oxides such as quartz, silica, alumina, silica titania, silica zirconia, silicate glass, lanthanum glass, barium glass, strontium glass, fluoroaluminosilicate glass; hydroxides such as calcium hydroxide and strontium hydroxide; or organic polymers. These thickeners may be used alone or in combination of two or more. Further, since the blending amounts of the first and second thickeners (B1) and (B2) are small, even when they are composed of inorganic oxides, the degree of their hydrophobization hardly affects the effects of the present invention. Therefore, commercially available thickeners can be used without particular limitation regardless of whether they have a surface treatment or the type of treatment agent in the case of having a surface treatment. From the viewpoints of thickening effect and ease of availability, the thickener of the present invention is particularly preferably fumed silica having a surface treatment.

[0041] The blending amounts of the first thickener (B1) and the second thickener (B2) of the present invention in the first agent and the second agent are 3.5 to 5.5 parts by mass, and preferably 4 to 5 parts by mass, respectively, with respect to 100 parts by mass of the first polymerizable monomer (A1) and the second polymerizable monomer (A2) from the viewpoint of adjusting to a suitable sagging property and discharge pressure.

[0042] By the blending amounts of the above-mentioned first and second thickeners (B1) and (B2), the sagging property can be improved without reducing the discharge property (fluidity when extruded from a syringe container).

[0043] The first thickener (B1) and the second thickener (B2) of the present invention may have the same composition or different compositions, but from the practical viewpoint such as productivity, it is preferable that they have the same composition.

[0044] (c) First and second inorganic fillers (C1), (C2) As the first and second inorganic fillers (C1) and (C2) of the present invention, general inorganic fillers composed of inorganic spherical powder particles or powder particles having an irregular shape (such as particles obtained by pulverization) that are usually used in the field of dental materials are used. Here, general inorganic fillers are usually hydrophobically treated with a general surface treatment agent typified by a silane coupling agent or the like.

[0045] The hydrophobization treatment with a surface treatment agent means that a hydrophilic functional group such as a silanol group on the surface of the inorganic filler chemically or physically acts with the surface treatment agent and is immobilized (including immobilization by chemical bonding as well as immobilization by adhesion or adsorption), and the surface is modified to a hydrophobic surface. However, the surface of the inorganic filler is not completely hydrophobized at this time, and hydrophilic functional groups (acid points) remain on the surface. In this specification, as an index of the amount of hydrophilic groups (acid points) remaining on the surface of the inorganic filler, the above-mentioned "change amount Δa of the color difference a before and after adding methyl red measured in anhydrous toluene" is used. * of the change amount Δa * m is used.

[0046] Specifically, for a dispersion in which an inorganic filler is dispersed in anhydrous toluene, the a * value (a * m0 ) and the a * value (a * m1 ) obtained after adding methyl red to the dispersion: Δa * m = a * m1 - a * m0 value (change in color value) was used. For general inorganic fillers, Δa * m (hereinafter, also simply referred to as "MR color value") was more than 0 and less than 10. This is because, due to a general surface treatment agent, the surface is partially hydrophobized, so it is less than 10, but since some hydrophilic groups remain, the value exceeds 0.

[0047] Incidentally, the measurement of a * m1 and a * m0 can be performed as follows. That is, after drying at 100 °C for 3 hours or more, 1 g of an inorganic filler stored in a desiccator containing phosphorus pentoxide is placed in a sample tube with an inner diameter of about 16 mm, and then 3 g of anhydrous toluene is added and shaken vigorously to disperse it so that there are no aggregates. After dispersion, the sample tube is allowed to stand still to sediment the inorganic filler. After complete sedimentation, place the sample tube so that the measurement hole of a color difference meter ("SE7700", manufactured by Nippon Denshoku Industries Co., Ltd.) previously measured against a white background is located at the center of the bottom of the sample tube, and measure the color difference against a black background. The a * value at this time is taken as a * m0 . After the color difference measurement, add 1 drop (about 0.016 g) of an anhydrous toluene solution of 0.004 mol / L methyl red (manufactured by Tokyo Chemical Industry Co., Ltd.) stored under light shielding to the sample tube, shake and let it stand still in the same way, and then measure the color difference. The a * value at this time is taken as a * m1 .

[0048] The MR color values of the first and second inorganic fillers (C1) and (C2) in the present invention are each greater than 0 and less than 10. That is, as the inorganic fillers of the present invention, common inorganic fillers that have been subjected to ordinary hydrophobization treatment are used.

[0049] The MR color value of the first inorganic filler (C1) in the first agent of the present invention and the MR color value of the second inorganic filler (C2) in the second agent may be different from each other or may be the same.

[0050] The average particle diameters of the first and second inorganic fillers (C1) and (C2) of the present invention are each 0.1 μm or more and 10 μm or less. This is the particle diameter of common inorganic fillers used in the field of dental materials. It becomes possible to easily adjust the sagging property and discharge property of the paste from easily available materials.

[0051] Here, the average particle diameters of the first and second inorganic fillers (C1) and (C2) mean the average particle diameters of the primary particles constituting the inorganic fillers. Specifically, a photograph of the inorganic filler (powder) is taken with a scanning electron microscope, and 30 or more particles observed within the unit visual field of the photograph are selected, and the average value obtained by obtaining each primary particle diameter (maximum diameter) is meant. The above average particle diameter of the inorganic filler is obtained, for example, by taking a photograph of the powder with a scanning electron microscope (manufactured by JEOL Ltd., "JSM-7800F Prime") at a magnification of 5000 to 100000 times, measuring the number (30 or more) and primary particle diameter (maximum diameter) of the particles observed within the unit visual field of the photograph, and calculating the number-average primary particle diameter by the following formula based on the measured values.

Number

[0052] The compounding quantity of the first inorganic filler (C1) of the present invention is 181.5 to 295 parts by mass, preferably 210 to 250 parts by mass, from the viewpoint of adjusting the paste properties having suitable sagging property and discharge property, with respect to 100 parts by mass of the first polymerizable monomer (A1). Similarly, the compounding quantity of the second inorganic filler (C2) of the present invention is 181.5 to 295 parts by mass, preferably 210 to 250 parts by mass, from the viewpoint of adjusting the paste properties having suitable sagging property and discharge property, with respect to 100 parts by mass of the second polymerizable monomer (A2).

[0053] The first and second inorganic fillers (C1), (C2) (that is, general inorganic fillers) of the present invention are not particularly limited, but include amorphous silica, quartz, alumina, titania, zirconia, barium oxide, yttrium oxide, lanthanum oxide, ytterbium oxide and other metal oxides, silica - zirconia, silica - titania, silica - titania - barium oxide, silica - titania - zirconia and other silica - based composite oxides, borosilicate glass, aluminosilicate glass, fluoroaluminosilicate glass and other glasses, barium fluoride, strontium fluoride, yttrium fluoride, lanthanum fluoride, ytterbium fluoride and other metal fluorides, calcium carbonate, magnesium carbonate, strontium carbonate, barium carbonate and other inorganic carbonates, magnesium sulfate, barium sulfate and other metal sulfates, etc. are adopted. In particular, the inorganic filler of the present invention is preferably a silica - based composite oxide. The first and second inorganic fillers (C1), (C2) of the present invention may be used alone or in combination of two or more kinds.

[0054] The above - mentioned general surface treatment agents for the first and second inorganic fillers (C1), (C2) of the present invention are not particularly limited. For example, hydrophobic agents preferably used include those similar to the above - mentioned inorganic fillers. As the surface treatment agents for the first and second inorganic fillers (C1), (C2), only one kind may be used, or two or more kinds may be used in combination.

[0055] In particular, the first and second inorganic fillers (C1) and (C2) of the present invention are preferably silica-based composite oxide particles surface-treated with at least one surface treatment agent selected from vinyltriethoxysilane, vinyltrimethoxysilane, vinyl-tris(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, κ-methacryloyloxydodecyltrimethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, γ-glycidoxypropyl-trimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl-trimethoxysilane, γ-ureidopropyl-triethoxysilane, γ-chloropropyltrimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, and methyltriethoxysilane. Further, it is preferably not surface-treated with a surface treatment agent other than the above surface treatment agent as in Patent Document 2. By using the inorganic filler of the present invention which is not treated with a special surface treatment agent as in Patent Document 2 and is treated with a surface treatment agent that is commonly used due to its high reactivity, complicated operations can be omitted, and the sagging property and the discharge property can be easily adjusted.

[0056] The first inorganic filler (C1) and the second inorganic filler (C2) may have the same composition or different compositions, but preferably have the same composition from a practical viewpoint such as productivity.

[0057] Whether or not the above inorganic filler is surface-treated with a silane coupling agent can be confirmed by performing inorganic analysis of the surface of the inorganic filler by transmission electron energy dispersive X-ray analysis (TEM-EDX) or wavelength dispersive fluorescent X-ray analysis (WDX).

[0058] (c) Organic peroxide (D) The organic peroxide (D) of the present invention acts as an oxidizing agent for a redox reaction.

[0059] The compounding amount of the organic peroxide (D) of the present invention is 0.5 to 10 parts by mass, preferably 2 to 6 parts by mass, with respect to 100 parts by mass of the first polymerizable monomer (A1). By satisfying this range, high polymerization activity and favorable storage stability are achieved.

[0060] Examples of the organic peroxide (D) that can be preferably used in the present invention typically include ketone peroxide, peroxyketal, hydroperoxide, diaryl peroxide, peroxyester, diacyl peroxide, and peroxydicarbonate. In particular, from the viewpoint of storage stability, it is preferable to use hydroperoxide as the organic peroxide (D) of the present invention. As the organic peroxide (D), only one type may be used, or two or more types may be used in combination.

[0061] Examples of peroxyketals include 1,1-bis(t-hexylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)cyclododecane, 2,2-bis(t-butylperoxy)butane, n-butyl 4,4-bis(t-butylperoxy)valerate, and 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane.

[0062] Examples of hydroperoxides include p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, and t-butyl hydroperoxide. Examples of dialkyl peroxides include α,α-bis(t-butylperoxy)diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, and the like.

[0063] Examples of diacyl peroxides include isobutyryl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic acid peroxide, m-toluoylbenzoyl peroxide, benzoyl peroxide, and the like.

[0064] Examples of peroxydicarbonates include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis(4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-methoxybutyl peroxydicarbonate, di(3-methyl-3-methoxybutyl) peroxydicarbonate, and the like.

[0065] Examples of the peroxy esters include α,α-bis(neodecanoylperoxy)diisopropylbenzene, cumyl peroxy neodecanoate, 1,1,3,3-tetramethylbutyl peroxy neodecanoate, 1-cyclohexyl-1-methylethyl peroxy neodecanoate, t-hexyl peroxy neodecanoate, t-butyl peroxy neodecanoate, t-hexyl peroxy pivalate, t-butyl peroxy pivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, 1-cyclohexyl-1-methylethyl peroxy-2-ethylhexanoate, t-hexyl peroxy 2-ethylhexanoate, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxy isobutyrate, t-hexyl peroxy isopropyl monocarbonate, t-butyl peroxy maleic acid, t-butyl peroxy 3,5,5-trimethylhexanoate, t-butyl peroxy laurate, 2,5-dimethyl-2,5-bis(m-toluoylperoxy)hexane, t-butyl peroxy isopropyl monocarbonate, t-butyl peroxy 2-ethylhexyl monocarbonate, t-hexyl peroxy benzoate, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, t-butyl peroxy acetate, t-butyl peroxy-m-toluoyl benzoate, t-butyl peroxy benzoate, bis(t-butylperoxy)isophthalate, and the like.

[0066] (d) Thiourea compound (E) The thiourea compound (E) of the present invention acts as a reducing agent in a redox reaction. As the thiourea compound (E), any known thiourea compound can be used. The thiourea compound refers to a compound having a structure of =N-C(=S)-N=.

[0067] The compounding amount of the thiourea compound (E) of the present invention is 0.5 to 2.5 parts by mass, preferably 1 to 2 parts by mass, with respect to 100 parts by mass of the second polymerizable monomer (A2). When the compounding amount is 0.5 parts by mass or more, particularly high curability can be obtained. When the compounding amount is 2.5 parts by mass or less, storage stability is easily ensured.

[0068] Examples of the thiourea compound (E) of the present invention that can be preferably used include thiourea, methylthiourea, ethylthiourea, n-propylthiourea, isopropylthiourea, cyclohexylthiourea, benzylthiourea, phenylthiourea, acetylthiourea, benzoylthiourea, adamantylthiourea, 1-(2-pyridyl)-2-thiourea, 1-(2-tetrahydrofurfuryl)-2-thiourea, N,N'-dimethylthiourea, N,N'-diethylthiourea, N,N'-di-n-propylthiourea, N,N'-di-isopropylthiourea, N,N'-dicyclohexylthiourea, N,N'-diphenylthiourea, trimethylthiourea, triethylthiourea, tri-n-propylthiourea, triisopropylthiourea, tricyclohexylthiourea, tetramethylthiourea, tetraethylthiourea, tetra-n-propylthiourea, tetraisopropylthiourea, tetracyclohexylthiourea, ethylenethiourea, 4,4'-dimethyl ethylenethiourea, and the like. In particular, as the thiourea compound (E) of the present invention, acetylthiourea, 1-(2-pyridyl)-2-thiourea or benzoylthiourea can be preferably used. As the thiourea compound (E), only one kind may be used, or two or more kinds may be used in combination. When two or more thiourea compounds are used, the reference mass is the total mass of those thiourea compounds.

[0069] (e) Copper compound (F) The copper compound (F) of the present invention can particularly effectively obtain the action of promoting the redox reaction between the organic peroxide (D) and the thiourea compound (E). Therefore, by including the copper compound (F) as an essential component in the second agent, chemical polymerization-type curing is promoted, and sufficient curing is easily obtained.

[0070] Although the copper compound (F) of the present invention is not particularly limited, from the viewpoint of storage stability, it is preferable to use a divalent copper compound. As the copper compound (F) of the present invention, a monovalent copper compound can be used in combination with the divalent copper compound, but from the viewpoint of storage stability, the monovalent copper compound is contained only in a trace amount so as not to affect the storage stability, or it is preferably not substantially contained. In this case, in particular, it is preferable that the first agent does not substantially contain a monovalent copper compound. When a monovalent copper compound is contained in the first agent, the monovalent copper compound may act as a reducing agent for the organic peroxide (D), and the storage stability may deteriorate.

[0071] The blending amount of the copper compound (F) of the present invention is 0.001 to 0.05 parts by mass, preferably 0.003 to 0.03 parts by mass, based on 100 parts by mass of the second polymerizable monomer (A2). When the blending amount is 0.001 part by mass or more, particularly high curability can be obtained. When the blending amount is 0.05 part by mass or less, excellent storage stability is easily obtained.

[0072] The copper compound (F) of the present invention may be a hydrate or an anhydride. Only one type of copper compound (F) may be used, or two or more types may be used in combination.

[0073] Examples of the copper compound (F) that can be preferably used in the present invention include copper(II) chloride, copper(II) sulfate pentahydrate, copper(II) nitrate, copper(II) trifluoromethanesulfate, copper(II) acetate monohydrate, copper(II) acetylacetonate, copper(II) naphthenate, copper(II) salicylate, copper(II) benzoate, copper(II) methacrylate, copper(II) butyl phthalate, copper(II) gluconate, dichloro(1,10-phenanthroline)copper(II), disodium ethylenediaminetetraacetate copper(II) tetrahydrate, copper(II) dimethyldithiocarbamate, copper(II) diethyldithiocarbamate, copper(II) hexafluoroacetylacetonate, bis(1,3-propanediamine)copper(II) dichloride, bis(8-quinolinolato)copper(II), and the like.

[0074] (f) Other additives In the first agent and the second agent of the present invention, other additives such as a polymerization inhibitor, an ultraviolet absorber, a fluorescent agent, an antioxidant, a pigment, an antibacterial agent, and an X-ray contrast agent can be blended within a range that does not inhibit their effects.

[0075] The first agent of the present invention may contain other inorganic fillers other than the first thickener (B1) and the first inorganic filler (C1). Similarly, the second agent of the present invention may contain other inorganic fillers other than the second thickener (B2) and the second inorganic filler (C2). The first agent and the second agent may each contain 1 part by mass or less of other inorganic fillers as a range that does not inhibit the effects of the present invention.

[0076] The kit for preparing a dental cement of the present invention is particularly preferably used for dental cement, but is not limited thereto, and can also be preferably used for other dental applications.

Examples

[0077] Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples.

[0078] 1. First, each component used in the examples and comparative examples will be described. · First and second polymerizable monomers (A1), (A2) Bis-GMA: 2,2-bis[4-(3-methacryloyloxy)-2-hydroxypropoxyphenyl]propane (M value: 13.60) 3G: Triethylene glycol dimethacrylate (M value: 2.01) D-2.6E: 2,2-bis(4-methacryloxypolyethoxyphenyl)propane (M value: 25.2) UDMA: 1,6-bis(methacrylethyloxycarbonylamino)trimethylhexane (M value: 3.6957)

[0079] · First and second thickeners (B1), (B2) ZD-30ST (Fumed silica "Reolosil ZD-30ST" manufactured by Tokuyama Corporation, average primary particle size 0.007 μm) MT-10 (Fumed silica "Reolosil MT-10" manufactured by Tokuyama Corporation, average primary particle size 0.015 μm)

[0080] · First and second inorganic fillers (C1), (C2) F1: Silica zirconia filler with an average particle size of 3 μm F2: Silica zirconia filler with an average particle size of 0.2 μm

[0081] · Organic peroxide (D) PO1: 1,1,3,3-Tetramethylbutyl hydroperoxide PO2: Cumene hydroperoxide

[0082] · Thiourea compound (E) BzTU: N-Benzoylthiourea PyTU: 1-(2-Pyridyl)-2-thiourea

[0083] · Copper compound (F) (catalyst) Cu1: Copper(II) acetylacetonate Cu2: Copper(II) acetate monohydrate

[0084] · Other components BHT: Dibutylhydroxytoluene (polymerization inhibitor)

[0085] The M values of the first and second polymerizable monomers (A1), (A2) and the MR color values of the first and second inorganic fillers (C1), (C2) used above were measured as follows.

[0086] · Measurement of M value The M values of the first and second polymerizable monomers (A1), (A2) (hereinafter simply referred to as "polymerizable monomers") used above were measured as follows. First, in a constant temperature chamber at 25°C, 2.00 g of distilled water and 1.00 g of polymerizable monomer are introduced into a 50 ml glass sample bottle. Then, several drops (about 0.2 ml in total) of methanol are added dropwise thereto, the lid is closed, and the mixture is shaken by hand and allowed to stand, and the state of the mixture is visually confirmed. This operation is repeated in the mixture after standing until the polymerizable monomer dissolves to form a uniform solution state. The total mass (g) of methanol added dropwise until uniformity is determined, and the obtained value (g) is defined as the M value. The measurement was carried out in the same manner even when the polymerizable monomer was a mixture containing a plurality of types.

[0087] ·Measurement of MR color development value After drying at 100°C for 3 hours or more, 1 g of an inorganic filler stored in a desiccator containing phosphorus pentoxide is placed in a sample tube with an inner diameter of about 16 mm. Then, 3 g of anhydrous toluene is added and shaken vigorously to disperse it so that there are no aggregates. After dispersion, the sample tube is allowed to stand to sediment the inorganic filler. After complete sedimentation, a color difference meter (「SE7700」, manufactured by Nippon Denshoku Industries Co., Ltd.) whose standard has been measured in advance on a white background is placed so that the measurement hole is located at the center of the bottom of the sample tube, and the color difference is measured on a black background. At this time, the a * value is designated as a * mb At this time, 1 drop (about 0.016 g) of an anhydrous toluene solution of 0.004 mol / L methyl red (manufactured by Tokyo Chemical Industry Co., Ltd.) stored under light shielding is added to the sample tube. After shaking and standing in the same manner, the color difference is measured. At this time, the a * value is designated as a * ma At this time, the following formula: Δa * m = a * ma - a * mb is used to obtain Δa * m and the obtained value is defined as the MR color development value.

[0088] 2. Next, the dental cements according to Examples 1 to 19 and Comparative Examples 1 to 7 were prepared and evaluated by the following method.

[0089] Example 1 After dissolving 3 parts by mass of PO1 and 0.33 parts by mass of BHT in 100 parts by mass of a polymerizable monomer (A1) composed of 6 parts by mass of BisGMA, 34 parts by mass of 3G, and 60 parts by mass of D-2.6E, 228.8 parts by mass of an inorganic filler (C1) composed of 4.5 parts by mass of ZD-30ST, 135.5 parts by mass of F1, and 93.3 parts by mass of F2 were mixed to prepare the first agent.

[0090] Also, after dissolving 1.5 parts by mass of BzTU, 0.01 parts by mass of Cu1, and 0.17 parts by mass of BHT in 100 parts by mass of a polymerizable monomer (A2) composed of 6 parts by mass of BisGMA, 34 parts by mass of 3G, and 60 parts by mass of D-2.6E, 228.8 parts by mass of an inorganic filler (C2) composed of 4.5 parts by mass of ZD-30ST, 135.5 parts by mass of F1, and 93.3 parts by mass of F2 were mixed to prepare the second agent.

[0091] The average values of the M values of the above-prepared polymerizable monomers (A1) and (A2) were 16.6, respectively. Also, the MR color values of the above-used inorganic fillers (C1) and (C2) were 1.3 for F1 and 0.26 for F2.

[0092] The first agent and the second agent thus prepared were mixed in equal amounts to prepare a dental cement, and the evaluations of (1) extrudability and (2) sagging property were performed by the methods shown below, respectively. The evaluation methods of the above (1) to (2) will be described below.

[0093] [Extrudability (extrusion pressure)] A mixing tip (medmix T-Mixer (Outlet S)) was attached to a double syringe (medmix TWO-COMPONENT SYSTEMS 5 mL cartridge (Ratio 1:1)) filled with equal amounts of the above-mentioned first agent and second agent. This was fixed to a compression tester ("Autograph AG5000D", manufactured by Shimadzu Corporation) with the discharge port facing downwards. Using a 5t compression jig, a compressive force was applied to the plunger of the syringe at a test speed of 5 mm / min, and the test force (N) detected at this time (i.e., the force required to discharge the paste from the discharge port) was measured as "discharge pressure / N". From this value, the dischargeability was evaluated as follows. Poor dischargeability: When the discharge pressure exceeds 30 N Good dischargeability: When the discharge pressure is 30 N or less Particularly good dischargeability: When the discharge pressure is 26 N or less

[0094] [Dripping property] The kneaded paste-like dental cement (about 0.1 g) was placed on a slide glass and left for 1 minute. During this time, the end of the paste was marked with a marker. Then, the slide glass was set vertically so that the marked part was on the lower side and left standing in a thermostat at 23°C. After 3 minutes, the distance the paste moved (the moving distance), that is, the length from the marked point (initial value: 0 mm) to the lower end of the dental cement, was measured with a vernier caliper as "dripping / mm". From this value, the dripping property was evaluated as follows. Poor dripping property: When the drip exceeds 4 mm Good dripping property: When the drip is 4 mm or less Particularly good dripping property: When the drip is 2 mm or less

[0095] In addition, each evaluation was performed on the dental cement mixed immediately after preparing the first agent and the second agent, and the dental cement mixed after preparing the first agent and the second agent and storing them at 65°C for 40 days, and the dripping property and dischargeability were examined. The evaluation results after storing at 65°C for 40 days and then mixing are shown in Table 1.

[0096] Examples 2 to 19, Comparative Examples 1 to 5 In Example 1, the first agent and the second agent were produced in the same manner except that the composition was as shown in Table 1, filled into syringe containers, and (1) the sagging property of the dental cement immediately after production and after storage at 65°C for 40 days, and (2) the ejection pressure of the dental cement immediately after production and after storage at 65°C for 40 days were evaluated. Table 1 shows the evaluation results of the ejectability and sagging property of the dental cement after storage at 65°C for 40 days. In the table, the leftward arrow (←) means "the same as above".

[0097]

Table 1

[0098]

Table 2

[0099] As a result, in Examples 1 to 19, the ejection pressures were all 30 N or less, and the ejectability was good. Also, in Examples 1 to 19, the sags after storage at 65°C for 40 days were all 4 mm or less, and the sagging property was good. Thus, it can be seen that in Examples 1 to 19, the paste properties at the initial stage of production were maintained.

[0100] On the other hand, in Comparative Examples 1 to 7, it can be seen that neither good sagging property nor good ejectability was obtained, and the paste properties at the initial stage of production were not maintained.

[0101] Specifically, in Comparative Example 1 where a dental cement in which the M value of the components (A1) and (A2) in the first and second agents was greater than 18 was produced, the sagging property was good, but the ejection pressure exceeded 30 N and the ejectability was poor. Also, in Comparative Example 3 where a dental cement in which the M value of the components (A1) and (A2) in the first and second agents was less than 14 was produced, the ejectability was good, but the sag exceeded 4 mm and the sagging property was poor.

[0102] In Comparative Example 2 in which a dental cement was produced with the blending amounts of components (B1) and (B2) less than 3.5 parts by weight in the first and second agents, the extrudability was good, but the sag exceeded 4 mm and the sagging property was poor. Further, in Comparative Example 4 in which a dental cement was produced with the blending amounts of components (B1) and (B2) more than 5 parts by mass, the sagging property was good, but the extrusion pressure exceeded 30 N and the extrudability was poor.

[0103] In Comparative Example 5 in which a dental cement was produced with the blending amounts of components (C1) and (C2) more than 295 parts by mass in the first and second agents, the sagging property was good, but the extrusion pressure exceeded 30 N and the extrudability was poor. Further, in Comparative Example 6 in which a dental cement was produced with the blending amounts of components (C1) and (C2) in the first and second agents less than 181.5 parts by mass, the extrudability was good, but the sag exceeded 4 mm and the sagging property was poor.

[0104] Further, in Comparative Example 7 in which a dental cement was produced with the blending amount of component (E) in the second agent exceeding 2.5 parts by mass, the sag exceeded 4 mm and the sagging property was poor.

Claims

1. A dental cement preparation kit comprising a first agent and a second agent that are subcontracted to each other, and for preparing a dental cement by mixing the two agents, wherein the first agent comprises: 100 parts by mass of a first polymerizable monomer (A1) having an M value indicating a hydrophobicity degree of 14 to 18; 3.5 to 5.5 parts by mass of a first thickener (B1) having an average particle diameter of 0.003 μm or more and less than 0.1 μm; 181.5 to 295 parts by mass of a first inorganic filler (C1) having an average particle diameter of 0.1 μm or more and 10 μm or less; 0.5 to 10 parts by mass of an organic peroxide (D); and the second agent comprises: 100 parts by mass of a second polymerizable monomer (A2) having the M value of 14 to 18; 3.5 to 5.5 parts by mass of a second thickener (B2) having an average particle diameter of 0.003 μm or more and less than 0.1 μm; 181.5 to 295 parts by mass of a second inorganic filler (C2) having an average particle diameter of 0.1 μm or more and 10 μm or less; 0.5 to 2.5 parts by mass of a thiourea compound (E); and 0.001 to 0.05 parts by mass of a copper compound (F); and the M value represents the minimum value of the content (parts by mass) of methanol in a mixed solution comprising 1 part by mass of the first polymerizable monomer (A1) or the second polymerizable monomer (A2), 2 parts by mass of water, and methanol, which becomes a homogeneous solution at 25°C. The change amount Δa of the color difference a of the first inorganic filler (C1) and the second inorganic filler (C2) before and after adding methyl red, measured in anhydrous toluene ＊ is respectively more than 0 and less than 10, a kit for preparing dental cement. ＊ ｍ ​

2. The dental cement preparation kit according to claim 1, wherein each of the first polymerizable monomer (A1) and the second polymerizable monomer (A2) comprises 0% by mass or more and less than 1% by mass of a polymerizable monomer having an M value of 0 or more and less than 2, 35 to 55% by mass of a polymerizable monomer having an M value of 2 or more and less than 15, and the balance of a polymerizable monomer having an M value of 15 or more and less than 35.

3. The first inorganic filler (C1) and the second inorganic filler (C2) are each silica-based composite oxide particles surface-treated with at least one surface treatment agent selected from vinyltriethoxysilane, vinyltrimethoxysilane, vinyl-tris(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, κ-methacryloyloxydodecyltrimethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, γ-glycidoxypropyl-trimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl-trimethoxysilane, γ-ureidopropyl-triethoxysilane, γ-chloropropyltrimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, and methyltriethoxysilane. The kit for preparing a dental cement according to claim 1.

Images