JPH0548768B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates in particular to curable compositions for dental composite materials. [Prior art and problems to be solved by the invention] Dental composite materials are used as substitute materials for tooth structure that has been partially damaged by accidents or caries. Various properties are required, such as water resistance, discoloration resistance, abrasion resistance, low thermal expansion, and high mechanical strength. Furthermore, dental composite materials are used by filling the tooth cavity in the form of a paste-like mixture consisting of a monomer and a filler, and then polymerizing and curing it, so the affinity of the monomer with the tooth structure is improved. Another important requirement is that the volume shrinkage due to curing is small. The various properties required for such dental composite materials are influenced by the filler component, which is the dispersed phase, but are also greatly affected by the properties of the polymer component, which becomes the continuous phase when the monomer hardens. . Therefore, many studies have been conducted on monomer components, which are precursors of the continuous phase, with the aim of improving various properties of composite materials. Conventionally, the monomer components of dental composite materials include:
bis-phenol A diglycidyl methacrylate (hereinafter referred to as bis-phenol A diglycidyl methacrylate) described in U.S. Pat. No. 3,066,122
(abbreviated as GMA) has been used as the main component. However, since this monomer has a very high viscosity, it is difficult to disperse filler in high proportions when used in dental composite materials. Therefore, it is common to use various low-viscosity methacrylic acid derivatives or acrylic acid derivatives as diluents. As such diluents, for example, methyl methacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, etc. have been used as disclosed in Japanese Patent Publication No. 46-24869. However, recently, dental composite materials have come to be applied to molars, which are in a harsher environment than anterior teeth, so it is necessary to further improve their discoloration resistance, abrasion resistance, water resistance, and mechanical properties. has been requested.
However, the above-mentioned monomer composition could not satisfy these requirements. That is, the mechanical strength of the cured composite material using the monomer composition described above was low, and the affinity with the tooth structure was also insufficient. Several attempts have been made in recent years to improve the above drawbacks. For example, 2,2-bis(4-methacryloxypolyethoxy)phenylpropane is disclosed in JP-A-57-185207, 1,2-bis(3-methacryloxy-2-
Hydroxypropoxy)ethane, JP-A-1983-
No. 138107 discloses pentaerythritol tetramethacrylate and the like. However, even if these monomers are used alone as components of composite materials, they do not have the compatibility with tooth structure, low water absorption, abrasion resistance, low thermal expansion, and mechanical strength required for dental composite materials. It was not possible to satisfy various characteristics such as. Therefore, the development of monomer compositions that meet these demands has become an important technical issue. [Means for Solving the Problem] As a result of intensive research on dental monomer compositions, the present inventors have found that mechanical properties such as compressive strength and tensile strength can be improved by mixing specific monomers in specific proportions. It has been discovered that a dental composite material with excellent properties, good affinity with tooth structure, and low water absorption can be obtained. That is, the present invention provides (1) (i) (A) the following formula (However, R ¹ is a hydrogen atom or an alkyl group,
l and m are integers of 0 or more. ) A component shown by (B) the following formula (However, R ² is a hydrogen atom or an alkyl group,
n is an integer greater than or equal to 0. ), and (C) the following formula (However, R ³ is a hydrogen atom or an alkyl group.) It mainly consists of the C component represented by: A component is 20 to 60% by weight, B component is 10 to 50% by weight, and C component is 20 to 60% by weight. % of a monomer composition, (ii) a filler, and (iii) a polymerization catalyst. A feature of the present invention is a monomer composition in which three types of monomers, component A, component B, and component C, are used simultaneously and in a specific blending ratio. Component A used in the present invention is a monomer represented by the following formula. (However, R ¹ is a hydrogen atom or an alkyl group,
l and m are integers of 0 or more. ) The component A used in the present invention is not particularly limited by the type of R ¹ and the numbers of l and m, as long as it is a monomer represented by the above formula. However, when considering the mechanical strength of the polymer obtained from the monomer composition and the affinity with tooth structure, R ¹ is a hydrogen atom or a methyl group,
l and m are each integers of 0 to 4, and 2≦l+
It is preferable that m≦4. Moreover, the B component used in the present invention is a monomer represented by the following formula. (However, R ² is a hydrogen atom or an alkyl group,
n is an integer greater than or equal to 0. ) The B component used in the present invention may be a monomer represented by the above formula, but for the same reason as the A component, R ² is a hydrogen atom or a methyl group,
It is preferable that n is an integer of 0 to 3. Furthermore, the C component used in the present invention is a monomer represented by the following formula. (However, R ³ is a hydrogen atom or an alkyl group.) The C component is not particularly limited as long as it is a monomer represented by the above formula. However, for the reasons stated in the explanation of component A above, R ³ is preferably a hydrogen atom or a methyl group. The blending ratio of the A component, B component, and C component described above is as shown by the shaded area in Figure 1, where the A component is 20-
60% by weight, 10-50% by weight of B component, 20% of C component
60% by weight, preferably 20-50% by weight of component A, 15-40% by weight of component B, and 20-60% by weight of component C, and further 20-30% by weight of component A, and 20-30% by weight of component B. It is most preferable that the content of the C component is 20-40% by weight and the content of the C component is 30-50% by weight. When a monomer composition outside the above range is used as a monomer component of a dental composite material, the following disadvantages occur. That is, if the content of component A is larger than this range, the affinity with the tooth structure will decrease, and furthermore, it will become difficult to mix a large amount of filler when preparing a composite material. Conversely, if the content of component A is smaller than this range, the amount of water absorption increases. If the content of component B is larger than this range, mechanical strength will decrease and water absorption will increase. On the other hand, if the content of component B is smaller than this range, the affinity with tooth structure will decrease. Furthermore, if the content of the C component is larger than this range, the affinity with the tooth substance tends to decrease, and conversely, if the content of the C component is smaller than this range, the mechanical strength decreases. Other monomers may be added to the monomer composition of the present invention within a range that does not impair the above-mentioned properties, for example, in a range of 0 to 50% by weight based on the monomer composition. As other monomers, radically polymerizable monomers can be used without particular limitation. Typical examples that are particularly suitable for use include bis
- A monomer having an acryloyl group or a methacryloyl group such as -GMA, triethylene glycol dimethacrylate, and 1,1,1-trimethylolpropane trimethacrylate. Further, as the polymerization catalyst for the curable composition used in the present invention, any known polymerization catalyst can be used without any restriction. Typical examples of commonly used catalysts include peroxides such as benzoyl peroxide, 4-chlorobenzoyl peroxide, and lauroyl peroxide, and photopolymerization catalysts such as benzoin methyl ether, It is also possible to use camphorquinone and the like. The amount of the catalyst used is generally 100% of the total monomer component.
0.01-5 parts by weight, preferably 0.1 parts by weight
-2 parts by weight may be used. Furthermore, as the monomer activator used in the present invention, known activators can be used. Typical examples of those commonly used are N,N-dimethyl-p-toluidine, N,N-bis-(2-
hydroxyethyl)-4-methylaniline, N,
These are amines such as N-bis-(2-hydroxyethyl)-3,4-dimethylaniline. The amount of the activator used is generally based on 100 parts by weight of the total monomer components.
It may be used in a proportion of 0.01 to 5 parts by weight, preferably 0.1 to 2 parts by weight. Furthermore, a filler may be added to the curable composition of the present invention. The filler is not particularly limited, and any filler that can be used as a filler for dental composite materials may be used. Generally, quartz powder, glass powder,
Aluminum oxide powder, silica powder, aluminum nitride powder, boron nitride powder, etc. can be used. In addition, the present inventors previously proposed Japanese Patent Application Laid-Open No. 58-110414.
The inorganic oxide powder shown in the above publication is also suitable. These powders may be used as they are, but they may be coated in advance with the polyfunctional monomer, unsaturated monomer, or a mixture of these monomers, or coated with γ-methacryloxypropyltrimethoxysilane or vinyltriethoxysilane. It is also suitable to use it after treatment with a coupling agent such as. The amount of these fillers used is generally 60 to 90% of the total amount of all monomer components and filler.
It may be used in an amount of 70 to 90% by weight, preferably 70 to 90% by weight. Furthermore, since this curable composition has good affinity with tooth structure, it can also be applied to dental sealants by reducing the filler content and increasing the fluidity of the paste. In this case, the amount of these fillers used is preferably 20 to 70% by weight of the total amount of all monomer components and fillers. [Effects] The curable composition of the present invention is characterized by excellent mechanical strength, particularly when used as a dental composite material, high affinity with tooth structure, and low water absorption. Furthermore, by taking advantage of its affinity for tooth structure, it can also be applied to curable compositions for dental sealants and dental adhesives. EXAMPLES In order to specifically explain the present invention, Examples will be given below, but the present invention is not limited to these Examples. The properties of the polymer obtained by polymerizing the curable composition of the present invention were measured by the following methods. (1) Compressive strength Knead the paste and
After polymerizing for a minute, the test pieces were immersed in water at 37°C for 24 hours. Its size and shape are 4 in diameter
It is cylindrical with a height of 10 mm. This test piece was attached to a testing machine (Toyo Baudouin, UTM-5T), and the compressive strength was measured at a crosshead speed of 10 mm/min. (2) Tensile strength Knead the paste and
After polymerizing for a minute, the test pieces were immersed in water at 37°C for 24 hours. Its size and shape are 6 in diameter
It is cylindrical with a length of 6 mm and a height of 6 mm. This test piece was mounted on a testing machine (Toyo Baudouin, UTM-5T), and the tensile strength was measured at a crosshead speed of 10 mm/min. (3) Surface hardness Knead the paste and harden it at 37°C for 30
After polymerizing for a minute, the test pieces were immersed in water at 37°C for 24 hours. Its size and shape are 2.5×10
It is a plate-shaped piece of ×10 mm. The measurement used a micro Brinell hardness test. (4) Thermal expansion coefficient: Mix the paste and
A test piece was prepared by curing for a period of time. Its size and shape are the same as those used in the compression test. The measurement was performed using Thermoflex manufactured by Rigaku Denki Co., Ltd., and was determined based on the coefficient of linear expansion between 20°C and 50°C. (5) Water absorption rate Knead the paste and paste at 37℃ for 30 minutes.
After polymerizing for minutes, abrasive paper (Nihon Kenshi, No. 1000)
After polishing the surface, it was stored in an anhydrous magnesium sulfate desiccator at 37°C until it reached a constant weight. Thereafter, it was immersed in water at 37°C, and its weight was measured 24 hours later. The water absorption rate is calculated by dividing the increased weight (mg) by the surface area (cm ² ) of the test piece before immersion. The size and shape of this test piece was a plate with dimensions of 1.0 x 10 x 10 mm. (6) Marginal sealability for cavities (compatibility with tooth structure)
First, adhesive () solution and () solution were prepared according to the formulations shown below. Adhesive () solution Triethylene glycol dimethacrylate bis-GMA 2-hydroxyethyl methacrylate Styrene-maleic anhydride copolymer Benzoyl peroxide Benzoyl peroxide 2,6-di-tert-butyl-4-methylphenol 42.9% by weight 27.2 Weight % 19.4 weight % 10.0 weight % 0.49 weight % 0.01 weight % Adhesive () liquid 2-hydroxyethyl methacrylate Adhesive () liquid 2-hydroxyethyl methacrylate 2,6-di-tert-butyl-4-methylphenol p- Sodium toluenesulfinate N,N-dihydroxyethyl para-toluidine ethanol 13.0% by weight 0.01% by weight 1.3% by weight 0.69% by weight 85.0% by weight Next, 3 mm in diameter and 2 mm in depth was applied to the labial surface of an extracted human tooth.
After forming a cavity and etching the enamel part with 40% phosphoric acid for 60 seconds, apply a thin mixture of the above adhesives () and () to the cavity wall, and apply equal amounts of paste and paste. After practicing,
Filled. After 1 hour of filling, store in water at 37℃.
One day and one month later, a percolation test was conducted in which the sample was immersed in fuchsin aqueous solutions at 4° C. and 60° C. 60 times for 1 minute alternately to test the margin sealing properties. The evaluation method was to cut the extracted tooth down the center and examine whether there was any dye (fuchsin) intruding between the cavity wall and the filling. Example 1 A filler made of silica and titania (hereinafter referred to as silica/titania filler) was obtained according to the example of JP-A-58-110414. As a result of observation using a scanning electron microscope, the shape of the silica/titania filler was spherical, the particle size was in the range of 0.10 to 0.20 μm, and the standard deviation value of the particle size was 1.20. The specific surface area determined by the BET method was 120 m ² /g. A part of the obtained silica/titania filler was
The monomers were added to bis-GMA/triethylene glycol dimethacrylate at a mixing ratio of 6/4 so that the silica/titania filler content was 78% by weight, and polymerized in the presence of a catalyst (benzoyl peroxide). A polymer-coated filler was obtained in this way, and the polymer-coated filler was ground to a size of 10 to 100 microns. Next, each component was premixed so that the paste and the paste had the following composition ratio. Paste Silica/Titania Filler Polymer Coating Filler Monomer Composition Benzoyl Peroxide Benzoyl Peroxide 2,6-Di-T-T-Butyl-4-Methylphenol 28.0% by weight 42.0% by weight 29.46% by weight 0.53% by weight 0.01% by weight Paste Silica /Titania filler polymer coating filler monomer composition N,N-dihydroxyethyl para-toluidine N,N-dihydroxyethyl para-toluidine 2.6-di-tert-butyl-4-methylphenol
28.0% by weight 42.0% by weight 29.54% by weight 0.45% by weight 0.01% by weight The composition of the monomer composition in the paste is bis
-GMA 60% by weight, triethylene glycol dimethacrylate 40% by weight, and the composition of the monomer composition in the paste is A component 25% by weight, B component 25% by weight.
% by weight, and the C component is 50% by weight. However, as component A, component B, and component C, monomers having the following structures were used. Component A: A mixture of the following a ₁ and a ₂ at a molar ratio of 7:3 (l + m = 2.6) a ₁ : _a2 : B component: C component: Equal amounts of the above paste and paste were taken, kneaded for 30 seconds at room temperature, and the properties of the hardened product were measured. As a result, the compressive strength was 3730 Kg/cm ² and the tensile strength was 521.
Kg/cm ² , surface hardness 51.8H _B , coefficient of thermal expansion 36.2ppm,
The amount of water absorbed was 0.47 mg/cm ² . The results are shown in Table 1. Examples 2 to 6 and Comparative Examples 1 to 5 The same types of monomers as described in Example 1 were used as the A component, B component, and C component of the monomer composition, and the paste and the monomer composition therein were The polymer was cured in the same manner as in Example 1, except that the composition ratio was changed to the composition ratio shown in Table 1, and the properties of the obtained polymer were measured and shown in Table 1.

[Table] Examples 7 to 10 A component, B component of the paste described in Example 1,
A test was conducted under the same conditions as in Example 1, using monomers each having a different structure in place of the monomer used as component C. Table 2 summarizes the structures of the monomers used and the results.

[Table] Example 11 A paste was prepared according to the recipe shown below. Paste Silica/Titania Filler Polymer Coating Filler Monomer Composition Camphorquinone Camphorquinone 2,6-ditertiarybutyl-4-methylphenol
28.0% by weight 42.0% by weight 29.8% by weight 0.19% by weight 0.01% by weight The composition of the monomer composition is the same as the monomer composition described in Example 1. Next, according to the method described in Example 1 (6), the margin sealing property for the cavity (compatibility with tooth substance) was examined. However, since the above paste is a visible light polymerizable type, after filling the above paste into the cavity of an extracted human tooth, it was irradiated with visible light for 30 seconds using a white light (manufactured by Takara Belmont). The test method and evaluation method before and after is Example 1
This is the same as (6). The test results are shown in Table 3. Examples 12 to 14, Comparative Example 6-8 Instead of the monomer composition described in Example 11, a monomer composition having the same composition as that used in Examples 1-4 and Comparative Example 1-3 was used. The test was conducted under the same conditions as in Example 11. The monomer compositions used and the results are summarized in Table 3.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 shows A constituting the monomer composition of the present invention.
It is a drawing which shows the composition ratio of a component, B component, and C component.

Claims (1)

[Claims] 1 (i) (A) The following formula (However, R ¹ is a hydrogen atom or an alkyl group,
l and m are integers of 0 or more. ) A component shown by (B) the following formula (However, R ² is a hydrogen atom or an alkyl group,
n is an integer greater than or equal to 0. ), and (C) the following formula (However, R ³ is a hydrogen atom or an alkyl group.) It mainly consists of the C component represented by: A component is 20 to 60% by weight, B component is 10 to 50% by weight, and C component is 20 to 60% by weight. % of a monomer composition, (ii) a filler, and (iii) a polymerization catalyst.