JPH0425248B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a dental composition containing an organic composite filler. For dental materials whose main constituent is organic resin, various physical properties such as hardness, compressive strength, abrasion resistance, and water absorption are important, and inorganic fillers are blended into the resin to improve these properties. , so-called composite resins are being developed. However, in this case, since the inorganic filler and the organic resin have significantly different properties, they often lack interfacial compatibility such as compatibility and adhesion, and cannot exhibit sufficient improvement effects. In order to improve this point, dental materials have been proposed in which, for example, a filler treated with a silane coupling agent is added to the glass surface, but a sufficient improvement has not yet been achieved. The present invention solves the above problems, and includes:
By polymerizing at least one carboxylic acid monomer selected from acrylic acid, methacrylic acid, and crotonic acid and at least one radically polymerizable vinyl monomer in a polymerization system in which an inorganic compound is dispersed. The object of the present invention is to provide a dental composition comprising the resulting organic composite filler and a vinyl compound. The composition of the present invention is characterized by an organic composite filler in which an inorganic compound obtained by polymerizing the carboxylic acid monomer and vinyl monomer in the presence of an inorganic compound and an organic polymer are strongly integrated. It is possible to significantly improve the hardness, mechanical strength, appearance, and other properties of the dental molded cured product obtained by using it together with a vinyl compound. The organic composite filler constituting the composition of the present invention can be obtained by polymerizing a carboxylic acid monomer and one or more other polymerizable vinyl monomers in a polymerization system in which an inorganic compound is dispersed. The manufacturing method is not particularly limited. An example of a preferred manufacturing method is to suspend and disperse a vinyl monomer and an inorganic compound in an aqueous medium under temperature conditions that do not cause a thermal polymerization reaction, and then add a carboxylic acid monomer and stir. Depending on the method, a method may be mentioned in which an aqueous heterogeneous polymerization reaction is caused and the polymerization is carried out for a predetermined period of time. The carboxylic acid monomer used to form the organic composite filler of the present invention has a sulfonic acid group as an active site that brings about polymerization activity, and exhibits strong unification between the produced polymer and the inorganic compound. It has a double bond as an active site. In addition, the inorganic compounds used in the production of the organic composite filler of the present invention include those according to the periodic law,
, group metals, transition metals and their oxides, hydroxides, chlorides, sulfates, sulfites, carbonates, phosphates, silicates, and mixtures and complex salts of these metals, among which barium sulfate , silicon dioxide, aluminum oxide, titanium oxide, talc, quartz powder, glass powder, glass beads, glass fiber, barium salt, glass filler containing lead salt, silica gel, carbon fiber, zirconium oxide, tin oxide, vinyl The activation of the monomer and the strong coalescence effect with the polymer are particularly remarkable and preferred. One of the major features of the present invention is that it can be applied to inorganic compounds for which ordinary coupling treatment is not effective, and the shape and size of the inorganic compound can also be selected. Further, as the vinyl monomer used in the production of the organic composite filler of the present invention, any ordinary vinyl monomer that can be radically polymerized can be used.
Among them, methyl methacrylate is particularly preferable because it has a specifically high polymerizability and good cohesiveness between the produced polymer and the inorganic compound. When using a mixture of two or more types of monomers, using methyl methacrylate as one component can be said to be a preferable application method, especially from the viewpoint of polymerization activity. Incidentally, during the polymerization, a radical polymerization initiator such as benzoyl peroxide, azobisisobutyronitrile, potassium persulfate, etc. can be used as necessary. The concentration of the carboxylic acid monomer when obtaining the organic composite filler is about 0.05 to 100% by weight, preferably 0.1% by weight based on the total weight of the inorganic compound and vinyl monomer.
It is used in amounts of ~50% by weight, particularly preferably 0.5-30% by weight. In most cases, it is preferred to increase the amount of carboxylic acid monomer as the vinyl monomer content increases. The weight ratio of vinyl monomers or mixtures thereof to inorganic compounds used can vary within a wide range, from about 500:1 to 1:
5, preferably about 50:1 to about 1:1. The amount of water is about 1% to several hundred times, preferably about 10% to 10 times, based on the total weight of the inorganic compound and vinyl monomer. The reaction is preferably carried out at a temperature of about 10 to 100°C, under an atmosphere of an inert gas, such as nitrogen.
Preferably it is carried out at 20-80°C. The specific reaction temperature here is selected as appropriate depending on the vinyl monomer used, but it is important to carry out the reaction at a temperature that suppresses thermal polymerization to a negligible level, and does not cause extreme thermal polymerization. When carried out at high temperatures, the integrity and uniformity of the resulting composite filler is inhibited. Reaction time is 30 minutes to about 15 hours. The resulting organic composite filler can be dried at a temperature ranging from about 10 to 300°C, preferably from about 50 to 200°C. Note that the interaction between the surface of the inorganic compound and the polymer applied by the method of the present invention goes beyond adhesion in a physical sense due to simple adsorption or van der Waals forces, etc. This fact is clear from the fact that even after extraction treatment with a good solvent for vinyl polymers, a large amount of unextracted polymer is observed. The vinyl compound blended with the organic composite filler to form the composition of the present invention may be a monofunctional vinyl compound or a polyfunctional vinyl compound. Examples of monofunctional vinyl compounds include styrene, acrylonitrile, vinyl acetate, methyl acrylate and methacrylate, ethyl acrylate and methacrylate,
Examples include butyl acrylate and methacrylate, hydroxyethyl acrylate and methacrylate, methoxyethyl acrylate and methacrylate, glycidyl acrylate and methacrylate, methacryloyloxyethyl trimellitic acid and its acid anhydride. In addition, examples of polyfunctional vinyl compounds include the following general formula: (In the formula, R ₆ is a hydrogen atom or a methyl group, and p is an integer of 1 to 20.) Ethylene glycol diacrylate and methacrylate, diethylene glycol diacrylate and methacrylate, triethylene glycol diacrylate and methacrylate, polyethylene glycol Diacrylates and methacrylates, 1,
4-butanediol diacrylate and methacrylate, 1,3-butanediol diacrylate and methacrylate, 1,6-hexanediol diacrylate and methacrylate, glycerin diacrylate and methacrylate and the following general formula _Bisphenol A diglycidyl acrylate and methacrylates, urethane diacrylate and methacrylates, trimethylolpropane triacrylate and Examples include methacrylate, pentaerythritol tetraacrylate and methacrylate, bisphenol A diacrylate and methacrylate. Even if one type of these acrylates and methacrylates is used,
You may use two or more types in combination. In addition, these vinyl compounds are
It is preferable to mix it in a range of 0.001 to 100 times (by weight). If the amount of the vinyl compound used is outside the above range, it will be difficult to successfully form a dental molding. The dental composition of the present invention is composed of a mixture of an organic composite filler obtained using the carboxylic acid monomer as a polymerization initiator and a vinyl compound that is a raw material for manufacturing matrix resin, and is therefore used as a dental material. However, in obtaining a desired cured molded product, it is preferable to use a polymerization initiator for polymerizing and curing the vinyl compound, although it depends on the type of vinyl compound used. As the polymerization initiator, any known compound can be used, but in the case of heat curing, substances that can decompose at high temperatures and initiate polymerization, such as benzoyl, cumene hydroperoxide, t-butyl hydroperoxide, etc. oxide, dicumyl peroxide, acetyl peroxide, lauroyl peroxide, azobisisobutyronitrile, etc. Further, in the case of polymerization and curing at room temperature, for example, a combination of peroxide and amines, peroxide and sulfinic acids, or peroxide and cobalt compounds can be used. When using a combination of polymerization initiators, the composition of the present invention can be divided into two parts, one containing peroxide and the other containing amines, sulfinic acids, or cobalt compounds. . When using a combination of polymerization initiators, the composition of the present invention can be divided into two parts, one containing the peroxide, and the other containing amines, sulfinic acids, or cobalt compounds. The composition of the present invention may also be prepared by using a photosensitizer such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, etc.
It can also be cured by ultraviolet irradiation. The amount of polymerization initiator used to cure the composition of the present invention is 0.05 to 10% by weight based on the vinyl monomer.
It is. The composition of the present invention may also contain colorants, polymerization inhibitors, ultraviolet absorbers, oxidation stabilizers, and the like, if necessary. The dental composition according to the present invention contains an organic composite filler in which an inorganic compound and an organic polymer are strongly integrated, so that the interfacial affinity between the inorganic filler and the organic resin is significantly improved. Therefore, the cured product obtained by curing this material has high hardness, mechanical properties, and an excellent appearance that cannot be obtained with conventional dental materials. Next, the present invention will be explained in more detail with reference to Examples. Note that parts in the examples indicate parts by weight. Example 1, Comparative Examples 1 and 2 Silicon dioxide powder (manufactured by Fuji Davison Chemical Co., Ltd., 38.7 g of Thyroid (trademark) 266) was suspended and dispersed in 270 ml of deionized water, and the mixture was purged with nitrogen for 30 minutes. Next, 30.0 g of methyl methacrylate as a vinyl monomer was added under nitrogen flow and vigorous stirring. Next, the reaction solution was heated to 50°C in a hot water bath, and after confirming that the added monomer was uniformly dispersed, a solution of 6.5 g of acrylic acid dissolved in 10 ml of deionized water as a carboxylic acid monomer was gradually added. In addition, a polymerization reaction was carried out at the same temperature for 8 hours. After the reaction was completed, the product was filtered under reduced pressure, thoroughly washed with deionized water, and then dried with hot air at 100°C to remove moisture, yielding 61.2 g of an organic composite filler. This composite filler has a polymer content of 27% as measured by a calcination method, and a 50-hour Soxhlet extraction test using hot benzene as an extraction solvent revealed that the polymer content after the extraction process was 20%.
It was found that the surface of the silicon dioxide powder and most of the polymer composited by this method were extremely strongly integrated.
The thus obtained composite filler, a mixed solution of polymethyl methacrylate powder (manufactured by Mitsubishi Rayon Co., Ltd., Acrycon (trademark) AC) and methyl methacrylate monomer (weight ratio = 2:1), triethylene glycol dimethacrylate and benzoyl peroxide as the first
Blend according to the mixing ratio shown in the table, mix the mixture mechanically,
Filled into a plaster mold and heated at 60℃ for 3 hours, then
It was dry cured at 100°C for 1 hour. After curing, it was stored in water at 37°C for 24 hours, and then used as a sample for measuring physical properties. The compressive strength and indirect tensile strength of the cured product are
Shown in the table. For comparison, when silicon dioxide powder was treated with a silane coupling agent (with 3-methacryloyloxypropyltrimethoxysilane) instead of the composite filler according to the present invention, the untreated silicon dioxide powder was Similar evaluations were also conducted for the case where they were blended.

[Table] As is clear from Table 1, the composite filler according to the present invention has superior mechanical properties compared to dental materials made of conventionally used silane-treated fillers and untreated fillers. It can be seen that a cured product having the following properties can be obtained. In addition, the composite filler according to the present invention has extremely good wettability with the liquid resin, so it is easy to composite, and the appearance of the prepared cured test piece is
It was significantly cleaner than the comparative example. Example 2, Comparative Examples 3 to 4 In Example 1, polymethyl methacrylate-
Powder-liquid polymerization was carried out in the same manner as in Example 1, except that bisphenol A diglycidyl methacrylate was used instead of the methyl methacrylate monomer mixture, and the compressive strength and indirect tensile strength of the resulting composition were measured. The results are shown in Table 2.

[Table] As is clear from Table 2, the untreated filler shown in Comparative Example 4 cannot be used to produce cured specimens, and the conventionally used silanized filler shown in Comparative Example 3 cannot be used. Although the physical strength values are at an extremely low level, the composite filler according to the present invention has a remarkable strength improvement effect and is found to provide a cured product for dental materials having excellent mechanical properties. Example 3, Comparative Example 5 38.7 g of aluminum oxide powder (special grade reagent) as an inorganic compound was subjected to an aqueous heterogeneous polymerization reaction in the same manner as in Example 1 to obtain 60.0 g of an organic composite filler. Such composite fillers have a polymer content of 23%
The polymer content after extraction treatment was 19%. The composite filler thus obtained was blended in the same manner as in Example 2, and the mechanical strength of the cured product was measured. The results are shown in Table 3.

[Table] As is clear from Table 3, the strength properties of the untreated filler shown in Comparative Example 5 are at an extremely low level, whereas the composite filler of the present invention has a remarkable strength improving effect. and provides a cured product for dental materials with excellent mechanical properties. Furthermore, the composite filler according to the present invention has extremely good wettability with the liquid resin, so it is easy to form a composite, and the appearance of the prepared cured test piece was significantly cleaner than that of the comparative example. Example 4, Comparative Example 6 38.7 g of barium sulfate powder (special grade reagent) as an inorganic compound was subjected to an aqueous heterogeneous polymerization reaction in the same manner as in Example 1 to obtain 61.5 g of an organic composite filler. Such composite fillers have a polymer content of 24%
The polymer content after extraction treatment was 18%. The thus obtained composite filler was blended in the same proportion as in Example 3, and the mechanical strength of the cured product was measured. The results are shown in Table 4.

[Table] As is clear from Table 4, the untreated filler shown in Comparative Example 6 cannot produce cured test pieces, whereas the cured test pieces of the composite filler according to the present invention are extremely clean. A cured product for dental materials which has a good appearance and excellent mechanical properties was obtained. Example 5 Example 1 except that methacrylic acid was used instead of acrylic acid as the carboxylic acid monomer.
A cured product was obtained in the same manner as above. The compressive strength of the cured product is
1890Kgf/ ^cm2 , indirect tensile strength is 450Kgf/
It was warm in ^cm2 . Moreover, the appearance of the cured test piece was significantly cleaner than those of Comparative Examples 1 and 2. Example 6 Example 1 except that crotonic acid was used instead of acrylic acid as the carboxylic acid monomer.
A cured product was obtained in the same manner as above. The compressive strength of the cured product is
1850Kgf/ ^cm2 , indirect tensile strength is 430Kgf/
It was warm in ^cm2 . Moreover, the appearance of the cured test piece was significantly cleaner than that of Comparative Examples 1 and 2.

Claims (1)

[Scope of Claims] 1. Polymerization of at least one carboxylic acid monomer selected from acrylic acid, methacrylic acid, and crotonic acid and at least one radically polymerizable vinyl monomer in which an inorganic compound is dispersed. A dental composition comprising an organic composite filler and a vinyl compound obtained by polymerization in a system. 2. The dental composition according to claim 1, wherein the main component of the vinyl monomer is methyl methacrylate.