JPH0524884B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a dental material that has low viscosity, excellent curability, and improved mechanical properties of the resulting cured product. In the present invention, "dental materials" include not only dental composite filling materials for filling and repairing tooth cavities, but also denture base materials, dental crown materials, luting materials, orthodontic adhesives, and cavity filling materials. Includes application adhesive and tooth fissure sealant. (Prior art and its problems) Conventionally, as the polymer monomer constituting dental materials, for example, 2,2'-bis[4-(3-methacryloxy-2-
Hydroxypropoxy)phenyl]propane (hereinafter simply referred to as BIS-GMA) is widely used. There are two methods for producing BIS-GMA, the first of which is an addition reaction between bisphenol A and glycidyl methacrylate.
However, BIS-GMA produced by such a method inevitably contains unreacted glycidyl methacrylate.
There was a risk that this would cause damage to the vital dental pulp. Another method is to add methacrylic acid to bisphenol A di-glycidyl ether. In this case, there is a risk that unreacted methacrylic acid may remain, and although this may contribute to adhesion to the tooth structure, there is still a high risk of damaging the vital dental pulp. In any of these methods, the above BIS-
It is extremely difficult to remove the above-mentioned unreacted substances and by-products during the production process of GMA, and the reality is that it is difficult to obtain highly pure BIS-GMA free from the above-mentioned problems. Furthermore, if a large amount of dimethacrylate represented by n=1, n=2, n=3 in structural formula (i), which will be described in detail later, is contained as a by-product, the viscosity increases and the curability of the dimethacrylate increases. Various problems were unavoidable, such as a significant decrease in mechanical properties of the cured product. (Means and effects for solving the problems) The present inventors have arrived at the present invention as a result of intensive studies to obtain high-purity BIS-GMA that can solve the above problems. That is, the present invention has the structural formula, A dental material comprising a polymerizable dimethacrylate (A) represented by the above formula (i) in which the content of n=0 is 95% by weight or more, and a polymerization initiator (B). As mentioned above, the dental material of the present invention contains less methacrylic acid as a residual monomer than the conventional BIS-GMA with low purity, and the risk of damaging the living dental pulp is significantly reduced. n=0 of the polymerizable dimethacrylate shown in (i)
By having 95% by weight or more of the ingredients,
= Compared to the conventional low-purity BIS-GMA in which one or more components exceed 5% by weight, it has a lower viscosity and is easier to handle, has improved curability, and has better mechanical strength of the resulting cured product. It has the effect of The dimethacrylate represented by the above-mentioned structural formula (i) of the present invention has the structural formula: It can be obtained by addition reaction of the epi-bis type epoxy resin represented by the formula and methacrylic acid using, for example, benzyltrimethylammonium chloride or dimethylaminoethyl methacrylate as a catalyst by a conventional method. In this case, it is an addition reaction between an epi-bis type epoxy resin in which the n=0 content of formula (ii) is 95% by weight or more and methacrylic acid, and the acid value is 2 (KOHmg/
It is necessary that the acid value of the polymerizable dimethacrylate exceeds 2, which is undesirable because it poses a danger to the living dental pulp.
If it is less than 95% by weight, the viscosity, curability and mechanical properties of the cured product will be impaired. In the present invention, only the dimethacrylate monomers according to the above formulas (i) and (ii) can be used as the polymerizable material, but if necessary, other monomers copolymerizable with these dimethacrylates may be used. It can also be diluted and used by adding body. Such other copolymerizable monomers include monofunctional monomers, polyfunctional monomers, or mixtures thereof. As a monofunctional monomer, the general formula: (In the formula, R ₁ is hydrogen or a methyl group, and R ₂ is an alkyl group having 1 to 14 carbon atoms.) Examples include various (meth)acrylate monomers represented by the following formula. In addition, as polyfunctional monomers, general formulas, (In the formula, n is an integer of 1 to 14, R ₁ is hydrogen or methyl group) Di(meth)acrylates represented by 1,4-
Butanediol di(meth)acrylate, 1,6
-Hexanediol di(meth)acrylate, glycerin di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, bisphenol A dimethacrylate, neopentyl glycol di(meth)acrylate, 2, Examples include 2'-di(4-methacryloxypolyethoxyphenyl)propane (2 to 10 ethoxy groups in one molecule). The polymerization initiator used in the present invention includes a peroxide and accelerator system that can initiate polymerization at a relatively low temperature;
Alternatively, a photosensitizer that can be activated by light energy and initiate the polymerization of ethylenic double bonds is desirable, but in applications where the material of the present invention is hardened at high temperatures (for example, dentures), it may decompose at high temperatures. Substances capable of initiating polymerization of ethylenic double bonds may also be used. The peroxide and accelerator system may be a mixture of peroxide and amine, such as benzoyl peroxide and N,N'-diethanol-P-toluidine;
There are mixtures of peroxides and cobalt promoters, such as mixtures of methyl ethyl ketone peroxide and cobalt naphthenate. Photosensitizers include biacetyl, benzyl, α
-naphthyl, β-naphthyl, acetonaphthacene,
These include camphuaquinone. In addition, when such a photosensitizer is in a state excited by light energy, it can be treated with a reducing agent such as propylamine, hexylamine, triethylamine, dimethylaminoethyl methacrylate, N,N'-dimethylaniline,
It is preferable to use ethylenediamine, trimethylenediamine, hexamethylenediamine, triamine, allylthiourea, etc. in combination. Particularly in recent years, visible light-curable dental materials have been attracting attention due to concerns over the effects of ultraviolet light on the human body.For such uses, a system of α-diketone and a reducing agent as a polymerization initiator is suitable, and camphoraquinone is particularly suitable. , (In the formula, R ₁ , R ₂ , and R ₃ are all alkyl groups) A system with a reducing agent represented by the structural formula, such as P-dimethylaminobenzoic acid isoamyl ester or P-dimethylaminobenzoic acid ethyl ester, is preferable. Substances that can decompose and initiate polymerization at high temperatures include benzoyl peroxide, acetyl peroxide,
Examples include peroxides such as lauroyl peroxide and cumene hydroperoxide, and 2,2'-azobisisobutyronitrile. The amount of these polymerization initiators used is
The amount ranges from 0.1 to 10 parts by weight per 100 parts by weight. When a mixture of peroxide and an accelerator is used as a polymerization initiator, the material is divided into two parts in advance, and one part contains the peroxide and the other part contains the accelerator, thereby curing the material during storage. It is necessary to prevent If the amount of the polymerization initiator used is less than 0.1 parts by weight, the polymerization time will be long, and if it exceeds 10 parts by weight, the storage stability will deteriorate, which is not preferable. In this invention, fillers that can be added as necessary include high hardness materials such as soda glass, barium glass, strontium glass, quartz, amorphous silica, borosilicate glass, alumina aluminosilicate, and glass ceramics.
Examples include inorganic powder with a small coefficient of thermal expansion, so-called organic composite filler in which the surface of the inorganic powder is coated with an organic polymer such as dimethacrylate polymer, and organic polymer powder such as polymethyl methacrylate. The shape of the filler may be spherical, platelet-like, fibrous whisker-like, or even irregular. When an inorganic filler is used, it is preferable to perform an appropriate surface treatment, and examples of such surface treatment include treatment with a silane coupling agent such as vinyltrichlorosilane or γ-methacryloxypropyltrimethoxysilane. . As for the size of the filling material,
It is 1000 microns or less, preferably 100 microns or less, and the amount of filler added is preferably in the range of 18 to 230% (volume ratio) based on the monomer. Furthermore, the material of the present invention may optionally contain an ultraviolet absorber,
A coloring agent, a polymerization inhibitor, etc. can be added. The dental material of the present invention can be used for various purposes as described above, such as a tooth filling material and a tooth crown material. For example, when used as a tooth filling material, the above-mentioned material is filled into a tooth according to a conventional method and hardens into a cured product within a few minutes. (Effects of the Invention) As is clear from the examples below, the material of the present invention has a low viscosity, is easy to handle, exhibits excellent curability, and has short inter-crosslink molecules and a high crosslink density, so it absorbs water. It exhibits extremely excellent properties such as a low amount, high Knoop hardness and high bending strength, and can solve the above-mentioned problems such as a low risk of damaging the living dental pulp. (Example) Next, the present invention will be explained in more detail with reference to Examples. In the examples, "parts" means parts by weight. Example 1 The structural formula is and n=0 is 95% by weight or more
Bis-type epoxy resin, YD-8125 (manufactured by Toto Kasei Co., Ltd.) 67 parts, methacrylic acid 33 parts, hydroquinone monomethyl ether 0.01 part as a polymerization inhibitor,
One part of benzyltrimethylammonium chloride chloride as a catalyst was placed in a flask equipped with a condenser, a thermometer, and a stirrer, and the temperature was raised to 80°C and held for 5 hours, then further raised to 110°C and held for 3 hours. After confirming that the acid value of the product had become 2 or less, the reaction was terminated to obtain dimethacrylate [IA] represented by the above formula (i). The properties of the obtained dimethacrylate [I-A] were compared with commercially available BIS-GMA (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name D-GMA), and the results are shown in Table 1. Next, 60 parts of this dimethacrylate [I-A], 40 parts of triethylene glycol dimethacrylate, and 1 part of Perbutyl 0 (tertiary butyl peroxyethylhexanoate manufactured by NOF Corporation) were added and mixed thoroughly, and the mixture was heated at 80°C. A sample plate was prepared by heating for 2 hours and then 120°C for 3 hours, and its water absorption and various mechanical properties were measured. The results are shown in Table 2. For comparison, a sample plate was prepared using D-GMA (BIS-GMA manufactured by Shin Nakamura Chemical Co., Ltd.) in place of the dimethacrylate [I-A], and the other conditions were the same as above, and various properties were similarly measured. are shown in Table-2. As is clear from Tables 1 and 2, the dimethacrylate according to the present invention has a lower viscosity than D-GMA, which is a conventional BIS-GMA monomer, has extremely good operability in various ways, and can be used as a free acid. Since the amount of damage is small, it is judged that there is little risk of damage to the living dental pulp. Furthermore, the cured product obtained according to the present invention showed good results in terms of water absorption resistance and mechanical properties. Example 2 Dimethacrylate [I-
A], triethylene glycol dimethacrylate,
Quartz powder (particle size 60 mesh or less) surface-coated with γ-methacryloxypropyltrimethoxysilane,
N,N'-diethanol-P-toluidine, benzoyl peroxide, and ultrafine silicic anhydride (Aerosil 380, manufactured by Nippon Aerosil Co., Ltd.) as a viscosity modifier were blended in the proportions shown in Table 3, and a universal paste and Adjusted catalyst paste. For comparison, a similar paste was prepared in exactly the same manner except that the above D-GMA was used instead of the above dimethacrylate [IA]. Equal amounts of the prepared universal pastes (A, B) and catalyst pastes (A', B') were weighed and kneaded, and cured at room temperature to determine compressive strength (ASTM D695), Brinell hardness, The amount of water absorbed and the compressive strength after water absorption were measured. Table 4 shows the results obtained.
Shown below. As is clear from Table 4, the dental composite material using dimethacrylate according to the present invention exhibited superior mechanical properties and good water resistance compared to D-GMA. Example 3 The above dimethacrylate [I-A] according to the present invention
60 parts, triethylene glycol dimethacrylate
The various photoinitiators shown in Table 5 were added to 40 parts, thoroughly kneaded, and then irradiated for 30 seconds using a visible light irradiator (manufactured by Shofu Co., Ltd., DAY LIGHT) to evaluate the curing speed. are shown in the same table. In particular, a system of camphoraquinone and P-dimethylaminobenzoic acid isoamyl ester as a photoinitiator showed the best curability.

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[Table] Water absorption was calculated by dividing by the surface area.

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Claims (1)

[Claims] 1. Structural formula (in the formula, n = 0, 1, 2, 3), and the content of the compound having the structural formula of the above formula (ii) where n = 0 is 95
It is an addition reaction product of epoxy type epoxy resin and methacrylic acid, which has an acid value of 2% by weight or more.
(KOHmg/1g of resin) or less, the structural formula is A dental product comprising a polymerizable dimethacrylate (A) which is represented by the above formula (i) and has a structural formula where n=0 is 95% by weight or more, and a polymerization initiator (B) as constituent elements. material. 2. Claim 1 further characterized in that the polymerizable dimethacrylate (A) is configured to contain 5% by weight or less of a compound having the structural formula of the above formula (ii) where n=1. Dental materials listed in section. 3. The dental material according to claim 1, further comprising an appropriate amount of filler as a constituent element. 4 The polymerization initiator (B) consists of a peroxide and an accelerator, and the polymerizable dimethacrylate (A) contains the peroxide in a part and the accelerator in the other part. The dental material according to claim 1, characterized in that: 5. The dental material according to claim 1, wherein the polymerization initiator (B) is a system of α-diketone and a reducing agent. 6 The α-diketone is camphorquinone, and the reducing agent has the following structural formula, (wherein R1, R2, and R3 are alkyl groups), the dental material according to claim 5.