JPH05262615A - Dental composite resin - Google Patents

Abstract

PURPOSE:To obtain the subject dental composite resin capable of providing a cured material excellent in abrasion resistance by using a bisurethane acrylate methacrylate as a polymerizable monomer in combination with a polymerization initiator and a filler. CONSTITUTION:The objective composite resin is obtained by using a bisurethane acrylate methacrylate (e.g. a compound of formula II) of the formula [R<1> and R<2> are each an acryloyloxyalkyl; R<3> is H or an acryloyloxyalkyl; R<4> is a (substituted)aliphatic alkylene; R<5> and R<6> are each a methacryloyloxyalkyl; R<7> is H or a methacryloyloxyalkyl; n is 0 or 1] as a polymerizable monomer in combination with a polymerization initiator (e.g. camphorquinone) and a filler (e.g. superfine silica powder and ground silica powder). The above- mentioned polymerizable monomer is obtained, e.g. by reacting an organic diisocyanate containing two isocyanate groups in the molecule with a methacrylic acid ester containing an OH group in the molecule and an acrylic acid ester also containing an OH group in the molecule.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dental composite resin, and more particularly, it relates to a dental composite resin excellent in abrasion resistance of a cured product.

[0002]

2. Description of the Related Art In recent years, a dental composite resin having a polymerizable monomer, a polymerization initiator and an inorganic filler as constituent elements has been improved in functional properties such as strength and abrasion resistance, and reproduction of color tone and tooth morphology. The progress in operability such as ease of use has been appreciated, and it has come to be used for filling and restoration of beetles, materials for crowns, and many other applications. Recent dental composite resins have made great strides in comparison to earlier products, but fracture and wear in the oral cavity are still observed. When observing the state of this wear with an electron microscope, it was observed that the resin portion of the matrix was worn first, and the filler was left behind and was protruding, and even in the products with various conventional improvements, the matrix resin component Vulnerability is a problem. Therefore, in order to further improve the abrasion resistance of the composite resin, it is most important to strengthen the resin component of the matrix.

Conventionally, there have been many proposals for improving the resin component. Early composite resins were based on simple bifunctional monomers such as bisphenol A glycidyl dimethacrylate and triethylene glycol dimethacrylate. In order to improve it, the application of polyurethane, which is known as a resin having good abrasion resistance, to the dental material field was attempted. As such, there is a proposal to use (meth) acrylate having a urethane bond in the molecule.
JP-A-47-247 describes an adduct of an aromatic dimethacrylate with a mono- or diisocyanate, and JP-A-49-30468 discloses a reaction product of an aliphatic diisocyanate and a hydroxyalkyl methacrylate. The use of is suggested. Many dental fillers using such urethane (meth) acrylate monomers have been commercialized, but the clinical wear resistance of these products has not been as excellent as expected. Therefore, it has been difficult to achieve clinically meaningful abrasion resistance simply by diverting polyurethane into a dental material.

On the other hand, there have been proposals intended to improve wear resistance by increasing the crosslink density of the resin component of the composite resin. As such, there is a proposal to use a polyfunctional polymerizable monomer having three or more (meth) acrylic acid groups in the molecule. Examples of such materials include JP-A-50-97682 (filler composition consisting of trifunctional methacrylate monomer, inorganic powder and curing agent) and JP-A-50-156298 (1 to 4 functional monomer). The use of trimethylolpropane tri (meth) acrylate or tetramethylolmethanetetra (meth) acrylate described in a composite resin consisting of a photosensitizer and a filler is also disclosed in JP-A-2-56.
Dental fillers containing tetramethylolmethane tri (meth) acrylate or tetramethylolmethane tetra (meth) acrylate as described in No. 408 have been proposed. These polyfunctional monomers are very excellent monomers from the viewpoint of polymerizability, but when these monomers are polymerized, the resin is hard and brittle so that the resin is cracked only by the stress associated with the polymerization shrinkage. Becomes Furthermore, the composite resin using such a monomer has almost the same performance as a conventional product in terms of clinical results in the oral cavity, particularly fracture resistance and abrasion resistance.

JP-A-57-85355 and JP-A-56-152408 describe that both the abrasion resistance improvement by using the urethane monomer and the hardness / polymerization property improvement of the polyfunctional monomer are incorporated. There is a proposal of a tetrafunctional monomer obtained by reacting 1 mol of hexamethylene diisocyanate with 2 mol of glycerin dimethacrylate. Certainly, the composite resin using this monomer is superior in abrasion resistance to conventional ones, and in many cases, a large amount of abrasion that requires re-repair is not observed in clinical observation for up to 10 years, but in many cases However, the surface of the restoration is roughened or deformed as compared with immediately after the restoration, and further improvement in wear resistance is desired.

By the way, in the proposal of the polymerizable monomer in the conventional patent, acrylate and methacrylate are often described in parallel. Of these, acrylates are very excellent in polymerizability, but inferior in weather (water) resistance. On the other hand, methacrylate has relatively poor polymerizability, but is very excellent in weather resistance. Conventional dental materials often use methacrylate, which has excellent storage stability and oral stability (a type of water resistance), but the degree of polymerization is higher than that of materials that use acrylate. (Reaction rate of monomer) was slightly inferior. Therefore, as a proposal of a dental resin composition using a polymerizable monomer having both an acrylic group and a methacrylic group in the molecule, JP-A-63-107954 (1 urethane bond in the molecule, 1 acrylate) Group, an acrylic / methacrylic acid mixed ester having one methacrylate group) and JP-A-64-87608 (polymerizable compound having an acryloyloxyl group and a methacryloyloxyl group in one molecule). Although these proposals differ from the conventional proposals in that they clearly contain both an acrylic group and a methacrylic group in one molecule, they are still insufficient from the viewpoint of abrasion resistance in the oral cavity. Met.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a dental composite resin which has very excellent abrasion resistance in the oral cavity.

[0008]

Means for Solving the Problems As a result of intensive studies for solving the above-mentioned problems, the present inventor has found that the above-mentioned problems in a composition containing a polymerizable monomer, a polymerization initiator and a filler as main components. Is represented by the following chemical formula 2,
It has been found that this is achieved by a dental composite resin characterized by being bisurethane acrylate methacrylate.

[0009]

[Chemical 2] (In the formula, R ¹ and R ² are each an acryloyloxyalkyl group, R ³ is a hydrogen atom or an acryloyloxyalkyl group, R ⁴ is an aliphatic alkylene group with or without a substituent, R ⁵ and R ⁶ represents a methacryloyloxyalkyl group, R ⁷ represents a hydrogen atom or a methacryloyloxyalkyl group, and n represents an integer of 0 or 1.)

The dental composite resin of the present invention is excellent in abrasion resistance in the oral cavity because the polymerizable monomer of Chemical formula 2 has two abrasion-resistant urethane bonds in one molecule,
It is presumed that the polymerization rate was improved and the crosslink density of the cured product was increased by having two or more acryloyl groups each having a high polymerizability and a methacryloyl group each having a good weather resistance.

Such a polymerizable monomer is obtained, for example, by reacting an organic diisocyanate having two isocyanate groups in the molecule with a methacrylic acid ester having a hydroxyl group in the molecule and an acrylic acid ester having a hydroxyl group in the molecule. Is obtained by In a urethane-based monomer using an aromatic isocyanate as an organic diisocyanate, an aliphatic diisocyanate is used because the polymer using the same tends to be discolored.

Aliphatic diisocyanates having two isocyanate groups in the molecule used in the synthesis of the bisurethane acrylate methacrylate are tetramethylene diisocyanate, hexamethylene diisocyanate,
2,2,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, cyclohexylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate and the like can be mentioned.

Examples of the acrylic acid ester having a hydroxyl group that reacts with the diisocyanate include glycerol-1,3-diacrylate, trimethylolpropane diacrylate and tetramethylolmethane triacrylate. Further, as the methacrylic acid ester having a hydroxyl group, for example, glycerol-1,
Examples thereof include 3-dimethacrylate, trimethylolpropane dimethacrylate, and tetramethylolmethane trimethacrylate.

Among the monomers obtained by reacting these precursors, the following compounds are particularly preferable.

[0015]

[Chemical 3]

[0016]

[Chemical 4]

[0017]

[Chemical 5]

[0018]

[Chemical 6]

[0019]

[Chemical 7]

Further, a polymerizable monomer copolymerizable with the bisurethane acrylate methacrylate can be used at the same time. As such a monomer, methacrylic acid alkyl ester (having 1 to 10 carbon atoms in the alkyl group),
Polyalkylene glycol dimethacrylate (2 carbon atoms
~ 20), ethylene glycol oligomer dimethacrylate (2-10 mer), bisphenol A dimethacrylate, 2,2-bis [p- (γ-methacryloxy-β-
Hydroxypropoxy) phenyl] propane, 2,2-
Di (4-methacryloxypolyethoxyphenyl) propane (2-10 ethoxy groups in one molecule), trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol hexaacrylate, etc. Methacrylic acid esters are mentioned.

As the polymerization initiator used in the composite resin of the present invention, a photopolymerization type initiator can be used. For example, JP-A-48-49875 (camphorquinone and amine), JP-A-57-203007 (camphorquinone and organic peroxide and amine), JP-A-60.
-26002 (camphorquinone and N, N-dimethylbenzoic acid alkyl ester), JP-A-60-14960
No. 3 (camphorquinone and aldehyde and organic peroxide), JP-A-60-197609 (camphorquinone and mercaptan), Japanese Patent Application No. 61-290780 (camphorquinone and azo compound), etc. Examples of the photopolymerization initiator that utilize visible light of
Further, a heat polymerization type initiator can be used,
Examples thereof include initiators such as peroxides and azo compounds having a use temperature range of 100 ° C. Further, it is also possible to use a room temperature polymerization type initiator which mixes the two packaged products at the time of use to initiate polymerization, and in this case, for example, benzoyl peroxide as a polymerization initiator and diethanol toluidine as an accelerator can be used. Such aromatic tertiary amines and aromatic sulfinates can be used.

As for the filler, silicon dioxide (quartz,
Quartz glass, silica gel), alumina, silicon as the main component, various heavy metals containing various boron and / or aluminum, various ceramics, diatomaceous earth, kaolin, clay minerals such as montmorillonite, activated clay, synthetic zeolite, mica Conventionally known substances such as calcium fluoride, calcium phosphate, calcium phosphate, barium sulfate, zirconium dioxide and titanium dioxide can be used.

For the surface treatment of the filler, a silane coupling agent usually used, for example, ω-methacryloxyalkyltrimethoxysilane (carbon number between methacryloxy group and silicon atom: 3-12), ω-methacryl Organosilicon compounds such as roxyalkyltriethoxysilane (carbon number between methacryloxy group and silicon atom: 3 to 12), vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltriacetoxysilane are used.

[0024]

The contents of the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Examples 1-5 and Comparative Examples 1-5 Various polymerizable monomers shown in Table 1 and camphorquinone 1
After mixing 2 parts by weight of dimethylaminoethylmethacrylate, 28 parts by weight of the mixture and silica 2
A photopolymerizable dental composite resin was prepared by thoroughly mixing and kneading parts by weight and 70 parts by weight of pulverized quartz powder. Next, these composite resins are 10m in diameter.
After photopolymerization was carried out in a mold for producing a cylindrical sample having a height of 10 mm and a height of 10 mm, a sample absorbed in water at 37 ° C. for 1 week was subjected to a wear resistance test. The test method was to use bovine anterior teeth as the opposing teeth, confine its labial surface only to the enamel portion, and horizontally move an ellipse-shaped flat surface with a major axis of about 15 mm with an amplitude of 4 mm. The cycle was repeated 50,000 times, in which the cylindrical sample prepared from the composite resin was impacted with the end face of the bovine tooth under a load of 40 kg and the sample was separated from the tooth again after 1 second.
The weight of the composite resin was measured before and after the test, and Table 1 shows the weight loss as the amount of wear. Compared with the comparative example, the resin of the example has a friction amount of about 1/2 to 1/3, and it is clear that the composite resin of the present invention has excellent wear resistance.

[0026]

[Table 1]

Examples 6 to 10 and Comparative Examples 6 to 10 Photopolymerizable dental composite resins prepared in the same manner as in Examples 1 to 5 and Comparative Examples 1 to 5 were placed in a mold and polymerized, A resin plate having a width of 2 cm, a length of 3 cm and a thickness of 3 mm was prepared. Next, this plate was immersed in water at 70 ° C. for 10 days for the purpose of promoting deterioration due to water absorption. Then 300
A resin plate was rubbed 40,000 times with a toothbrush (denter lion) using a toothbrush applied with g. Table 2 shows the results of measuring the depths of fifteen grooves from the deepest order of wear marks (grooves) using a contact-type surface roughness measuring instrument and determining the average value thereof. In the example, the depth of the wear scar is very shallow compared to the comparative example, and even under the condition of being easily deteriorated by water absorption,
It is clear that it has excellent wear resistance.

[0028]

[Table 2]

[0029]

EFFECTS OF THE INVENTION By using bisurethane acrylate methacrylate as the polymerizable monomer, it is possible to provide a dental composite resin having extremely excellent abrasion resistance in the oral cavity.

Claims (1)

[Claims] 1. A dental composite comprising a polymerizable monomer, a polymerization initiator and a filler as main components, wherein the polymerizable monomer is bisurethane acrylate methacrylate represented by the following chemical formula 1. Resin. [Chemical 1] (In the formula, R ¹ and R ² are each an acryloyloxyalkyl group, R ³ is a hydrogen atom or an acryloyloxyalkyl group, R ⁴ is an aliphatic alkylene group with or without a substituent, R ⁵ and R ⁶ represents a methacryloyloxyalkyl group, R ⁷ represents a hydrogen atom or a methacryloyloxyalkyl group, and n represents an integer of 0 or 1.)