JPH0967223A - Dental composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pasty dental composition having specific consistency, capable of impressing operation in the oral cavity, consisting of a combination of a specific thermoplastic elastomer, a (meth)acrylate-based monomer, and a polymerization initiator. SOLUTION: This dental composition with a consistency of 13-40 comprises (A) a thermoplastic elastomer composed of each at least one thermoplastic polymer block >=3000 in number-average molecular weight made from an aromatic vinyl monomer and elastomer polymer block, (B) a (meth)acrylate-based monomer, and (C) a polymerization initiator. The elastomer polymer block is at least one kind of polymer block especially selected from polyisoprene and isoprene-butadiene copolymers, being pref. a thermoplastic elastomer >=40mol% in vinyl bond content which is pref. a hydrogenated product or an unsaturated carboxylic acid adduct or its derivative adduct.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a dental composition. More specifically, it relates to a dental composition having a paste property that allows impression operation in the oral cavity. The composition of the present invention can be used as a material for dental wearing articles such as denture bases, orthodontic bases, temporary crowns, etc., which involve an impression operation in the oral cavity or on a plaster model.

[0002]

2. Description of the Related Art At present, in dental treatment, a denture base made of a polymerizable resin composition for a floor (hereinafter sometimes referred to as resin) is worn on a patient who has lost teeth due to age or the like. . In general, the denture base wearer remarkably absorbs the ridges, thins the mucous membrane that is responsible for cushioning, and collapses the alveolar bone due to bone resorption. It has been pointed out that compatibility with the oral cavity is reduced.

When the compatibility between the denture base and the oral cavity is reduced,
In general, a denture base mucosal surface called rebase (reformation) is reformed to restore compatibility with the oral cavity. Rebase methods can be broadly divided into two types: indirect methods and direct methods. The indirect method is a method of taking an impression of the shape of the oral cavity using an impression material, reproducing the oral model with the same shape as the oral cavity in the laboratory, and using the model to form the mucosal surface of the old denture base It is. On the other hand, in the direct method, a rebase material is laid on the mucosal surface of the denture base, the impression operation is performed in the oral cavity in the same way as the usual impression acquisition, and curing is performed while maintaining the shape of the obtained impression Is a method of performing rebasing. As described above, the indirect method is performed in a laboratory and requires many steps, so that it takes a considerable period of time to perform rebase. Cause trouble. In addition, since many impression operations are required during rebasing, errors during impression are likely to occur, and the possibility of lowering compatibility with the oral cavity is higher than in the direct method. For these reasons, the direct law is widely accepted at present.

[0004] The rebase material is generally made of a hard material having the same hardness as the denture base resin. However, when there is bite pain due to thinning of the oral mucosa,
Even if the compatibility with the oral cavity is restored, pain may still remain, and a soft material having appropriate viscoelasticity is often used in order to provide cushioning properties in place of mucous membranes. Conventionally, as a soft rebase material by a direct method, a soft resin in which a plasticizer is blended with an acrylic resin, a silicone resin-based lining material, and the like have been used [Kusakari et al., “Tooth World Outlook,” Vol. 72, No. 6, No. (1988), 1267-
1272]. These soft rebase materials are composed of a powder and a liquid, or two pastes, and are prepared so as to be hardened by kneading them immediately before use.

On the other hand, Japanese Patent Application Laid-Open No. 52-503 discloses that
(A) styrene-butadiene block copolymer,
(B) a liquid prepolymer of polybutadiene or a butadiene-styrene copolymer, (c) a photopolymerizable monomer,
A photosensitive resin composition for flexographic printing plates comprising (d) a photopolymerization initiator and (e) a thermal polymerization inhibitor optionally added is disclosed. From this composition, a molded article having rubber elasticity is obtained.

[0006]

By the way, it has been pointed out that the above-mentioned soft rebase material has a problem in that when it is inserted into the oral cavity, it is stimulated by the monomer of the raw material or stimulated by heat generated during curing. In addition, the cured product obtained from these soft rebase materials contains many air bubbles and has a high water absorption rate. However, there is also a problem that the bacterium is strongly contaminated by oral bacteria and has a strong odor.
Looking at each material, in the case of a soft resin in which a plasticizer is mixed with an acrylic resin, a problem is that the plasticizer is eluted in the oral cavity and the resin itself gradually hardens.
In addition, the silicone-based rebase material has problems that it is easily soiled in the oral cavity due to the nature of the material itself and that it has poor adhesiveness to the denture base and is easily peeled off during wearing.
Furthermore, denture stabilizers and tissue conditioners that have been used frequently in recent years lack stability in the oral cavity and are decomposed or hardened, so that they are limited to temporary use.

On the other hand, in the composition disclosed in Japanese Patent Application Laid-Open No. 52-503, a liquid prepolymer of polybutadiene or a butadiene-styrene copolymer enhances the adhesiveness to the oral mucosa and makes the impression operation difficult. To

The present invention has been made in view of the above-mentioned prior art, has a paste property suitable for performing an impression operation in the oral cavity, and has a suitable viscoelasticity stable in the oral cavity for a long period of time. It is an object of the present invention to provide a dental composition that can be maintained for a long time and that provides a cured product that is less contaminated in the oral cavity.

[0009]

The above object is achieved by (a) the aromatic vinyl monomer having a number average molecular weight of 3,000.
A thermoplastic elastomer having one or more blocks each of the above-mentioned thermoplastic polymer block (A) and elastomer polymer block (B), (b) a (meth) acrylate monomer and (c) a polymerization initiator, 13 ~ 40
A dental composition is characterized by having a consistency of.

The thermoplastic elastomer (a) used in the present invention comprises a thermoplastic polymer block (A) comprising an aromatic vinyl monomer and an elastomer polymer block (B).
And containing. One block (A) and one block (B) may be present in the thermoplastic elastomer (a), but a plurality of blocks may be present respectively.

The thermoplastic polymer block (A), which is a component of the thermoplastic elastomer (a), comprises aromatic vinyl monomer units and has a number average molecular weight of 3,000 or more. Examples of the aromatic vinyl monomer unit include styrene, 1-vinylnaphthalene, 2-vinylnaphthalene,
Examples include 3-methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene and the like. Of these, styrene is preferred. There is no particular limitation on the bonding manner of these monomer units, and a structure in which one of these monomer units is polymerized alone or a structure in which two or more monomer units are copolymerized may be used. .

The number average molecular weight of the thermoplastic polymer block (A) of the aromatic vinyl monomer unit needs to be 3,000 or more, and 3,000 to 1,000,000.
00 is preferable. The number average molecular weight of the block A is 3,0
If it is less than 00, a paste having excellent impression cannot be obtained.

[0013] The content of the thermoplastic polymer block (A) in the thermoplastic elastomer (a) is preferably in the range of 5 to 70% by weight. More preferably, 5 to 30
% By weight. When the content of the thermoplastic polymer block (A) is 5 to 70% by weight, the compatibility with the (meth) acrylate-based monomer (b) described later is good, and a paste having desired properties can be obtained.

The elastomer polymer block (B) in the thermoplastic elastomer (a) is composed of monomer units constituting a known thermoplastic elastomer. The bonding mode of the monomer units is not particularly limited, and may have a structure in which one of the monomer units is polymerized alone, or a structure in which two or more types of monomer units are copolymerized.

[0015] Among them, a thermoplastic elastomer polymer composed of at least one monomer unit selected from isoprene, isobutylene, butadiene and butyl acrylate, a hydrogenated product of the polymer, and an unsaturated carboxylic acid or Adducts of the acid derivatives are preferred. The block (B) composed of these polymers is
One of the above-mentioned elastomer polymer, its hydrogenated product and its adduct may be used as a component, or a plurality of the above may be used as a component.

Further, as the block (B), a thermoplastic elastomer polymer composed of at least one selected from polyisoprene and isoprene-butadiene copolymer and having a vinyl bond content of 40 mol% or more;
Also preferred are hydrogenated products of the polymer and adducts of unsaturated carboxylic acids or derivatives of the acid in the polymer. Similarly to the above, these may be composed of one of the elastomer polymer, its hydrogenated product and its adduct, or may be composed of plural components. Here, the vinyl bond content refers to an ethylenic double bond in a side chain generated by the following bonding mode among all carbon-carbon double bonds contained in an elastomer polymer block of polyisoprene or isoprene-butadiene. (Mol%).

The unsaturated carboxylic acid and its derivative to be added to the thermoplastic elastomer polymer include maleic anhydride, maleic acid, fumaric acid, acrylic acid, itaconic acid, crotonic acid and the like.

The elastomeric polymer block (B) containing isoprene and butadiene monomers forms a 1,2 bond or a 3,4 bond depending on the polymerization mode to form an ethylenic double bond in a side chain. This ethylenic double bond is 1,
It is more reactive than the double bond of the main chain formed by 4 bonds and can be copolymerized with the (meth) acrylate monomer (b). Therefore, the elastomer (a) having the polymer block having the bond gives a paste having excellent polymerization curability, and the polymer cured product has a small permanent set due to chemical cross-linking, and thus is suitable.

The content of the elastomer polymer block (B) in the thermoplastic elastomer (a) is preferably in the range of 30 to 95% by weight, more preferably 70 to 95% by weight.

Examples of the thermoplastic elastomer (a) include diblocks, triblocks, multiblocks, star-shapes having a polystyrene block, and taper-types in which the boundaries between blocks are gradually changed by random copolymerization. Styrene-isoprene-based elastomer, styrene-butadiene-based elastomer which is a thermoplastic elastomer containing a polystyrene-based block copolymer,
Styrene-isoprene-butadiene-based elastomer, styrene-isobutylene-based elastomer, styrene-butyl acrylate-based elastomer and the like can be mentioned.

Among these, Japanese Patent Application Laid-Open No. 2-102212
Thermoplastic elastomers disclosed in
In the molecule, two or more blocks of an aromatic vinyl monomer having a number average molecular weight of 3,000 or more and 40,000 or less and one block of isoprene and / or isoprene-butadiene having a vinyl bond content of 40 mol% or more are included. And the molecular weight is 40,000 or more and 300,0 or more.
The block copolymer of not more than 00 has, in addition to the above properties,
Since the polymer cured product of the present invention is fitted in the mouth and bites, it is particularly suitable because it has excellent vibration damping performance.

A paste containing an elastomer generally tends to recover from creep. This phenomenon indicates that when taken out after performing an impression in the oral cavity, it is easy to return to the pre-impression form over time, indicating that it is not suitable for impression. However, by having a thermoplastic elastomer block composed of an aromatic vinyl monomer, creep recovery is unlikely to occur, and a composition having excellent impression can be obtained.

The rubber hardness of the thermoplastic elastomer (a) is not particularly limited, but is preferably in the range of 30 to 90. Here, the rubber hardness refers to JIS K 62
This is a value measured using a durometer type A according to No. 53.

As the (meth) acrylate monomer (b), either a monofunctional (meth) acrylate or a polyfunctional (meth) acrylate can be used. As the monofunctional (meth) acrylate, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
Hexyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, myristyl (meth) acrylate and stearyl (meth) acrylate such as alkyl (meth) acrylate (alkyl group having 1 to 20 carbon atoms), methoxyethyl ( Meth) acrylate, 2-phenoxyethyl (meth) acrylate,
Methoxy polyethylene glycol (meth) acrylate (degree of polymerization 2 to 10), tetrahydrofurfuryl (meth)
Examples include acrylate, isobornyl (meth) acrylate, undecenyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate (HEMA), and dimethylaminoethyl (meth) acrylate.

Examples of the polyfunctional (meth) acrylate include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and neopentyl glycol. Di (meth) acrylate,
Alkylene glycol di (meth) acrylate (alkylene group having 1 to 20 carbon atoms) such as 1,6-hexanediol di (meth) acrylate and 1,10-decanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, Polyalkylene glycol di (meth) acrylates such as triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate and polyethylene glycol di (meth) acrylate (where the alkylene group has 2 to 4 carbon atoms;
And a polymerization degree of 2 to 200), glycerin di (meth) acrylate, 2,2′-bis [p- (γ-methacryloxy-
β-hydroxypropoxy) phenyl] propane (Bi
s-GMA), bisphenol A dimethacrylate,
2,2′-bis (4-methacryloxypolyethoxyphenyl) propane (2 to 10 ethoxy groups per molecule),
Examples thereof include 1,2-bis (3-methacryloxy-2-hydroxypropoxy) butane, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and urethane (meth) acrylate. These (meth) acrylate monomers are used alone or in combination of two or more.

Among these, the alkyl (meth) acrylate and the alkylene glycol di (meth) acrylate are the thermoplastic elastomers (a) used in the present invention.
It is particularly high in compatibility with and is suitable. It is desirable that these alkyl (meth) acrylates or alkylene glycol di (meth) acrylates are contained in the (meth) acrylate-based monomer (b) in an amount of 40% by weight or more.

As the (meth) acrylate monomer (b), n-hexyl (meth) acrylate, n
When a monofunctional (meth) acrylate having an alkyl group or an alkenyl group having a large number of carbon atoms (6 or more carbon atoms) such as lauryl (meth) acrylate or n-stearyl (meth) acrylate is mainly used, a soft cured product is obtained. Is obtained. On the other hand, as the (meth) acrylate-based monomer (b), methyl (meth) acrylate, n-butyl (meth)
When a monofunctional (meth) acrylate or polyfunctional (meth) acrylate having an alkyl group or an alkenyl group having a small number of carbon atoms such as acrylate is mainly used, a relatively hard cured product tends to be obtained.

Examples of the polymerization initiator (c) in the present invention include a photopolymerization initiator, a thermal polymerization initiator and a room temperature polymerization initiator. Examples of the photopolymerization initiator include camphorquinone, diacetyl, 2,3-pentanedione, benzyl, α-diketones such as acenaphthenequinone and phenanthraquinone, benzoin methyl ether, benzyl dimethyl ketal, benzophenone, and 2-ethyl. Thioxanthone and the like can be mentioned. These photopolymerization initiators,
It is optionally used as a photopolymerization initiator system in combination with a reducing agent such as a tertiary amine, an aldehyde or a mercaptan. Examples of such tertiary amines include N, N-dimethylaminoethyl methacrylate, ethyl N, N-dimethylaminobenzoate, bis-N, N-dimethylaminobenzophenone, N, N-dimethylaminobenzaldehyde and N-phenyl. Examples thereof include glycine, morpholino methacrylate, triethanolamine, N-methyldiethanolamine, 2-n-butoxyethyl N, N-dimethylaminobenzoate, and isoamyl N, N-dimethylaminobenzoate. Examples of the aldehyde include citronellal, lauryl aldehyde, o-phthaldialdehyde, p-octyloxybenzaldehyde and the like. Examples of the mercaptan include 1-decanethiol, thiosalicylic acid, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 4-mercaptoacetophenone, 4-t-butylthiophenol, and the like. it can. Further, a system in which an organic peroxide such as benzoyl peroxide is added to the photopolymerization initiator system is also preferably used.

Examples of the thermal polymerization initiator include peroxides such as benzoyl peroxide, di-t-butyl peroxide and cumene hydroperoxide, azo compounds such as azobisisobutyronitrile, and tetramethylthiuram disulfide. Initiators such as can be used.

Further, as the room temperature polymerization initiator, redox type initiators such as organic peroxide / aromatic tertiary amine type and organic peroxide / aromatic tertiary amine / aromatic sulfinic acid type are used. It

When a combination of an oxidant and a reducing agent is contained as the polymerization initiator (c), from the viewpoint of storage stability, they are dividedly packed so that they are not mixed with each other, and they are mixed immediately before use. There is a need to.

The blending amounts of the thermoplastic elastomer (a), the (meth) acrylate-based monomer (b) and the polymerization initiator (c) in the dental composition of the present invention depend on the kind of the thermoplastic elastomer (a) used and Although it varies depending on the molecular weight, the type of the (meth) acrylate-based monomer (b), etc., it is usually the heat of the thermoplastic elastomer (a), the (meth) acrylate-based monomer (b) and the polymerization catalyst (c). The plastic elastomer (a) is 40 to 80% by weight, the (meth) acrylate-based monomer (b) is 60 to 20% by weight, and the polymerization catalyst (c) is 0.
The amount of component (a) is preferably 50 to 5% by weight.
-60% by weight, component (b) is 50-40% by weight, (c)
The component is 0.1-3% by weight.

The composition of the present invention has a number average molecular weight of 3 in addition to the thermoplastic elastomer (a), the (meth) acrylate monomer (b) and the polymerization initiator (c).
A polymer having no block of an aromatic vinyl monomer unit having a molecular weight of not less than 000 (hereinafter abbreviated as polymer (d)) was used to adjust the paste properties of the composition and the properties of the cured product. Can be added in an amount not exceeding 10% by weight.

As the polymer (d), known polymers are used without any particular limitation. Examples thereof include isoprene rubber, butadiene rubber, styrene-butadiene rubber (random copolymer), hydrogenated styrene-butadiene rubber, chloroprene rubber, Nitrile rubber, butyl rubber, ethylene-propylene rubber, chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, polysulfide rubber, silicone rubber, fluorine rubber, urethane rubber, polyolefin thermoplastic elastomer, polyurethane thermoplastic elastomer, polyester thermoplastic Elastomers such as elastomers, polyamide-based thermoplastic elastomers, 1,2-polybutadiene-based thermoplastic elastomers, ethylene-vinyl acetate-based thermoplastic elastomers, and polyvinyl chloride-based thermoplastic elastomers And the like. However, a liquid prepolymer having a relatively low molecular weight selected from polybutadiene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, and derivatives thereof is not included in the polymer (d) of the present invention. The addition of these liquid prepolymers significantly increases the adhesion to the oral mucosa, making the impression manipulation in the oral cavity difficult. Further, as the polymer (d), polyethylene, polypropylene, polyvinyl chloride, polystyrene, polymethyl methacrylate,
Polyethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polycarbonate, nylon, polyurethane, polychloroprene, polyvinyl fluoride, polyethylene oxide, polyoxymethylene, polyacrylonitrile, polyvinyl alcohol, polyvinylidene chloride, polyvinylidene fluoride, cellulose, polyester, Conventionally known polymers such as polyamide and cellulose acetate can also be used.

If necessary, a small amount of hydroquinone, hydroquinone monomethyl ether, butylhydroxyl toluene and the like may be added to the composition of the present invention as a polymerization inhibitor. In order to enhance the stability of the thermoplastic elastomer, a small amount of an antioxidant, a light stabilizer or the like can be added. Furthermore, in order to adjust the properties of the paste and the cured product to more suitable ones, various lubricants, surfactants,
Inorganic fillers, plasticizers and the like may be added in small amounts, and pigments, dyes, and fibers for mimic blood vessels may be added to give the composition a gingival color.

The composition of the present invention is usually provided as a paste by mixing a thermoplastic elastomer (a), a (meth) acrylate monomer (b), a polymerization initiator (c) and the like. As a mixing method of each component, a known method is used without any particular limitation, and examples thereof include kneading with a solvent and melt kneading. Specifically, a thermoplastic elastomer (a), (meth)
A method of dissolving the acrylate-based monomer (b) and the polymerization initiator (c), mixing them uniformly, and then removing the solvent, or a method of kneading using a kneader such as Laboplast mill (manufactured by Toyo Seiki Co., Ltd.) Etc., which allows a uniform paste to be prepared. The resulting paste is
It is preferable to perform a defoaming treatment.

The dental composition of the present invention has a consistency in the range of 13 to 40, and has a paste property suitable for impression operation in the oral cavity. Preferred consistency is 15 or more 3
The range is 5 or less. The paste consistency referred to in the present invention refers to a value measured by the method described in ISO4823 (1992 edition), and represents the hardness of the paste,
It is an indicator of the fluidity of the paste. If the consistency of the paste is out of the above range, the impression operability in the oral cavity is impaired, which is not desirable.

The dental composition of the present invention is excellent not only in the ability to take an impression in the oral cavity, but also in the property of retaining the shape after taking the impression. Such a property has a stress relaxation rate when the paste is plastically deformed by applying a constant load to the paste (in the present invention, a value measured by a method described in Examples described later is a stress relaxation rate) as an index. It can be shown quantitatively.

The dental composition of the present invention has a stress relaxation rate of 9
It is 0% or more, and when the paste is plastically deformed, the force applied to maintain the plastic deformation is extremely small.
Therefore, the impression shape obtained is retained well even if the impression is taken in the oral cavity, removed from the oral cavity, and left as it is. The stress relaxation rate of the paste is 9
If it is less than 0%, the impression shape obtained will change with the lapse of time unless the force for holding the deformation is applied to the plastically deformed paste, and the rebase obtained by hardening this It is not desirable because the compatibility between the material and the oral cavity is impaired.

The procedure for forming a rebase material from the composition of the present invention is as follows. That is, the composition of the present invention is laid on the mucosal surface of the denture base, and an impression is taken in the oral cavity. Thereafter, the denture base is removed by removing from the oral cavity and polymerizing and hardening by a method such as light irradiation or room temperature polymerization while maintaining the impression after collection.

As the rebase material of the composition of the present invention, a cured product having an appropriate rubber elasticity can be obtained by using the specific thermoplastic elastomer (a), and the rubber elasticity is maintained for a long time. Furthermore, by using the (meth) acrylate monomer (b), the water absorption of the obtained cured product is low, and a low value of water absorption is maintained over a long period of time. In addition, the amount of eluted substances from the cured product is small, and the contamination in the oral cavity can be suppressed low.

The composition of the present invention is not limited to a rebase material, and can be used as a material for dental wearing articles such as denture bases, orthodontic bases, temporary crowns, etc., which involve an impression operation in the oral cavity. Further, it can be used not only as an impression operation in the oral cavity but also as a material for a dental wearing article on a plaster model or the like.

[0043]

The present invention will be described in detail with reference to the following examples. The present invention is not limited to this embodiment.

In this example, the paste properties of the composition, the mechanical properties of the cured product obtained from the composition, and the water absorption were measured by the following methods.

(1) Consistency of composition Measured according to the method described in ISO 4823. That is, at 25 ° C., 0.5 ml of the composition is formed into a cylindrical shape having a diameter of 10 mm and placed on a glass plate. Another glass plate and a weight (total of 1500 g) are gently placed on the top of the columnar composition, and after 5 seconds, the glass plate 2 and the weight are removed. For the shape of the composition spread on the glass plate, the maximum and minimum dimensions between the parallel cut lines were determined, the average was calculated, and 1 m
Expressed in units of m. This test is repeated three times to obtain consistency.

(2) Stress relaxation rate of composition The composition is packed in a container having a depth of 7 mm and a diameter of 30 mm to prepare a measurement sample. Rheometer [Fudo Kogyo Co., Ltd.]
Under the condition of 25 ℃, the diameter of 2
A 0 mm spherical jig is pushed in at a speed of 50 mm per minute until the weight applied to the spherical jig reaches 500 gf. When the load (f ₀ ) applied to the spherical jig reaches 500 gf, the crosshead is stopped and maintained for 60 seconds. The load (f ₁ ) applied to the jig after 60 seconds is measured, and the stress relaxation rate is calculated by the following formula.

[0047]

[Equation 1]

(3) Rubber hardness of cured product A mold having a diameter of 10 mm and a thickness of 10 mm is filled with the composition,
Dental light irradiator [Alpha Light, Kuraray Co., Ltd.]
For 10 minutes and polymerized and cured, and the obtained cured product was used as a test piece. After the test piece was immersed in water at 37 ° C. for one day, the rubber hardness was measured using a durometer type A (manufactured by Furusato Seiki Seisakusho) according to JIS K6253.

(4) Fatigue durability of cured product A mold having a diameter of 10 mm and a thickness of 10 mm was filled with the composition,
Dental light irradiator [Alpha Light, Kuraray Co., Ltd.]
Was irradiated with light for 10 minutes to polymerize and cure, and the obtained cured product was used as a test piece to perform a compression fatigue test in water at 37 ° C. That is, the test piece was immersed in water at 37 ° C., and using a servo pulser-4880 (manufactured by Shimadzu Corporation), a sine wave (5H with a maximum compression load of 2 kgf and a minimum compression load of 0.2 kgf) was used.
z) was repeatedly applied up to 1,000,000 times and the change in displacement was observed. When the displacement reached 3 mm or more (30% of the total length of the test piece), the measurement was stopped at that time.

(5) Water Absorption and Dissolved Amount of Hardened Material The method was as described in ISO1567. That is, a mold having a diameter of 20 mm and a thickness of 1 mm was filled with the composition and irradiated with alpha light for 10 minutes for polymerization and curing, and the obtained cured product was used as a test piece. The test piece was placed in a desiccator, kept in an oven at 37 ± 2 ° C. for 23 hours, transferred to a desiccator kept at 23 ± 2 ° C., and after one hour, the test piece was taken out of the desiccator, and the mass of the test piece was measured. Weigh to the nearest 0.2 mg. This operation is repeated until the weighed value of the mass of the test piece reaches a constant value within a range of 0.2 mg within 24 hours, and the weighed value at this time is taken as the mass of the test piece (W ₁ ). next,
The test piece is immersed in distilled water at 37 ± 2 ° C. for 7 days, then taken out with tweezers, the surface water is wiped off, and the mass of the test piece is weighed (W ₂ ). Then, the test piece after such operation is put in a desiccator kept at 37 ± 2 ° C,
After being kept in the oven for 23 hours, transferred to a desiccator kept at 23 ± 2 ° C., and after 1 hour, the test piece is taken out from the desiccator. This operation is repeated until the measured value of the mass of the test piece reaches a constant value within a range of 0.2 mg within 24 hours (measured value at this time: W ₃ ). When the volume of the test piece is V (mm ³ ),
Water absorption (μg / mm ³ ) and elution amount (μg / mm ³ )
Is calculated from the following formula.

[0051]

[Equation 2]

[0052]

(Equation 3)

Example 1 Styrene-isoprene thermoplastic elastomer (SI
S) and having a styrene content of 20% by weight, Hibler VS-1 [manufactured by Kuraray Co., Ltd.] 60 g, n-lauryl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., hereinafter abbreviated as LM) 38 g, 1,10-decane. 2 g of diol dimethacrylate (manufactured by Kyoeisha Chemical Co., Ltd., hereinafter abbreviated as DD), 0.5 g of camphorquinone (hereinafter abbreviated as CQ), 2-dimethylaminoethyl methacrylate (hereinafter DMAEMA)
0.5 g) and benzoyl peroxide (hereinafter abbreviated as BPO) 0.5 g were dissolved and mixed at room temperature to form a paste. Table 1 and Table 2 show the properties of the obtained paste, the mechanical properties of the cured product obtained from the paste, and the water absorption.

Example 2 Styrene-butadiene thermoplastic elastomer (SB
S) with a styrene content of 23% by weight
-TR2825 [manufactured by Japan Synthetic Rubber Co., Ltd.] 60 g, L
M38g, DD2g, CQ0.5g, DMAEMA0.
5 g and 0.5 g of BPO were dissolved and mixed at room temperature to form a paste. Table 1 and Table 2 show the properties of the obtained paste, the mechanical properties of the cured product obtained from the paste, and the water absorption.

Example 3 60 g of the Hibler VS-1 used in Example 1, 38 g of isodecyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., hereinafter abbreviated as IDM), 2 g of DD, 0.5 g of CQ and DMAE.
0.5 g of MA and 0.5 g of BPO were dissolved and mixed at room temperature to form a paste. Table 1 and Table 2 show the properties of the obtained paste, the mechanical properties of the cured product obtained from the paste, and the water absorption.

Example 4 60 g of the Hibler VS-1 used in Example 1, 38 g of tridecyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., hereinafter abbreviated as TDM) 38 g, DD2 g, CQ 0.5 g, DMAE
About 0.5 g of MA and 0.5 g of BPO is about 1 methylene chloride.
00 ml was added and dissolved and mixed, and the solvent was removed by evaporation to form a paste. Table 1 and Table 2 show the properties of the obtained paste, the mechanical properties of the cured product obtained from the paste, and the water absorption.

Example 5 Styrene-isoprene thermoplastic elastomer (SI
S), with a styrene content of 20% by weight, Hibler VS-3 (manufactured by Kuraray) 60 g, LM38 g, DD2
g, CQ 0.5 g, DMAEMA 0.5 g, BPO0.
5 g was melted and mixed at room temperature to form a paste. Table 1 and Table 2 show the properties of the obtained paste, the mechanical properties of the cured product obtained from the paste, and the water absorption.

Example 6 60 g of the Hibler VS-1 used in Example 1, LM
38g, DD2g, CQ0.5g and DMAEMA
0.5 g was dissolved and mixed at room temperature to form a paste. Table 1 shows the properties of the obtained paste, the mechanical properties and the water absorption of the cured product obtained from the paste, and the like.

Example 7 54 g of the Hibler VS-1 used in Example 1 and N239SV (manufactured by Nippon Synthetic Rubber Co., Ltd.) which is a nitrile rubber 6
g, LM38g, DD2g, CQ0.5g, DMAEM
A 0.5 g and BPO 0.5 g are dissolved and mixed at room temperature,
Pasted. Table 1 shows the properties of the obtained paste, the mechanical properties of the cured product obtained from the paste, and the water absorption amount.
Shown in

Example 8 60 g of the Hibler VS-1 used in Example 1 was used.
6-hexanediol dimethacrylate (manufactured by Kyoeisha Chemical Co., Ltd., hereinafter abbreviated as HD) 40 g, CQ 0.5 g, DM
0.5 g of AEMA and 0.5 g of BPO were dissolved and mixed at room temperature to form a paste. Table 1 shows the properties of the obtained paste, the mechanical properties and the water absorption of the cured product obtained from the paste, and the like.

Example 9 Styrene-isoprene thermoplastic elastomer (SI
SSR) JSR-SIS5000 (manufactured by Japan Synthetic Rubber Co., Ltd.) 50 g and maleic anhydride 2 g are used in a plastic coder (manufactured by Brabender Co.) at 150 ° C. and 80 rpm.
Reaction for 30 minutes under conditions, maleic anhydride modified SIS
I got 20 g of the maleic anhydride-modified SIS, 30 g of JSR-TR2825 used in Example 2, LM38
g, DD2g, CQ0.5g, DMAEMA0.5g and BPO0.5g were dissolved and mixed at room temperature to form a paste. Table 1 shows the properties of the obtained paste, the mechanical properties and the water absorption of the cured product obtained from the paste, and the like.

COMPARATIVE EXAMPLE 1 70 g of N239SV which is a nitrile rubber and 28.5 LM
g, DD1.5g, CQ0.5g, DMAEMA0.5
g and BPO 0.5 g were melt mixed at room temperature to form a paste. The obtained paste had a consistency of 19 and a stress relaxation rate of 88%. This paste, after measuring the stress relaxation rate,
It was observed that when the spherical jig was removed and left to stand, the deformation given by the spherical jig gradually became smaller and the shape returned to its original shape. From this, it can be understood that the paste has a poor impression.

Comparative Example 2 A tissue tender (manufactured by Kamemizu Kagaku Co., Ltd.), which is commercially available as a denture base soft rebase material, was prepared according to the manufacturer's instructions by using a powder agent [mainly polyethylmethacrylate (PEMA)] and a liquid agent [(meth) acrylate]. A mixture containing a system monomer as a main component] was mixed, and the rice cake-shaped mixture was charged into a predetermined mold and heat-polymerized. The mechanical properties and water absorption of the obtained cured product are shown in Tables 1 and 2. The paste of this material gradually hardened over time. Also, the fatigue resistance of the cured product was poor.

Comparative Example 3 Triad VLC (manufactured by Dentsply), which is commercially available as a denture base hard rebase material, was used for comparison of paste properties. This product is provided as a paste-like composition, and contains an organic polymer powder containing inorganic fine particles as a filler. Paste consistency is 1
1. The stress relaxation rate was 88%. Since this paste was a hard paste and had a low stress relaxation rate, the impression operability in the oral cavity was poor.

Comparative Example 4 55 g of the Hibler VS-1 used in Example 1 was mixed with Nisso PB. B-2000 (Nippon Soda) 45 g, CQ 0.5 g, DMAEMA 0.5 g
And 0.5 g of BPO were dissolved in 300 g of methylene chloride, and after uniformly dissolving, methylene chloride was distilled off under reduced pressure to form a paste. This paste had a strong adhesiveness, and when the impression operation was performed in the oral cavity, the paste adhered to the oral mucosa and the impression operation could not be performed. Table 1 shows the properties of the obtained paste, the mechanical properties and the water absorption of the cured product obtained from the paste, and the like.

[0066]

[Table 1]

[0067]

[Table 2]

As is clear from Tables 1 and 2, the composition of the present invention has a paste property suitable for impression operation in the oral cavity. Further, the obtained cured product has high fatigue resistance, long-term stable mechanical properties, and has a small amount of water absorption and a small amount of eluate, and thus is excellent in stain resistance.

Example 10 The mucosal surface of a PMMA denture base was further ground to build up the same paste as that obtained in Example 1. A denture base with built-up paste is placed in the oral cavity and an impression is taken. After taking the impression, the denture base is taken out of the oral cavity, and the unnecessary portion of the paste that has protruded is removed. The denture base was immersed in water and exposed to oxygen as much as possible for 5 minutes with a dental light irradiator (Alpha Light) to polymerize and cure. The denture base thus ribbed had good oral compatibility and did not give pain to the oral mucosa.

[0070]

EFFECTS OF THE INVENTION According to the present invention, there is provided a dental composition having a paste property that allows impression operation in the oral cavity. The cured product obtained from the composition of the present invention has long-term stable mechanical properties and is also excellent in stain resistance in the oral cavity.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mizuho Maeda 36, Towada, Kamisu-cho, Kashima-gun, Ibaraki Pref. Kuraray Co., Ltd. Inventor Eiichi Masuhara 2-5-11 Honkomagome, Bunkyo-ku, Tokyo (72) Inventor Naoto Masuhara 2-5-11 Honkomagome, Bunkyo-ku, Tokyo (72) Inventor Jiro Tarumi 2-6, Tsutsujigaoka, Akishima-shi, Tokyo 21-510

Claims (4)

[Claims] 1. A thermoplastic elastomer comprising (a) a thermoplastic polymer block (A) composed of an aromatic vinyl monomer having a number average molecular weight of 3,000 or more and an elastomer polymer block (B), each having one or more blocks. ,
A dental composition comprising (b) a (meth) acrylate-based monomer and (c) a polymerization initiator and having a consistency of 13 to 40. 2. An elastomeric polymer block (B) comprising:
Thermoplastic elastomer polymer composed of at least one monomer selected from the group consisting of isoprene, isobutylene, butadiene and butyl acrylate, hydrogenated product of the thermoplastic elastomer polymer, and unsaturation of the thermoplastic elastomer polymer The dental composition according to claim 1, which is at least one polymer block selected from a carboxylic acid or an adduct of a derivative of the acid. 3. An elastomeric polymer block (B) comprising:
The dental composition according to claim 1, which is a thermoplastic elastomer polymer having at least one polymer block selected from polyisoprene and isoprene-butadiene copolymer and having a vinyl bond content of 40 mol% or more. 4. The thermoplastic elastomer polymer is at least one selected from a hydrogenated product of the thermoplastic elastomer polymer and an unsaturated carboxylic acid or an adduct of a derivative of the acid of the thermoplastic elastomer polymer. The dental composition according to claim 3.