JP2005179236A - Radically polymerizable composition for dental material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a composition for a dental material, having excellent balance between hydrophilicity and water resistance from the viewpoint of adhesiveness to dentin, low shrinkability to control minute leakage, compensation of contraction by swelling and retention of mechanical strengths during swelling. <P>SOLUTION: The radically polymerizable composition for the dental material comprises a specific tertiary hydroxy group-containing (meth)acrylate as an essential component. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a radically polymerizable dental material composition containing a specific monomer as an essential component.

  In the field of dental materials, many (meth) acrylic monomer compositions are used. It can be used in a wide range of applications, including crown restoration materials such as chemically and photopolymerizable composite resins, adhesives between composite resins or metals and enamel or dentin, sealants, artificial crown materials, polycarbonate crowns, Examples include temporary crown materials, denture base materials, denture base lining materials, repair materials, impression materials, etc. with immediate-curing resins for crowns. These are characterized by superior aesthetics compared to other metal materials and resistance to impacts compared to ceramic materials. However, the environment in the oral cavity is never a good environment for polymerizing (meth) acrylic monomers. For example, when a thermal initiator is used, a reaction temperature range from room temperature to body temperature must be used. For this reason, the polymerization may not be completely completed, and even when a photoinitiator is used, it is difficult to uniformly irradiate light on the cavity surface of a complicated shape, and there is a portion where the polymerization is not completely completed. Occur. For this reason, the residual monomer gradually diffuses, and there is a problem in that the dental pulp tissue may be damaged and necrotic.

  This problem has been avoided to some extent by the use of polyfunctional monomers and is now triethylene glycol dimethacrylate and 2,2-bis [4- (3-methacryloyloxy-2-hydroxypropoxy) phenyl] propane (Bis-GMA). Is generally used. However, when these polyfunctional monomers are used, the volume shrinkage during polymerization is large, so the interface between the tooth and the composite resin peels off, creating gaps, and irritating substances and bacteria enter through the gaps. Leakage issues will arise. Therefore, the present situation is that the addition of a large amount of an inorganic filler suppresses polymerization shrinkage and prevents minute leakage. As the content of the inorganic filler increases, the processability becomes remarkably inferior, and improvement is still required.

  On the other hand, various attempts have been made to use etching and primers as an attempt to firmly bond a general-purpose composite resin to a tooth. At present, it is based on a method in which the tooth surface that has been decalcified by etching is treated with a primer and bonded to the composite resin with a bonding agent. As this primer, 2-hydroxyethyl methacrylate (2-HEMA), which is a methacrylate monomer having a hydroxyl group, is also used. The purpose of this etching and primer treatment is to improve the mechanical adhesion due to the micro-throwing effect, but the procedure is complicated and the operation time is long, and if it is contaminated with saliva during the operation, the adhesive strength is significantly reduced. In addition, there is a need for improvement due to concerns about the effects on the dental pulp and surrounding tissues. Attempts to improve adhesion to tooth by mixing polyacrylic acid aqueous solution with cement are also known, but use is limited because of low polymerization curability and reduced mechanical strength due to moisture. There was a case. Further, it is disclosed that the number of hydroxyl groups is important in the use of dental adhesives, and that a highly hydrophilic (meth) acrylate has poor adhesion and water resistance characteristics, and the balance between adhesion and water resistance is important. (See Patent Document 1).

JP 05-004942 A

  Therefore, the present invention is a performance required throughout the composition for dental materials, such as adhesion to the tooth, low shrinkage to suppress microleakage, compensation for shrinkage due to swelling, and mechanical strength during swelling. It is an object of the present invention to provide a composition for a dental material that is excellent in the balance between hydrophilicity and water resistance in terms of retention of water.

  The present inventor has a dental material composition that is interposed between layers of a restoration material such as a tooth and a tooth, a tooth and a composite resin or metal, or a dental material useful as a material for a composite resin. As a result of various studies from the viewpoint of molecular design of the (meth) acrylate to be blended, when (meth) acrylate having a tertiary hydroxyl group is blended as an essential component, excellent adhesiveness, curability, and moderate swelling It has been found that a radically polymerizable dental material composition can be obtained which can realize the performance required throughout the dental material composition in a well-balanced manner, such as the ability to seal the edge by the edge and the maintenance of the mechanical strength during swelling.

  That is, this invention relates to the radically polymerizable dental material composition characterized by including the tertiary hydroxyl group containing (meth) acrylate of Formula (1) as an essential component.

（式中、Ｒ_１、Ｒ_２は独立して炭素数１〜４のアルキル基、Ｒ_３は繰り返し単位毎に独立してメチル基又は水素原子、Ｒ_４はメチル基又は水素原子を表し、ｎは１から３の整数を示す。）
なお、本発明における（メタ）アクリレートとはメタクリレートとアクリレートの両者を意味する。

(Wherein R ₁ and R ₂ are each independently an alkyl group having 1 to 4 carbon atoms, R ₃ is independently a methyl group or a hydrogen atom for each repeating unit, R ₄ is a methyl group or a hydrogen atom, and n Represents an integer from 1 to 3.)
The (meth) acrylate in the present invention means both methacrylate and acrylate.

  Since the radically polymerizable dental material composition of the present invention contains a tertiary hydroxyl group-containing (meth) acrylate monomer, it provides a cured product with excellent water resistance as well as excellent adhesion to the tooth. Therefore, for crown restoration materials such as chemical polymerization and photopolymerization type composite resins, adhesives between composite resins or metals and enamel or dentin, sealants, artificial crown materials, polycarbonate crowns and crowns It is useful in the fields of temporary crown materials, denture base materials, denture base lining materials, repair materials, impression materials, primers, bonding agents, etc.

  The radical polymerizable dental material composition according to the present invention is characterized in that a tertiary hydroxyl group-containing (meth) acrylate is contained as an essential component. The tertiary hydroxyl group has hydrophilicity, but also exhibits water resistance due to the influence of the alkyl group present in the adjacent carbon. By using the tertiary hydroxyl group-containing (meth) acrylate as an essential component, hydrophilicity and water resistance are achieved. Excellent physical properties with excellent balance of properties. For example, when the composition of the present invention is used as a dental filler, the hardened dental filler absorbs saliva in the oral cavity and swells and expands in volume, thereby suppressing microleakage. It is difficult to cause a decrease in mechanical strength due to swelling, a decrease in adhesiveness caused by the swelling, and the like, which has been a concern in the past.

  As components other than the essential components of the radical polymerizable dental material composition in the present invention, known components are blended as necessary. For example, when used as a dental adhesive or a composite resin, the essential components and radicals are used. It contains a copolymerizable vinyl monomer and a radical polymerization initiator, and is composed of an organic filler or an inorganic filler as required.

  The tertiary hydroxyl group-containing (meth) acrylate, which is an essential component used in the present invention, is preferably a compound of formula (1), such as 2-hydroxy-2-methylpropyl (meth) acrylate, 3-hydroxy-1, 3- Examples thereof include dimethylbutyl (meth) acrylate and 3-hydroxy-3-methylbutyl (meth) acrylate, but 2-hydroxy-2-methylpropyl (meth) acrylate of formula (2) (hereinafter 2-HBMA) is more preferable. . These may be used alone, or a plurality of these may be selected and used.

（式中、Ｒ_５はメチル基又は水素原子を表す。）

(In the formula, R ₅ represents a methyl group or a hydrogen atom.)

  The content of the tertiary hydroxyl group-containing (meth) acrylate, which is an essential component of these dental material compositions, is preferably 3% by weight or more, more preferably 5% by weight or more, and particularly preferably 15% by weight or more. . When the amount is less than 3% by weight, the amount of the functional group of the tertiary hydroxyl group introduced is small, so that the characteristics of the present invention are hardly exhibited.

Examples of vinyl monomers capable of radical copolymerization with essential components include hydroxy (meth) acrylates, (meth) acrylates, aromatic vinyl compounds, vinyl compounds, α-olefins, N-substituted maleimides, acrylamides, and vinylpyrrolidone. And polyfunctional monomers. The kind and content can be selected according to the purpose of use, and several kinds may be used in combination. For example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl Alkyl (meth) acrylates such as (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxy (meth) acrylates such as glyceryl mono (meth) acrylate, (meth) acrylic Carboxyl group-containing (meth) acrylates such as acids, (meth) acrylates having an anhydrous carboxyl group, (meth) acrylates having a phosphate group, 2- (meth) acryloyloxyethyl phosphoric acid (Meth) acrylates having phospholipid-like functional groups such as choline, aromatic vinyl compounds such as styrene, α-methylstyrene and chlorostyrene, vinyl compounds such as acrylonitrile, methacrylonitrile, acrolein and methacrolein, ethylene and propylene Α-olefins such as N-substituted maleimides such as N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide, acrylamides, and vinylpyrrolidones. Moreover, as a polyfunctional monomer, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,3-butylene glycol di ( (Meth) acrylate, propylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2,2-bis (4-methacryloyloxyphenyl) propane, 2,2-bis (4-methacryloyloxyethoxyphenyl) propane, 2,2-bis [4- (3-methacryloyloxy-2-hydroxypropoxy) phenyl] propane, di (methacrylic) Multifunctionality such as (Iloxyethyl) trimethylhexamethylenediurethane, tetramethylolmethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate Examples thereof include polyfunctional olefins such as (meth) acrylates and divinylbenzene. In particular, triethylene glycol di (meth) acrylate and 2,2-bis [4- (3-methacryloyloxy-2-hydroxypropoxy) phenyl] propane (Bis-GMA) are generally preferably used.

  The radically polymerizable dental material composition of the present invention can be easily cured by inducing radicals by heat, ultraviolet rays, electron beams or the like. Therefore, as the radical polymerization initiator added to this composition, any known radical polymerization initiator can be used as long as it generates radicals by heat, ultraviolet rays, electron beams, or radiation. Among these, a photopolymerization initiator that generates radicals by ultraviolet rays, electron beams, and radiation is particularly preferably used.

  Examples of the photopolymerization initiator include diketones such as camphorquinone, acetophenone, 2,2-dimethoxy-2-phenylacetophenone, diethoxyacetophenone, 1-hydroxy-cyclohexyl-phenylketone, 2-methyl-1- [4. -(Methylthio) phenyl] -2-morpholinopropanone-1, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-hydroxy-2-methyl-1-phenyl- Acetophenone derivatives such as propan-1-one, benzophenone, 4,4′-bis (dimethylamino) benzophenone, 4-trimethylsilylbenzophenone, benzophenone derivatives such as 4-benzoyl-4′-methyl-diphenyl sulfide, benzoin, benzoin ethyl ether The Zone in propyl ether, benzoin isobutyl ether, benzoin derivatives such as benzoin isopropyl ether, methylphenyl glyoxylate, etc. 2,4,6-trimethylbenzoyl diphenylphosphine oxide.

  These photopolymerization initiators are preferably used in the composition of the present invention in an amount of 0.01 to 15% by weight, more preferably 0.1 to 10% by weight. It is preferable to add a photosensitizer. As the photosensitizer, known photosensitizers such as N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, triethanolamine, triethylamine, dimethylaminoethyl methacrylate may be used alone or Two or more types can be used in combination. The most preferred combination includes a combination of a diketone and a reducing agent that can be easily cured with visible light, such as a combination of camphorquinone and dimethylaminoethyl methacrylate.

  Moreover, it is preferable to mix | blend a filler suitably according to the objective. Examples of the filler include inorganic fillers such as glass or quartz fiber, quartz powder, aluminum oxide, titanium oxide, and silicates, and organic fillers such as finely pulverized polymethyl methacrylate. Moreover, it is preferable to add and color a pigment according to the color of the patient's teeth. A filler subjected to a coupling treatment with silanes can be particularly preferably used. X-ray opaque fillers such as barium sulfate and zirconium dioxide can also be blended.

  Hereinafter, the present invention will be described in more detail with reference to examples when used as a dental adhesive between a dental substance and a composite resin having a general composition. The composition obtained by adding an inorganic filler or changing the composition of the composition, such as use as a composite resin or use as a primer, is not limited, and the tertiary hydroxyl group of the essential component used in the present invention Both are useful because they take advantage of the good balance between hydrophilicity and water resistance.

[Evaluation of adhesive strength]
The surface of the naturally extracted milk tooth is polished with water-resistant polishing paper No. 600 under finger pressure to expose a flat enamel or dentin. Phosphoric acid treatment was performed, washed with water, sprayed with compressed air and dried to prepare an adherend surface. The molded article of the filler composition which is the other adhesive is a mold obtained by mixing 15 parts by weight of Bis-GMA, 15 parts by weight of triethylene glycol dimethacrylate, and 70 parts by weight of silica particles of 0.2 μm to 0.3 μm. The inner surface was cast and polymerized, and the end face was prepared by polishing in the same manner as the tooth. After applying the adhesive composition adjusted for each composition, it was adhered by irradiating with visible light at 500 mW / cm ² for 2 minutes using a halogen lamp equipped with a filter that transmits a region from 400 nm to 500 nm. The tensile strength was defined as the adhesive strength. The tensile strength was evaluated using a tensile tester (Autograph, manufactured by Shimadzu Corporation) at a crosshead speed of 2 mm / min.

[Evaluation of water resistance]
The adhesive obtained above was immersed in pure water at 80 ° C. for 24 hours to evaluate the adhesion.

[Evaluation of curability]
Each composition introduced into the mold was irradiated with visible light under the same conditions as the above bonding conditions to obtain a cured product. About 1 g of this cured product was cut into a rectangular parallelepiped shape, immersed in 10 g of ethanol at room temperature for 24 hours, the weight before and after immersion was measured, and the weight reduction rate was defined as the gel fraction.

<Example 1>
36 parts by weight of 2-HBMA, 50 parts by weight of triethylene glycol dimethacrylate, 10 parts by weight of methacryloxyethyl trimellitic acid, 2 parts by weight of camphorquinone, and 2 parts by weight of dimethylaminoethyl methacrylate were mixed immediately before use to prepare an adhesive composition. Obtained. The adhesive composition was applied to the adherend surface, irradiated with visible light and cured, and the adhesive strength and water resistance were evaluated. The results are shown in Table 1.

<Example 2>
18 parts by weight of 2-HBMA, 18 parts by weight of sodium methacrylate, 50 parts by weight of triethylene glycol dimethacrylate, 10 parts by weight of methacryloxyethyl trimellitic acid, 2 parts by weight of camphorquinone and 2 parts by weight of dimethylaminoethyl methacrylate are mixed immediately before use. As a result, an adhesive composition was obtained. The adhesive composition was applied to the adherend surface, irradiated with visible light and cured, and the adhesive strength and water resistance were evaluated. The results are shown in Table 1.

<Comparative Example 1>
36 parts by weight of sodium methacrylate, 50 parts by weight of triethylene glycol dimethacrylate, 10 parts by weight of methacryloxyethyl trimellitic acid, 2 parts by weight of camphorquinone and 2 parts by weight of dimethylaminoethyl methacrylate are mixed immediately before use to form an adhesive composition Got. The adhesive composition was applied to the adherend surface, irradiated with visible light and cured, and the adhesive strength and water resistance were evaluated. The results are shown in Table 1.

<Comparative example 2>
Admixture of 36 parts by weight of 2-hydroxyethyl methacrylate, 50 parts by weight of triethylene glycol dimethacrylate, 10 parts by weight of methacryloxyethyl trimellitic acid, 2 parts by weight of camphorquinone, and 2 parts by weight of dimethylaminoethyl methacrylate immediately before use. A composition was obtained. The adhesive composition was applied to the adherend surface, irradiated with visible light and cured, and the adhesive strength and water resistance were evaluated. The results are shown in Table 1.

Table 1
Example No. Example 1 Example 2 Comparative Example 1 Comparative Example 2
Adhesive strength (kgf / cm ² )
Enamel 113 128 120 90
Dentin 110 100 110 50
Water resistant enamel 112 108 70 80
Dentin 98 80 42 46

  The curability of Examples 1 and 2 was all good, and the gel fraction was 98% or higher for all. Moreover, when this hardened | cured material was immersed in the pure water of 40 degreeC for 24 hours, it confirmed that a weight increase and volume expansion were carried out. It was confirmed that when the cured product was dried under reduced pressure and swollen again, this water absorption swelling behavior could be repeatedly induced.

  As described above, the radically polymerizable dental material composition using tertiary hydroxyl group-containing (meth) acrylate as an essential component is excellent in adhesiveness to the tooth and swells upon contact with water under conditions that promote water absorption. Even so, it can be seen that the adhesive strength is small and the mechanical properties are maintained.

Claims (2)

A radically polymerizable dental material composition comprising a tertiary hydroxyl group-containing (meth) acrylate of formula (1) as an essential component.

(Wherein R ₁ and R ₂ are each independently an alkyl group having 1 to 4 carbon atoms, R ₃ is independently a methyl group or a hydrogen atom for each repeating unit, R ₄ is a methyl group or a hydrogen atom, and n Represents an integer from 1 to 3.) The radical polymerizable dental material composition according to claim 1, wherein the tertiary hydroxyl group-containing (meth) acrylate of formula (1) is 2-hydroxy-2-methylpropyl (meth) acrylate represented by formula (2).

(In the formula, R ₅ represents a methyl group or a hydrogen atom.)