JP3452592B2 - Dental cement hardener - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hardening agent for dental cement used for tooth restoration, root canal treatment, periodontal tissue treatment, etc. More specifically, it provides a dental cement excellent in water resistance and durability. The present invention relates to a possible cement hardening agent.

[0002]

2. Description of the Related Art Dental cement is composed of cement powder components such as zinc oxide and aluminosilicate glass, and liquid components for cement hardening such as phosphoric acid aqueous solution and polyacrylic acid aqueous solution. Obtained by kneading. For example, zinc phosphate cement is one in which an aqueous solution of phosphate and orthophosphoric acid is added to a powder containing ZnO as a main component. This zinc phosphate cement stimulates dental pulp in the early stage of mixing, and shrinks when hardening. However, there was a problem that the water resistance was poor.

On the other hand, polyacrylic acid-ZnO-based dental cement has no pulp irritation, but its adhesive strength to tooth structure and mechanical strength as a filling material have not been clinically sufficient. In particular, since dental cement is occluded many times in a highly humid oral cavity, it is required to have severe water resistance such that its adhesive strength and mechanical strength will not deteriorate for a long time even under high humidity. However, the present situation is that a satisfactory dental cement has not yet been obtained.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cement hardening agent capable of forming a dental cement having excellent adhesiveness, mechanical strength and water resistance.

[0005]

Means for Solving the Problems The constitution of the present invention for solving the above problems is such that a dental cement hardening agent is (meth)
Acrylic acid and organic acid monomers having a (meth) acryloyl group in the molecule, especially

[0006]

[Chemical 3]

[Wherein R ¹ is hydrogen or a methyl group, R ² is a lower alkylene group, X is OPO (OH) ₂ or SO ₃ H, n
Represents an integer of 1 to 4] or

[0008]

[Chemical 4]

[Wherein R ¹ is hydrogen or a methyl group, R ² is a lower alkylene group, X is OPO (OH) ₂ , COOH, SO ₃
[Indicates any of H]].

[0010]

The present invention is intended to improve various properties of hardened cement which cannot be achieved by a conventional aqueous solution of polyacrylic acid by copolymerizing a specific (meth) acrylic acid type monomer with (meth) acrylic acid. Is.

The organic acid monomer having a (meth) acryloyl group in the molecule used in the present invention has a (meth) acryloyl group and an acid group such as a phosphoric acid group, a carboxyl group or a sulfonic acid group. , (Meth) acrylic acid and a monomer copolymerizable with (meth) acrylic acid [of course, (meth) acrylic acid is not included in the organic acid monomer in the present invention]. Among these organic acid monomers having a (meth) acryloyl group, preferable ones are

[0012]

[Chemical 5] [Wherein R ¹ is hydrogen or a methyl group, R ² is a lower alkylene group, X is OPO (OH) ₂ or SO ₃ H, and n is an integer of 1 to 4] or

[0013]

[Chemical 6] [Wherein R ¹ is hydrogen or a methyl group, R ² is a lower alkylene group, and X is any of OPO (OH) ₂ , COOH, and SO ₃ H], and are compounds (1) and (2). .

Specific examples of the compound (1) represented by the above formula (1) include CH ₂ ═CH—COO—CH ₂ CH ₂ OP.
_{O (OH) 2, CH 2} = C (CH 3) -COO-CH 2 CH
₂ OPO (OH) _{2 and the} like are CH ₂ ═CH—CONH—C as specific examples of the compound (2) represented by the above formula (2).
_{(CH 3) 2 CH 2 -SO} 3 H, CH 2 = C (CH 3) -CO
_{NH-C (CH 3) 2} CH 2 but -SO ₃ H and the like,
Of course, it is not limited to the above, and the method for producing the monomer is not particularly limited.

These organic acid monomers may be used alone or in combination.
It is used by copolymerizing at least one species with (meth) acrylic acid. The copolymerization ratio (weight ratio) of the organic acid monomer and (meth) acrylic acid is preferably 1:99 to 60:40, and is 2:
More preferably, it is 98 to 20:80. 1 organic acid monomer
If it is less than 10% by weight, the effect of improving water resistance and the like will not be exhibited, and if it exceeds 60% by weight, the viscosity of the copolymer as an aqueous solution is too high and the workability when mixed with the cement powder component becomes poor. In addition, there is a problem in that the concentration of the aqueous solution becomes extremely thin in order to reduce the viscosity, which causes deterioration of the physical properties of the hardened cement product, which is not preferable.

Copolymerization of both is carried out by a conventional method, and the production method is not limited. For example, an initiator such as ammonium persulfate and a polymerization inhibitor such as hydroquinone are added, and 60
It can be obtained by carrying out bulk polymerization at about -100 ° C for 1 to 20 hours.

The dental cement hardening agent of the present invention can be obtained by using the produced copolymer as an aqueous solution. The concentration of the aqueous solution can be appropriately selected according to the molecular weight and composition of the copolymer, and is generally about 5 to 70% by weight. Further, the produced copolymer is pulverized by a method such as freeze-drying and then pulverized into a cement powder, and then mixed with water or an aqueous solution of the above copolymer (which may be diluted). A kneading method can also be adopted.

The cement powder to be kneaded with the above-mentioned dental cement hardening agent according to the present invention may be a zinc oxide type, a glass ionomer type or any other type as long as it is a dental cement powder. The mixing ratio of the curing agent and the powder is appropriately selected depending on the material composition.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples. The present invention is not limited to the examples below. Example • Polymerization and Preparation of Cement Hardener A mixture of 0.36 g of ammonium persulfate and 50 mg of hydroquinone added to 8 g of a mixture of various organic acid monomers and acrylic acid shown in Table 1 was placed in a glass tube, which was replaced with nitrogen and sealed. Was polymerized at 80 ° C. for 15 hours. The copolymer was dialyzed and lyophilized to prepare a cement hardener as a 40% aqueous solution. Acrylic acid homopolymer (A
The curing agent of A) was listed as a comparative example.

Compression test and indirect tensile test 1.0 g of each of the above curing agents and 1.8 g of commercially available dental carboxylate cement powder (Carlon SMEP: manufactured by Sankin Industry Co., Ltd.) were kneaded for 30 seconds to prepare cement mud. . This cement mud is filled in a designated Teflon mold and allowed to cure at room temperature for 30 minutes, then used for compression testing (6 mmφ x
12 mm) and test pieces for indirect tensile test (6 mmφ × 6 mm) were prepared. Autograph AG for compression and tension tests
S-500 (manufactured by Shimadzu Corporation) was used and the crosshead speed was 2 mm / min. The test pieces were immersed in water at 37 ° C. for 48 hours and then subjected to the test.

Adhesive strength A stainless steel rod having a diameter of 7 mm and a length of 30 mm is used as the adherend for the adhesive strength test, and the adherend surface is emery paper #
Polished at 1000. A tape having a hole with a diameter of 5 mm was attached to the surface to be adhered to define the adhesion area, and the mixture was butt-bonded with another stainless steel rod by kneading cement mud. This was left at room temperature for 30 minutes, then stored in water at 37 ° C for 48 hours, and left at 37 ° C for 24 hours and then immersed in water at 4 ° C and 60 ° C for 1 minute each for a thermal cycle of 1000 The adhesive strength was measured at the cross head speed of 1 mm / min by the autograph as to what was repeated.

Bovine Dentin Adhesion Test After embedding bovine anterior teeth in wax, emery paper #
Polishing was carried out at 600 to expose the dentin surface to be adhered. A tape with a 4 mmφ hole is attached to the dentin surface to define the adhesion area and a small amount of cement mud (powder-liquid ratio is cement powder: hardener =
After applying 1.8 g: 1.0 g), a cement hardening body of 6 mmφ × 12 mm (based on cement manufactured by Shofu Co., Ltd.) in which a hook for adhesion test is embedded and hardened in advance is pressure-welded,
A butt test piece was prepared. This test piece is at 37 ° C RH
After storing in a 100% atmosphere for 1 hour and in water at 37 ° C. for 24 hours, a tensile test was conducted by an autograph at a crosshead speed of 1 mm / min. Table 1 also shows the types of monomers, the copolymerization ratios, and the respective test results.

[0023]

[Table 1] Even in the case of methacrylic type, the present invention showed good results.

[0024]

When the cement hardening agent of the copolymer according to the present invention is used, the adhesive strength after the thermal cycle is high,
It can be seen that the water resistance and durability were greatly improved. In addition, a cement hardener which can provide a hardened product having a compressive strength and a tensile strength which are equal to or higher than those of the acrylic acid homopolymer and which has excellent performance as a dental cement was obtained.

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-63-316708 (JP, A) JP-A-58-83605 (JP, A) JP-A-3-130210 (JP, A) JP-A-60- 78906 (JP, A) JP-A-3-227906 (JP, A) JP-A-3-232810 (JP, A) JP-A-63-201106 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61K 6/00-6/10

Claims (2)

(57) [Claims] 1. A (meth) I der obtained by copolymerizing an organic acid monomer having a (meth) acryloyl groups in the acrylic acid and molecular, organic acid monomer, the following formula ## STR1 ## [However, R ¹ is hydrogen or methyl group, R ² is lower alkylene
Group, X is OPO (OH) ₂ or SO ₃ H, n is 1 to 4
A compound represented by an integer] . 2. (Meth) acrylic acid and (meth) acrylic acid in the molecule.
) Copolymerized with an organic acid monomer containing an acryloyl group
Be those obtained by, the organic acid monomer, the following formula ## STR2 ## [Where R ¹ is hydrogen or a methyl group, R ² is a lower alkylene group, X is OPO (OH) _2, COOH, indicate either SO ₃ H] teeth which is a compound represented by < br /> Cement hardener for medical use.