JPH0627049B2 - Dental cement hardening liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a dental cement hardening liquid, and more specifically, a novel cement hardening liquid having a markedly improved adhesiveness to tooth structure, disintegration rate and kneading property. The present invention relates to a dental cement hardening liquid containing an aqueous dispersion of a graft copolymer.

Compared with composite resins, glass ionomer cements used for dentistry have an extremely slight harmful effect on pulpal pulp, and exhibit adhesiveness to both enamel and dentin, and have a margin sealing property. It is useful for restoration of the anterior tooth portion as well as joint fitting of prostheses, temporary sealing, lining, and manufacturing.

<Prior Art> Dental cement hardening liquid has almost no pulp irritation,
Moreover, it is the only cement that has adhesive properties. Conventionally, various studies have been made on the dental cement hardening liquid, for example, Japanese Patent Publication Nos. 54-21858 and 55.
-8019 or JP-A-54-149296 describes a dental cement composition containing a chelating agent in order to improve desired treatment time, curing rate and crushing resistance.

However, in the above composition, the amount of the chelating agent added is 0.01 to 10% by weight, and particularly preferably 5% by weight, that is, 10% by weight or less based on the polycarboxylic acid. In reality, the adhesiveness, which is important as a liquid, cannot be fully satisfied.

Further, Japanese Patent Publication No. 50-26573 proposes a dental carboxylate cement hardening liquid, and although the operability and the crushing resistance are improved, the addition amount of an organic acid of 2 or more bases is a polycarboxylic acid. For 0.1-5.0
Since the amount is 10% by weight or less and 10% by weight or less, there is a drawback that satisfactory adhesiveness cannot be obtained as in the case of the above composition.

Furthermore, Journal of Dental Research (Journal
of Dental Research, Vol. 59, No. 6, p. 1050 (1980), describes a method for synthesizing a polycarboxylic acid used in a glass ionomer cement. As the polycarboxylic acid, polyacrylic acid, a copolymer of acrylic acid and methacrylic acid, a copolymer of acrylic acid and itaconic acid,
Examples thereof include a copolymer of acrylic acid and alkenoic acid, a copolymer of acrylic acid and acrylamide, and a copolymer of acrylic acid and methyl acrylate.

Furthermore, in Japanese Patent Publication No. 61-4826, (In the formula, R ₁ is a hydrogen atom or a methyl group, R ₂ is a carbon atom of 2
Alternatively, it represents an alkylene group of 3, and n represents an integer of 2 to 9. However, an acid anhydride bond may be formed between two carboxyl groups on the benzene ring. ), A composition comprising a trimellitic acid ester or an acid anhydride thereof and at least one polymerizable compound having an ethylenic saturated bond has excellent adhesiveness to metals, teeth, etc. Proposed.

However, the above composition requires an etching operation with a 30% by weight phosphoric acid aqueous solution on the tooth structure, and therefore the operation is complicated, and since the polymerizable compound is used as it is, it is irritating to dental pulp. Has the drawback of giving.

Furthermore, in JP-A-63-201106, CH ₂
Unsaturated monomer represented by _{= CH-COO (CH 2 CH} 2 O) 2 CH 3, obtained by copolymerization of unsaturated monomers containing said monomer copolymerizable with the carboxylic acid group It has been proposed that the dry Knoop hardness can be improved by using a dental cement hardening liquid containing a copolymer for glass ionomer cement.

However, the fact is that it is not known at all to incorporate a graft copolymer having a carboxylic acid group into a dental cement hardening liquid to obtain a hardening liquid for an aqueous dispersion.

<Problems to be Solved by the Invention> An object of the present invention is to provide excellent control of curing speed and crushing resistance,
Moreover, it is to provide a dental cement hardening liquid of an aqueous dispersion having excellent adhesiveness and disintegration rate.

<Means for Solving the Problems> According to the present invention, an aqueous dispersion containing a polymer containing a carboxylic acid group, a graft copolymer containing a carboxylic acid group, and a polybasic acid, wherein the aqueous dispersion 25 to 49.9 wt% of the polymer and 0.1 to 25 wt% of the graft copolymer so that the total amount of the polymer and the graft copolymer is 40 to 50 wt%. The total amount of the above-mentioned polymer and the above-mentioned graft copolymer is 1
Provided is 11 to 20 parts by weight with respect to 00 parts by weight, and a dental cement hardening liquid of an aqueous dispersion is provided.

The present invention will be described in more detail below.

The dental cement hardening liquid of the present invention is an aqueous dispersion containing a polymer having a specific amount of carboxylic acid groups, a graft copolymer having a specific amount of carboxylic acid groups, and a specific amount of polybasic acid. Is characterized by.

The graft copolymer used in the present invention is a copolymer which does not dissolve in water but is dispersible and has a carboxylic acid group. That is, preferably composed of a hydrophilic side chain containing a polymer of an unsaturated monomer having a carboxylic acid group and a hydrophobic main chain having no carboxylic acid group, or having a carboxylic acid group A hydrophilic main chain containing a polymer of an unsaturated monomer,
It is a cationically reactive graft copolymer composed of a side chain having no carboxylic acid group.

In the present invention, the polymerizable monomer for forming the graft copolymer is an unsaturated monomer having the carboxylic acid group, specifically, (meth) acrylic acid, itaconic acid, maleic acid. , Glutaconic acid, aconitic acid,
Citraconic acid, mesaconic acid, fumaric acid, tiglic acid, crotonic acid, muconic acid, isocrotonic acid, 3-butenoic acid,
Preferable examples include cinnamic acid, abietic acid, maleic anhydride, itaconic anhydride, or substituted products or derivatives thereof, and an unsaturated monomer having no carboxylic acid group, specifically, for example, methyl ( (Meth) acrylate, ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, 2-ethylhexyl (meth ) Acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate,
2-hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, glyceryl (meth) acrylate, dimethylamidoethyl (meth) acrylate,
Diethylaminoethyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate,
2,3-dibromopropyl (meth) acrylate, trimethylolethane (meth) acrylate, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, vinyl acetate, styrene, α-methylstyrene, 2,
2-bis [(meth) acryloyloxypolyethoxyphenyl] propane, 2,2'-bis [4- (3-methacryloyloxy-2-hydroxypropoxy) phenyl] propane, (meth) acrylonitrile, acrolein or their substitution products Or a derivative etc. can be mentioned preferably.

The smaller the average molecular weight (polymerization average) of the graft copolymer, the lower the viscosity of the aqueous dispersion, which is suitable for kneading operability, but when it is less than 1000, the characteristics of the polymer in the glass ionomer are lost, and when it exceeds 80,000, the aqueous dispersion Since the viscosity of the liquid increases and the kneading operability deteriorates, the range of 1000 to 800,000 is preferable, and the range of 2000 to 250,000 is particularly preferable. Also,
The molecular weight of the side chain is preferably in the range of 500 to 300,000, particularly 1
The range of 0000 to 100,000 is desirable. Furthermore, in order to improve physical properties such as disintegration rate, adhesion to dentin, durability, and kneading operability, the unsaturated monomer containing a carboxylic acid group is added in an amount of 50 to 98% by weight in the graft copolymer. %, And more preferably 70 to 95% by weight.

In the present invention, in order to adjust the graft copolymer, by polymerizing an unsaturated monomer having a carboxylic acid group,
Obtaining the main chain of the graft copolymer, and then polymerizing an unsaturated monomer having no carboxylic acid group in the obtained main chain or by polymerizing an unsaturated monomer having no carboxylic acid group Then, the main chain of the graft copolymer is obtained, and then the unsaturated monomer having a carboxylic acid group is polymerized. The polymerization reaction in preparing the graft copolymer includes, for example, a redox reaction initiator such as a cerium salt, a polymer containing a peroxide group, a polymer containing a diazo group, a polymer containing a double bond, and a mercapto group. It can be synthesized by a method of polymerizing using a polymer, a polymer containing an anion-generating group or a method of utilizing a condensation reaction between macromonomers or polymers. Further, the polymerization reaction is
It can be performed by known radical polymerization, ionic polymerization, photopolymerization, or the like. The polymerization reaction may be performed by a known method and is not particularly limited. For example, radical polymerization is preferably carried out at a reaction temperature of 0 to 200 ° C. and a reaction time of 1 to 20 hours. If the temperature is lower than 0 ° C, the reaction rate is slow, and a high molecular weight product may not be obtained.
If the temperature exceeds 0 ° C, a side reaction occurs and a polymer having desired physical properties cannot be obtained, which is not preferable. If the reaction time is less than 1 hour, the polymerization reaction does not proceed sufficiently, the monomer remains, and the yield decreases, which is not preferable. When the polymerization reaction is carried out in an organic solvent, the molecular weight can be controlled relatively easily, so that a polymer having desired physical properties can be easily obtained.

The polymer containing a carboxylic acid group used in the present invention is not particularly limited, for example, polyacrylic acid usually used for carboxylate cement or glass ionomer cement, acrylic acid-acrylic acid-itaconic acid copolymer,
Polyitaconic acid, acrylic acid-maleic acid copolymer and the like can be preferably used, and it is particularly preferable to use a polymer having high crushing resistance. The molecular weight of the polymer is
It is preferably 1000 to 500000.

In the dental cement hardening liquid of the present invention, the content ratio of the polymer and the graft copolymer is such that the total amount of the polymer and the graft copolymer in the aqueous dispersion is 40 to 5.
It is necessary to contain the polymer in an amount of 25 to 49.9% by weight, and the graft copolymer in an amount of 0.1 to 25% by weight, particularly preferably 0.3 to 15% by weight, so that the amount becomes 0% by weight. . At this time, when the content ratio of the polymer is less than 25% by weight, that is, when the graft coaggregate exceeds 25% by weight, the crushing resistance is lowered, and the content ratio of the polymer is 49.9% by weight.
When the content is more than 0.1% by weight, that is, when the content of the graft copolymer is less than 0.1% by weight, the adhesiveness, disintegration property, durability, etc. are deteriorated.

Examples of the polybasic acid used in the present invention include tartaric acid, citric acid, malic acid, malonic acid, maleic acid, fumaric acid, phthalic acid, pimelic acid, nicotinic acid, oxalic acid, succinic acid, glutaric acid, glutamic acid, glutathioic acid. , Oxaloacetic acid, azelaic acid, aspartic acid, adipic acid, itaconic acid, aconitic acid, mesaconic acid, muconic acid, glutaconic acid, citraconic acid, trimellitic acid, pyromellitic acid, etc. Preferable examples thereof include organic acids or inorganic acids such as orthophosphoric acid, pyrophosphoric acid and tripolyphosphoric acid, which can be used alone or as a mixture.

In the present invention, the mixing ratio of the polybasic acid is in the range of 11 to 20 parts by weight, preferably 15 to 10 parts by weight, based on 100 parts by weight of the total amount of the polymer and the graft copolymer.
It is in the range of 20 parts by weight. When the blending ratio is less than 11 parts by weight, the improvement of the adhesiveness is not sufficient, and when it exceeds 20 parts by weight, the disintegration rate is lowered, so that the above range is required.

To prepare the dental cement hardening liquid of the present invention, a polymer containing a carboxylic acid group, a graft copolymer containing a carboxylic acid group, and a polybasic acid are dispersed in water in the above-mentioned specific ratio. Can be obtained by

In the present invention, the method of using the dental cement hardening liquid,
For example, it is preferable to mix the dental cement hardening liquid of the present invention with a known cement powder in a weight ratio of 1: 1 to 3: 1. The cement powder is not particularly limited and may be, for example, 25 to 35 wt% silicate, 10 to 20 wt% hydroxide, 2 to 15 wt% metal oxide, 25 to 35 wt% fluoride, and phosphorus. A mixture of 5 to 15% by weight of acid salt and 2 to 8% by weight of carbonate can be used, and a powder for zinc phosphate cement obtained by firing a mixed component consisting of zinc oxide and magnesium oxide is obtained. It can also be used as a mixture. The particle size of the cement powder is
A particle size range of 100 microns or less, preferably 0.1 to 10 microns is desirable. The cement powder is not particularly limited as long as it can be kneaded at a filling consistency by changing the powder-liquid ratio, and a cement powder mixture having a high powder-liquid ratio can be used depending on the preferable surface characteristics of the cement powder.

<Effects of the Invention> The dental cement hardening liquid of the present invention contains a specific amount of a polymer having a carboxylic acid group, a graft copolymer having a carboxylic acid group, and a polybasic acid, and thus has particularly excellent adhesion. The properties and disintegration rate in the mouth can be imparted to the dental cement.

<Example> Next, an example and a comparative example will be specifically described. The parts in the examples are parts by weight, and the molecular weight is the weight average molecular weight measured by the GPC method (gel permeation chromatography).

Production Example 1 (Production of Graft Copolymer) In a polymer of methyl methacrylate, a macromonomer whose one end is methacrylate (number average molecular weight = 2)
000) 5 parts, acrylic acid 20 parts, itaconic acid 5 parts, ethyl alcohol 120 parts and 2,2'-azobisisobutyronitrile 0.1 part were charged into the reaction layer, and nitrogen substitution was carried out for 30 minutes at a temperature of 95. Refluxed at 8 ° C for 8 hours. After completion of the reaction, the solvent was removed under reduced pressure, 300 parts of distilled water was added thereto, and freeze-dried. The polystyrene reduced molecular weight by GPC of the obtained graft copolymer was 56400.

Production Example 2 Production Example 1 except that a polymer of n-butyl methacrylate (number average molecular weight 6000) was used in place of methyl methacrylate, the compounding amount of ethyl alcohol was 50 parts, and further 50 parts of isopropyl alcohol was added. Similarly, a graft copolymer was prepared. The polystyrene reduced molecular weight by GPC of the obtained graft polymer was 60300.

Examples 1 to 6 The graft copolymer obtained in Production Example 1 or Production Example 2,
The carboxylic acid group, polybasic acid and distilled water shown in Table 1 are shown in Table 1.
The mixture was blended in the blending ratio shown in to obtain a dental cement hardening liquid as an aqueous dispersion. Then, about 30 parts of the obtained hardening liquid and 1.8 parts of the dental cement powder shown in Table 2 were obtained.
The mixture was kneaded for about 60 seconds, and its disintegration rate and adhesive strength were measured according to the following measuring methods. The results are shown in Table 3. In addition, Table 1 shows the composition and the amount ratio of the obtained curing liquid.

Measurement method 1. Disintegration rate The disintegration rate was measured according to JIS T6602 except that a 0.001 M lactic acid aqueous solution was used instead of distilled water.

2. Adhesive Strength A dental cobalt-chromium alloy rod was adhered to the dentin-polished surface of the bovine anterior tooth by glass ionomer cement and immersed in water at 37 ° C. for 24 hours, and then the compression shear adhesive strength was measured.

Comparative Examples 1 to 3 After preparing a dental cement hardening liquid using the polymer shown in Table 1, polybasic acid and distilled water, the dental cement powder shown in Table 2 was kneaded in the same manner as in Examples 1 to 6. Then, the disintegration rate and the adhesive strength were measured. The results are shown in Table 3.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshitaka Goto 2-24-5 Umezono, Tsukuba City, Ibaraki Prefecture (72) Inventor Masayo Nakayama 2-15-5 Umezono, Tsukuba City, Ibaraki Prefecture

Claims (1)

[Claims] 1. An aqueous dispersion containing a polymer containing a carboxylic acid group, a graft copolymer containing a carboxylic acid group, and a polybasic acid, wherein the polymer and the graft copolymer are contained in the aqueous dispersion. It contains 25 to 49.9% by weight of the polymer and 0.1 to 25% by weight of the graft copolymer so that the total amount with the polymer is 40 to 50% by weight, and further contains a polybasic acid. Total amount of the polymer and the graft copolymer 100
A dental cement hardening liquid of an aqueous dispersion, characterized by containing 11 to 20 parts by weight based on parts by weight.