JP2883741B2 - Dental cement hardener - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention provides a hardened cement material which is excellent in operability and kneadability when mixed with a powder component comprising a dental cement powder, and which is excellent in physical strength such as crush resistance. Dental cement hardener.

[0002]

BACKGROUND OF THE INVENTION Dental cement compositions are used as dental restorative fillers, inlay or crown cements,
Widely used for bonding materials and backing materials for orthodontic teeth. The dental cement composition is usually composed of a dental cement powder, and further, if necessary, a powder component comprising an X-ray contrast agent powder and a filler powder (extending agent), and an aqueous cement hardener solution.

[0003] These dental cement compositions are prepared by mixing and kneading the powder component in a dry powder form with an aqueous solution of a cement hardener immediately before use, filling the kneaded material into an affected area to form a hardened cement material. is there.

[0004] As the aqueous cement hardener solution, an aqueous solution of a linear acrylic acid polymer or a copolymer of acrylic acid and another copolymerizable unsaturated monomer is most widely used. Although the advantages and problems of the aqueous cement hardener solution have already been clarified, a common major problem is that the kneadability with the powder component is not sufficient.

[0005] Usually, a powder component composed of cement powder and a hardener aqueous solution are mixed and kneaded at a fixed ratio on a kneading plate (or kneaded paper), and before the hardening reaction substantially proceeds, that is, It must be applied to the affected area while the fluidity is high, so that the kneading operation must be completed in a short time. In addition, if the kneading is not performed sufficiently in a short time, the original performance of the dental cement composition is not exhibited, and as a result, the final performance of the hardened cement material tends to vary.

However, it is difficult to mix the above-mentioned powder component, which is inherently incompatible with water, uniformly with the aqueous solution of the curing agent in a short time, and it is not easy to knead with a spatula or the like.
The training required a high degree of skill. In view of such circumstances, the present inventors have conducted intensive studies and as a result, have found a hardening agent which is excellent in kneadability with the powder component and the like, and which can obtain a cement hardened material having excellent physical strength, and the present invention. It has been reached.

[0007]

That is, the present invention relates to an unsaturated carboxylic acid monomer or a monomer thereof in an aqueous medium in the presence of an X-ray contrast agent powder and / or a filler powder.
The present invention relates to a dental cement hardener comprising a polymer-X-ray contrast agent composite or a polymer-filler composite obtained by polymerizing a mixed monomer with another copolymerizable unsaturated monomer.

Hereinafter, the present invention will be described in detail.

As the X-ray contrast agent powder used in the present invention, various known X-ray contrast agents which are usually used for dental X-ray contrast agents can be used without any particular limitation.

Specific examples include barium sulfate, bismuth subcarbonate, bismuth oxide, silver powder, anhydrous zinc lactate, aluminum sulfate, potassium, and titanium oxide.

The particle size of the X-ray contrast agent powder is determined by the polymer obtained.
From the viewpoint of the dispersion stability of the aqueous suspension of the X-ray contrast agent complex, the average particle diameter is suitably 50 μm or less, preferably 1 to 10 μm. The filler powder used in the present invention is used as a bulking agent and does not substantially react with a curing agent.Specifically, magnesium oxide, bismuth oxide, calcium oxide, silica, Typical examples include alumina, cryolite, aluminum phosphate, aluminum fluoride, calcium fluoride, calcium hydroxide and the like.

The average particle size of the filler powder is suitably 50 μm or less, preferably 0.01 to 10 μm, from the viewpoint of the dispersion stability of the aqueous suspension of the obtained polymer-filler complex.

The unsaturated carboxylic acid monomer which is a constituent monomer of the polymer used in the present invention includes acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, aconitic acid, glutaconic acid, sicolaconic acid, One of mesaconic acid, tiguric acid and the like, or a mixture of two or more of these, may be mentioned as a typical example.

The other copolymerizable unsaturated monomer is acrylonitrile, methyl acrylate, methyl methacrylate, vinyl acetate, vinyl propionate, methyl itaconate, styrene, 2-hydroxyethyl methacrylate, or a mixture thereof. Mixtures of more than one species are mentioned as representative.

The average molecular weight of the obtained polymer is preferably about 1,500 to 150,000, and the proportion of unsaturated carboxylic acid monomer in the polymer is preferably about 90 to 100% by weight. However, the present invention is not limited to these.

As the aqueous medium used in the present invention, water or water as a main component, water-soluble alcohols,
For example, a medium in which ethanol, isopropanol, hydrophilic glycol, polyhydric alcohol, a lower alkyl ether thereof and the like are mixed is exemplified.

Next, a typical method for producing the dental cement hardener of the present invention will be described, but it is needless to say that the present invention is not limited to this method.

A known polymerization initiator such as a persulfate, hydrogen peroxide, an organic peroxide or an oxidation-reduction system, and a chain transfer agent for adjusting the molecular weight, if necessary, are added.
An unsaturated carboxylic acid monomer or another monomer copolymerizable with the unsaturated carboxylic acid monomer is dropped into an aqueous medium in which a line contrast agent powder and / or a filler powder are dispersed, and radically polymerized. The polymerization conditions are not particularly limited, but generally it is appropriate to carry out the polymerization at 50 to 100 ° C. under normal pressure. The ratio between the X-ray contrast agent powder and / or the filler powder and the monomer is not particularly limited, except for physical and chemical conditions that substantially hinder polymerization. Considering the stability of the aqueous suspension of the linear contrast agent complex or the polymer-filler complex and the original function as a curing agent, the weight ratio is (0.1 to 1).
0): (99.9 to 90) is appropriate. However, since the reactivity differs depending on the type of the dental cement powder or the monomer, a suitable ratio can be appropriately selected.

The cement hardener of the present invention thus obtained is prepared by polymerizing the cement-hardening agent of the present invention in the above-mentioned aqueous medium to obtain an aqueous suspension of the polymer-X-ray contrast agent composite or the polymer-filler composite. The suspension, or the suspension whose concentration has been adjusted with an aqueous medium, is temporarily subjected to polymer-X by means such as freeze-drying.
It is also possible to prepare a dry powder of a linear contrast agent composite or a polymer-filler composite, and to disperse and suspend it again in an aqueous medium before use. However, it is desirable to remove and purify unreacted residual monomers and the like. For example, a dry powder of a polymer-X-ray contrast agent complex or a polymer-filler complex is once prepared by a freeze-drying method as a means thereof. This is preferably re-suspended and dispersed in an aqueous medium to provide a highly safe and stable cement hardener. The solid concentration of the aqueous suspension of the cement hardening agent is arbitrarily determined depending on the type of the monomer, the type of the X-ray contrast agent and / or the type and the particle size of the filler component. ~ 70
% By weight is appropriate.

The aqueous suspension of the cement setting agent of the present invention comprises
Immediately before use, a dental cement composition is prepared by mixing and kneading with a dental cement powder and, if necessary, a powder component comprising an X-ray contrast agent powder and a filler powder.

The dental cement powder includes zinc phosphate cement, polycarboxylate cement containing zinc oxide as a main component, calcium phosphate cement containing calcium phosphate as a main component, fluoroaluminosilicate glass and alkaline earth aluminofluorosilicate. Representative examples include glass ionomer cements such as metal salt glass, but are not limited thereto.

The dental cement powder contains 8% of the powder component.
It is desirable from 5% to 100% by weight from the viewpoint of the physical strength of the cured cement product obtained.

The polymer-X of the present invention as described above
The reason that the aqueous suspension of the hardener comprising the linear contrast agent complex or the polymer-filler complex improves the kneadability with the powder component is not clear, but is presumed to be due to the following reasons. .

The surface of the X-ray contrast agent powder and / or the filler powder constituting the composite as a curing agent is brought into contact with a monomer, and the surface of the X-ray contrast agent powder and / or the filler powder is blended. When the monomer is polymerized while keeping the state well wet, the X-ray contrast agent powder and / or the secondary agglomerate composed of the aggregates of the primary particles of the filler powder are loosened apart, and finally A polymer-X-ray contrast agent complex wrapped with a polymer having a polymer chain having a good affinity for an aqueous medium,
Alternatively, it is considered that fine particles of the polymer-filler composite are formed, and a good dispersion system is completed.

As described above, the generation of the polymer and the reduction and dispersion of the X-ray contrast agent or the filler particles are caused by the fact that the polymerization catalyst is crushed and powdered with the progress of the polymerization reaction in catalytic chemistry. Can be easily inferred from the facts that have been confirmed.

The polymer of the present invention thus obtained
When the dry powder component is brought into contact with an aqueous suspension of an X-ray contrast agent or a curing agent composed of a polymer-filler complex, the powder components are easily incorporated into the aqueous suspension system, and quickly interact with each other. It is considered that the wettability and conformability are improved, and the dispersion stability is improved. As a result, the fluidity is improved, the resistance during kneading is reduced, and the operability and kneadability are improved.

It has been confirmed that once such a stable system is formed in a certain kind of colloid or emulsion system, it is easy to take in a new medium and the process rapidly shifts to dispersion stabilization. Signs well with facts. Such effects are also supported by some data.

For example, a dry powder component having the same particle size distribution is mixed with a curing agent having the same concentration, that is, a conventional polyacrylic acid polymer aqueous solution, and a polymer-X-ray contrast agent complex or polymer-filled material of the present invention. Each of the aqueous composite suspensions was mixed with an aqueous suspension, and the same amount of the kneaded material in the initial stage of kneading was dropped on a glass plate to obtain a polymer-X-ray contrast agent composite or a polymer which is a curing agent of the present invention -The use of the aqueous filler complex suspension resulted in a thinner film thickness. This also proves that the powder components are easily loosened and kneaded in a short time to form a uniform dispersion state.

The aqueous suspension (L) of the curing agent comprising the polymer-X-ray contrast agent complex or the polymer-filler complex of the present invention is mixed with the powder component (P) immediately before use, and generally, Is mixed at a ratio of (P) / (L) (weight ratio) of 1 to 3,
It is kneaded and used for use, at that time, the initial curing speed,
For example, ethylenediaminetetraacetic acid, dihydroxytartaric acid, salicylic acid, 2,4- and 2,6-dihydroxybenzoic acid, citric acid, nitrilotriacetic acid, tartaric acid, and other molecules to improve hardness, adhesion, crushing resistance, disintegration rate, etc. A compound having two or more carboxyl groups in the
It is preferable to add a chelating agent such as β-diketone or polyglycol to the whole by several weight%.

[0030]

The dental cement hardener comprising the polymer-X-ray contrast agent composite or the polymer-filler composite of the present invention is different from the conventional hardeners in that the powder component consisting of dry cement powder and When mixing, its operability and kneadability are excellent,
Therefore, it can be sufficiently kneaded in a short time without requiring much skill. In addition, it has the effect of obtaining a hardened cement material having excellent physical strength such as crushing resistance and the like, and having no variation in final performance.

[0031]

The present invention will be described in more detail with reference to the following examples. In the examples, "parts" and "%" are shown on a weight basis.

[0032] <Preparation method of glass ionomer cement powder> Al ₂ O ₃ 100 parts, SiO ₂ 175 parts, Na ₃ AlF ₆ 30
Parts, 207 parts of CaF ₂ , 32 parts of AlF ₃ , and 60 parts of AlPO ₄
Mix, bake at 1150 ° C, then pulverize 400
The mixture was passed through a mesh sieve to obtain a glass ionomer cement powder.

Example 1 64.0 parts of water, 8.00 parts of ethanol, 4.00 of itaconic acid
Of a flask containing 0.10 parts of barium sulfate powder and 0.10 parts of barium sulfate powder, the mixture was kept at 80 ° C., and a mixture of 0.70 parts of ammonium persulfate (APS) with 4.00 parts of water as a polymerization initiator was added. After that, 16.00 parts of acrylic acid was uniformly dropped by a dropping funnel over 2 hours. After completion of the dropwise addition, a mixture of 0.30 parts of APS and 4.00 parts of water was added as an additional catalyst, and aging was further performed at 80 ° C. for 90 minutes. Next, in order to remove the unreacted monomer, it was freeze-dried and dried, and 49.50 parts of the obtained powder and 45.0 parts of water were mixed to produce an aqueous suspension of a curing agent.

Example 2 An aqueous suspension of a curing agent was prepared in the same manner as in Example 1 except that 1.00 part of barium sulfate powder was used.

Example 3 An aqueous hardener suspension was prepared in the same manner as in Example 1, except that the barium sulfate powder was replaced by 0.10 parts of bismuth subcarbonate powder.

Example 4 In Example 3, 0.10 part of bismuth subcarbonate powder was added to 1.0 part.
An aqueous hardener suspension was prepared in the same manner as in Example 3 except that the amount was 0 part.

Example 5 An aqueous suspension of a curing agent was prepared in the same manner as in Example 1, except that the barium sulfate powder was replaced by 0.10 parts of magnesium oxide powder.

Example 6 In Example 5, 0.10 parts of magnesium oxide powder was added to 1.
A curing agent aqueous suspension was produced in the same manner as in Example 5 except that the amount was changed to 00 parts.

Example 7 An aqueous suspension of a curing agent was produced in the same manner as in Example 1 except that the barium sulfate powder was replaced by 0.10 parts of calcium hydroxide powder.

Example 8 In Example 7, 0.10 part of calcium hydroxide powder was added to 1.
A curing agent aqueous suspension was produced in the same manner as in Example 7 except that the amount was changed to 00 parts.

Example 9 An aqueous suspension of a curing agent was produced in the same manner as in Example 1 except that maleic acid was used instead of itaconic acid. Example 10 The procedure of Example 1 was repeated, except that 4.00 parts of itaconic acid was replaced with a
A mixture of 2.00 parts of taconic acid and 2.00 parts of aconitic acid
Aqueous suspension of a curing agent in the same manner as in Example 1 except that
A liquid was produced. Example 11 In Example 1, instead of 16.00 parts of acrylic acid,
14.00 parts of acrylic acid and 2.0 of methyl methacrylate
Hardening was performed in the same manner as in Example 1 except that 0 parts of the mixture was used.
An aqueous suspension of the agent was prepared. Example 12 In Example 1, instead of 16.00 parts of acrylic acid,
A mixture of 14.00 parts of acrylic acid and 2.00 parts of styrene
Aqueous suspension of a curing agent in the same manner as in Example 1 except that
A liquid was produced. Example 13 In Example 1, 16.00 parts of acrylic acid was replaced with acrylic acid.
Cured in the same manner as in Example 1 except that the acid is 20.00 parts.
Aqueous suspensions were prepared.

Comparative Example 1 An aqueous suspension of a curing agent was produced in the same manner as in Example 1 except that barium sulfate powder was not added.

Each hardener aqueous solution thus obtained 9.
Liquid (L) consisting of 5 parts and 0.5 part of tartaric acid, and powder (P) consisting of 18.0 parts of the above glass ionomer cement powder
Were kneaded for 30 seconds, and the crushing resistance 24 hours later was measured according to the method described in JIS T 6602 for dental cement.
The kneadability test was determined as follows. Kneadability test: 0.30 parts of powder (P) and 0.2 of liquid (L)
Take 0 part on kneaded paper, knead for 15 seconds, place the kneaded cement composition on a glass plate, weigh 20 g
Put a 100g weight on the glass plate,
The average value of the maximum diameter and the minimum diameter of the sample that spread when 10 minutes had elapsed was determined, and this was used as a measure of kneadability (fluidity).
The larger the average value, the better the kneadability.

The results are shown in Table 1 below.

[0045]

[Table 1] As is clear from Table 1, all of the dental cement compositions of the examples using the hardener of the present invention had a higher crushing resistance and kneading strength than those of Comparative Example 1 using the conventional hardener. The character was excellent.

Claims (1)

(57) [Claims] 1. Polymerizing an unsaturated carboxylic acid monomer or a mixed monomer of said monomer and another copolymerizable unsaturated monomer in an aqueous medium in the presence of an X-ray contrast agent powder and / or a filler powder. A dental cement hardener comprising a polymer-X-ray contrast agent composite and / or a polymer-filler composite obtained by the method described above.