JPH0699181B2 - Tetracalcium phosphate curable composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a curable composition for medical use.

The conventional art and the problems to be solved by the present invention include a curable composition for medical use, which is used for medical purposes as a bone defect filling material,
There are bone cements, cement-filling cements for artificial bones and living bodies, etc. For dentistry, cements for cementing, filling cements,
There are temporary cement, root canal filling material, and lining material. A typical example of a known medical curable composition is a dental cement, ZnO.
+ Orthophosphoric acid aqueous solution type zinc phosphate cement, ZnO + Polycarboxylic acid aqueous solution type carboxylate cement, Si
Examples include O ₂ , Al ₂ O ₃ , Na ₃ AlF ₆ + polycarboxylic acid aqueous solution type glass ionomer cement, ZnO + eugenol type eugenol cement, and SiO ₂ + BIS-GMA resin type resin cement. Examples of curable compositions for medical use include methyl methacrylate polymer + methyl methacrylate monomer-based bone cement. Zn which is the main component on the powder side
O, Al ₂ O ₃ , SiO ₂ , CaF ₂ , Ca (OH) ₂ , methyl methacrylate polymer, etc. cannot be expected to have an affinity for living bodies. Therefore, with the idea that a substance consisting of the same or similar components as those of the bone or tooth is desirable as a component of the curable composition, hydroxyapatite (Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ ) which is an inorganic component of the bone or tooth is considered. Or as a cement with tricalcium phosphate having a composition close to this as an aggregate or a part thereof,
JP-A-58-83605, JP-A-59-88251, JP-A-59-182263
Etc. However, these cements, when using resins, need to fully consider the problems of additives and residual monomers such as bone, dental pulp irritation and heat of polymerization, and hydroxyapatite alone has no chemical activity. , ZnO and other chemically active substances must be added, which is not much different from conventional ZnO-based cements, and the problem is that physical properties such as adhesive strength and pressure resistance are not sufficient only by the hydration condensation reaction. is there.

Means for Solving the Problems In order to solve the problems relating to the curable composition such as dental cement described in the preceding paragraph, the present inventors have mainly used calcium phosphate-based compounds whose powders are close to bone and tooth components. As a component, do not include metal oxides such as ZnO. The curing liquid has excellent biocompatibility. It has sufficient physical properties as a curable composition for medical use and can be used as a bone substitute material depending on the site to be used. As a result of research on the development of a curable composition satisfying the above condition, it was found that a curable composition consisting of tetracalcium phosphate (hereinafter abbreviated as 4CP) powder and a curing liquid satisfies these conditions. .

That is, 4CP is a calcium phosphate compound that is an inorganic component of bones and teeth, and its chemical activity is in the top rank among calcium phosphate-based compounds, and an aqueous solution of a polymer or copolymer of inorganic acid, organic acid, unsaturated organic acid, etc. Since it reacts with physiological saline and hardens at room temperature, it is clinically moldable like clay work. The applications of these curable compositions include artificial bone materials, cement-filling cements for artificial bones and living bodies, root canal filling materials, bone formation promoting materials in tooth extraction sockets, dental cements, pulp-protecting materials, and teeth. Peripheral disease treatment materials, dental filling materials, etc. are considered.

Original 4C which is the main component of the powder of the curable composition according to the present invention
P may be produced by any method. The raw materials are CaCO ₃ , CaO, Ca (OH) ₂ as the Ca source, P ₂ O ₅ , H ₃ P as the P source.
Contains O ₄ , (NH ₄ ) H ₂ PO ₄ , (NH ₄ ) ₂ HPO ₄ , both Ca and P
CaHPO ₄ Ca (H ₂ PO ₄ ) ₂ , Ca ₂ P ₂ O _{7 and the} like are conceivable, and there are various production methods depending on the raw materials, which is one of the known methods.

CaHPO ₄ · 2H ₂ O was obtained by heating 2 h at _{500 ℃ γ-Ca 2 P 2} O
₇ times of CaCO ₃ was mixed with ₇ times, and this was pulverized and mixed in an automatic mortar for 1 hour, baked at 1680 ° C. for 1 hour, and then left to cool in the air.

The powder of 4CP produced by such a method shows a curing action when kneaded with a curing solution such as a polycarboxylic acid aqueous solution, an organic acid aqueous solution, an inorganic acid aqueous solution, and a physiological saline solution, and is a powder of a curable composition for medical use. Can be. However, the 4CP powder
Since the bulk density is low, the upper limit of the powder-liquid ratio when kneading with the curing liquid is low, and the strength of the cured product cannot be obtained. In order for the cured product to exhibit high strength, it is necessary to develop 4CP powder with a large upper limit of powder-liquid ratio.

The inventors of the present invention process 4CP, have a large bulk density, have a large upper limit of the powder-liquid ratio, and invent a method for producing 4CP powder having a fineness distribution capable of obtaining high strength. I arrived.

The 4CP powder of the present invention thus improved can be produced by a method in which 4CP is pressure-molded, further sintered, and the sintered body is crushed. 1.
Pressure molding conditions and sintering conditions should be determined so that they fall within the range of 2 g / cm ³ to 2.8 g / cm ³ .

The curable liquid constituting the curable composition for medical use of the present invention is not only a polycarboxylic acid known in the art but also an aqueous solution of a polymer of an unsaturated carboxylic acid or a copolymer of two or more kinds of unsaturated carboxylic acids, It may be physiological saline, an aqueous solution of an inorganic acid, an aqueous solution of an organic acid, or an aqueous solution containing phytic acid, tetrahydrofuran tetracarboxylic acid or the like as a main component. Further, in the case of the polymer having these carboxyl groups, powder may be used in addition to the above-mentioned aqueous solution.

The present invention will be described in more detail by way of examples.

Comparative Example 1 CaHPO ₄ · 2H ₂ O obtained by heating 2 h at _{500 ℃ γ-Ca 2 P 2} O
₇ mol of dried CaCO ₃ was mixed with 1 mol, mixed well, and calcined in air at 1680 ° C. for 1 hour. After firing 500
The temperature was lowered to 10 ° C / min at a rate of 10 ° C / min, and then it was left to cool in the air.
The produced powder was confirmed to be 4 CP from the X-ray diffraction pattern. This 4CP was pulverized with a dry ball mill and then passed through a 350-mesh sieve to give a powder for a curable composition. This powder and polyacrylic acid aqueous solution (average molecular weight
(16,000, concentration 40%) was uniformly mixed and kneaded to obtain a curable composition mud, and curing time and crushing resistance were measured according to JIS T6602 Dental Zinc Phosphate Cement Test Method. The results are shown in Table-I.

Example 1 4CP produced by the same method as in Comparative Example 1 was lightly crushed to give an inner diameter of 30 m.
Approximately 20 g was filled in a m-shaped mold and uniaxially compressed to 800 Kg / cm ₂ to obtain a molded body. The molded body was fired at 1800 ° C. for 1 hour and allowed to cool in the air. The density of the sintered body was 2.32 g / cm ³ , and it was confirmed from the X-ray diffraction pattern that it was 4 CP. The powder was roughly pulverized in a mortar, further pulverized by a dry ball mill, and then passed through a 350-mesh sieve to give a powder for a curable composition. The crushing resistance and the solidification time of the cured product were measured and the results are shown in Table-I.
It was shown to.

Example 2 A curable composition powder is produced in the same manner as in Example 1,
The crushing resistance and the coagulation time were measured and the results are shown in Table-I.
However, the molding uses a rubber press and the pressure is 1200 Kg / c
It was set to m ² , and the test was performed at 1800 ° C. for 1 hour. The density of the sintered body is 2.41
It was g / cm ³ .

Claims (1)

[Claims] 1. Ca ₄ P ₂ O ₉ powder is calcined to obtain a density of 1.2 to 2.8 g.
After being made into a sintered body in the range of / cm ³ , it is pulverized and powdered with tetracalcium phosphate [Ca ₄ P ₂ O ₉ ] as the main component and a polymer of unsaturated carboxylic acid or two or more kinds of unsaturated carboxylic acid. A curable composition comprising a powder or an aqueous solution of an acid copolymer.