JPH02102657A - Filling material for osteodefective, osteospace and root canal parts - Google Patents

Abstract

PURPOSE:To improve practicable curing time and strength and excellent bioaffinity by incorporating alpha-tricalcium phosphate and tetracalcium phosphate as essential components into the above filling material and further incorporating at least >=1 kinds of the hydroxide or oxide of alkali metals or alkaline earth metals therein. CONSTITUTION:The weight ratio of the alpha-tricalcium phosphate and tetracalcium phosphate is preferably 9:1 to 1:9, more particularly preferably 8:2 to 1:9. The hydroxide or oxide of alkali metals or alkaline earth metals is the compd. which can adjust the pH of the cured matter of the filling material for the osteodefective, osteospace and root canal parts to the neighborhood of neutrality of about 7 pH; for example, the oxide is exemplified preferably by caustic soda, caustic alkali, magnesium hydroxide, calcium hydroxide, etc., and the oxide is preferably exemplified by Na2O, K2O, MgO, CaO, etc. The content ratio to the hydroxide or oxide into the filling material is preferably 0.5 to 20wt.%, and is more particularly preferably changed property according to the compsn. ratio of the alpha-tricalcium phosphate and tetracalcium phosphate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a filling material for bone defects, bone voids, and tooth root canals. More specifically, it relates to a filling material for bone defects, bone voids, and tooth root canals, in which at least one hydroxide or oxide of an alkali metal or alkaline earth metal is added to a calcium phosphate compound as a main component. .

[Conventional technology]

Various studies have been conducted on filling materials for bone defects, bone voids, and tooth root canals.

For example, medical use characterized by comprising a powder mainly composed of α-tricalcium phosphate and/or tetracalcium phosphate and an aqueous solution of at least one of malic acid, citric acid, succinic acid, and glycolic acid. Curable compositions (Japanese Unexamined Patent Publication No. 62-83348) and the like have been proposed.

However, the medical curable compositions are generally highly acidic, and therefore are highly irritating to living tissues, which may cause inflammation in living organisms.

This is because the concentration of the organic acid used is as high as 25 to 60% by weight. For example, by reducing the concentration of the organic acid to 25% by weight or less, the acidity of the cured product can be lowered and the pH of the cured product can be adjusted to around neutrality. However, in this case, the time required for curing the composition becomes longer and the strength of the cured product decreases significantly, making it unusable.

[Problem to be solved by the invention]

Therefore, it is an object of the present invention to have a curing time and strength that can be used practically, and to have a neutral pH of around 7, so that there is little irritation to living organisms, and when it is filled into living organisms. It is an object of the present invention to provide a filling material for bone defects, bone voids, and tooth root canals that does not cause inflammation or the like and has excellent biocompatibility.

[Means to solve the problem]

According to the present invention, it contains α-tricalcium phosphate and tetracalcium phosphate as main components, and further contains at least one hydroxide or oxide of an alkali metal or alkaline earth metal. A filling material for a bone defect, a bone void, and a tooth root canal is provided.

The present invention will be explained in more detail below.

The compound used as the main component in the present invention is:

Preferably, α-tricalcium phosphate and tetracalcium phosphate synthesized by a dry method or a wet method, and specifically, for example, calcium hydrogen phosphate dihydrate (Ca
HP O, 2 Hx O) is decomposed at a temperature of about 500°C to produce calcium pyrophosphate (Ca, P, 07), and this calcium pyrophosphate and calcium carbonate (Ca
After mixing COz) in molar ratios of 1:1 and 1:2, and then calcining each at a temperature of about 1000 °C,
α-Tricalcium phosphate and tetracalcium phosphate or e.g. calcium hydroxide (Ca(O)
H) 2) Drop phosphoric acid (H, PO,) into the aqueous solution,
After producing a precipitate with a desired composition, drying the precipitate;
α-Tricalcium phosphate and phosphoric acid synthesized by a wet method are preferred, and α-tricalcium phosphate and phosphoric acid synthesized by a wet method are then produced by baking at a temperature of 1250 to 1500° C. for 3 to 6 hours. 4-calcium can suppress the hydration activity and therefore it is possible to extend the hardening time of the filler to some extent.

This is desirable because it improves operability.

In the present invention, the α-tricalcium phosphate and tetracalcium phosphate are preferably pulverized using a pulverizer such as a mortar, a Braun pulverizer, or a ball mill, and used as a powder having a particle size of 100 mesh or less. The particle size is 1
When the mesh size is 0.00 mesh or less, the composition becomes uniform when used as a filling material for bone defects, bone voids, and tooth root canals, and the curing time can be easily controlled.

The weight ratio of α-tricalcium phosphate and tetracalcium phosphate that can be used in the present invention is preferably 9:1 to 1:9, particularly preferably 8:2 to 1:9. If the amount of α-tricalcium phosphate is more than 9:1, the pH of the cured product will drop too much, and in order to bring the pH to about 7, a pH adjuster of more than 20% by weight is required, which is described below. As you do,
This is undesirable because it causes collapse of the hardened bone defect, bone void, and tooth root canal filling material. On the other hand, if the amount of tetracalcium phosphate is greater than 1:9, the pH value used will be lower! ! A small amount of conditioning agent is sufficient, but the hardening time is shortened and bone defects,
This is not preferable because it makes it difficult to fill the living body with the bone cavity and tooth root canal filling material.

The hydroxide or oxide of an alkali metal or alkaline earth metal used in the present invention adjusts the pH of the cured filling material for bone defects, bone voids, and tooth root canals of the present invention to around neutrality of about 7. Compounds that can, for example,
Examples of the hydroxide include caustic soda (NaOH), caustic potash (KOH), and magnesium hydroxide (M g (OH
) 2) , Calcium hydroxide (Ca (OH) 2)
etc., and the oxides include Na, ○, K z O,
Preferable examples include MgO, Ca○, and the like.

The hydroxide or oxide of the alkali metal or alkaline earth metal must contain at least one type,
The content in the filling material for bone defects, bone voids, and tooth root canals is preferably in the range of 0.5 to 20% by weight, especially depending on the composition ratio of α-tricalcium phosphate and tetracalcium phosphate. It is preferable to change it appropriately. If the content of alkali metal or alkaline earth metal hydroxides or oxides is less than 0.5% by weight, it will not be possible to adjust the pH sufficiently, and if the content is more than 20% by weight, the content of the filler will deteriorate. If the pH during curing becomes too high, the curing time becomes long and the strength decreases. Furthermore, the filling material for bone defects, bone voids, and tooth root canals of the present invention tends to expand slightly during hardening, but this property can be effectively utilized. That is, by setting the content ratio of the hydroxide or oxide of the alkali metal or alkaline earth metal within the above-mentioned range, it is possible to cause appropriate expansion, and it is possible to cause the expansion to occur in bone defects, bone voids, or tooth root canals. Since it is possible to prevent loosening of the hardened material that may occur after filling with the filling material, it can be particularly preferably used as a tooth root canal filling material, for example.

In order to prepare the filling material for bone defects, bone voids, and tooth root canals of the present invention, the above-mentioned α-tricalcium phosphate and tetracalcium phosphate and the at least one alkali metal or alkaline earth metal are used. It can be obtained by mixing the hydroxide or oxide of the compound using a known stirrer or the like.

In addition, in the filling material for bone defects, bone voids, and tooth root canals according to the present invention, the use of components other than the above-mentioned components is not specifically excluded, and if necessary, for example, hydroxyapatite and/or Alternatively, a component with good biocompatibility such as β-tricalcium phosphate can be used in addition to the above-mentioned components.

In the present invention, in curing the filler, for example, the weight of the powdered α-tricalcium phosphate, tetracalcium phosphate, and the hydroxide or oxide of an alkali metal or alkaline earth metal is It is preferable to mix an organic acid aqueous solution with a powder-liquid ratio of 0.5 to 3.0. If the powder-liquid ratio is less than 0.5, the curing time will be too long, and the cured filler material will be This is not preferable because the strength of the material decreases. If the powder/liquid ratio exceeds 3.0, the powder and liquid will be too hard to mix, resulting in poor operability, which is not preferable. The organic acid aqueous solution is not limited to any type of organic acid as long as it is not toxic to living organisms, but may include the so-called TCA cycle (tricarboxylic acid cycle).
acid cycle), one or two of organic acids such as phosphoric acid, malic acid, tartaric acid, malonic acid, and succinic acid.
Mixtures of more than one species can be particularly preferably used. These organic acids are usually used in the form of an aqueous solution, and the concentration of the aqueous solution is preferably 20% to 60% by weight based on the weight of the aqueous solution. If the concentration is less than 20% by weight, the curing time will be too long, and if it exceeds 60% by weight, the curing will be too fast and the operability will deteriorate, which is not preferable.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

u''L Calcium hydrogen phosphate dihydrate [Manufactured by Junsei Kagaku Co., Ltd. 1
1 mole is decomposed at a temperature of 550°C to obtain calcium pyrophosphate, and this calcium pyrophosphate and equimolar amount of calcium carbonate [manufactured by Kanto Kagaku Co., Ltd.] are mixed, and then 1
After calcining at a temperature of 000°C for 5 hours, α-tricalcium phosphate was synthesized by baking at a temperature of 1350°C for 3 hours.Next, the molar ratio of calcium pyrophosphate and calcium carbonate was set to 1=2 Tetracalcium phosphate was synthesized in the same manner as in the previous step except for the following steps.

The α-tricalcium phosphate and tetracalcium phosphate were ground using a mortar so that the particles could pass through a 100-mesh sieve.

Calcium hydroxide [manufactured by Junsei Kagaku Co., Ltd.] as a pH adjuster was mixed with the α-tricalcium phosphate and tetracalcium phosphate synthesized by the above method at the weight ratio shown in Table 1 to give a concentration of 35% by weight. % citric acid [Hyozan Pharmaceutical Co., Ltd. 1
The F aqueous solution was mixed at a powder-liquid ratio of 1.2 and cured. Table 1 shows the results of measuring various physical properties of this cured product.

To measure the compressive strength, a slurry filler composition was poured into a 7 an φ, 14 nnL container, and after hardening, it was taken out and placed in a phosphate buffer solution adjusted to pH = 6.8 and temperature of 37 °C. After 24 hours, the sample was taken out and its compressive strength was measured while still wet using a universal testing machine RL125 model manufactured by Instron. In addition, to measure the pH, add about 33 nn to 1 ml of MEM medium for cell culture.
．． Add a 5m++ thick cured product and adjust the pH of the medium after 24 hours.
It was carried out by measuring.

TeCP Tetracalcium diphosphate As is clear from Table 1, the bone defect of the present invention.

The effect of adding calcium hydroxide as a pH adjusting agent in bone cavity and tooth root canal filling materials is remarkable in all proportions of α-tricalcium phosphate and tetracalcium diphosphate; I was able to keep it close. By adding the pH adjuster, the compressive strength was slightly lower than when it was not added, but the strength reduction was within a range that would not cause any problem in practical use.

Filling materials for bone defects, bone voids, and root canals of the present invention were manufactured by the same method as in Example 1, except that tetracalcium phosphate was synthesized by a wet method, and the physical properties were measured. I did it. The results are shown in Table 2.

When synthesizing tetracalcium phosphate using the wet method,
Calcium hydroxide in water 3Ω [Junsei Kagaku Co., Ltd. HE]
2 mol was dissolved, and while stirring this aqueous solution, phosphoric acid [manufactured by Junsei Kagaku Co., Ltd.] was added dropwise to 1 mol (molar ratio 2:1) to produce a slurry-like precipitate. , dried. Next, the dried precipitate was calcined at 1350°C for 3 hours.As is clear from Table 2, when tetracalcium phosphate synthesized by the wet method was used, the tetracalcium phosphate synthesized by the dry method was The curing time was longer than in the case of 1, and therefore the operability when used as a filler was extremely excellent, and the compressive strength of the cured product was also improved.

1.0 g each of α-tricalcium phosphate and tetracalcium phosphate synthesized by the method described in Kanshu Ohba Example 1, pH
Calcium hydroxide as a regulator [Junsei Kagaku Co., Ltd. I
A filler containing 0.16 g (equivalent to 7.5% by weight) of 1.1% by weight was prepared using an aqueous solution of citric acid [manufactured by Raiyu Yakuhin Kogyo Co., Ltd.] with a concentration of 35% by weight. A cell proliferation rate test was conducted on a cured product that had been cured at a pH of 1.2, and at the same time, a cured product containing no pH adjuster was also produced and a cell proliferation rate test was conducted in the same manner. This cell proliferation rate test
The test was carried out on a disk-shaped hardened material with a diameter of 33 mm and a thickness of 1.51 placed in 5 ml of M medium, and the number of L929 cells per day was calculated. The results are shown in FIG.

As is clear from FIG. 1, when no pH adjuster was used, the number of cells rapidly decreased, but when the pH adjuster was used, cell proliferation was observed, indicating that bone defects caused by the present invention The superiority of this material as a filling material for areas, bone cavities, and tooth root canals has been proven.

〔Effect of the invention〕

As mentioned above, the filling material for bone defects, bone voids, and tooth root canals according to the present invention has values that can be used practically in both curing time and strength, and the pH of the cured product is kept neutral around 7. can be maintained. Therefore, it can be used as a filling material for bone defects, bone cavities, and tooth root canals, which does not cause inflammation when filled into a living body, has low irritation to the living body, and has high biocompatibility.

[Brief explanation of drawings]

Claims (1)

[Claims] A bone defect, a bone characterized by containing α-tricalcium phosphate and tetracalcium phosphate as main components, and further containing at least one hydroxide or oxide of an alkali metal or alkaline earth metal. Filling material for cavities and tooth root canals.