JP2956249B2 - Calcium phosphate cement for living body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a calcium phosphate cement for a living body which can be used as a filling material for a bone defect or a bone cavity or a dental root canal filling material.

[0002]

2. Description of the Related Art Conventionally, calcium phosphate cements which are hardened by kneading with water are widely known (FC
REPORT, Vol. 6 (1988), pp. 475-4
80, JP-A-64-37445, etc.) and as a biocement. However, the conventional calcium phosphate cement has little stimulus to the living body, but has low strength and has a problem when applied to a portion to which a load is applied.

[0003] Various cement compositions in which a fibrous substance is mixed into a cement powder to improve the strength have been proposed. For example, JP-A-59-161307 discloses a cement composition obtained by mixing a nylon powder with a powder consisting of apatite and zinc oxide.
Japanese Patent No. 447 proposes a cement composition in which pulp fibers are mixed with a powder made of zinc oxide eugenol cement. However, all of the above-mentioned cement compositions have a problem in terms of composition for use in living bodies, although the physical properties of the cement itself are improved. Japanese Patent Application Laid-Open No. Hei 2-167171 discloses that apatite floc is mixed with bone cement containing PMMA as a main component to improve the physical properties of the bone cement.
Bone cement containing MMA as a main component has a problem in its own biocompatibility. Further, since the fibrous substance used in the cement composition is a relatively large fibrous or flocculent body, it is inferior in operability at the time of kneading cement, and the obtained cured product has a large variation in strength. There are also problems.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a calcium phosphate cement for living organisms that is excellent in biocompatibility, high in strength, has little variation in strength, and is excellent in operability during kneading. .

[0005]

According to the present invention, α-type tribasic calcium phosphate and dibasic calcium phosphate are mixed with Ca /
A calcium phosphate cement for living body comprising a powder and a liquid mainly composed of a mixture mixed so as to have a P molar ratio of 1.40 to 1.498, wherein the powder further contains apatite whiskers based on the whole amount of the powder. There is provided a calcium phosphate cement for living organisms, characterized in that the cement content is 0.1 to 5% by weight.

Hereinafter, the present invention will be described in detail.

[0007] The calcium phosphate cement for living bodies of the present invention is characterized in that a powder mainly composed of a mixture of α-type tricalcium phosphate and dicalcium phosphate having a specific mixing ratio further contains apatite whiskers in a specific ratio. It is characterized by.

[0008] In the calcium phosphate cement for living body of the present invention, α-type tribasic calcium phosphate and dibasic calcium phosphate used as the main components of the powder react in the presence of water to produce octacalcium phosphate and harden. It is. As the second calcium phosphate, commercially available second calcium phosphate
Preferred examples include calcium phosphate dihydrate. The reaction proceeds most rapidly at pH 6-8.

The mixing ratio of the α-type tribasic calcium phosphate and the dibasic calcium phosphate is 1.4 in terms of Ca / P molar ratio.
It is necessary to be in the range of 0 to 1.498, and in order to further increase the strength, the Ca / P molar ratio is particularly preferably set to 1.47 to 1.495. The Ca / P molar ratio is 1.40.
When it is less than 1.498 or more than 1.498, the strength of the cured product is reduced, so it is necessary to be within the above range.

[0010] In the calcium phosphate cement for living body of the present invention, the apatite whisker contained in the powder is used.
Is a component for improving the strength and the like of the hardened cement. As the apatite whisker, for example, a fine apatite whisker having an average length of 10 to 20 μm, a minor axis of 0.3 to 2.0 μm, and an aspect ratio (c-axis length / a-axis length) of 20 to 40 is preferably used. preferable. To prepare the apatite whisker, a calcium phosphate slurry is used.
After adding and dissolving citric acid in the autoclave, it can be easily obtained by hydrothermal treatment in an autoclave. As the calcium phosphate used at this time, apatite, third
Calcium phosphate and the like can be preferably mentioned, and the amount of the citric acid used is preferably 1 mol or more per 1 mol of solid content in the calcium phosphate slurry. If the amount of the citric acid is less than 1 mol, a part of the solid content remains undissolved, which is not preferable. Further processing conditions when performing the hydrothermal treatment, 150 ~ 250 ℃,
The pressure is preferably in the range of 1.0 to 3.0 MPa for 1 to 10 hours.

The content of the apatite whisker in the powder is 0.1 to 5% by weight based on the whole powder. When the amount is less than 0.1% by weight, the strength of the cured product is not improved. When the amount is more than 5% by weight, the viscosity of the cement paste becomes high, and the strength is reduced without bubbles coming out during kneading. It is necessary to be within the above range.

As the liquid agent used in the present invention, water alone is sufficient, but in order to further improve operability,
Mucopolysaccharides such as sodium chondroitin sulfate and sodium hyaluronate, and water-soluble sodium salts such as sodium succinate and sodium lactate for shortening the curing time may be used.

The mixing ratio of the powder and the liquid is preferably in the range of 3.5 to 1.5: 1 by weight. If the mixing ratio of the powder is less than 1.5, it takes a long time to cure, and if it exceeds 3.5, the operability at the time of kneading deteriorates, which is not preferable.

Further, the calcium phosphate cement of the present invention may contain barium sulfate, bismuth subcarbonate,
X-ray contrast agents such as doform; antibacterial agents such as iodoform and chlorhexidine may be added for use.

[0015]

The calcium phosphate cement for living body of the present invention is based on a calcium phosphate cement having a specific composition rich in biocompatibility and an apatite whisker.
Excellent biocompatibility, high strength and little variation in strength. Further, the calcium phosphate cement for living body of the present invention,
Since the powder contains the apatite whisker in the above-described ratio, the fluidity and operability of the cement paste during kneading are superior to calcium phosphate cement not containing the apatite whisker. Of the hardened cement body can be increased, and the strength of the hardened cement body can be increased. Furthermore, since it is rich in fluidity, it can be filled into every corner of a part having a complicated form or a narrow part.

[0016]

The present invention will be described below in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0017]

Reference Example 1 α-type tribasic calcium phosphate and dibasic calcium phosphate (manufactured by Wako Pure Chemical Industries, Ltd .; dibasic calcium phosphate dihydrate, special grade) having a Ca / P molar ratio of 1.40;
1.43, 1.46, 1.47, 1.495, 1.49
8 to obtain a cement powder.
Next, 100 parts by weight of the obtained powder and 60 parts by weight of water as a liquid were kneaded and hardened. When the pH of the cement paste at the time of curing was measured using litmus test paper,
All were in the range of pH 6-8. The setting time and the compressive strength of the obtained cured cement were measured. Table 1 shows the results. The curing time is in accordance with JIS R5201,
The compressive strength is set cement hardened material (7mmφ, 14mmL)
Was immersed in an artificial body fluid for 3 days, taken out and measured in a wet state using a universal testing machine manufactured by Instron.

[0018]

Reference Example 2 The curing time and compressive strength were measured in the same manner as in Reference Example 1, except that the α-type tribasic calcium phosphate and the dicalcium phosphate were changed to Ca / P molar ratios of 1.33 and 1.499. Table 1 shows the results.

[0019]

[Table 1]

[0020]

Reference Example 3 10 g of synthetic hydroxyapatite powder was added to 5
The suspension was suspended in 00 ml of water to obtain a calcium phosphate slurry. After adding 25 g of citric acid to 500 g of the obtained slurry and dissolving the suspension, the mixture was filled in an autoclave,
Hydrothermal treatment was performed at 200 ° C., 2 MPa, and 5 hours. After the completion of the treatment, the obtained slurry was added to 1 liter of distilled water.
After washing with, filtering and drying at 100 ° C. in a drier. The obtained powder is subjected to a scanning electron microscope (trade name “T-20”, manufactured by JEOL Ltd.) and an X-ray analyzer (trade name “RU-200”, manufactured by Rigaku Denki Co., Ltd.) As a result, an apatite whisker having an average length of 10 μm, a minor axis of 0.5 μm, and an aspect ratio (c-axis length / a-axis length) of 20 was obtained.

[0021]

Examples 1 to 6 The apatite whisker obtained in Reference Example 3 was mixed at 900 ° C. with a cement powder in which α-type tricalcium phosphate and dicalcium phosphate were mixed so that the Ca / P molar ratio was 1.48. After baking at 0.1% by weight (Example 1), 0.5% by weight (Example 2), 1% by weight (Example 3), 2% by weight (Example 4),
Cement dusts were prepared by adding and mixing to 3% by weight (Example 5) and 5% by weight (Example 6).
Next, 50 parts by weight of water was mixed with 100 parts by weight of the obtained powder and cured. At this time, the cement paste was rich in fluidity and very excellent in operability. The compressive strength of the obtained cured product was measured in the same manner as in Reference Example 1. Table 2 shows the results.

[0022]

Comparative Examples 1 and 2 The amount of apatite whisker added in Example 1 was 0% by weight (Comparative Example 1) and 7% by weight (Comparative Example 2).
A cement hardened body was prepared in the same manner as in Examples 1 to 6, except that the compressive strength was measured. Table 2 shows the results.
The cement paste obtained at this time was hard and inferior in fluidity and operability.

[0023]

Comparative Examples 3 and 4 Apatite whiskers were 3% by weight of potassium titanate whiskers (manufactured by Otsuka Chemical Co., Ltd.) (Comparative Example 3), and carbon silicon whiskers (manufactured by Tokai Carbon Co., Ltd.) 3 A cured product was prepared in the same manner as in Examples 1 to 6 except that the content was changed to wt% (Comparative Example 4), and the compressive strength was measured. Table 2 shows the results.

[0024]

[Table 2]

As is clear from the results shown in Table 2, the calcium phosphate cement for living body of the present invention has high strength,
It can be seen that there is little variation in strength.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C04B 28/34 C04B 28/34 // (C04B 28/34 14:38) (72) Inventor Hiroyasu Takeuchi Yokoze, Chichibu-gun, Saitama 2270 Yokoze, Machi-Ota Mitsubishi Ceramics Research Laboratory (58) Fields investigated (Int.Cl. ⁶ , DB name) A61L 25/00 A61K 6/033 C04B 12/02 C04B 14/38 C04B 28/34

Claims (1)

(57) [Claims] 1. A biological calcium phosphate cement comprising a powder and a liquid containing a mixture of α-type tricalcium phosphate and dicalcium phosphate in a Ca / P molar ratio of 1.40 to 1.498 as a main component. A calcium phosphate cement for living body, characterized in that the dust further contains 0.1 to 5% by weight of apatite whiskers based on the total amount of the dust.