JP3166019B2 - Method for producing ultra-fast setting calcium phosphate cement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-fast-setting calcium phosphate cement useful as a medical dental cement.

[0002]

2. Description of the Related Art Conventionally, simply mixing with water has resulted in 37
There is known a hydraulic calcium phosphate cement which cures in a short time under conditions of 100 ° C. and 100% humidity (Japanese Patent Application Laid-Open No. 64-64).
No. 37445, “FC Report” vol. 6 (19
88), p475-480). The hydraulic calcium phosphate cement has a pH range before and after hardening and maintains a neutral region.Therefore, there is no biological irritation, and it is useful as a medical and dental cement, but practically sufficient strength cannot be obtained. However, there is a problem that the curing time is slightly long. In particular, in order to use as a dental cement, it is required that the setting time is less than 5 minutes. Therefore, it is impossible to use the hydraulic calcium phosphate cement as a dental backing agent, an indirect pulp capping agent and the like. is there. In order to shorten the curing time, a method of increasing the powder / liquid ratio during kneading and kneading the mixture more firmly is also known, but there is a problem that the fluidity is lost.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing an ultra-fast-setting calcium phosphate cement which has no biological irritation, is practically operable, and has an extremely short setting time.

Another object of the present invention is to provide an inexpensive method for producing ultra-fast hardening calcium phosphate, which has high strength and can effectively reuse cement which has been hardened once.

[0005]

According to the present invention, after hardening a calcium phosphate cement, 0.3 to 10% by weight of a reground powder obtained by grinding is mixed into a calcium phosphate cement powder, and then the mixed powder is mixed. Provided is a method for producing an ultra-fast-setting calcium phosphate cement, which comprises grinding and mixing powder while grinding.

Hereinafter, the present invention will be described in more detail.

[0007] In the method for producing an ultrafast-setting calcium phosphate cement of the present invention, first, after hardening calcium phosphate, a specific amount of reground powder obtained by grinding is mixed into the calcium phosphate cement powder.

[0008] The calcium phosphate cement used in the present invention is preferably a cement containing α-type tribasic calcium phosphate, quaternary calcium phosphate or the like as a main component. A mixture, a mixture of α-type tribasic calcium phosphate with dibasic calcium phosphate and / or monobasic calcium phosphate, and a mixture of quaternary calcium phosphate with dibasic calcium phosphate and / or monobasic calcium phosphate can be preferably exemplified. In addition, the reground powder obtained by hardening the calcium phosphate cement and then grinding is not necessarily the same as the main component cement,
Any one selected from calcium phosphate cements that are normally considered may be used. Furthermore, although the reground powder is cured once, any of those cured in air and those cured in water can be used. Particle size of reground powder is 1
It is preferably 50 μm or less, more preferably 20 to 100 μm. If it exceeds 150 μm, the fluidity of the cement paste tends to be impaired, which is not preferred. On the other hand, the specific surface area is desirably 10 to 50 m ² / g. When a small amount of the pulverized powder is added to the calcium phosphate cement, the fine crystals on the surface act as nuclei for the reaction, and the hardening time of the cement can be greatly reduced. The content of the pulverized powder is 0.3 to 10% by weight, preferably 0.5 to 5% by weight of the whole powder. If the amount is less than 0.3% by weight, the desired effect is not sufficiently exhibited.

The method of mixing the re-ground powder and the calcium phosphate is not particularly limited, but it can be easily achieved by, for example, mixing for 10 to 30 minutes using a shaker mixer or the like.

Next, in the production method of the present invention, the ultra-fast-setting calcium phosphate cement of the present invention can be prepared by grinding and mixing the whole mixed powder while rubbing.

The above-mentioned grinding and mixing performed while rubbing can be easily performed by mixing for 20 to 60 minutes using, for example, a crusher or the like, and the obtained mixed powder is added by grinding and mixing. Since the reground powder is rubbed into the surface of the unreacted powder, a kind of surface modification is performed, and the effect of the reground powder as a core is maximized. Also, by adjusting the amount of the reground powder as a core, the strength of the cured body can be adjusted, and furthermore, the curing time can be adjusted. For example, the curing time can be extremely shortened to about 3 minutes. It can be used as a dental backing agent or an indirect pulp capping agent, which was not possible in the past.

[0012]

According to the method of the present invention for producing ultra-rapid hardening calcium phosphate cement, after the reground powder is mixed, the whole powder mixture is ground and mixed together, so that the function as the core of the reground powder is maximized. Thus, sufficient strength and the like can be obtained with a small amount of addition. In addition, the curing time can be adjusted by changing the amount of addition, and it can be shortened to ultra-fast hardness, so that it can be used as a dental backing agent, indirect pulp capping and the like. Furthermore, since the calcium phosphate cement which has been hardened once can be reused, an inexpensive calcium phosphate cement can be provided.

[0013]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

[0014]

[Synthesis Example 1] Synthesis of α-type tribasic calcium phosphate 3 mol of high-purity calcium hydroxide (manufactured by Calceed Co., Ltd.) is suspended in 10 liters of water, and 2 mol of phosphoric acid is diluted with water to 40 wt. % Aqueous solution was gradually stirred and dropped, and allowed to stand for 1 day (room temperature), and dried at 110 ° C. for 24 hours in a drier (trade name “DV61”, manufactured by Yamato Scientific Co., Ltd.). This aggregate was fired at 1400 ° C. for 3 hours (trade name “Super Burn”, manufactured by Motoyama Corporation). Finally, the mixture was pulverized with a crusher (trade name: “Agitator crusher No. 20” manufactured by Ishikawa Plant Co., Ltd.) and passed through an 88 μm sieve.

[0015]

[Synthesis Example 2] Synthesis of Quaternary Calcium Phosphate Using 4 mol of calcium hydroxide and 2 mol of phosphoric acid, the dried agglomerate was calcined at 1000 ° C for 3 hours, taken out and pulverized, and further 1400 ° C. The operation was performed in the same manner as in Synthesis Example 1 except that the mixture was calcined for 3 hours, and finally passed through a 88 μm sieve.

[0016]

Example 1 The α-type tribasic calcium phosphate and dibasic calcium phosphate dihydrate (special grade, manufactured by Wako Pure Chemical Industries, Ltd.) obtained in Synthesis Example 1 were mixed at a weight ratio of 95: 5. A cement powder was obtained. The obtained cement powder and water are kneaded at a kneading ratio of cement powder: water = 100: 40 (parts by weight), hardened, allowed to stand in the air for 24 hours and air-dried. The product was pulverized with a product of “Ishikawa Plant Co., Ltd., trade name“ Vertical crusher No. 20 ”) and passed through a 150 μm sieve. Next, the obtained re-ground powder was added to the same cement powder as the above-mentioned cement powder in an amount of 0, 0.3, 0.5, 2, 5, 10 and 15% by weight, based on the total amount of the powder. About 3 to 15% by weight of the additive, the mixture was further ground and mixed by a crusher for 30 minutes. At this time, the ones in which the added amount of the reground powder is 0 and 15% by weight are for comparison.

Next, a curing liquid shown in Table 1 was added to 100 parts by weight of the finally obtained cement powder, and JIS T 66
The curing time was measured in accordance with No. 02. The cured product (diameter 7)
mmφ, height 14 mm) was immersed in physiological saline for 7 days, taken out, and the compressive strength was measured according to JIS R1608. The testing machine used was a universal testing machine manufactured by Instron, trade name "1125 type". Table 2 shows the results.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

Comparative Example 1 The same procedure as in Example 1 was carried out except that the grinding and mixing after the addition of the reground powder was omitted. Table 3 shows the results.

[0021]

[Table 3]

[0022]

Example 2 Except that the quaternary calcium phosphate obtained in Synthesis Example 2 and the dibasic calcium phosphate dihydrate used in Example 1 were mixed in a weight ratio of 70:30,
Performed in the same manner as in Example 1. Table 4 shows the results.

[0023]

[Table 4]

[0024]

Comparative Example 2 The same operation as in Example 2 was carried out except that the grinding and mixing after the addition of the reground material was omitted. Table 5 shows the results.

[0025]

[Table 5]

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C04B ^7/ 00-28/36 C01B 25/32 A61K 6/033 A61L 27/00

Claims (1)

(57) [Claims] After hardening a calcium phosphate cement, 0.3 to 10% by weight of a reground powder obtained by grinding is mixed into a calcium phosphate cement powder, and then ground and mixed while rubbing the mixed powder. A method for producing a super-fast setting calcium phosphate cement, which is characterized in that: