JPH06172007A - High-strength cement of calcium phosphate - Google Patents

Abstract

PURPOSE:To obtain a high-strength cement of calcium phosphate having workability not reducing even by blending in high powder liquid ratio and high strength and neither irritation to organism nor deterioration. CONSTITUTION:High-strength cement of calcium phosphate comprises 90-70wt.% alphatype calcium tertiary phosphate, 5-25wt.% calcium quaternary phosphate and 5-10wt.% calcium secondary phosphate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to high-strength calcium phosphate, and more particularly to high-strength calcium phosphate cement that can be used in medical and dental fields.

[0002]

2. Description of the Related Art Calcium phosphate cement is
It is known that when it is kneaded with water under the condition of 100% humidity, it cures in a short time (Japanese Patent Laid-Open No. 64-37445). The cement comprises α-type tricalcium phosphate, second type
Although it is a cement composed of calcium phosphate, it is known to be useful as a medical / dental cement because it has no biostimulation because it maintains a neutral range without changing the pH before and after hardening. However, there is a drawback that practically sufficient strength cannot be obtained. Conventionally, in order to increase the strength of such cement, a method of increasing the powder-liquid ratio (P / L) at the time of kneading has been adopted, but on the other hand, the viscosity of the kneaded cement paste increases and There is also a drawback that it leads to a decrease in sex. Further, the cement has a problem that its strength deteriorates in the long term.

[0003]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a high-strength calcium phosphate cement that has no biostimulation, does not deteriorate workability even when kneaded at a high powder-liquid ratio, and has high strength and no deterioration. To provide.

[0004]

According to the present invention, 90 to 70% by weight of α-type tricalcium phosphate, 5 to 25% by weight of quaternary calcium phosphate, and 5 to 25% by weight of dibasic calcium phosphate.
Provided is a high strength calcium phosphate cement comprising a powder consisting of 10% by weight.

The present invention will be described in more detail below.

The high-strength calcium phosphate cement of the present invention contains a powder consisting of 90 to 70% by weight of α-type tertiary calcium phosphate, 5 to 25% by weight of fourth calcium phosphate, and 5 to 10% by weight of second calcium phosphate. It is characterized by the combination of the respective components and the amount ratio thereof. Further, other additive components may include, for example, β-type tribasic calcium phosphate, octacalcium phosphate, monobasic calcium phosphate, calcium phosphate compounds such as hydroxyapatite, and alumina, zirconia, and the like having high biocompatibility.

The α-type tribasic calcium phosphate and the tetrabasic calcium phosphate use calcium hydroxide and phosphoric acid in a predetermined molar ratio, for example, calcium hydroxide is suspended in water, phosphoric acid is added, wet synthesis is performed, and then dried. It can be obtained by a method such as firing, crushing, etc. Further, as the dicalcium phosphate, a commercially available dicalcium phosphate dihydrate can be used.

The quaternary calcium phosphate used in the present invention is a component which reacts with α-type tricalcium phosphate or dibasic calcium phosphate to be hardened, and in the present invention, it is particularly utilized for increasing its strength. Since the reaction between the fourth calcium phosphate and the α-type third calcium phosphate or the reaction between the fourth calcium phosphate and the second calcium phosphate is slower than the reaction between the α-third calcium phosphate and the second calcium phosphate, the reaction is delayed with respect to the initial reaction. Become. Therefore, the fourth
When calcium phosphate is added, the fluid state continues for a long time after the cement and the hardening liquid are kneaded, and as a result, the cement and the solution can be kneaded at a higher powder-liquid ratio, so that the strength can be increased. Further, since the quaternary calcium phosphate is slow-hardening, the strength is developed after a long time, and it is possible to prevent the strength deterioration of the hardened body. The effects of adding quaternary calcium phosphate are as follows. The cement composed of α-type tribasic calcium phosphate and dibasic calcium phosphate has a Ca / P molar ratio in the range of 1.50 to 1.00 even if the blending amount of each component is changed. However, since this cement is converted to apatite in vivo after hardening,
Ca / P molar ratio of hydroxyapatite is understood to be extra PO ₄ ³ ~ is released upon conversion because it is 1.67. This may have an unfavorable effect on the living body such as locally decreasing the pH. Therefore, an alkaline substance that absorbs PO ₄ ³ is required. The fourth calcium phosphate is C
When the a / P molar ratio is 2.0, Ca during conversion to apatite
² + to release the absorbed PO ₄ ³ ~ a.

The content of quaternary calcium phosphate is 5% by weight.
If it is less than 25% by weight, the effect as a retarder is not exerted, and if it exceeds 25% by weight, the initial strength becomes too low to be used. Further, the blending amounts of the α-type tribasic calcium phosphate and the dibasic calcium phosphate should be determined in consideration of the blending amount of the fourth calcium phosphate, but when the α-type tribasic calcium phosphate exceeds 90% by weight, the curing becomes slow, Again 7
If it is less than 0% by weight, the strength is low. On the other hand, if the amount of dibasic calcium phosphate exceeds 10% by weight, the strength will be low, and if it is less than 5% by weight, the curing will be slow. In order to further increase the strength of the cement, that is, to increase the powder-liquid ratio when the cement and the hardening liquid are kneaded, the firing temperature of the main component α-type tricalcium phosphate should be 1400 ° C or higher and less than 1500 ° C. Is preferred. If it is less than 1400 ° C, the effect of strengthening may not be exhibited, and if it exceeds 1500 ° C, α'type third
It is not preferable because it may be transferred to calcium phosphate to reduce the hydration activity.

[0010]

The high-strength calcium phosphate cement of the present invention has a high strength because it can increase the powder-liquid ratio during kneading, and can also prevent long-term deterioration. Furthermore, there is no biotoxicity due to local pH drop.

[0011]

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

Synthesis Example 1 Synthesis of α-type tricalcium phosphate 3 mol of high-purity calcium hydroxide (manufactured by Calceed Co., Ltd.) was suspended in 10 liters of water, and 2 mol of phosphoric acid was diluted with water to 40 After the completion of the dropwise addition of the aqueous solution of about 1% by weight with stirring, the mixture was allowed to stand for 1 day (room temperature) and dried at 110 ° C. for 24 hours with a dryer (Yamato Scientific Co., Ltd., trade name “DV61 type”). This aggregate was baked at 1400 ° C. for 3 hours (manufactured by Motoyama, trade name “Super Burn”). Finally, it was crushed with a crusher (manufactured by Ishikawa Factory Co., Ltd., trade name "Kakuran crusher Tate No. 20") and passed through a 88 μm sieve.

Synthesis Example 2 Synthesis of quaternary calcium phosphate Synthesis was carried out in the same manner as in Synthesis Example 1, except that 4 mol of calcium hydroxide and 2 mol of phosphoric acid were used. 10 dried agglomerates
Calcination at 00 ℃ for 3 hours, take out and crush, then 140
It was calcined at 0 ° C. for 3 hours. Finally, it was passed through a 88 μm sieve.

[0014]

Examples 1 to 4 Table 1 shows the α-type tribasic calcium phosphate synthesized in Synthesis Examples 1 and 2, the fourth calcium phosphate, and the second dibasic calcium phosphate dihydrate (special grade manufactured by Wako Pure Chemical Industries, Ltd.). The mixture was mixed at a ratio, water was added so that the powder-liquid ratio shown in Table 1 was obtained, and the mixture was kneaded. The fluidity of the kneaded cement pastes were all the same.

Next, the curing time was measured according to JIS T 6602, and the cured product (diameter 7 mm, height 14 mm)
After soaking in physiological saline at 7 ° C for 1,7,28 days, remove
The compressive strength was measured according to JIS R 1608 while wet. The testing machine used was a universal testing machine manufactured by Instron Co., Ltd. under the trade name "1125 type". The results are shown in Table 1.

[0016]

[Table 1]

[0017]

[Examples 5 and 6] Table 2 shows the combination of α-type tricalcium phosphate synthesized in Synthesis Examples 1 and 2, quaternary calcium phosphate, and dicalcium phosphate dihydrate (special grade manufactured by Wako Pure Chemical Industries, Ltd.). Mix in a ratio of water and powder: liquid = 100: 4
After kneading at a ratio of 0 (weight ratio), the mixture was cured and dried at room temperature. The next day, it was pulverized to 300 μm or less, and 5 g each was put into an Erlenmeyer flask containing 50 ml of physiological saline.
Then, the Erlenmeyer flask was capped and left at 37 ° C. for 120 hours to measure the pH of the liquid. The results are shown in Table 2. The one to which quaternary calcium phosphate was added clearly had a high pH, suggesting that PO ₄ ³ was captured.

[0018]

[Table 2]

[0019]

[Comparative Examples 1 to 4] The powders used in Example 1 were mixed at the compounding ratio shown in Table 3 and compared with Examples 1 to 4. The results are shown in Table 3.

[0020]

[Table 3]

[0021]

Comparative Example 5 The powders used in Examples 5 and 6 were mixed at the compounding ratio shown in Table 4 and compared with Examples 5 and 6. The results are shown in Table 4.

[0022]

[Table 4]

Claims (1)

[Claims] 1. α-type tribasic calcium phosphate 90-70% by weight, quaternary calcium phosphate 5-25% by weight, second
A high-strength calcium phosphate cement containing a powder consisting of 5 to 10% by weight of calcium phosphate.