JPS6278142A - Whitlockite sintered body and manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Applications The present invention relates to a sintered body of whitlockite as a biomaterial that can be used for repairing bones, teeth, and blood vessels, and a method for producing the same.

B Summary of the Invention The present invention provides an atomic ratio of (Ca+Sr)/P of 1.40 to 1.
．． 75 and containing Sr in an amount such that the atomic ratio of S r / (Ca + s r) is θ ~ 0.05. Add H and PO4 to a mixed emulsion of (OH)1 and Sr(OH) and react. Calcium phosphate and strontium phosphate coprecipitated were filtered out, dried and calcined, and Sr was added in atomic ratio. / (Ca+S r) is 0 to 0
．． 05, and then molding and firing.

C. Conventional technology Before 1970, metals and plastics were mainly used as implant materials for artificial bones, artificial tooth roots, etc. However, when these materials were implanted into the body for a long period of time, It could not be used completely safely because it could cause chemical and physical changes such as dissolution, corrosion, and swelling in the body.

Many studies were conducted to eliminate these drawbacks, and as a result, the focus shifted to the use of ceramics.
Artificial joints made of compact alumina were first used in 1970.

Separately, in 1971, in the United States, five
5if2-Na,O is a combination of iO1-Na2O glass and oxides of calcium and phosphorus, which are biological components.
-Ca O-P, O, type glass (bioglass) has also appeared.

Problems that the invention aims to solve By the way, the former ceramic is an implant material mainly made of alumina, and although it has a certain degree of compatibility with living cells and tissues, it has no active interaction with living tissues. The disadvantage of poor binding properties cannot be eliminated.

The latter type of bioglass solves these problems, and animal experiments have shown that it has a high affinity to bond directly to bone tissue without any problems in bonding with living tissue. has been done.

However, the biggest drawback of this product is that its mechanical strength is extremely low.

Furthermore, the fact that this bioglass contains elements that are not included in living tissue remains a factor that will pose a problem in the future.

Under these circumstances, by around 1975, ceramics (tricalcium phosphorescence!-, TCP
) were announced simultaneously in West Germany and the United States.

The mineral name of this material is whittrockite.

Witlochite is said to be compatible with bone tissue, to have osteoinductive properties, and to bond with new bone in a short period of time.

Witlockite sintered body is an implant material with good biocompatibility in terms of its composition and crystal structure, and it is well understood that it has good compatibility with living cells and tissues. The material had poor sinterability and there was room for further improvement in terms of mechanical strength.

Means for Solving the Ew4 Problem The present invention has been developed through further study in response to the above-mentioned requirements, and is based on an atomic ratio of (Ca+Sr)/P of 1.
40 to 1.75 and further contains Sr with an Sr/(Ca+Sr) ratio of 0 to 0.05 in atomic ratio. This is the method for producing the solids.

F action The witrockite sintered body of the present invention has a valence of 2 and an ionic radius of 0.113 nm Sr added to TCP, so that it can be combined with Ca++ having a different ionic radius of 0.099 nm. Since it adopts a close-packed structure by substitution, it has the effect of improving the sinterability of whitlockite and increasing the mechanical strength of the sintered body.

G Examples Hereinafter, the structure and effects of the present invention will be specifically explained by showing several examples.

Example I C6(OH), and Sr(OH)a as Sr/(Ca+Sr
) was mixed in an amount such that the atomic ratio was 0.01, a predetermined amount of the H3PO4 aqueous solution was gradually dropped into the aqueous solution 101 with stirring, and the reaction was allowed to occur at room temperature.

After aging, the contents of the 1*t sample were dried in a dryer at 90° C. for 3 days.

Thereafter, the powder was calcined at 800° C. for 3 hours using a SiC furnace, and the powder was examined by X-ray diffraction, and it was confirmed that it was a pure Wit) and Lokai) crystal.

3.0% by weight of PVA (polyvinyl alcohol) was added as a binder to this whitlockite powder, and the mixture was mixed in a milling machine and granulated into particles that could pass through 80 meshes.

After compression molding this powder under a pressure of 0.6t/-, it was molded using a hydrostatic press to 1.5t/c+g? After pressurizing to obtain a molded body, it was fired in air at 1150°C for 3 hours.

When this fired body was examined by X-ray diffraction again, it was confirmed that it was pure whitlockite.

The following table shows changes in shrinkage rate, relative density, compressive strength, and bending strength of the fired body relative to the molded body when the amount of Sr(OH)a added was changed.

Example 2 After dispersing and dissolving 1 kg of Ca(OH) in 101 g of distilled water, a certain amount of H3PO4 was gradually added dropwise without stirring to obtain amorphous wittrochite.

After aging for 3 days, the precipitated product was ground and dried in an oven at 85° C. and then ground in a seeder.

A certain amount of Sr is added to this powder in SrCO3 and SrO, respectively.
1Sr(OH)t, SrCl t, SrF,, Sr
(NOs) g, S r s (P 04)! , SrHPO
4, Sr'(HzP Oa)i, SrSO, etc. were added and mixed.

After calcining at 800℃ for 3 hours in a SiC heating element furnace,
Mixing and pulverization was carried out in a ball mill for 4 hours, and after drying, a powder passing through 80 meshes was obtained.

3.0% by weight of PVA was added as a binder to the calcined powder, which was then molded and fired in the same manner as in Example 1.

When the fired body was crushed and examined by X-ray diffraction, it was confirmed that it was a pure wittrochite powder.

In addition, in the step of adding the Sr compound, the added Sr
When the characteristics of the sintered body were investigated with respect to changes in the amount of O added, the following results were obtained.

In addition, a certain amount of Sr compound was added and mixed to the powder which was calcined at 800°C for 1 hour using Kanthal exothermic sintering, and then the same treatment as above was carried out to obtain a sintered body. However, the characteristic values of this sintered body were similar to those shown in the table above.

*Example 3 H3PO4 was added by the same method as Example 1.2, but
The amount added was smaller than that in Example 1.2.

This was treated and fired as in the previous case.

When the sintered body was examined using an X-ray line, it was found that it contained 83% by weight of whittlochite and 17% by weight of hydroxyabatite.
(CaxS ry(Pot)s(OH)z, x
+y=10).

When we investigated the compressive strength characteristics of this sintered body, we found that it was 6320'
kg f/cd (at this time Sr/(C
a+Sr).

From the above results, it can be seen that even if hydroxyapatite is mixed with witrockite, the result of adding Sr appears.

Example 4 Flash stone (CaHPO4.2H,
This was heat-treated at 500° C. in air.

The product thus obtained was determined to have β-Ca by X-ray diffraction.
It was confirmed that it was 1P,O,.

After adding a certain amount of CaO to this powder and mixing it, a C
a s (P O4) t was obtained.

Furthermore, β-
Cas(Po4)s is obtained, and Sr is added to the powder as Sr content.
COs was added and mixed, and the mixture was calcined at aOO°C for 2 hours in an exothermic closed furnace, and then mixed and pulverized using a ball mill.

Next, PVA was added as a binder, and the sized powder was molded by spraying and fired in the same manner as in Example 1.

When the fired body was crushed and examined by X-ray diffraction, it was confirmed that it was whitrockite.

In addition, when we investigated the characteristics of a sintered body with a Sr/(Ca+Srl ratio of 0.02), we found that the bending strength of the additive-free sintered body was 10.
1490 compared to 5.8 kg f /cd.
kg f/d.

Example 5 Witlockite sintered bodies were implanted into the femur and jawbone of adults as artificial tooth roots and artificial bones, and the bone affinity was examined over a period of 14 months. As is clear from the reference photos, there was no rejection reaction. This was not observed at all, and it was recognized that the bone affinity was extremely excellent.

Note that the reference photo is Sr/(Ca +
This is an X-ray photograph taken 6 months after surgery, showing the case where a whitlockite sintered body with S R )=0.01 was used and applied to an adult as an artificial tooth root.

H Effects of the Invention By implementing the present invention, it is possible to easily form a material that has the contradictory properties of compatibility with bone tissue, new bone induction, and mechanical strength, which have been observed in conventional artificial bones and artificial tooth root materials. This has the effect of making it possible to bond to living tissue in a short time.

Claims (5)

[Claims] (1) Contains Sr in the range of 0<Sr≦0.05 in Sr/(Ca+Sr) ratio, and (Ca+Sr)/P ratio is 1.4
Willochite (Ca_3(PO_4)) is made by forming a Ca-P compound of 0 to 1.75 and firing this
_2) Sintered body. (2) Contains Sr in the Sr/(Ca+Sr) ratio of 0<Sr≦0.05, and contains hydroxyapatite (Ca_
A Ca-P compound containing 1_0PO_4)_6(OH)_2) in the range of 0%<hydroxyapatite≦50% based on the total weight of the compound and having a (Sr+Ca)/P ratio of 1.40 to 1.75. Witlokite sintered body made by molding and firing. (3) Ca(OH)_2 and Sr(OH)_ containing Sr in the range of 0<Sr≦0.05 in Sr/(Ca+Sr) ratio
A method for producing a whitlocite sintered body, which comprises dropping H_3PO_4 into the mixed suspension of No. 2 and aging the resulting coprecipitate, followed by drying, molding, and sintering. (4) Using flash stone as a Ca source, 500
℃ to form Ca_2P_2O_7, and further CaO
Mix and heat at 1200℃ to make Ca_3(PO_4)_
2. A method for producing a whitlockite sintered body according to claim 3, which comprises using a sintered body of whitlockite according to claim 3. (5) Ca_3 (PO_4)_2 obtained from flash stone
The method for producing a whitlockite sintered body according to claim 3 or 4, which comprises further mixing CaO with the mixture and heating the mixture in steam at 1200°C.