JPS6179462A - Porous artificial bone material - 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 Field of Industrial Application The present invention relates to a new artificial bone material suitable for use in orthopedics and oral surgery.

More specifically, the present invention relates to a novel artificial bone material that easily binds to living tissue when implanted in the body, and is rapidly dissolved and absorbed to replace new bone.

Conventional technology In recent years, along with advances in the medical industry, 1. Research into artificial bone materials for prosthetics for bones lost due to traffic accidents or diseases such as bone tumors is becoming increasingly popular. By the way, when implanting an artificial material into a living body, it is necessary to transport a material that is non-toxic, safe, has high mechanical strength, and is easily bonded to living tissue. It is said that it is preferable that the bone disappears naturally and is replaced with new bone.

To meet these requirements, artificial tooth roots and artificial bones made of sintered bodies of tricarium phosphate, hydroxyapatite, or special apatite quasi-crystal structure calcium phosphate compounds have been proposed (Japanese Patent Application Laid-Open No. 1983-1992). -548
Publication No. 41).

By the way, in order to make it easier for artificial bone or tooth roots to bond with living tissue when implanted in the body, it is necessary to make them porous so that the living tissue can enter the pores and fix them. necessary and to achieve this purpose,
Pore diameter 0.03-1.2. It is also known to use a porous calcium phosphate sintered body having a certain degree of pores (Japanese Patent Application Laid-Open Nos. 56-149389, 1982-7856).
Publication No.).

However, if calcium phosphate-based sintered bodies are made porous, their mechanical strength will be significantly reduced, making it impossible to obtain the strength required for artificial bone, so they cannot be used particularly for the treatment of large-scale bone defects. Traditionally, this has required the use of non-metabolizable materials such as titanium, stainless steel, and alumina, or the use of bone grafts from other parts of the patient's own body.

Problems to be Solved by the Invention When conventional non-metabolizable materials such as titanium, stainless steel, and alumina are used as artificial bones, they must be removed through surgery after they have completely healed, or they can be left in the body as a foreign body. In addition, transplanting bone from other parts of the patient's body would require additional surgery on areas other than the affected area, which would place an unnecessary burden on the human body.

Therefore, an object of the present invention is to have an artificial material that, when implanted in a living body, has a high mechanical strength that can sufficiently withstand prosthesis of a large-scale bone defect, and that can be easily bonded to living tissue. It is an object of the present invention to provide a new artificial bone material that can naturally disappear in a living body and be replaced with new bone, and therefore does not impose unnecessary burdens on the human body such as reoperation.

Means to Solve the Problems The present inventors first discovered a material with a pore diameter of 10 to 10, which is suitable as an artificial aggregate.
It has continuous pores of 100μm and at least 100Kf/
We have developed a sintered hydroxyapatite with a bending strength of i (Japanese Patent Application No. 58-129087), but as a result of further research, we have developed a porous material with pores with a pore diameter of 0.1 to 2 farts. The inventors have discovered that the above objects can be achieved by constructing an artificial bone material, and have come to form the present invention.

That is, the present invention provides an artificial bone material made of a calcium phosphate-based sintered body and having pores of 0.2 to 2 mm in pore diameter, preferably 0.15 to 1. The present invention provides a porous artificial bone material characterized by being a hydroxyapatite sintered body having pores.

The artificial bone material of the present invention has an average particle size of 0.1 to 10μ, for example.
Adding 10 to 40 parts by weight of a thermally decomposable substance with an average particle size of 20 to 100 μm and 10 to 40 parts by weight of a thermally decomposable substance with an average particle size of 0.2 to 2 mm to 100 parts by weight of hydroxyapatite powder of m, It can be manufactured by molding into a desired shape and firing at a temperature of 900 to 1400°C. Although the firing can be carried out without applying pressure, it is preferable to carry out the firing by applying a pressure of 300 to 1000 Kp/cd using, for example, a hot press.

The hydroxyapatite to be removed may be synthetic apatite produced by a dry method or a wet method, or may be a variety of biological apatite recovered from bones and teeth of vertebrates. It is desirable to use this raw material, hydroxyapatite, that has been ground into as fine a powder as possible, but due to limitations in equipment such as grinders and classifiers, and handling problems, the average particle size should be in the range of 0.1 to 10 pm. are used.

Next, the thermally decomposable substance is mixed in order to form continuous pores with a desired pore size when sintering the hydroxyapatite, so one with an average particle size of 20 to 100 μm and one with an average pore size of 0. Two types of 2 to 2 m+n are used. This thermally decomposable material is hydroxyapatite powder 100%
It is necessary to add 10 to 40 parts by weight per part by weight.

If the amount is smaller than this, sufficient continuous pores will not be formed, and if the amount is larger than this, the apparent density and mechanical strength will inevitably decrease. As this thermally decomposable substance, an organic compound such as crystalline cellulose is suitable.

Any means may be used to mix the hydroxyapatite powder and crystalline cellulose as long as they can be mixed uniformly. For example, hydroxyapatite powder and crystalline cellulose may be mixed as is using an appropriate mixer, or hydroxyapatite powder may be formed into granules with a particle size of 20 to 200 μm and then mixed with crystalline cellulose. may be mixed. Furthermore, it is also possible to wet the surface of crystalline cellulose with water or other solvent and apply hydroxyapatite uniformly thereto.

A binder such as polyvinyl alcohol is added to the mixture thus prepared, if necessary, and the mixture is molded into a desired shape and fired at a temperature of 900 to 1400°C.

Firing time is usually 0.5 to 3 hours.

The artificial bone material of the present invention also has an average particle size of 0.1 to 10 μm.
For 100 parts by weight of hydroxyapatite powder, the average particle size is 2
10 to 40 parts by weight of a thermally decomposable substance with a particle size of 0 to 100 μm is added and formed into granules, and then granules with an average particle size of 0.2 to 2 m are added.
It can also be produced by adding and mixing the thermally decomposable substances of m, adding a binder if necessary, molding into a desired shape, and firing at a temperature of 900 to 1400°C.

The artificial bone material obtained in this way usually has a molecular weight of 80 to 130
It has a bending strength of Kp/ctd, a porosity of 30-40%, and a water absorption rate of 20-40%.

Next, the porous artificial bone material of the present invention will be explained according to the accompanying drawings. The drawing is an enlarged cross-sectional view showing the entire structure of the porous artificial bone material, which is made from a matrix of sintered hydroxyapatite having micropores 2, and continuous pores 3 are formed throughout. It has a structure. The aforementioned micropore diameter 2 has a pore diameter of 20 to 100 μm, preferably 50 to 80 μm, and by setting the pore diameter to this level, 7.
Enables the entry of capillaries with a diameter of ~10 μm,
Bone tissue is formed by bone granulation and hydroxyapatite is absorbed by the appearance of osteoclast-like multinucleated giant cells.

Effects of the Invention The artificial bone material of the present invention has micropores with a pore diameter of 20 to 100 μm and is made of hydroxyapatite with a bending strength of at least 100 Kg/cnl, so the overall strength is high. In addition to being expensive, the pore diameter is 0.1~
Since it is a porous body with pores of 2 mm, it easily binds to living tissue, and the artificial bone material of the present invention is rapidly dissolved and absorbed in vivo by the action of osteoclasts (50 to 100 μm). Since it is replaced with new bone by bone granulation, it is suitable for use in oral surgery and orthopedic surgery.

implementation row Next, the present invention will be explained in more detail with reference to Examples.

Column 1 Hydroxyl abatai synthesized by wet method) i After calcining at 900°C for 1 hour, the average particle size was 0 using a ball mill.
．． It was ground to 5 μm. Next, 2% by weight of polyvinyl alcohol was added as a binder to this, and the particle size was adjusted to 50 to 1.
It was granulated into 00 μm granules.

Next, 100 parts by weight of the granules thus obtained and an average particle size of 8
15 parts by weight of crystalline cellulose of 0 μm and an average particle size of 0.
2 rrrm of crystalline cellulose was mixed with 15 parts by weight, and press-molded at a molding pressure of 500 Kf/era to obtain 1350
It was baked at ℃ for 1 hour.

In this way, the average pore size is 50-80 μm and the average pore size is 0.
．． An artificial bone material consisting of an apatite sintered body with a porosity of 32 and having continuous pores of 2 ff 1 m was obtained.

The bending strength of the material part of this item is 145.5) f/c
The overall bending strength at rd was 102.8 y/crd.

Row 2 The same hydroxyapatite powder as in Example 1 was calcined at 900°C for 1 hour, then ground to an average particle size of 0.5 μm, and 100 parts by weight of the hydroxyapatite powder was mixed with 2 parts by weight of polyvinyl alcohol and an average particle size of 30 μm.
After adding 15 parts by weight of microcrystalline cellulose powder and mixing, it was formed into granules, and the average particle size ITrr! Add 15 parts by weight of crystalline cellulose of
Press molded at 9/crl and 1 at 1350°C.
Baked for an hour. In this way, an artificial bone material having almost the same physical properties as Example 1 was obtained.

A small piece (3x4x6 t
Ran) K was prepared and sterilized according to conventional methods, and then implanted into the mandibles of five rabbits weighing between 2.5 and 3 years old. When reared for 8 weeks, some of the apatite sintered bodies were absorbed and The surface of the apatite sintered body and the new bone were completely combined.

In this way, it was confirmed that the artificial bone of the present invention can be used clinically as a filling material for jaw bone defects.

For comparison, a product with a micropore diameter of 1 to 5 μm was manufactured in the same manner as in row 1, and tested by implanting it in the mandible of a rabbit in the same manner. I couldn't.

[Brief explanation of the drawing]

The drawing is an enlarged cross-sectional view showing the tissue structure of the artificial bone material of the present invention. In the figure, reference numeral 1 indicates a hydroxyapatite matrix, 2 indicates micropores, and 3 indicates continuous pores.

Claims (1)

[Claims] 1 Pore diameter 0.2 made of calcium phosphate sintered body
A porous artificial bone material having pores of ~2 mm, characterized in that the calcium phosphate-based sintered body is a hydroxyapatite sintered body having micropores with a pore size of 20 to 100 μm.