JPH09173436A - Bioprocsthetic member and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bioprosthetic member which can be early agglutinated to a bone and fixed thereto and is excellent in strength, and is capable of arbitrarily controlling a partial difference in composition, and the shape and arrangement of holes. SOLUTION: A bioprosthetic member 1 comprising a calcium phosphate material and the other ceramic materials and which has in vivo harmlessness is formed in multi-layers different in mixing ratio of two kinds of materials in such a manner that, as it separates from the bone fixing surface 2, the content proportion of calcium phosphate material is decreased in stages. Further, plural ceramic green sheets prepared by two kinds of material powder at different mixing ratio are stacked and integrated, and burnt to manufacture a bioprosthetic member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bioprosthesis member for constructing an artificial root or the like for bone function and joints of limbs due to illness or disaster, or artificial tooth root for tooth reconstruction lost due to old age, illness, etc. It is about.

[0002]

2. Description of the Related Art Calcium phosphate materials such as hydroxyapatite and tricalcium phosphate have weaker strength than ceramic materials such as alumina and zirconia, but they have excellent osteoconductivity that these materials do not have. Therefore, there has been proposed a composite ceramic material having excellent osteoconductivity and strength, in which a material such as alumina or zirconia is used as a base and the surface in contact with the bone is coated with a calcium phosphate material.

As a method for producing this composite material, a method has been proposed in which a slip made of a calcium phosphate material is applied to the surface of a substrate before firing and then fired.

[0004]

However, the above prior art has the following problems. That is, in the above method,
The concentration of the calcium phosphate material with respect to the depth from the surface cannot be controlled accurately, and the applied slip tends to diffuse not only in the depth direction of the applied surface but also in the plane direction. For this reason, the concentration of the calcium phosphate material in the surface portion of the base becomes low, and the amount of binding between the calcium phosphate materials at the interface between the coating layer and the base is small, resulting in a problem in bonding strength. Furthermore, in the prior art, since the coating layer of the calcium phosphate material is formed on the surface, it was not possible to form the porous surface on the substrate.

[0005]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, the present invention is a member comprising a calcium phosphate material and a ceramic material which is not biohazardous other than that, wherein the concentration distribution of the calcium phosphate material is arbitrarily controlled, It is an object of the present invention to provide a method for manufacturing a bioprosthetic member that has a large degree of fusion with bones, a large fixing force, and a large strength.

[0006]

In order to solve the above-mentioned problems of the prior art, the bioprosthesis member of the present invention is a member composed of calcium phosphate material and other ceramic material which is not harmful to the living body and has bone fixation. In order to reduce the content ratio of the above calcium phosphate material stepwise as the distance from the surface increased, the composition ratio of these two kinds of materials was changed to a multilayer structure. Further, the bioprosthetic member as described above is manufactured by a process of stacking a plurality of ceramic green sheets prepared by adjusting the above-mentioned two kinds of material powders with different compounding ratios and firing them.

[0007]

The present invention is a type of bioprosthetic member composed of a calcium phosphate material and other non-biologically harmless ceramic materials, which contains a large amount of calcium phosphate material on the surface thereof, and the content ratio thereof gradually decreases toward the inside. The composition of the living body prosthesis itself is made of the material having a gradient composition ratio, or the structure of such a material is attached to the surface of the substrate. With this structure, the calcium phosphate material adheres to the new bone on the surface of the bioprosthesis member to promote the growth thereof and to be fused with the growing new bone. Such a fixing action can be further strengthened by adding an anchoring function (mechanical engagement relationship) by forming a large number of communication holes with regularity. Furthermore, even at the interface portion where the compounding ratio changes stepwise, the same materials are in contact with each other, so that the strength against shear stress is large.

Further, the bioprosthesis member having the above-mentioned structure utilizes a ceramic multi-layer technology in electronic parts and the like, and a plurality of ceramics prepared by adjusting powders of calcium phosphate material and other non-biologically harmless ceramic materials with different mixing ratios. This can be realized by a process of stacking and integrating green sheets and firing the same. According to such a method, the compounding ratio of the calcium phosphate material and the ceramic material can be controlled arbitrarily and surely, and a machine can be used. By providing holes in the green sheet and freely controlling the arrangement, size, form, etc. of the holes, it is possible to obtain the most advantageous hole shape from the viewpoint of easy bone penetration and anchoring function.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a bioprosthesis member 1 according to an embodiment of the present invention.
Is a member composed of a calcium phosphate material known to have a bio-fusion ability and a ceramic material other than that which is not harmful to the living body. Due to the difference in the compounding ratio between the calcium phosphate material and the ceramic material, As shown in the figure, the same layer has a uniform composition in a multilayer structure.

It may be difficult to confirm the interface of the bioprosthetic member 1 only by visual observation.
As a method for confirming the multi-layered structure, a stepwise concentration change of calcium and phosphorus can be confirmed by performing wavelength dispersive X-ray microanalyzer analysis (EPMA) in the direction perpendicular to the interface.

As the calcium phosphate material, hydroxyapatite [Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ , tricalcium phosphate Ca ₃ (PO ₄ ) ₂ and octacalcium phosphate Ca ₈ H ₂ (PO ₄ ) ₆
・ 5H ₂ O, etc. are available. On the other hand, other biomaterials that are not harmful to the body other than calcium phosphate materials include alumina and zirconia ceramics.

In the bioprosthetic member 1, the upper and lower surfaces are both bone fixing surfaces 2 and 2, and the fixing layers 3 and 3 as a surface layer including the bone fixing surfaces 2 and 2 are mainly made of a calcium phosphate material. (Although it may be a layer consisting only of a calcium phosphate material), on the other hand, the above-mentioned fixing layers 3, 3
The inner side of the is an inner layer 4 in which the content ratio of the calcium phosphate material gradually decreases as the distance from the bone fixation surfaces 2 and 2 increases.

In the bioprosthesis member 1 thus constructed, since the density of the calcium phosphate material on the bone fixing surface 2 is high, the calcium phosphate material on the surface of the bioprosthesis member 1 adheres to the new bone to promote its growth and grow. It heals with the new bone that has come.

Further, since the same material is in contact with the interface where the compounding ratio of the calcium phosphate material and the above ceramic material changes, that is, the interface between the fixed layer 3 and the inner layer 4, or the interface between the pair of different inner layers 4 and 4, the material is contacted. Are fixed and have a high strength against shear stress. In addition, although the compounding ratio of the calcium phosphate material and the ceramic material changes stepwise, the coefficient of thermal expansion also changes stepwise, so the difference in coefficient of thermal expansion between adjacent pairs of layers is small, and in the manufacturing process It is difficult for cracks to occur.

The amount of change in the content of the calcium phosphate material or the ceramic material in the pair of adjacent layers is preferably 30% or less. this is,
This is because if the content exceeds 30%, the shear strength at the layer interface decreases, or the difference in thermal expansion coefficient increases, and cracks may occur in the manufacturing process.

The bioprosthesis member 1 thus configured
Examples of the method of use include use as an artificial intervertebral disc or artificial vertebral body mounted between the upper and lower bones, and other interosseous blocks.

As a method of manufacturing the bioprosthetic member 1, the ceramic multilayer technology in electronic parts and the like can be applied. That is, a plurality of green sheets prepared by adjusting powders of calcium phosphate material and other ceramic materials with different compounding ratios based on a known method are laminated and integrated by a known method, and the green sheets are fired at an appropriate temperature, as described above. The bioprosthesis member 1 having the fixing layer 3 and the inner layer 4 can be obtained.

An advantage of such a manufacturing method is that the compounding ratio can be controlled arbitrarily and surely, and further, when mechanical stress is applied to deform the green sheet, for example, bending can be achieved. The bioprosthesis member 1 can be formed into a shape or other shapes.

Next, FIG. 3 shows a bioprosthetic member 1 according to another embodiment.
The cross-sectional structure of the bioprosthesis member 1 is shown in which only one of the upper and lower surfaces is the fixed body 3, and is used as a bone prosthesis when a part of the surface of the bone is removed due to a bone tumor or the like. In addition to being usable, as shown in FIG. 4, for example, an artificial hip joint as a base, a bioprosthesis member 1 is embedded in a recess 7 provided in an osteosynthesis surface 6 of a femoral component 5 (with the fixing layer 3 on the bone side). ), The fusion between the femoral component 5 and the bone can be accelerated.

5 to 6 show a bioprosthesis member 1 according to another embodiment, in which the bioprosthesis member 1 has a plurality of columnar holes 8 which are opened in the bone fixation surface 2 in the vertical direction. At the stage of the green sheet in the method of manufacturing the bioprosthetic member 1 described above, a large number of holes 8 are formed in the green sheet 9 before lamination as shown in FIG.
As described above, the holes 8 may communicate with each other in the vertical direction.

FIG. 8 is a cross-sectional view showing a modified example of the hole arrangement in the bioprosthesis member 1. As shown in the figure, the holes 8 open in the bone fixing surface 2 and at a substantially constant depth. The new bone grows into the hole 8 having a three-dimensional structure in the bioprosthetic member 1,
The three-dimensional structure of the bone tissue makes it possible to firmly hold the bioprosthetic member 1 in the living body. In addition, by freely controlling the arrangement, size, shape, and the like of the holes 8, it is possible to obtain the shape of the holes 8 that is most advantageous in terms of easy bone penetration and an anchoring function.

[0022]

Embodiments of the present invention will be described below.

Example 1 A zirconia powder having an average particle diameter of 0.5 μ and an apatite powder having an average particle diameter of 1.0 μ obtained by calcination and pulverization were contained in a ratio shown in Table 1 in 100% by weight of a raw material powder, and a dispersant 0.8 to 3.0% by weight, organic binder 8
To 14% by weight and 0.2% by weight of antifoaming agent,
The slip is adjusted by adding to 80 wt% and the thickness is 0.2 m by the doctor blade method using this slip.
m green sheets were produced. This green sheet was cut into a desired size, and a large number of holes were formed in the green sheet by punching.

[0024]

[Table 1]

There are two types of hole patterns.
A green sheet made of 1, 3, and 5 raw material powder was provided with round holes with a diameter of 1.0 mm at a pitch of 1.5 mm. Type B is No. Round holes with a diameter of 2.0 mm were made 3.0 m on the green sheet made from raw material powders 1, 2, and 4.
It was opened at m pitch.

These six kinds of green sheets were used as raw material powder N
o.・ Pore type) = 1A, 1A, 1B, 1A, 2, 3, 4,
8 layers were laminated in the order of 5 [2 to 5 are non-porous] to obtain a bioprosthetic member.

Next, this bioprosthetic member was attached to a plate material cut out from a CIP compact of the same material as the zirconia powder, and the raw material powder No. 1 containing 100 vol% of the zirconia powder was used. After bonding and drying on the surface of No. 5, 1300 ° C in an oxidizing atmosphere
A bioprosthesis member was obtained by calcining in (1), and a fixed layer composed only of apatite powder and three layers continuous with the fixed layer were porous and the remaining layers were nonporous.

Example 2 100% by weight of raw material powder containing alumina powder having an average particle size of 0.1 μ and apatite powder having an average particle size of 1.0 μ calcinated and pulverized was used as a dispersant. 0.8 to 3.0% by weight, organic binder 1
0 to 16% by weight, antifoaming agent 0.2% by weight, and water 3
The slip was adjusted by adding 0 to 80% by weight, and a green sheet having a thickness of 0.3 mm was produced by an extrusion method using this slip. This green sheet was cut into a desired size, and No. 5 in the order 1, 2, 3, 4, 5
The layers were laminated.

[0029]

[Table 2]

Next, on the side surface of the cylinder produced by the cast molding method using the same material as the alumina powder, the laminated green sheet was made of No. 80 vol% alumina powder. The surface of the bioprosthetic member of the present invention is adhered on the surface of No. 5, dried, and then fired at a temperature of 1300 ° C. in an oxidizing atmosphere so that the surface is apatite and the content ratio of the apatite is gradually reduced according to the distance. Obtained.

[0031]

The bioprosthesis member of the present invention is a member composed of a calcium phosphate material and a ceramic material other than that, which is not harmful to the body, and the content ratio of the calcium phosphate material is gradually increased as the distance from the bone fixation surface increases. Since the composition ratio of these two kinds of materials is made different so as to decrease, the calcium phosphate material adheres to the new bone and promotes its growth on the surface, and the calcium bone material is fused with the newly grown bone. Furthermore, even at the interface portion where the compounding ratio changes stepwise, the same materials are in contact with each other, so that the strength against shear stress is large.

Further, according to the method for manufacturing a bioprosthetic member of the present invention, since the multilayer technology of electronic parts is applied, the above-mentioned 2
It is possible to control the blending ratio of various materials arbitrarily and reliably, and by using a machine to make holes in the green sheet and freely control the arrangement, size, and shape of the holes, bone invades. It is possible to obtain a hole shape that is the most advantageous in terms of ease of operation and anchoring function.

[Brief description of the drawings]

FIG. 1 is a perspective view of a bioprosthetic member of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a cross-sectional view taken along the line XX of FIG. 1, showing a bioprosthetic member in another form.

FIG. 4 is a perspective view of a tibial component as a bioprosthetic member of the present invention.

FIG. 5 is a perspective view of a bioprosthetic member according to another embodiment of the present invention.

FIG. 6 is a sectional view taken along line YY of FIG. 5;

FIG. 7 is a perspective view showing a green sheet having a large number of holes.

8 is a cross-sectional view taken along the line YY of FIG. 5, showing a modification of the hole arrangement.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bioprosthetic member 2 Bone fixing surface 3 Fixing layer 4 Inner layer 5 Femoral component 6 Bone joint surface 7 Recessed portion 8 Hole 9 Green sheet

Claims (3)

[Claims] 1. A bioprosthesis member comprising a calcium phosphate material and other non-biologically harmless ceramic material, at least a part of the surface of which mainly contains the calcium phosphate material as a bone-fixing surface, and is separated from the bone-bonding surface. A bioprosthesis member obtained by gradually reducing the content ratio of the calcium phosphate material. 2. The bioprosthesis member according to claim 1, wherein the bone fixation surface is formed with a number of holes that are open to the bone fixation surface in a regular manner. 3. Production of a bioprosthesis member including a step of laminating and integrating a plurality of ceramic green sheets prepared by adjusting powders of a calcium phosphate material and other non-biologically harmless ceramic materials with different compounding ratios, and firing them. Method.