JPH0739578A - Metallic implanting article and preparation thereof - Google Patents

Abstract

PURPOSE:To provide a metallic implanting article for safe use wherein the article made from joined sphere beads being inseparable in organism. CONSTITUTION:The article consisting of a joined metallic sphere beads 1 is sintered on a surface of metallic substrate 2 in a manner having a rough surface of concavo-convex, wherein the distance between two peaks of adjacent two beads being in a range of not more than three times and not less than one-half of the average sphere diameter, or the beads 1 being filled up the gap with metallic powder and being sintered on a metallic substrate 2 so as to the gap being filled up to not more than one-third of the average diameter of beads.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal material to be embedded in a living body such as an artificial joint and an artificial tooth root material. More specifically, after the metal material is embedded in a living body, the surrounding living tissue and An improved metallic bioimplant for strengthening the bond between them and a method of manufacturing the same.

[0002]

2. Description of the Related Art In the treatment of defects in joints and bones of a living body, an artificial material mainly made of metal is embedded. Since these are essentially incompatible with living tissues, the surface of the embedding material is conventionally mechanically shallowly grooved, and in addition, an organic adhesive is used to bond the living bone. However, since the adhesive is accompanied by heat generation when it is solidified, it may affect living tissues around the adhesive. Therefore, the method using the organic adhesive has a short service life.

As a cementless type that does not use an adhesive, there is a cementless type in which a porous member made of a thin metal wire is bonded to the surface of an embedding material. In this case, if a part of the wire rod is broken during handling, the broken glove may damage the doctor's gloves to be operated, and in addition, there is a concern that the fixing effect may be insufficient due to insufficient rigidity of the metal wire rod. Similarly, spherical beads are formed on the surface of the embedding material by forming a porous surface and binding the same by growth infiltration of living tissue.
There is a bead type in which layers are combined. In this case, there are many practical examples because there is no defect like the wire-bonded type. However, there is a concern that the beads may be exfoliated in vivo due to the following reasons.

[0004] As the metallic bioimplant, stainless steel, cobalt alloy, pure titanium and titanium alloy are used, and the material is taken up in the international standard ISO and some countries. As for the beads, it is common to use the same material for the base material and the beads because of the reason that they are based on corrosion in body fluids. The size of the void formed by stacking the beads is
It must be one that allows the infiltration of biological tissue, and spherical beads and particle sizes have been selected to ensure this. On the one hand, this is
It is supposed to weaken the binding of the beads. In particular, the embedded substrate surface and the particles of the spherical metal beads have one contact point,
Even if they are bonded by the vacuum sintering method, the bonding strength must be low. Since general brazing materials cannot be applied due to medical conditions such as toxicity to the living body and allergies, selection of vacuum sintering conditions for improvement of bonding strength with homogeneous materials, due to necking phenomenon at the joining point, I depended on good necking. For this reason, the bead type leaves a concern that the beads may be exfoliated in the living body, and improvement of this point has been demanded.

The conventional bead type manufacturing method is
In order to place the beads on the part to be bonded, a shallow flat bottom dent was made on the side of the base material so as not to spill, and the beads were filled therein and sintered and bonded in a vacuum or non-oxidizing atmosphere. In this case, there is a drawback that the arrangement position of the base material at the time of sintering is limited so that the beads do not fall off. Also,
To bond beads to a curved surface, sintering was performed while holding a mold made of heat-resistant ceramics. Since the holding of the beads by the mold material is a combination of the base material and the rigid material of the mold material, it is not possible to completely prevent the beads from leaking out, and if there is a missing piece, the replenishment work is performed manually. The application points are limited by these groove processing and the mold application method, and it may not be applicable to the protruding part that should be structurally most strongly bonded to the living body, and the shape of the embedding material itself is different from the human body shape etc. Since there are so many kinds of materials, it is very difficult to perform the bead bonding work.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention An object of the present invention is that the metallic bioimplant material is compatible with living tissue.
In many cases, spherical beads of the same quality as the embedding material are bonded to a part of the surface, and living tissue grows and penetrates into large and small voids formed therein, so that the embedding material is fixed in the living body. The present invention provides a bead-type bio-implantable material that can be used with peace of mind without the beads peeling off in vivo.

The present invention also provides a method for producing a metal bio-implant, in which spherical beads are surely bonded even if the surface of the metal substrate is not flat.

[0008]

As is apparent from the scope of the claims of the present invention, in claim 1, spherical metal beads are bonded to the surface of a metal base material having a rough surface of peaks and valleys to form a porous layer. It is a metal bio-embedded material characterized by the above. The bonding portion of the beads to the base material was a combination of a sphere and a surface in the conventional method, but it is different in the present invention in that the base material side is previously subjected to roughening of peaks and valleys. . Then, the processing can be performed by knurling, shot blasting, or other mechanical methods, but there is a case where the base material side portion on which the beads are to be arranged is not necessarily flat or close to it, and in that case, the round surface It can be carried out by a method by shot blasting using a blast material having Most of the spherical beads arranged on the surface roughened by these methods come in contact with the base material at a plurality of points or surfaces, and rely on the bonding strength for the sintering necking by the single-point contact in the conventional method. Certainly improves the strength. The upper layer portion of the beads, that is, the portion where the beads are in contact with each other does not pose a problem because the individual beads have a large number of joints.

According to claim 2, spherical metal beads having a particle size range of substantially ± 20% with respect to the average particle size, and peaks and peaks that are 1/2 or more and 3 times or less of the average particle size of the beads. The metallic bioimplant according to claim 1, wherein a metallic base material surface including a rough surface having a space of is used. An object of the technical advance of the present invention is to improve the bonding strength between the base material and the spherical metal beads as compared with those which have been practically used in the past, so that it can be applied to more patients, and
The point is to increase the number of joints between the substrate and the beads. Since the essence is to provide peaks and troughs on the base material side in advance as the means, the diameter of the beads and the interval between the peaks and peaks of the base material are related to each other. A strong bond can be obtained. The means of processing mountains and valleys are
Methods such as knurling, grinding and cutting can be used, but the method using shot blasting is most practical for parts that are complicated in shape and have curved surfaces.

[0010] Claim 3 discloses one embodiment of a working means for bonding beads to the surface of a base material. A metal base material having a rough surface of peaks and valleys on the surface is prepared, and the surface is 800 ° C or lower. Characterized in that a composite obtained by applying an adhesive for evaporation or incineration and removal by incineration and then adhering beads to the surface is vacuum-sintered and bonded at 800 to 1500 ° C in a state of being embedded in ceramic powder. It is a manufacturing method of a metal bioimplant.
The operation is facilitated by once adhering the spherical metal beads at a room temperature using an adhesive to dispose them on a required portion of the substrate. However, if the adhesive reacts with the beads or the base material, or if it remains after sintering, it spreads to medical problems and must be evaporated or burned off at a temperature midway before reaching the sintering temperature. Most organic adhesives containing no metal element can be used practically. Next, the bead is bonded to the base material by sintering without using a brazing material having a lower melting point than those, because the medical treatment by the third element other than the beads and the base material contained in the brazing material is used. It considers the physical problem. Sintering is preferably performed in a vacuum furnace, and is effective in removing the adhesive at a temperature as low as possible that does not affect the beads or the base material.

In order to prevent the beads from separating from the substrate due to the removal of the adhesive in the initial stage of vacuum heating, heating is performed in a state of being embedded in the powder of heat-resistant ceramics. As a result, the adhesive passes through the grains of the ceramic powder and is sucked into the vacuum pump, and the beads are retained without moving even after the adhesive is exhausted.
Raise to sintering temperature.

[0012] Claim 4 shows one method of using the adhesive. That is, an adhesive that evaporates or burns off at 800 ° C. or less and spherical metal beads are mixed in advance, and this is bonded to a metal base material having a rough surface of a mountain and valley to form a composite. The method for producing a metal bioimplant according to the above. Since the adhesive that disappears at a low temperature during the sintering and bonding of the beads to the base material and does not affect the material of the beads or the base material, it may be mixed with the beads in advance. . Such a method is effective for correcting a corner portion having a narrow shape and a peripheral edge portion of a perforated base material portion in the bioimplant.

[0013] A fifth aspect of the present invention is to provide a further reinforced bio-implant for preventing the metal bio-implant, which is the object of the present invention, from causing exfoliation of beads during its function in a living body. This is a method in which fine metal powder having the same chemical composition as that of the beads is bonded to the periphery of the beads to solidify the periphery. The specific means is that spherical metal beads having a particle size range of substantially ± 20% with respect to the average particle size and 1/3 of the average particle size of the spherical metal beads between the surface of the metal base material.
It has a layer of metal fine powder of the following particle size, and is characterized in that the spherical metal beads, the metal fine powder and the metal base material are bonded in a state where the spherical metal beads are embedded in the layer of metal fine powder. It is a metal bioimplant. Although such a bond-enhanced type of beads is more expensive than the method in which the base is provided with peaks and valleys, it may be necessary depending on the subsequent living condition of the patient to which it is applied.

[0016] A sixth aspect of the present invention shows one embodiment of the method for producing a metallic bio-implant according to the fifth aspect, in which the surface of the metallic base material is coated with an adhesive that evaporates or burns off at 800 ° C or lower. Then, the fine metal powder is adhered, and the spherical metal beads are embedded in the fine metal powder, and the composite is embedded in the ceramic powder and vacuum-sintered at 800-1500 ° C. It is a method for producing a characteristic metallic bioimplant. This method facilitates the work of closely aligning the beads with respect to a relatively flat portion in the portion where the beads of the biological implant are arranged.

A seventh aspect of the present invention relates to the method of using the fine metal powder according to the sixth aspect, wherein the fine powder and the adhesive are mixed in advance so that a fine striped portion or an artificial dental root material is obtained. It is intended to facilitate the correction work of the minute part material and the fine powder bonding work in claim 6. The means for this is to mix a metal base material surface with an adhesive that evaporates or burns off at 800 ° C or less and fine metal powder consisting of 1/3 or less of the average particle size of the spherical metal beads. The method for producing a metal bio-embedded material according to claim 6, wherein the composite body is used in which spherical metal beads are placed so as to be embedded in the fine metal powder after coating.

[0016]

According to the present invention, in the treatment of a disease of a living bone, spherical metal beads are bonded to a specific portion of the surface of the material to be embedded so that the metal material to be embedded is compatible with living tissue.
It is intended to provide a product having a bonding force improved as compared with a conventional practical method and a method for producing the same so that the beads do not peel off while functioning in a living body regardless of forming a porous layer. Regarding the required joint strength, it is difficult to specify the necessary condition due to the complicated condition of living bones around the body, the application site and age, and the usage environment. If the peeling resistance of is increased, the application will be expanded. Here, the role of the spherical beads is to have through-holes in order for biological tissue to grow and enter easily, and the beads must be spherical. Although the particle size is selected depending on the application site, the size of the beads and the gap between the beads can be ensured by selecting the particle size of the beads because of the uniform particle size, and the bonding strength can be varied. In doing so, it is necessary to make the particle sizes uniform.

In the present invention, the range of ± 20% of the average particle size is extremely strict as the current bead manufacturing technology, but it is a value based on the practical results in this application. The present invention has been made on the basis of the range. Form a bead layer on the substrate, the result of the shear test,
It was found that the joint between the bead and the base material was more easily peeled off than the joint between the bead and the bead. Therefore, the present invention provides
It was obtained as a result of improving this part.

According to the prior art, the sphere of the beads and the surface of the base material are joined at a single point contact, and when sintered and joined, necking occurs at this contact, and the contact is formed as a joint surface, but at one point. In the present invention in order to increase this, in the present invention, the base material surface is processed to have ridges and valleys in advance, multiple points or surface contacts are obtained depending on the processed shape, and as a result of the shear test, it is confirmed that the peel resistance is improved. did. The distance between the peaks was set to 1/2 to 3 times the average particle size of the beads. There are many particles that achieve at least two-point bonding at the minimum 1/2, and two-point bonding is possible even if it is smaller than this, but the effect of external force when beads separate is almost in the direction along the substrate surface. Since this is a shearing force, this value was set in a form in which resistance on the substrate side was also added. In addition, three times the maximum value means that a plurality of beads are accommodated between the peaks of the base material at this value, but even in that case, the shape is surrounded by beads of at least a plurality of contact points. The depth is not regulated by the present invention. Even if there are beads in deep valleys, they do not become the starting point of peeling supported by the substrate against shearing force.

The portion where the spherical metal beads are arranged is limited to a specific portion because of its functional reason. The position is not always a flat surface, but may be a curved surface, a narrow corner, or a linear thin portion. Since it is difficult to place the spherical metal beads in such a place, an adhesive is used in the present invention. Adhesives that chemically react or alloy with substrates and beads pose new medical challenges and are completely removed at the lowest possible temperature before entering the sinter bonding operation. Must be done. Any organic substance containing substantially no metal element can be used in the present invention. Vacuum furnace processing has the advantage that it can be removed at low temperatures. Therefore, in the present invention, the sintering temperature of 800 to 1500 is set so that it can be performed in one process.
The condition is that it is an adhesive that can be removed at a temperature of less than ° C.

Further, in this case, if the beads are embedded in the ceramic powder so that the beads remain in that position even after the adhesive loses its adhesive effect during the temperature rise, it can be applied to a place other than a flat surface. it can. The adhesive is liquefied during vacuum heating, passes through the particles of the ceramic powder through the process of vaporization, and is deaerated and removed by a vacuum pump. The method using an adhesive can also be applied to a flat application site, but for example, a device having an artificial hip joint is only applied to a flat surface, and it may not be necessary to use an adhesive.

Among the bio-embedding materials, metallic materials include stainless steel, cobalt alloys, pure titanium and titanium alloys, and the base material and beads have the same chemical composition or the same system from the viewpoint of corrosion resistance in the living body. Is used. This is also one reason why brazing materials are not used. Therefore, the sintering joining method was adopted. The sintering temperature of these metals is 800-1500
The object can be sufficiently achieved by selecting the temperature between ° C.

There is a method of firmly bonding the first layer of beads using a fine metal powder, instead of providing peaks and valleys on the surface of the base material by a mechanical method. In the present invention, the fine particles of 1/3 or less of the average particle diameter of the spherical beads are used to harden the periphery of the portion of the first-layer beads that is in contact with the base material. This method is also common to the technique in which the base material is provided with ridges and valleys in that the bonding surface with the base material is increased through the fine powder. However, with respect to the layer of fine metal powder, there is an inconvenience that the fine powder fills the space between the spherical beads for the purpose of forming the original porous layer of spherical beads. Therefore, the thickness of the fine powder from the base material surface is preferably 1/3 or less of the average particle diameter of the beads. If it reaches 1/2, it cannot be said to be a porous layer.
To control this point, the particle size of the fine metal powder needs to be 1/3 or less of the average particle size of the metal beads. On the other hand, according to this method, from the second layer of the metal beads, the beads are joined to each other, and unlike the initial layer for merely forming peaks and valleys, they are reinforced with more joining points.

[0023]

[Examples and Comparative Examples] The base material, the spherical metal beads, and the fine metal powder each had a chemical composition corresponding to each ISO standard, and the combination thereof was made of the same material. The particle sizes of the beads and the fine metal powder are shown in Table 1. Since the beads were manufactured in a He atmosphere by the rotating electrode method, the particle size distribution width was extremely narrow, and it seems that they were within ± 20% of the average particle size obtained from the integrated distribution chart. Adjusted to.

As the adhesive, an acrylic commercial product (Dianal LR349 manufactured by Mitsubishi Rayon Co., Ltd.) is used, and a pure titanium material, which is feared that carbon in the adhesive most easily causes a chemical reaction, is used as a representative. Picking up the pure titanium fine powder shown in Table 1,
A mixture of 5 parts by weight of fine powder to 1 part of adhesive is applied on a pure titanium material to a thickness of 250 μm, and it is immersed in a zirconia powder with an average particle size of 355 μm in an alumina container and vacuumed. Heating was performed. When the vacuum degree was finally 10 ⁻⁴ Torr, the temperature was 500 ° C., and the holding time was 4 hours, carbon was not detected as a result of carbon analysis of the surface.

[0025]

[Table 1]

For the convenience of the shear test, the base material was a square member of 25 × 30 × 20 mm, and spherical metal beads were bonded to the surface of 25 × 20 mm under each condition. Table 2 shows the preparation conditions for each test material. Place a zirconia thin plate on the joint surface of the base material with a laser,
Careful work was done so that the beads were arranged closely. The knurling was used to process the base material before the beads were bonded to each other in various sizes. The shapes of the processed peaks and valleys were confirmed by cross-section inspection.

Adhesives are used for test piece No. 4 and test piece No. 1.
In the case of 0, the mixture was used by mixing the spherical metal beads 5 by weight with the ratio of the adhesive 1 and, in the case of the test piece No. 13, the adhesive was applied alone to the base material, and the spherical metal beads were coated thereon. Glued For test pieces Nos. 18 to 25, a case where the test piece Nos. 18 to 25 was applied alone to the base material and a case where the fine metal powder and the adhesive were mixed at a weight ratio of 5: 1 and adhered to the base material were used. did.

The vacuum heating was carried out under the conditions shown in Table 2, and the test pieces Nos. 4, 10, 13 and 18 to 25 were carried out in the state of being embedded in zirconia, alumina or silica, respectively.
Shear test was performed on the test pieces prepared under the conditions of Table 2,
The results are shown in Table 3. The shear test was performed in the direction of 25 mm on the test surface, and the direction was perpendicular to the knurls. The outline is shown in FIG. As the tester, use a general-purpose universal tester (Autograph 5000, made by Shimadzu), lower the load at a slow speed of 0.1 mm / min under a maximum load of 5 kgf, and draw a load-displacement curve with the connected computer. Then, the maximum load value was read as an evaluation value. From the results in Table 3, it was confirmed that the one according to the present invention exhibited a higher load than the one according to the conventional method, and particularly the one using the fine powder was remarkably improved.

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

EFFECTS OF THE INVENTION The strength condition for preventing spherical metal beads from peeling off in a living body in a metallic bio-implanted material cannot be quantitatively specified because there is a balance with the movement condition of the patient thereafter. However, the effect of the present invention is shown below based on the bonding strength of the prior art due to the fact that it is frequently used in view of selective management while having the problem of bead peeling. 1. By performing the roughening of the base material according to claim 1, the bonding strength of the spherical metal beads was about three times as high as the upper limit of the conventional technology. In this case, as a manufacturing technique, the bonding sites of the beads are possible without limitation according to the procedures described in claims 3 and 4. 2. According to claims 5, 6 and 7, when a fine powder of the same quality as the substrate is adhered in the intermediate technique with the aid of an organic fixing agent, followed by a de-adhesion agent and a sintering treatment, it is about the same as in the prior art. Bonding strength of 3 to 4 times can be obtained.

[Brief description of drawings]

FIG. 1 shows a procedure of a joint strength test.

[Explanation of symbols]

 1 beads 2 base material

Claims (7)

[Claims] 1. A metal bioimplant, wherein spherical metal beads are bonded to the surface of a metal base material having a rough surface of a mountain and valley to form a porous layer. 2. The particle size range is substantially ± 20 with respect to the average particle size.
% Of spherical metal beads, and a metal base material surface including a rough surface with ridges of ½ or more and 3 times or less of the average particle diameter of the beads. The metal biological implant material according to claim 1. 3. A metal base material having a rough surface of a mountain trough on its surface is prepared, and an adhesive for evaporating or incinerating at 800 ° C. or lower is applied to the surface, and then spherical metal beads are adhered to the surface. A method for producing a metal bio-embedded material, which comprises performing vacuum sintering bonding at 800 to 1500 ° C in a state where the obtained composite is embedded in ceramic powder. 4. A composite is formed by pre-mixing an adhesive that evaporates or burns off at 800 ° C. or lower with spherical metal beads, and adheres this to a metal base material having a rough surface of peaks and valleys on its surface. 4. The method for producing a metal bioimplant according to Item 3. 5. The particle size range is substantially ± 20 with respect to the average particle size.
% Of the spherical metal beads and the surface of the metal base material, and the spherical metal beads have a layer of fine metal powder having a particle diameter of 1/3 or less of the average particle diameter of the spherical metal beads. A metallic bioimplant, characterized in that spherical metal beads, fine metal powder, and a metallic base material are bonded together in a state of being embedded in a powder layer. 6. A metal base material surface is coated with an adhesive that evaporates or burns off at 800 ° C. or lower, then fine metal powder is adhered, and spherical metal beads are placed so as to be embedded in the fine metal powder. A method for producing a metallic bio-embedded material, which comprises subjecting the composite to a ceramic powder and performing vacuum sintering bonding at 800 to 1500 ° C. 7. The average particle size of the adhesive and the spherical metal beads that evaporate or incinerate at 800 ° C. or lower on the surface of the metal base material and 1 /
7. A biomedical implant made of metal according to claim 6, wherein a mixture obtained by mixing fine metal powder consisting of 3 or less is applied to a metal base material and further spherical metal beads are placed so as to be embedded in the fine metal powder. Manufacturing method of wrapping material.