JPS63226348A - Composite implant member - 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] [Industrial Application Field] The present invention relates to a composite implant member, and more specifically, the present invention relates to a composite implant member that has a porous structure that is important for promoting the invasion and growth of new bone tissue and improving the integration with the bone. The present invention relates to a composite implant member that has excellent strength and is easy to manufacture.

[Conventional technology] “Conventional technology”
Repair or prosthetics for damaged or missing bones, joints, teeth, etc.
Alternatively, as an alternative, implant members such as artificial bones, artificial joints, and artificial tooth roots have been put into practical use.

These implant components must not only meet the two major requirements of compatibility with the living body and strength, but also be made of materials that can enhance the integration with the living body by promoting the invasion and growth of bone tissue at the implanted site. be.

Therefore, materials are used in which a porous structure is formed in the surface layer, which is particularly effective in promoting the invasion and growth of new bone.

Among them, surface porous structures made of metal materials such as titanium, titanium alloy, zirconium, zirconium alloy, cobalt-chromium-molybdenum alloy, cobalt-chromium-tungsten-nickel alloy, and 316 stainless steel are compatible with living organisms. For example, practical research is progressing widely due to its excellent corrosion resistance and strength.
Metals, Vol. 51 (1981), No. 11, pp. 8-14].

Porous methods to improve integration with bone tissue include:
Powder sintering method and short fiber sintering method are the mainstream. In other words, the powder sintering method uses metal powder of an appropriate particle size to penetrate bone tissue.
This method involves pressure forming and sintering to leave countless small pores suitable for bone tissue growth.The short fiber sintering method involves cutting thin metal wires into short fibers, which are then used to create holes that are suitable for bone tissue invasion and growth. This is a method of pressure forming and sintering so as to leave countless small holes through which the implant is formed.The implant member obtained in this way can be produced by adjusting the particle size and fine wire diameter of the metal powder or by adjusting the compression force. The size of the small pores can be controlled arbitrarily, and the modulus of elasticity can be brought closer to that of bone by making it porous, which can alleviate stress concentration at the joint interface.Research into clinical practical application is also progressing rapidly. is being advanced.

[Problems to be solved by the invention] However, in both the powder sintering method and the short fiber sintering method, it is difficult to adjust the zero particle diameter or the short edge diameter, and to use a molding capsule or mold. Manufacturing is surprisingly troublesome as it requires pressure forming and sintering, and the porous layer is made by sintering and bonding powder or short fibers in point contact with each other. In terms of strength, it cannot be said to be sufficient, and for example, when used as an artificial tooth root material, the biting force during installation (approximately 41 to 91 kg for molars, approximately 23 to 46 kg for premolars, approximately 23 to 46 kg for canines) It is often experienced that the porous layer is destroyed and loses its integrity with the bone due to the impact of 14 to 34 kg (approximately 9 to 25 kg in the front teeth).

The present invention was made in view of these circumstances, and
Its purpose is to have numerous small holes suitable for bone tissue invasion and growth, to have sufficient strength to withstand biting force, body weight, and other external forces, and to be easy and inexpensive to manufacture. The present invention aims to provide a composite implant member that can

[Means for Solving the Problems] The structure of the composite implant member according to the present invention is such that thin metal wires are arranged on the outer periphery of the implant base material between the thin wires and on the outermost surface side of the layer wound with the thin wires. The gist is that it is wound so as to leave grooves with undercuts or holes that communicate with each other, and then sintered.

[Operations and Examples] The composite implant member of the present invention is illustrated in FIG. 1 (perspective explanatory view, in which 1 is an implant base material, 2 is a thin metal wire,
3 indicates bobbins), a thin metal wire 2 is fed out from the bobbin 3 and wound around the outer circumference of the rod-shaped implant base material 1 as described above, and a wound layer of the thin metal wire 2 is formed on the outer circumferential surface of the implant base material 1. form. In forming the wound layer, an appropriate gap is formed between the thin metal wires 2 that are wound next to each other, and the metal wires are wound so that the gap communicates with the outer peripheral surface of the layer. Do the following. For example, FIG. 2 is a partially enlarged sectional view showing a state in which the thin metal wire 2 is wound in a direction substantially perpendicular to the axis of the implant base material 1. In this example, the thin metal wire 2 is wound with an appropriate gap S. It is wrapped in only one layer. When a plurality of thin metal wires 2 are wound in the same direction, for example, as shown in FIG. Therefore, bone tissue cannot invade into the cavity S, and anything other than the cavity IllS in the outermost peripheral layer cannot contribute to improving the integrity with the bone at all. Furthermore, as shown in FIG. 4, when the thin metal wire 2 is tightly wound around the implant base material 1 without any gaps, the outer surface of the composite implant member (
In other words, the bone tissue B growing on the outer surface of the wound thin metal wire 2 only invades the recesses on the outer surface without undercuts, and an anchor effect cannot be obtained, making it impossible to obtain sufficient joint strength. However, as shown in Fig. 2, the thin metal wire 2
If you wind it with an appropriate gap S between them, the fifth
As shown in the figure, the bone tissue B growing on the outer peripheral surface of the composite implant member penetrates through the gap S to the deep undercut site, and a strong bonding force is exerted due to the interlocking effect and the anchoring effect.

Appropriate voids and blood circulation are essential for the growth and invasion of new bone in the living body, and for this purpose, the above-mentioned gap S
at least 50 μm or more, preferably 150 μm or more
Since a pore diameter of ~250 μm is required, the winding interval should be adjusted so that the gap S falls within this length range.

Further, the dimensions of the thin metal wire 2 used are not particularly limited, but
The preferred thickness is 0.1 to 3 mm to obtain strong bonding force.
φ, more preferably in the range of 0.2 to 1.0 amφ.

In the above example, the thin metal wire 2 is wound in one layer in a substantially parallel direction, but the thin metal wire 2 wound in the first layer, second layer, ... nth layer may be made to cross each other. If the winding method is adopted, the gaps S formed in each winding layer can be made to communicate with each other and also with the outermost surface side, as will be described in detail below. That is, Fig. 6 (schematic plan view) and Fig. 7 (
(partial longitudinal cross-sectional explanatory view) shows such a winding example, in which the thin metal wire 2 is wound approximately parallel to the implant base material 1 at a constant interval α, and the first layer of metal Thin wire 2a
and second layer metal thin wire 2b, second layer metal thin wire 2b
and the third layer of thin metal wire 2c, . . . are wound so that their respective winding directions intersect. If such a winding method is adopted, the gap Sa formed in the first layer, the gap sb formed in the second layer, the gap sb formed in the second layer, and the gap Sc formed in the third layer. . . . The gap 5 (n-1) formed in the (n-1)th layer and the gap Sn formed in the n-th layer all communicate with each other, and the thin metal wires 2a, 2b,・
- Three-dimensionally communicating voids can be formed in the -2n wound layer. And these gaps Sa, Sb,...
・By winding Sn so that the intervals α are each 50 μm or more, preferably 150 to 250 μm, the penetration of bone tissue into the gaps Sa, Sb, ...Sn
It is possible to allow the growth to proceed smoothly and to firmly connect and integrate the bone base and the composite implant member in the buried part.

In general, the preferred porosity of porous materials used as implant members is 15 to 65, considering the balance between bonding force due to invasion and growth of bone tissue and mechanical strength of the porous layer itself.
%, and as long as mechanical strength is guaranteed, it is said that a higher porosity is preferable, but with the above method, the porosity can be adjusted arbitrarily by changing the diameter of the thin metal wire 2 and the winding interval α. It is possible to form a porous layer on the surface of the implant member having the optimum porosity according to needs.

For example, as shown in FIG. 8, when the diameter of the thin metal wire 2 is d1 and the interval between each thin wire is α, the porosity can be determined by the following equation.

Porosity = 1- π (1/2d)2 /d (d + α) = 1- πd2 /4d (d + α) = 1-πd /4 (d + α) And when α = 0, the porosity (=1-πd /4d = 21.5%) as the minimum value, and the porosity can be freely adjusted by increasing α.

The preferred spacing α between the thin metal wires to advance the invasion and growth of bone tissue is 150 to 250 μm as described above, so from the above formula, the diameter of the thin metal wires is 0.15 to 2 cm, and the spacing α is 150 to 250 μm. The porosity of the porous layer when the porosity is changed within a range is as shown in Table 1 below, which shows that the porosity can be arbitrarily changed within a wide range.

(Margins below) Table 1 (%) As shown in Figure 6.7, the number of turns is not particularly limited in the case of mutually intersecting multi-layer winding, and may vary depending on the dimensions of the thin metal wire, the target dimensions for the implant component, etc. Although it can be determined arbitrarily depending on the
It reaches saturation after winding ~6 layers, so there is little point in winding more than that.

After winding as described above, a sintering process was performed in the wound state to bond the implant base material 1 and the wound thin metal wire 2 together, and then the wire was cut as shown in FIG. Thereafter, the head is further processed as shown in FIG. 10 to obtain a composite implant member (in this example, an artificial tooth root).

Sintering is preferably performed in a vacuum or inert gas atmosphere to prevent oxidation of the metal material, and the temperature can be set appropriately depending on the implant base material and the type of thin metal wire.
The annealing is usually carried out at a temperature of about 900 to 1,500°C, and the appropriate annealing time is about 1 to 5 hours.

Figures 11 and 12 briefly describe another manufacturing method of the composite implant member according to the present invention, in which the above-mentioned method is applied to the outer periphery of the implant base material 1, which is formed into a slightly smaller size according to the shape of the bone to which it is applied. In the same manner, wind the thin metal wire 2,
After that, it is made into an artificial bone by sintering. The thin metal wire 2 is wound around the implant base material 1 while rotating the implant base material 1 as shown in FIG.
Either a method of winding the thin metal wire 2 by drawing it out from the implant, or a method of winding the thin metal wire 2 by rotating the bobbin 3 around the implant base material 1 as shown in FIG. 12 may be adopted.

Further, the thin metal wire 2 can be wound over the entire surface of the implant base material 1 as shown in FIG. It is also possible to make it porous.

Any material can be used for the implant base material used in the present invention, as long as it does not have a negative effect on the living body and has enough strength to withstand external forces applied to the composite implant member after implantation. The most common are metals such as titanium, titanium alloys, zirconium, zirconium alloys, cobalt-chromium-molybdenum alloys, cobalt-chromium-tungsten alloys, stainless steel, and mineral sintered bodies such as alumina. In addition, although the most common shape is a cylinder, it may also be of irregular shapes such as a rectangular cylinder or an elliptical cylinder, and if it is used as an artificial joint, it may be molded into a suitable shape, etc. It can be changed arbitrarily depending on the situation.

The type of thin metal wire does not matter as long as it does not have a negative effect on the living body and has the strength to withstand external forces during use, but the most common type is the one exemplified above for the implant base material. It is metal. The dimensions of the thin metal wire are determined by taking into consideration the target porosity, etc., but usually those with diameters in the range of 0.1 to 3 mm are used.
The cross-sectional shape is not limited to a circular shape, but a modified cross-section can further promote the invasion and growth of new bone tissue.

In addition, when selecting the implant base material and gold R fine wire,
Expansion due to temperature changes after winding (including during sintering)
In order to prevent a gap from being created between the implant base material and the thin metal wire due to shrinkage, thereby reducing the integrity, it is preferable to select a thin metal wire with a coefficient of thermal expansion equal to or smaller than that of the implant base material.

[Effects of the Invention] The present invention is configured as described above, and its effects are summarized as follows.

(2) The porous layer can be formed only by winding a thin metal wire, and the manufacturing process can be significantly simplified compared to conventional powder sintered bodies or short fiber sintered bodies.

■As shown in Figures 1 and 9, by winding thin metal wires around a rod-shaped base material in multiple positions at predetermined intervals, subsequent sintering can be performed simultaneously, resulting in stable productivity and quality. You can increase your sexuality.

■Not only can the porosity of the porous layer be freely adjusted by changing the dimensions and winding interval of the thin metal wires, but also the pore size that is optimal for the penetration and growth of bone tissue can be ensured. It can be firmly bonded and integrated.

■Since the porous layer is formed by wire rods wound intersectingly, it is more porous than powder sintered bodies or short fiber sintered bodies, in which individual particles or short fibers are simply joined by sintering. The porous layer has high mechanical strength, and there is no fear that the porous layer will be damaged even when subjected to external force.

(2) Therefore, the composite implant member of the present invention can be widely used as dental artificial tooth roots, surgical artificial bones and joints, and orthopedic prosthetic materials.

[Brief explanation of the drawing]

Fig. 1 is a schematic perspective explanatory view illustrating the manufacturing method of a composite implant member according to the present invention, Fig. 2 is a partial vertical sectional view showing a composite implant member constructed by winding only one layer of thin metal wire, and Fig. 3 4.5 is a partial longitudinal cross-sectional view showing a composite implant member constructed by winding multiple layers of thin metal wire; FIG. The figures are explanatory diagrams illustrating a case in which the metal wire is made porous by crossing and winding each layer, and FIG. 6 shows a side view and FIG. 7.8 shows a partial cross-sectional view. 9 and 10 are perspective explanatory diagrams showing the sintering, cutting, and final processing conditions after winding the thin metal wire, FIGS. 11 and 12 are explanatory diagrams showing other examples of winding the thin metal wire, and FIG. Figure 14 is a sketch showing another composite implant member according to the present invention. 1... Implant base material 2, 2 a, 2 b, 2 c... Thin metal wire S, Sa, Sb... Gap 3... Bobbin d... Diameter of the thin metal wire α... Thin metal wire Winding interval 9th! Figure 11 Figure 13 Figure 14 Figure 12

Claims (2)

[Claims] (1) A thin metal wire is wound around the outer periphery of the implant base material so as to leave grooves with undercuts or holes communicating with each other between the thin wires and on the outermost surface side of the layer wound with the thin wires. A composite implant member characterized in that it is spun and sintered. (2) Claims in which the thin metal wire is selected from the group consisting of titanium, titanium alloy, zirconium, zirconium alloy, cobalt-chromium-molybdenum alloy, cobalt-chromium-tungsten-nickel alloy, and stainless steel. Composite implant member according to paragraph 1.