JP2000237296A - Biological prosthesis member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface structure that can control accurately the shape of holes for each product and guide optimally the bone in growing and entering in a ceramic biological prosthesis member. SOLUTION: This biological prosthesis member comprises a biologically harmless ceramics forming an artificial bone, an artificial joint, an artificial tooth root, or the like, and provided systematically with many holes 4 and 5 mutually communicatively, and provided with a plurality of small protrusions 6 of a height (h) of 100 to 300 μm, a maximum diameter (d) of 400 to 1000 μm, and d>=2h on the surface of the holes contacting the bone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bioprosthetic member constituting a bone function or a joint of a limb due to a disease or disaster, or an artificial joint used for reconstructing a tooth lost due to aging or disease. Things.

[0002]

2. Description of the Related Art Conventionally, as the bioprosthesis member having a porous body, a metal or ceramic member has been proposed. For example, (1) an organic material such as an organic resin powder or an organic resin fiber is dispersed in a ceramic material at the time of adjusting the material, and the material is pressed into a predetermined shape, and then the organic material is eliminated by firing; A ceramic slurry is poured into a mold in which the mesh-like organic material is arranged, dried, and then the organic material is eliminated by firing,
(3) A ceramic bead is bonded to a bioprosthesis member as in the invention of JP-A-1-300947. (4) A large number of holes are formed with regularity as in the invention of JP-A-8-173463. A large number of ceramic green sheets are laminated to form a three-dimensional porous body, which is then fired.

[0003] However, among the above-mentioned prior arts, except for those in which ceramic green sheets are laminated, none of them can accurately control the hole shape, and the hole shape varies, and bones increase and enter. There is a possibility that a portion where the optimum hole shape cannot be obtained may occur.

On the other hand, the method of obtaining a porous body by laminating the ceramic green sheets described above can accurately control the hole shape. Therefore, it is possible to design a porous body having an optimal pore shape for the invasion of bone, and early bone growth on the porous body and firm fixation with bone can be performed over the entire contact surface between the porous body and bone. Obtainable.

[0005]

However, the porous body obtained by laminating the above-mentioned ceramic green sheets has a flat opening surface, so that it has poor initial fitting properties at the time of bone implantation, and Under the shear load environment after bone healing, sufficient intraosseous fixation cannot be obtained against micromotion repeatedly generated between the bone and the porous body interface, and there is a possibility that the fixation between the bioprosthesis material and the bone may become loose. There were some issues.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a bioprosthetic member made of a harmless ceramic and having a large number of holes formed at desired locations with regularity. The height h = 100-300 μm and the maximum diameter d = 400-100 on the opening surface of the porous portion to be formed.
A plurality of small projections of 0 μm and d ≧ 2h are provided. Such small projections can be formed, for example, by applying a small amount of ceramic slurry from the needle tip once to ten times using a dispenser.

[0007]

A plurality of ceramic green sheets in which a large number of holes are regularly formed are stacked, and a height h = 100 on the surface of the holes.
３００300 μm, maximum diameter d = 400-1000 μm and d
By providing a plurality of small protrusions of ≧ 2h and firing, a three-dimensional porous body in which the positions of the holes are displaced at a certain depth and the surface is provided with the small protrusions is obtained.

This porous body can be used as a bioprosthetic member as it is, and can be bonded to the surface of the base material constituting the bioprosthetic member by integral sintering or bonding to form the surface structure of the bioprosthetic member.

[0009] The three-dimensional porous body has a function of supplying nutrients to the bones in which the bones have proliferated densely and which have entered the growth, and the bone tissue firmly holds the bioprosthetic member in the living body by its three-dimensional structure. Is possible. Further, by providing a plurality of small projections on the surface of the opening of the porous body, the initial fitting property of the bioprosthesis member in the bone is increased, and the anti-shear load force is increased even after a long period of time.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of a plate-shaped porous body 1 constituting a bioprosthesis member of the present embodiment, in which an opening surface in contact with a bone is viewed from the front. Made of bio-toxic ceramics such as zirconia,
The thin plates 2 and 3 provided with a large number of holes as shown in the sectional view of FIG. In addition, the height h = 100-300 μm and the maximum diameter d = 500-1000 on the surface of the opening in contact with the bone.
It is provided with a plurality of small projections 6 of μm and d ≧ 2h. In addition,
FIG. 2 shows only a cross section for convenience of explanation.

FIG. 3 shows two types of thin plates 2 and 3 constituting the porous body 1. The thin plate 2 in FIG. 3A is the first and third layers from the top, and the thin plate 3 in FIG. The porous body 1 is formed by laminating non-perforated thin plates as the fourth layer as the second layer.

Although the uppermost layer has the small protrusions 6, the small protrusions 6 are not shown in FIG.

As shown in FIG. 1, the porous body 1 in a state in which these thin plates 2 and 3 are laminated has a large pore size having an apparent pore diameter R = 500 μm to 1.5 mm when viewed from the front opening surface. Small-diameter holes 5 having a hole diameter r = 150 to 500 μm, which can be seen as the diameter holes 4, are regularly arranged. In FIG. 1, the thick regular hexagonal line indicates the shape of the hole on the surface of the opening, while the thin line indicates the edge of the hole in the lower layer that does not overlap the thick line.

As shown in the sectional view of FIG. 2, the large diameter holes 4 of the porous body 1 maintain the same shape in the thickness direction.
On the other hand, the small-diameter hole 5 has a portion where the hole diameter becomes small inside. Due to this difference, the difference between the apparent pore diameters R and r,
That is, the large diameter hole 4 and the small diameter hole 5 are formed. in addition,
As shown in FIG. 2, the large-diameter hole 4 and the small-diameter hole 5 communicate with each other.

The large-diameter hole 4 has an effect of supplying nutrients to the bone that has entered the porous body 1. Therefore, a large apparent hole diameter is required so that the bone grows to the extent that the bone is caught on the hole wall and overgrowth of the bone does not occur. If the apparent pore size is less than 500 μm, nutritional supplementation may be insufficient.

On the other hand, if the apparent hole diameter R exceeds 1.5 mm, the growth of the bone is sparse, and there is a possibility that the bonding strength with the bone and the shear strength with the bone may be insufficient.

Next, the small-diameter hole 5 has a diameter of 150 μm.
A hole having a diameter of about 500 μm is preferable.
Has the effect that bones grow densely and reach the bottom as much as possible. Incidentally, the apparent pore diameter r is less than 150 μm,
Bone is less likely to penetrate, while if it exceeds 500 μm, the bone cannot be made dense, and there is a possibility that the bonding strength with the bone and the shear strength with the bone may be insufficient.

The height h of the small projections 6 is 100 μm.
When the diameter is less than 300 μm, the effect of increasing the initial to long-term bone fixation force due to the provision of the projections on the surface is small. On the other hand, when the diameter is 300 μm or more, the initial bone fixation force is improved. 1 is too large, and there is a possibility that the fixation in the medium to long term may not be sufficiently improved.

When the maximum diameter d of the small projections 6 is smaller than twice the height h, the projections have a more columnar shape and may be broken under shear stress.

The density of the small projections 6 is 4 to 15 / c.
m ² is desirable. This existence density is 4 pieces / cm
^{When the number is} less than ^{2, the} effect of providing the projections is small. On the other hand, when the number exceeds 15 / cm ² , the area of the opening on the surface of the opening in contact with the bone becomes small, and the ingrowth of the bone (for the prosthesis member) (Ingrowth) amount may be reduced, which may cause a problem in fixation to bone.

By the way, as a method for producing such a porous body 1, a thickness of 100 to 1000 made of a ceramic material which is not harmful to the living body such as alumina or zirconia is used.
A number of holes are regularly formed in a green sheet of about μm by punching or the like to form a perforated thin plate, and a plurality of types having different hole shapes and arrangements like the thin plates 2 and 3 in FIG. 2 are prepared. Then, the holes are stacked as shown in the schematic diagram of FIG.

The small projections 6 can be formed by applying a small amount of ceramic slurry from the needle tip once to ten times using a dispenser. The maximum diameter of the projection largely depends on the outer diameter of the needle used. The height of the small projections h largely depends on the number of times of slurry application. By precisely injecting air with a dispenser at a constant pressure for a fixed time into a dedicated syringe containing the slurry, a fixed amount of slurry is discharged.

As another method of forming the small projections 6, a slurry is poured into a concave portion of an organic material having a concave portion, and the slurry is transferred to the surface of the porous body 1, or spherical ceramic beads are embedded by pressing into a green sheet. It is possible.

The shape of the small projections 6 is preferably one having a smooth surface such as a partial spherical shape. If the small projections 6 have many corners or have a spine shape, the stimulation to the bones is so strong that the growth of the bones is inhibited, or the bones are damaged by a large shear load. There is a fear.

Finally, the porous body 1 can be obtained by integrally firing under the above-mentioned laminated state. Therefore, in the cross section of the fired porous body 1, the interface does not actually appear clearly as shown in FIG. 2, but becomes unclear due to sintering integration.

Further, the porous body 1 can be used as a bioprosthetic member as it is, and can be bonded to the surface of a base constituting the bioprosthetic member by integral sintering or bonding to form a surface structure of the bioprosthetic member. The schematic diagram of FIG. 5 shows the femoral component F of the artificial knee joint having the porous body N produced by the above-described method and having a surface structure. Further, the schematic diagram of FIG. 6 shows a dental ceramic implant D in which a porous body N produced by the above-described method is joined to a bone-implanted portion. 4 to 6, the small projections 6 are excessively small when drawn. Therefore, the small projections 6 are omitted. Also,
The shape of the through hole is also shown schematically.

By implanting the bioprosthetic member into the bone, new bone grows and enters into the three-dimensionally structured pores, and the bone tissue firmly holds the bioprosthetic member in the living body by its three-dimensional structure. It is possible to hold.

FIG. 7 shows another example of the shape of the small projections 6 in silhouette. The small projections 6 have a shape whose outer surface is in the range of a hemisphere having a maximum diameter as a diameter. Preferred above.

Note that the present invention is not limited to these embodiments, and it goes without saying that the present invention can be implemented in any form without departing from the object of the invention.

Embodiments Hereinafter, embodiments of the present invention will be described.

Example 1 0.7% by weight of a dispersant, 12% by weight of an organic binder, 0.2% by weight of an antifoaming agent, and 14% of water based on 100% by weight of alumina powder having an average particle diameter of 0.4 μm
Was added to adjust the slip. Using this slip, a doctor blade method is used to obtain a thickness of 120 μm and 180 μm.
Four types of green sheets of m, 240 μm and 360 μm were prepared.

Among them, the thickness is 180 μm, 240 μm,
For the green sheet of 360 μm, the sheet was perforated by punching. 120 μm, 180 μm, 2
A green body was formed by laminating four green sheets in the order of 40 μm and 360 μm to form a porous body, which was calcined.

Alumina powder 1 of the same material as the green sheet
1% by weight of dispersant and 00% by weight of organic binder
4% by weight, 0.2% by weight of an antifoaming agent and 40% of water were added to adjust the slip. Using a dispenser (liquid precision metering device), a slip is applied eight times to one projection on the opening surface of the porous body calcined using this slip to produce a projection, as shown in FIGS. 1 and 2. The porous body 1 was obtained. This was calcined.

The porous body 1 is adhered to a plate material cut out of a rubber press material of the same material as the green sheet, dried, and baked at 1550 ° C. in an oxidizing atmosphere. Was obtained as a two-layer structure composed of a dense portion.

(Example 2) 2% by weight of a dispersant, 10% by weight of an organic binder, 4% by weight of a plasticizer, and 40% by weight of toluene were added to 100% by weight of zirconia powder having an average particle diameter of 0.6 μm, and slip was performed. Was adjusted, and a doctor blade method was used to adjust the thickness to 180 μm and 36 μm.
Two types of green sheets of 0 μm were prepared. Thickness 180
Three layers of 180 μm green sheets perforated by punching were laminated on a μm green sheet, and one layer of perforated green sheet having a thickness of 360 μm was laminated to produce a porous body.

A protrusion having the composition used in the preparation of the green sheet was applied to one protrusion six times on the surface of the opening of the porous body by a dispenser (liquid precision metering device) to form a protrusion.

The porous body 1 was adhered to a plate material cut out of a rubber press material of the same material as the green sheet, dried, and baked at 1450 ° C. in an oxidizing atmosphere. Was obtained as a two-layer structure composed of a dense portion.

Example 3 3% by weight of dispersant, 12% by weight of organic binder, 3% by weight of plasticizer, and 4% by weight of water based on 100% by weight of hydroxyapatite powder having an average particle size of 1 μm
0% was added to adjust the slip. Using this slip, a green sheet having a thickness of 300 μm was produced by a vacuum extrusion molding method. The green sheet was perforated by punching. Then, this green sheet was laminated up to six layers to produce a porous body.

Alumina powder 1 of the same material as the green sheet 1
3% by weight of a dispersant and 00% by weight of an organic binder
4% by weight, 0.5% by weight of an antifoaming agent and 60% of water were added to adjust the slip. Using a dispenser (precision liquid dispenser), a slip was applied four times to one protrusion on the surface of one side of the porous body calcined using the slip to form a protrusion. This was fired at 1300 ° C. in an oxidizing atmosphere. This porous body was bonded to a plate-shaped zirconia sintered body to obtain a bioprosthesis member of the present invention having a two-layer structure in which the surface structure was a hydroxyapatite porous body and the base material was a zirconia dense body.

Experimental Example (Experimental Example 1)
A shear load test was performed.

The porous body 10 used in this experiment was made of alumina, and as shown in FIG.
The upper and lower portions have a porous portion 12, and a small projection 6 is regularly provided on the surface of one side opening.

The number of the small projections 6 is 9 / cm ² , the heights of the projections are 200 μm, 300 μm, and 400 μm, and the maximum diameter d of the small projections 6 is 1.5 times, 2 times the height, Three types of test specimens were prepared, three times as large as a total of eight types (protrusions having a maximum diameter of less than 400 μm were difficult to form). A schematic diagram of each projection is shown in silhouette in FIG. Small protrusion 6
Is the maximum diameter d and the maximum height is h. Plate-shaped bovine bone fragments were prepared by thawing the frozen knee joint bones frozen immediately after slaughter and successively slicing with a micro-cutting machine.

The test was performed by inserting a test piece between two pieces of bovine bone. The evaluation was performed based on whether or not the small projections 6 were damaged at this time.

FIG. 10 is a schematic diagram of an experiment conducted to evaluate the effect of the projections provided on the surface of the opening of the porous body on the initial fixation in bone.

Table 1 shows the results of this test.

[0047]

[Table 1]

The breakage of the small projections was observed only in the group with d / h of 1.5 times. Damage is caused by the interface between the porous part and the protrusion,
Alternatively, it occurred inside the projection starting from the joint end between the porous portion and the small projection.

In the group in which the ratio was twice or three times, no breakage of the small protrusion was observed. As d / h becomes smaller, the shape of the small projections becomes closer to a columnar shape, and it can be inferred that the small projections are likely to receive a higher shear stress at the joint between the porous portion and the small projections. From this result, it is preferable that the maximum diameter of the small protrusion is twice or more the height of the protrusion from an engineering viewpoint.

(Experimental Example 2) The porous body used in this experiment was made of alumina, and as shown in FIG. 8, as shown in FIG. This is a structure in which projections are regularly provided. The height of the projection is 100
A total of six types of test pieces (n = 5) were prepared with three types of μm, 200 μm, and 300 μm, and the number of projections was 9 / cm ² or 5 / cm ² , respectively. The plate-shaped bovine bone fragments were prepared by thawing the frozen knee joint bones frozen immediately after slaughter and successively slicing them with a micro-cutting machine.

The test was performed by inserting a test piece between two bovine bone pieces in the same manner as in Experimental Example 1. Small projection 6 at this time
Was evaluated based on the presence or absence of breakage.

FIG. 11 shows the result at this time.

Looking at the relationship between the insertion and removal loads in each group, the number of projections provided was 5 / cm ² and the height of the projections was 100.
The relationship of “insertion load value> pull-out load value” was observed in the five groups except the μm group. Since the cancellous trabecular bone is broken by the frictional resistance at the time of insertion, the pull-out load in the vertical direction generally decreases. However, as the height of the projection increases, the difference between the two load values increases, and the 300 μm group Was a result that was lower than the pulling load value of the 200 μm group. At a projection height of 300 μm, there is a risk of breaking the fine cancellous trabecular bone, and there is a high risk of negatively affecting the initial fixation after implantation. Therefore, it was the most preferable result to provide a projection having a projection number of 9 / cm ² and a projection height of about 200 μm.

[0054]

As described above, according to the present invention, since it is made of a harmless ceramic and has a large number of holes formed at desired locations with regularity, it can be implanted and fixed in bone. The new bone grows and enters into the three-dimensionally structured pore, and the three-dimensional structure of the bone tissue makes it possible to firmly hold the bioprosthetic member in the living body.

In addition, the height h = 100-300 μm and the maximum diameter d = 500-100 on the surface of the opening in contact with the bone.
By providing a plurality of small projections of 0 μm and d ≧ 2h, the initial fixing force (the fixing force with the bone immediately after the operation) is increased,
Further, even after a long period of time, the anti-shear load force increases dramatically.

As described above, according to the present invention, an optimal surface structure is provided for a bioprosthetic member using ceramic.

[Brief description of the drawings]

FIG. 1 is a front view of a porous body constituting a bioprosthesis member of the present invention.

FIGS. 2 (a), (b), and (c) are each A-
It is A, BB, and CC sectional drawing.

3 (a) and 3 (b) are plan views of a thin plate constituting the porous body of FIG.

FIG. 4 is an explanatory view of a method for producing the porous body of FIG.

FIG. 5 is a perspective view of a biological prosthetic member according to another embodiment.

FIG. 6 is a perspective view of a biological prosthetic member according to another embodiment.

FIGS. 7A to 7F are silhouette diagrams showing examples of the shape of a small projection.

8A and 8B show a porous body used in an experimental example, where FIG. 8A is a front view, and FIG. 8B is a DD diagram of FIG.

FIGS. 9A to 9C are silhouette diagrams showing the shapes of small projections.

FIG. 10 is a schematic view of an experiment conducted to evaluate the effect of a projection provided on the surface of an opening of a porous body on initial bone fixation.

FIG. 11 is a bar graph showing the results of Experimental Example 2.

[Explanation of symbols]

 1, N porous body 2, 3 thin plate 4 large diameter hole 5 small diameter hole 6 small protrusion F artificial knee joint femoral component D dental ceramic implant

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4C081 AB03 AB05 AB06 BA13 BB04 BB08 CF031 CF121 CF151 DA02 DB04 DC02 DC04 DC05 EA02 EA03 EA04 EA12 4C097 AA01 BB01 CC01 CC02 CC03 CC05 CC06 CC12 DD06 DD07 MM02 A04A09 4A AA41 BA35 CA07 CA09 GA14 GA20

Claims (4)

[Claims] 1. A bioprosthetic member made of a harmless ceramic which constitutes an artificial bone, an artificial joint, an artificial tooth root, etc., wherein a large number of holes are regularly arranged at desired locations so as to communicate with each other, and the bone is prosthetic. Height h = 100 on the surface of the opening in contact with
３００300 μm, maximum diameter d = 400-1000 μm and d
A biological prosthetic member comprising a plurality of small protrusions of ≧ 2h. 2. The bioprosthesis member according to claim 1, wherein a plurality of types of porous thin plates made of the ceramic having different shapes and arrangements of the holes are laminated with the holes being displaced in the horizontal direction. 3. An existence density of the small projections is 4 to 15 protrusions / cm.
^{2. The} bioprosthetic member according to claim 1, wherein the member is 2. 4. The bioprosthetic member according to claim 1, wherein the outer surface of the small projection has a shape that exists in a range of a hemisphere having a maximum diameter d.