JPH08257109A - Endosteal implant and manufacture thereof - Google Patents

Abstract

PURPOSE: To enables improvement in fitting to organic tissues and cells by providing a cover layer with the surface thereof having an OH group on the surface of a core body. CONSTITUTION: For example, in an artificial root, the surface of a core body 1 is purified rough by a blasting treatment to form a cover layer 2 comprising titanium on the core body 1 by a plasma blasting method. Then, the surface 3 of the cover layer 2 undergoes a hydrophilic treatment to introduce an OH group into the surface of the cover layer 2. This enables improvement in fitting to organic tissues and cells without lowering of adhesion strength between the cover layer 2 made of titanium or titanium oxide and the core body 1 and changing of affinity to the organic issues. A cobalt-chromium based alloy can be used as a material of the core body 1 and the hydrophilic treatment is performed by an eximer laser irradiation after dripping or applying of hydrogen peroxide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endosseous implant (for example, artificial tooth root, artificial joint and artificial bone).

[0002]

2. Description of the Related Art In recent years, intraosseous implants (for example, artificial tooth roots and artificial joints) have come to be used in many clinical settings. The properties required for such an intraosseous implant (hereinafter referred to as “implant”) are, of course, excellent in strength and affinity with living tissues,
It is also extremely important that the new bone tissue easily penetrates into the superficial part and that the new bone tissue and the implant have a mechanism capable of enhancing the integrity. Therefore, there has been proposed an implant in which a coating layer made of a bioactive material having an excellent affinity for living tissue is plasma sprayed on the surface of a core body to form a sprayed coating having an uneven structure on the surface. (For example, JP-A-52
Although this implant can cope with complicated shapes and reduce costs, the current coating layer of bioactive material formed by plasma spraying has low adhesion strength to the core body. There was a problem.

Therefore, recently, a plasma coating of a coating layer made of titanium or titanium oxide, which has a high adhesion strength with the core body and an excellent affinity with living tissues, is formed on the surface of a metal core body such as titanium or titanium alloy. Many implants formed by the method have been proposed. (Reference: Plasma sprayed porous implant, Masakatsu Magome, et al., Biomaterial Vol.8 No.3 (1
990))

[0004]

In this implant, there is no problem in the adhesion strength between the core body and the coating layer made of titanium or titanium oxide, and the affinity for living tissue is excellent. As compared with the implant coated with the material, there is a drawback that it is inferior in compatibility (adhesiveness) with living tissues and cells.

The present invention has been made in order to improve such problems (deficiencies), and lowers good adhesion strength between the core body and the coating layer made of titanium or titanium oxide, and between living body tissue. It is an object of the present invention to provide an implant having improved compatibility (adhesion) with living tissues and cells without changing favorable affinity.

[0006]

Therefore, the first aspect of the present invention is to "in an intraosseous implant comprising at least a core body and a coating layer provided on the surface of the core body, having an OH group on the surface of the coating layer. An intraosseous implant (claim 1) "is provided. Further, the present invention secondly provides an “intraosseous implant (claim 2), wherein the coating layer is made of titanium or titanium oxide”.

The third aspect of the present invention is that the material of the core body is titanium, a titanium alloy or a cobalt-chromium alloy (claim 3). )"I will provide a. The fourth aspect of the present invention is a method for producing an intraosseous implant, which comprises "at least a step of forming a coating layer on a core and a step of surface-modifying the surface of the coating layer by a hydrophilic treatment by introducing an OH group ( Claim 4) "is provided.

In a fifth aspect of the present invention, "the hydrophilic treatment is performed by dropping or applying hydrogen peroxide (H ₂ O ₂ ) on the surface and then irradiating an excimer laser. A method for manufacturing an endosseous implant according to claim 4 (claim 5) is provided. In the sixth aspect of the present invention, "excimer laser irradiation has an output per pulse of 5 mJ / cm.
^{2 to} 10 J / cm ² ArF excimer laser (λ = 1
93 nm) or KrF excimer laser (λ = 248n)
m) is used to provide the method for producing an intraosseous implant according to claim 5 (claim 6).

[0009]

In the implant of the present invention, after the coating layer made of titanium or titanium oxide is formed on the core body by the thermal spraying method,
Since only the very surface of the coating layer was hydrophilized to introduce an OH group that has good compatibility (adhesion) with living tissues and cells to modify the surface, the adhesion strength between the core body and the coating layer was reduced. In addition, the familiarity (adhesiveness) with living tissues and cells is improved as compared with conventional implants without changing the good affinity with living tissues.

The core is washed as a pretreatment. More preferably, the surface is cleaned and roughened by blasting. In this case, the sandblasted material (alumina particles) when sandblasting is applied to the surface of the roughened core body.
However, there is a problem in that the adhesion strength between the core body and the coating layer varies due to the sticking and remaining. Therefore, sand blast pierced by a method of ultrasonic cleaning with an ultrasonic deburring device, a method of etching with acid or alkali, a method of performing anodic oxidation, a method of performing anodic oxidation after etching with acid or alkali, etc. It is preferable to remove the material.

The maximum surface roughness at this time is 20 to 40 μm.
The range is preferable, but the surface may be roughened in the case of etching with an acid or an alkali after the sandblast treatment or further performing anodic oxidation. However, 80
When the thickness is not less than μm or not more than 10 μm, the adhesive strength between the core body and the coating layer tends to decrease. With the method of performing ultrasonic cleaning with an ultrasonic deburring device, it is difficult to remove the stab of the sandblast material by general ultrasonic cleaning, so ultrasonic cleaning using a new technique capable of deburring is preferable. As this device, it is preferable to use an ultrasonic deburring device "Aquatron" manufactured by S & C Corporation. However, it is not limited to this.

Further, in the method of etching with an acid or an alkali, it is important that the unevenness formed on the surface of the core body by the sandblasting treatment is not changed as much as possible. Further, in the method of performing anodic oxidation or the method of performing anodic oxidation after etching with acid or alkali, a titanium oxide coating film is formed on the surface of the roughened core body, and titanium ion from the core body itself is formed. It plays the role of a protective film for preventing elution, and has the effect of significantly reducing the possibility of causing a metal allergic reaction.

Also, the core body is protected from corrosion in the living body. In this way, the contact area with the coating layer is increased by roughening the surface of the core body by sandblasting, and further, the sticking strength between the core body and the coating layer is further stabilized by removing the sticking of the sandblast material by the above method. To do. The titanium or titanium oxide coating layer provided on the core is provided by a thermal spraying method such as a plasma spraying method or a flame spraying method. The particle size of titanium or titanium oxide powder sprayed on this core is 5 to
It is preferable to use one having a particle size range of 45 μm, but not limited to this. As a result, a titanium or titanium oxide coating layer roughness suitable for growth invasion of new bone tissue can be obtained. If it is coarser than this, not only the thermal spraying efficiency deteriorates, but also the porosity becomes too large and the adhesion strength with the core body is greatly reduced. If it is finer than this, the titanium or titanium oxide coating layer roughness suitable for the growth and invasion of new bone tissue cannot be obtained, and the titanium or titanium oxide powder itself is easily burned, which is very dangerous.

The thickness of the coating layer of titanium or titanium oxide provided on the core may be determined within a range that does not adversely affect the adhesion strength with the core, but considering the shape and size specifications of the implant and productivity, 30 ˜50 μm is preferred. However, the thickness is not limited to this. The titanium or titanium oxide coating layer has high adhesion strength to the core and is stable in vivo.

The titanium oxide is preferably TiO _2, but is not limited to this. As a method for hydrophilizing the coating layer, hydrogen peroxide (H ₂ O ₂ ) is dropped or applied on the surface of the coating layer and irradiation with an excimer laser is performed. The OH groups generated by the decomposition of H ₂ O ₂ combine with the excited surface of the coating layer, and the surface is modified to improve the wettability with living tissues and cells and improve the “familiarity (adhesion)”. It

Hydrogen peroxide (H₂O₂) Is usually commercially available
Anything can be used. Also, the excimer laser
-The output per pulse is 5 mJ / cm²-10J /
cm ²ArF excimer laser (λ = 193 nm),
Or, use KrF excimer laser (λ = 248 nm).
be able to. Output per pulse is 5 mJ / cm ²
Below, OH groups cannot be efficiently generated.
The output per pulse is 10 J / cm²Above
A strong abrasion occurs on the surface of the coating layer, and the surface of the coating layer
Is unfavorable because it causes damage.

Lasers other than excimer lasers
The same effect can be obtained even with (for example, a CO ₂ gas laser) depending on the irradiation conditions, and therefore it is not limited to the excimer laser. The confirmation of the OH group after the hydrophilization treatment is performed by preparing a plate-like sample, taking an infrared absorption spectrum by the specular reflection method with FT-IR (Fourier conversion infrared spectrophotometer), and analyzing it. It can be analyzed (identified). FT-IR can be analyzed (identified) by ordinary IR (dispersive infrared spectrophotometer), but its sensitivity is poor.
It is preferable to analyze (identify) with (Fourier transform infrared spectrophotometer). By grasping the irradiation conditions of the excimer laser and the analysis (identification) results of the OH groups, stable surface modification becomes possible.

Since the hydrophilic treatment is a reaction on the extreme surface,
It has no effect on the interface between the core and the coating layer. Further, the implant after the hydrophilic treatment is washed, sterilized, and packaged, but the OH group is not removed in this step. The form of the implant may be any of blade type and cylinder type. Further, a screw may be used in the cylinder type. There may be a vent.

Further, the uneven structure of the implant surface may not be present on the entire surface of various implant forms. For example, in the case of a cylinder type, the flange portion may not have this surface uneven structure.
Rather, the cylinder-shaped collar may be mirror-finished. Further, regarding the hydrophilic treatment, there is no problem even if it is performed not only on the surface uneven structure portion of the implant but also on the collar portion. Further, in the artificial joint, it can be mainly used for a stem and a cup (artificial acetabulum). It can also be used on the surfaces of artificial bones, bone plates and bone screws.

The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

[0021]

EXAMPLE FIG. 1 is a schematic sectional view showing an artificial tooth root of this example. This artificial tooth root was produced by the following method. First, the core 1 made of titanium (diameter 4 mm, length 10 mm
The surface of the shell of the shell is cleaned and roughened by blasting (roughness 20 to 40 μm), and the coating layer 2 made of titanium is formed on the core 1 by plasma spraying (thickness 50 μm).
Then, the surface 3 of the coating layer was hydrophilized to produce the artificial tooth root shown in FIG.

[Adhesive Strength Test] Next, the present inventor confirmed that the adhesive strength between the core 1 of the artificial tooth root and the titanium coating layer 2 is not affected even if the coating layer surface 3 is hydrophilized. In order to do so, the sample shown in FIG. 2 was prepared and an adhesive strength test was conducted. The sample was prepared as follows. As the core body 1, there was prepared titanium having a diameter of 10 mm and a length of 10 mm, and one end surface of which was threaded. The end surface (plasma sprayed surface) not subjected to the screw processing is blasted with Al ₂ O ₃ to clean and roughen it (roughness 20 to 40 μm), and then Ar + He or N ₂ or H is applied using a plasma spraying machine. _The coating layer 2 was formed (thickness: 50 μm) by plasma spraying a titanium powder having a particle size of 5 to 45 μm in the plasma gas of ₂ . Then, hydrogen peroxide (H ₂ O ₂ ) is dropped or applied on the surface 3 of the coating layer to output 20 mJ / cm ² per pulse.
A while controlling within the range of ~ 80 mJ / cm ^2.
Irradiation with rF excimer laser (λ = 193 nm) was carried out to prepare a sample “invention sample S1” in which the surface 3 of the coating layer was surface-modified by introducing OH groups by hydrophilic treatment.
For comparison, a sample “Comparative Sample HS1” was prepared in exactly the same manner except for the hydrophilic treatment. Then, an adhesive strength test was performed according to JIS H8666.

As a result, the adhesion strength of both the sample S1 of the present invention and the comparative sample HS1 exceeded 30 MPa, and it was confirmed that the hydrophilic treatment had no influence (problem) at all. [Analysis of OH Group After Hydrophilization Treatment] Next, the present inventor prepared the following samples in order to confirm the state of the OH groups after hydrophilization treatment of the artificial tooth root sample of the present invention.

First, the length is 20 mm × 20 mm and the thickness is 2 m.
The surface of the titanium plate of m is blasted with Al ₂ O ₃ to clean and roughen the surface (roughness 20 to 40 μm), and then a plasma sprayer is used for 5 to 5 in a plasma gas of Ar + He or N ₂ or H _2. A titanium powder having a particle size of 45 μm was plasma sprayed to form a coating layer (thickness: 50 μm). Hydrogen peroxide (H ₂ O ₂ ) is dropped or applied on the surface of this coating layer to output 20 mJ / cm ² to 8 per pulse.
ArF while controlling within the range of 0 mJ / cm ^2.
An eximer laser (λ = 193 nm) was irradiated and the surface of the coating layer was subjected to a hydrophilic treatment to introduce an OH group to modify the surface to prepare a sample “Sample S2 of the invention”. Also,
For comparison, a sample “Comparative sample HS2” was prepared in exactly the same manner except for hydrophilization treatment, and FT-IR
An infrared absorption spectrum of each sample was taken by a (Fourier transform infrared spectrophotometer) by the specular reflection method and analyzed.

As a result, a clear spectrum of OH groups could be analyzed (identified) from sample S2 of the present invention. After implanting the sample S2 in the jawbone of an adult dog for 4 weeks, a tissue sample was prepared and the vicinity of the interface between the implant and the bone was observed. As a result, it was directly bonded to bone without intervening fibrous tissue and was covered with bone tissue.

[0026]

As described above, according to the present invention, a coating layer made of titanium or titanium oxide is formed on a core body having a roughened surface by a thermal spraying method, and then, the extreme surface of the coating layer is formed. Since the OH group, which has good compatibility (adhesiveness) with living tissues and cells, is introduced by the hydrophilic treatment to modify the surface, the good adhesion strength between the titanium or titanium oxide coating layer and the core is lowered. It is possible to provide an implant with which the familiarity (adhesiveness) with living tissues and cells is improved as compared with conventional implants, without changing the good affinity with living tissues.

[Brief description of drawings]

FIG. 1 shows an artificial dental root of the embodiment (1 of the endosseous implant).
It is a schematic sectional drawing which shows (type).

FIG. 2 is a schematic cross-sectional view showing the structure of an adhesive strength test sample.

[Explanation of symbols]

 1 ... Core 2 ... Covering layer 3 ... Hydrophilized surface

Claims (6)

[Claims] 1. An intraosseous implant comprising at least a core body and a coating layer provided on the surface of the core body, wherein the surface of the coating layer has an OH group. 2. The endosseous implant according to claim 1, wherein the coating layer is made of titanium or titanium oxide. 3. The intraosseous implant according to claim 1, wherein the material of the core body is titanium, a titanium alloy or a cobalt-chromium alloy. 4. A method for producing an intraosseous implant, which comprises at least a step of forming a coating layer on the core body and a step of surface-modifying the surface of the coating layer by a hydrophilic treatment by introducing an OH group. 5. The inside of the bone according to claim 4, wherein the hydrophilization treatment is performed by dropping or applying hydrogen peroxide (H ₂ O ₂ ) on the surface and then irradiating an excimer laser. Implant manufacturing method. 6. The excimer laser irradiation is ArF having an output per pulse of 5 mJ / cm ^{2 to} 10 J / cm ² .
The method for producing an intraosseous implant according to claim 5, which is performed by using an excimer laser (λ = 193 nm) or a KrF excimer laser (λ = 248 nm).