JPS6234558A - Production of bone implant - 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 The present invention relates to a method for manufacturing an intraosseous implant that does not elute harmful metal ions.

In recent years, so-called implantology, which restores lost parts and functions of living organisms by inserting and replacing artificial materials such as artificial organs, artificial blood vessels, artificial bones, and artificial tooth roots, has been in the spotlight. It is said that attempts at implants can be traced back to ancient times. In particular, in the last few years, a large number of implants have been performed on bone and tooth roots, and great results have been achieved in treatment and restoration of human function. However, as a biomaterial, there is currently no artificial bone or artificial tooth root that satisfies the necessary and sufficient conditions of being compatible with the living body, being safe, and being durable.

Conventionally, metal materials mainly used for artificial bones and artificial tooth roots include cobalt-chromium alloys, stainless steel, titanium, and tantalum.

On the other hand, in recent years, alumina or carbon-based materials have been poured as ceramic materials. Metal materials have excellent mechanical strength, particularly impact strength, but have many problems in their compatibility with biological tissue. For example, metal ions are eluted and act as a cytotoxic agent for bone cells surrounding the implant. Alternatively, there is an obstacle to the functioning of the remains, which is thought to be due to too good heat conduction. Among metal materials, especially titanium,
Tantalum has excellent corrosion resistance and has been used since the 1940s as fixation plates for skull bones, fractures, and implants in the jawbone, but it is not always satisfactory.

On the other hand, ceramics generally have good affinity with bone, allowing bone tissue to penetrate into the pores, providing strong fixation, and not reacting with tissue.
Although it has the advantage of being highly durable (resistant to corrosion and decomposition), it has the disadvantage of being weak against impact.

Conventionally, JP-A-5244095 and JP-A-52-82893 have been developed as implants that have both the characteristics of metal and ceramics.
, No. 53-28997 and No. 53-75209 propose a method in which the surface of a metal core material is thermally spray coated with ceramics. However, all of these methods used self-bonding bonding materials to improve the adhesion of the ceramic coating layer. There is a problem in that these bonding materials contain nickel, chromium, etc., which are harmful to living organisms if they are eluted.

The present invention provides an intraosseous implant that has high impact strength and is resistant to cracking without losing the above-mentioned advantages of ceramics, and does not elute metal ions that are injectable to living organisms.

That is, the present invention provides a method for manufacturing an intraosseous implant,
After thermally spraying titanium hydride on the surface of the metal core material to make the maximum surface thickness 15 to 100 μm, ceramics are thermally sprayed to form a ceramic coating on the surface of the metal core material. A method for manufacturing a characteristic intraosseous implant is provided.

According to the present invention, an intraosseous implant having the above features can be manufactured without using bonding materials containing metals that are harmful to living bodies.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a schematic diagram of an example of a canine mandibular intraosseous implant. In the figure, 1 is a mandible, 2 and 3 are natural teeth, 4 is an artificial tooth root, and 5 is an artificial tooth (crown) mounted on the artificial tooth root of 4. FIG. 2 is a partially cutaway view of an example of an intramaxillary implant according to the present invention, in which 6 is a metal implant (core material), 7 is a metal implant (core material),
is a ceramic layer containing unpierced pores that do not reach the metal. As shown in Fig. 2, the present invention coats the outer periphery of a metal implant material with a ceramic coating to prevent cracking from impact and to act on the bone tissue of the implant in the same way as ceramics. .

The metal implant core materials used in the present invention include Go-Cr alloys, stainless steel, titanium, titanium alloys, tantalum, and zirconium, which have been used conventionally for surgical purposes, and have very little harmful effect on living tissue. If it has appropriate mechanical strength, it can be used as is. Among these metal materials, titanium, titanium alloys, zirconium, and tantalum are preferable from the viewpoint of corrosion resistance.
Titanium is the best in terms of workability and safety.

Further, as the ceramic, materials such as hydroxyapatite, calcium phosphate, aluminum oxide, zirconium oxide, and titanium oxide can be used alone or as a mixture.

To control porosity within the ceramic layer, some porcelain may be co-sprayed into the sprayed material or baked onto the sprayed coating. In that case, dentin,
Enamel porcelain can be used. Among these materials, hydroxyapatite and aluminum oxide are used because of their affinity with living organisms. In particular, a system using a mixture of hydroxyapatite and aluminum oxide has the best compatibility with living organisms.

In order to obtain the intraosseous implant of the present invention, a metal material is processed into a predetermined shape by cutting, casting, forging, punching, electrical discharge machining, laser processing, powder metallurgy, or the like. Titanium hydride is thermally sprayed onto the surface of the obtained metal core material to roughen the surface. The ceramic material is then sprayed using commercially available thermal spray equipment, preferably plasma spray equipment.

The maximum surface roughness of the metal core material is from 15μm to 100μm.
A value between μm is desirable. If it is smaller than 15 μm, the adhesion of the sprayed ceramic coating will be insufficient.

Moreover, if it is larger than 100 μm, it becomes difficult to form a thin and homogeneous ceramic coating, which is not preferable. In particular, the maximum surface roughness is important for adhesion and homogeneity of the arytenoid.
Most preferably, the thickness is 20 to 60 μm.

In the present invention, prior to thermal spraying of titanium hydride, the metal core material is subjected to mechanical methods such as grinding, sandblasting, and grid blasting, as well as chemical etching with acid or alkali and electrolytic etching/etching. Preferably, the treated surface is coated with a thermal spray coating of titanium.

As the titanium coating material, titanium hydride, which produces titanium when decomposed by heat during thermal spraying, is desirable. Furthermore, plasma spraying is the most suitable method for thermal spraying in order to prevent titanium from oxidizing.

Unlike conventional self-bonding bonding materials containing easily eluted metals, the titanium coating has the advantage that it does not elute in vivo, so it does not need to be injected when used as an implant material.

When thermal spraying ceramic, areas that do not require thermal spraying are masked when the surface of the core material is exposed.

Depending on the site where the bone and meat implant 1- is used, the surface of the ceramic layer may be required to have a considerable degree of smoothness, such as in the case of an artificial joint.

In that case, the desired intraosseous implant is obtained by repeatedly applying porcelain and firing it in a vacuum furnace.

The present invention will be explained below with reference to Examples.

Example An intraosseous implant core material was created using a titanium material (JI3 type 2). That is, titanium was cut out by electrical discharge machining and polished to obtain an intraosseous implant core material.

This metal implant core material was grid-plasted using a blasting device (Henchblast device Mammoth type manufactured by Metco, UK) (the blasting material was Meticolai NIF, pressure 30
psi) was performed. Maximum surface roughness after plasting is 1
It was 0IIm.

Next, a plasma spraying device (manufactured by Metco +6FI gate-63)
An argon-hydrogen plasma jet flame (arc current 500 amperes) was generated using an argon-hydrogen plasma jet flame (arc current 500 amperes), and titanium hydride powder (Meteco, powder number XP-1157) was first sprayed as the first layer. A film with a thickness of about 50 μm was formed on the entire surface of the material. The composition of the obtained film was determined to be titanium by X-ray diffraction measurement (11,B).

The maximum surface roughness after f9 irradiation was 40 μm. The second layer is 8
0 wt% hydroxyapatite (particle size 10-100 μm) and 20 wt% aluminum oxide (Nippon Aborizai, W
A11120) mixed powder was sprayed to an average thickness of about 150 μm. The adhesion of the thermally sprayed coating was good, and the coating did not peel off even when bent at an angle of about 160 degrees. The main island was implanted into the mandible of a dog, and X-ray fluoroscopic observation was performed after 3 months had elapsed, and as a result, dense bone formation was observed around the implant.
4゜Comparative Example Implant core materials were prepared using titanium material in the same manner as in the examples. The prepared test piece was grid-plated in the same manner as in the example. The maximum surface roughness after blasting is 1
The surface roughness was 0 μm, which was one-fourth of the surface roughness of the first layer of titanium in the example. This test piece was plasma sprayed with a mixed powder of hydroxyapatite and aluminum oxide at an average of about 150I! Two injections were made to give a thickness of m.

The adhesion of the thermally sprayed coating is extremely poor, and it will stick to the surface with only a slight impact.
This resulted in separation and could not be used as an implant.

As described above, the present invention improves the drawbacks of ceramic implants that are prone to breakage by forming a ceramic plasma sprayed layer on the outer periphery of the metal, and has mechanical strength comparable to that of metal, while still being strong in bone tissue. The purpose of the present invention is to provide an intraosseous implant whose compatibility is equivalent to that of ceramics.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an example of mounting an implant in the mandibular bone. In the figure, 1 is a mandible, 2 and 3 are natural teeth, 4 is an intramandibular implant according to the present invention, and 5 is an artificial tooth (crown) mounted on the 4 intramandibular implant. FIG. 2(A) is a front view of a partial defect of an example of a jaw bone implant, and FIG. 2(B) is a side view thereof. In the figure, 6 is a metal core material having a predetermined surface roughness, 7 is a plasma sprayed layer of titanium hydride, and 8 is a plasma sprayed layer whose main component is ceramics. Figure 1

Claims (1)

[Claims] In the manufacturing method of intraosseous implants, titanium hydride is thermally sprayed on the surface of the metal core material to achieve a maximum surface roughness of 15 to 100μ.
1. A method for manufacturing an intraosseous implant characterized by forming a ceramic coating on the surface of a metal core material by thermally spraying ceramics after roughening the surface to a depth of m.