JPS6234559A - 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 without elution of 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, a large number of bone and tooth root implants have been performed over the past dozen years, and great results have been achieved in treatment and functional recovery. However, as a biomaterial, there is currently no artificial bone or artificial tooth root that satisfies the necessary and sufficient conditions of being biocompatible, safe, and 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 attracting attention as ceramic materials. Metal materials have excellent mechanical strength, especially impact strength, but have many problems with their affinity for living tissues. 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 around 1940 as a fixation plate for cranial bones, fractures, and implants in the jawbone, but it is not always satisfactory.

On the other hand, ceramics generally have good compatibility with bone, bone tissue penetrates into the pores, provides strong fixation, does not react with Mi fabric, and is highly durable (resistant to corrosion and decomposition). It has the disadvantage of being weak against shock.

Conventionally, JP-A-52-14095 and JP-A-52-8289 have been developed as implants that have both the characteristics of metal and ceramics.
3, No. 53-28997, and No. 53-75209 propose a method in which the surface of a metal core is coated with ceramic by thermal spraying. However, all of these methods used self-bonding bonding materials to improve the adhesion of the ceramic coating layer.

These bonding materials have a problem in that they contain nickel, chromium, and the like, 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 is a method for manufacturing an intraosseous implant, which involves roughening the maximum surface thickness of a metal core material to 15 to 100 μm, and then thermally spraying ceramics to form a ceramic coating on the surface of the metal core material. Provided is a method for manufacturing an intraosseous implant characterized by the following.

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 provides a ceramic coating on the outer periphery of a metal implant material so that it resists cracking against impact and acts on the bone tissue of the implant in the same way as ceramics. .

The metal implant core materials used in the present invention include Co-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 alloy, zirconium, and tankle are preferable from the viewpoint of corrosion resistance. especially,
Titanium is the best in terms of workability and safety.

Further, as the ceramic, materials such as hydroxyapatite, calcium oxide, aluminum oxide, zirconium oxide, and titanium oxide can be used alone or in 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 and enamel porcelain can be used. Among these materials, hydroxyapatite and aluminum oxide are suitable from the viewpoint of compatibility 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. The surface of the obtained metal core material is treated to roughen the surface. Next, the ceramic material was sprayed using commercially available thermal spraying equipment.
Preferably, the final spraying is performed using a plasma spraying device.

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 film homogeneity.
Most preferably, the thickness is 20 to 60 μm.

Methods for imparting the above-mentioned surface roughness to metal cores include mechanical methods such as grinding, sandblasting, and grid blasting, as well as chemical etching with acids and alkalis, and electrolytic processing/notching. Among these methods, blasting and chemical etching are preferable because they provide a surface into which the thermal spray material can easily penetrate.In particular, a system that uses both blasting and acid etching/notching provides the best coating. Adhesion can be obtained.

As the acid used for etching, sulfuric acid, hydrochloric acid, hydrofluoric acid, etc. can be used alone or in combination.

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 intraosseous implant is used, for example in the case of an artificial joint, the surface of the ceramic layer may be required to have a considerable degree of smoothness.

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 prepared using a titanium material (JIS Class 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 subjected to grid blasting (blasting material was Methycolyte VF, pressure 30 pst) using a blasting device (Bench Blast 'A C Mammoth type, manufactured by Metco, UK). The maximum surface roughness after blasting was 10 μm.

After blasting, the core material was immersed in a 30% aqueous sulfuric acid solution at 50° C. for 72 hours to perform etching. The maximum surface roughness after etching was 50 μm.

Next, a plasma spraying device (manufactured by Metco, 6 MM-6
An argon-hydrogen plasma jet flame (arc current of 500 amperes) was generated using an 80% by weight hydroxyapatite (particle size: 10-1
00 μm) and 20% by weight of aluminum oxide (WA 11120 manufactured by Nippon Aborizai) on average about
Thermal spraying was carried out so that the temperature was 0 μmr￥-. 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, the area around the implant was compressed by dense remains.

Comparative Example Implant core materials were created using titanium material in the same manner as in the Examples. The prepared test piece was subjected to grid blasting in the same manner as in the example, but no etching treatment was performed. The maximum surface roughness of the sprayed surface was 10 μm, and
It was 1/1. A mixed powder of hydroxyapatite and aluminum oxide was sprayed onto this test piece by plasma spraying in the same manner as in the example so that it had an average thickness of about 150 μm.

The adhesion of the thermally sprayed coating was extremely poor, and it peeled off at the slightest impact, making it unusable 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, has mechanical strength comparable to metal, and has an affinity with bone tissue. The present invention provides an intraosseous implant whose properties are equivalent to those 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 partially defective example of an intramaxillary implant, and FIG. 2(B) is a side view thereof. In the figure, 6 is a metal core material having a predetermined surface roughness, and 7 is a plasma sprayed layer whose main component is ceramics.

Claims (2)

[Claims] (1) In the method for manufacturing an intraosseous implant, the metal core material is roughened to a maximum surface roughness of 15 to 100 μm, and then ceramics are sprayed to form a ceramic coating on the surface of the metal core material. A method for manufacturing an intraosseous implant. (2) The manufacturing method according to claim (1), wherein the surface roughening of the metal core material is performed by acid etching.