JPH07124242A - Implant - Google Patents

Abstract

PURPOSE:To provide an implant of homogeneity and stable quality having biocompatibility, safety and a good mechanical property by using roll forged and swaged titanium as a substrate and applying a specific value to the tensile strength thereof. CONSTITUTION:Titanium subjected to a roll swaging process is used as a substrate, and the tensile strength thereof is maintained at a value between 510 and 740N/mm<2>. Also, the draft of the swaging process is kept at a value between 20 and 80%, provided that the draft is defined as 100 (S0-S1)/S0 (unit:%) where S0 is the cross-sectional area of the substrate before the swaging process and S1 is the cross-sectional area of the substrate after the swaging process. As a result, an implant having homogeneous and stable quality with the excellent biocompatibility and safety of a titanium material, but better mechanical properties than the titanium material can be provided. Also, a fracture or fatigue break can be prevented due to the improvement of the mechanical properties and, in addition, a thinner and smaller implant can be made.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to implants (eg artificial tooth roots, artificial tooth root superstructures, artificial joints, artificial bones, etc.).

[0002]

2. Description of the Related Art Titanium, which has excellent biocompatibility, is used as a base material for implants such as artificial tooth roots, superstructures for artificial tooth roots, artificial joints and artificial bones. However, when titanium is used as a base for artificial tooth roots, superstructures for artificial tooth roots, and artificial joints, for example, the mechanical strength is not always sufficient with respect to the occlusal force and the load at the time of walking, and it may break during use. It often causes fracture due to folding or fatigue.

[0003] Therefore, as measures for improving it, addition of trace impurities to titanium (addition of chemical components and structure control, ion implantation, etc.), use of various titanium alloys, nitriding and oxidation of titanium by heat treatment, sputtering and ion plating. And titanium nitride by physical treatment such as laser irradiation,
It has been proposed to form a coating layer of titanium oxide, titanium carbide or the like on the surface of a titanium base material, and work hardening the titanium base material by cold rolling.

[0004]

Titanium has a high mechanical strength due to the addition of trace amounts of chemical components such as oxygen and nitrogen, but it is difficult to obtain titanium of industrially stable quality. In fact, in Japan, it is very difficult to obtain other than JIS 2 type equivalents described in JIS-H4650. Also, mainly Ti
Titanium alloys represented by -6Al-4V have mechanical properties superior to those of titanium, but V alloys contained in the alloys.
There is concern about the influence of elution of Al and Al in the living body.

In addition, although various treatments on the surface of the titanium base material can be expected to improve strength, wear resistance and corrosion resistance due to an increase in surface hardness, they are treatments only on the surface and are not homogeneous. Therefore, there are problems that reliability of strength is uncertain and post-processing cannot be performed. Further, although work hardening of a titanium base material by cold rolling is also proposed, it is difficult to produce an implant other than a blade-type artificial tooth root with a dental implant, and a work-hardened surface of the base material and the inside There is a problem that homogenization is difficult.

[0006] Further, although cold drawing can obtain the effect of work hardening of the titanium base material, it is also difficult to homogenize the surface and the inside of the base material, and there is a problem in quality stability. An object of the present invention is to provide a homogeneous and stable implant having excellent biocompatibility and safety of titanium material and better mechanical properties than titanium material.

[0007]

Therefore, the present invention firstly provides an "implant (claim 1) characterized in that the base material is titanium subjected to rotary forging swaging." The present invention secondly provides the "implant according to claim 1 (claim 2)" in which the tensile strength of the substrate is 510 to 740 N / mm ² .

[0008] In the third aspect of the present invention, the implant according to claim 1 or 2 is characterized in that the workability of the swaging work defined by the following formula is 20 to 80%. Workability = 100. (S ₀ −S ₁ ) / S ₀ S ₀ : cross-sectional area of substrate before swaging, S ₁ : cross-sectional area of substrate after swaging (claim 3).

[0009]

Operation: Forging swaging according to the present invention (swa
Ging) is a process of hitting a material such as a wire, pipe, or bar with a tool that slides while rotating to reduce the thickness or diameter of the material, or increase the length or width of the material. Say. Examples of the rotary forging swaging method and apparatus are, for example, Japanese Patent Publication No. 64-9087 and Japanese Patent Publication No. 64-9088.
It is described in. The titanium to be processed may be any titanium that is normally used and available. JIS2
Titanium corresponding to seeds is preferable in terms of price and stable availability.

According to the rotary forging swaging, it is possible to uniformly compress the material in the cross-sectional direction and to improve the mechanical properties (tensile strength, proof stress, hardness, fatigue characteristics, etc.). Is obtained. For example, when a bar or wire rod corresponding to JIS type 2 is processed with a working ratio (area reduction rate) of 20 to 80%, the tensile strength is 343 to 51 before processing.
0 N / mm ² (standard value) to 510-740 N / mm ²
Can be easily and inexpensively increased.

The workability is defined by the following equation. Workability = {(Cross-sectional area before processing-Cross-sectional area after processing) / Cross-sectional area before processing} × 100% Tensile strength of the processed titanium base material is 510 N / m
If it is smaller than m ^2, the mechanical strength when used as an implant is insufficient. On the other hand, if it is more than 740 N / mm ² , the material loses elongation and becomes brittle, and cracks may occur during processing into an implant shape. Therefore, the tensile strength of the titanium base material subjected to the rotary forging swaging process according to the present invention is 510 to 740 N / mm ^2.
It is preferable that Particularly, the tensile strength is 600 to 70
The use of 0 N / mm ² is preferable because the mechanical strength when used as an implant is optimized.

If the workability is less than 20%, the work hardening of the material is not sufficient and the mechanical properties (tensile strength, proof stress, hardness, etc.) when used as an implant are insufficient. On the other hand, if it is more than 80%, the material loses elongation and becomes brittle, and cracks may occur when the material is subjected to rotary forging swaging or when processed into an implant shape. Therefore, the working ratio of the rotary forging swaging according to the present invention is preferably 20 to 80%. In particular, it is preferable that the workability is 50 to 70% because the mechanical properties and the homogeneity become extremely good.

The obtained rotary forging swaging material is
Various shapes can be processed, and for example, an implant having a complicated shape can be manufactured. In addition, since the composition of the raw material is not changed by the rotary forging swaging processing or the shape processing, the biocompatibility and the biosafety of the raw material titanium hardly change after the processing. Therefore, the obtained implant becomes homogeneous and stable in quality with biocompatibility and biosafety, which are characteristics of the titanium material, and mechanical properties better than those of the titanium material.

The titanium subjected to rotary forging swaging according to the present invention can be used as a base material for implants such as artificial dental roots, superstructures for artificial dental roots, artificial joints and artificial bones. For the artificial tooth root, a vapor deposition method, a sputtering method, an ion plating method, a flame spraying method, a flame jet method is applied to the surface of the base material (core body) of the artificial tooth root made of titanium subjected to the rotary forging swaging according to the present invention. Also included are composites of various materials such as metals, ceramics, glass ceramics and glass by physical methods such as plasma spraying and chemical methods such as acid treatment and anodizing treatment.

In the artificial root superstructure, what is usually called an abutment used in a portion that comes into contact with the gingiva, a core that serves as an abutment for connecting a crown, and an abutment and a core are integrated. However, the screw for connecting the artificial tooth root and the abutment, the screw for connecting the core and the crown, and the like are also included, but the present invention is not limited to these.

The artificial bone includes, but is not limited to, bone plates and bone screws. Hereinafter, the present invention will be specifically described with reference to Examples.
The present invention is not limited to these.

[0017]

[Example] (Tensile test) Pure titanium equivalent to JIS Class 2 with a diameter of 5 mm
A 6 mm rod (handled as a wire by JIS) was swaged into various diameters by a CNC rotary cold forging machine (manufactured by Japan Royal Seiki Co., Ltd.). Tensile tests of these processed materials were performed using a universal testing machine (Autograph, manufactured by Shimadzu Corporation), and tensile strength, elongation, and proof stress were determined according to JIS. The results are shown in Table 1.

Sample 1 is a bar material having a diameter of 5 mm swaged to a diameter of 4 mm (working degree 36%), sample 2
Is a bar material with a diameter of 6 mm swaged to a diameter of 5 mm (working degree 31%), and sample 3 is a bar material with a diameter of 6 mm swaged to a diameter of 4 mm (working degree 5
6%). The number of test samples is n = 3. Compared with the standard values of JIS Class 2 and JIS Class 3 of titanium wire and rod and titanium materials used in conventional implants, the titanium material that has been swaged according to the present invention is used as a base material for implants. It was confirmed that it has sufficient mechanical strength (tensile strength and proof stress) and is very excellent.

Further, in general titanium material, the mechanical properties (tensile strength, elongation, proof stress) vary widely depending on the purchased lot, but the mechanical properties are stabilized by swaging the titanium material. I was able to do it. Therefore, it has become possible to stabilize the quality of the implant as a base material for the implant. (Hardness test) A micro-Vickers hardness meter was used to measure the cross-sectional hardness distribution of a titanium material having a diameter of 5 mm and a diameter of 6 mm and the swaging processed material of Sample 3 at 2.5 mm intervals. As a result, it was confirmed that although the hardness of the titanium material varies greatly depending on the purchase lot, it is possible to achieve high hardness and homogenization by performing swaging. (Fatigue test) A fatigue test piece having a parallel portion with a diameter of 2 mm was prepared from a titanium material having a diameter of 5 mm and a swaging material of Sample 3, and a tensile fatigue test was performed using a 1 ton hydraulic servo fatigue tester. N curve data was obtained. as a result,
It was confirmed that the fatigue characteristics of the swaging material were excellent. (Machining test) Using a titanium material having a diameter of 5 mm and the swaging material of Sample 3, trial manufacture of implants (artificial roots and upper structural parts for artificial roots) was performed. As a result, it was found that the swaging material can be machined similarly to the titanium material, and a complicated implant or the like can be produced.

[0020]

[Table 1]

[0021]

Industrial Applicability As described above, according to the present invention, titanium which has been subjected to rotary forging swaging is used as the implant base material. Therefore, the titanium material has excellent biocompatibility and safety, and is superior to the titanium material. It is possible to provide a homogeneous and stable implant having excellent mechanical properties.

Further, since the mechanical properties are improved,
Not only can fracture and fatigue fracture be prevented, but it is also possible to make thinner and smaller implants. that's all

Claims (3)

[Claims] 1. An implant characterized by using titanium that has been subjected to rotary forging swaging as a base material. 2. The tensile strength of the substrate is 510 to 740.
The implant according to claim 1, wherein the implant has N / mm ² . 3. The implant according to claim 1, wherein the degree of processing of the swaging processing defined by the following formula is 20 to 80%. Workability = 100 (S ₀ −S ₁ ) / S ₀ (unit:%) S ₀ : cross-sectional area of base material before swaging processing S ₁ : cross-sectional area of base material after swaging processing