DE3914809C2 - Fatigue resistant surface - Google Patents

Description

The invention relates to a fatigue-resistant surface after the Preamble of claim 1.

In prostheses, in which one or more prosthesis Oberflä should grow together with the bone is made by suitable Shaping the prosthesis surface tries to wax to favor the bone.

In the publication "Surface-structured prostheses aus technical and medical point of view "on the 8th series of lectures of the working group implants medico-technical co on 17 November 1987 at the Oskar-Helene-Heim in Berlin, Page 25 to 38 is about ball-coated and over porous Surfaces reported. This occurs in the area of Rauhigkei at stress and tilting notch stresses, wel lead to fatigue fractures. This will increase the life drastically reduced implants.

The invention is based on the object, a fatigue-resistant Surface of the type mentioned above to be structured so that the possible notch stresses are minimized, at the same time early optimum connection of the surface with the material with which it is to be connected, z. B. bone, in the Growing surface.

This object is achieved by the characterizing Part of claim 1 solved.

The claims 2 to 6 represent advantageous embodiments of Invention claims. Claims 7 and 8 claim gene of the invention.  

Another advantage of the inventively designed Oberflä This consists in the fact that the surface which is in contact with it in Kon clock is not exposed to notch stress and that by the enlarged contact surface reduces the wing loading will be.

An embodiment will nä below with reference to the figure her explained.

The figure shows the contour 4 of a survey, represented by a section through this survey with a square plan, which is parallel to a side surface and which extends through the center of the survey. The scale can be changed by multiplication by a constant, without the surface losing its positive properties. The curve between points 1 and 2 can be described by the following function:

F (x) = 0.19433 x x 2 - 0.25925 x x + 1.2404 x x

where 1 has the coordinates (0; 0) and 2 has the coordinates (0.703; 0.182).

This curve section is also specified as a value table.

The curve between points 2 and 3 has no significance for the notch stress freedom. In the figure, grooves 5 are located in this area, which increase the Oberflä surface and z. B. gene ingrowth of the bone. These grooves have prosthesis surfaces preferably a depth between 30 and 300 microns. The height of the elevations is preferably between 0.3 and 3 millimeters. A top or bottom size limitation does not exist because the properties of the surface do not change with scale changes.

The abscissa distance of points 2 and 3 may be increased compared to the figure but not reduced.

The elevations are therefore 4-sided pyramids in the upper Part of the sides revolving transverse grooves as a substructure aufwei sen. They are close to each other, so that a two-dimensional a checkered structure arises.

With the same cross-sectional contour, the surveys can also have rectangular, polygonal or round floor plans.

Use find such surfaces in prostheses, z. B. at Knee prostheses and in the upper part of the shaft of hip joint prostheses.

In dentistry, the surface is suitable for artificial Tooth roots and for anchoring parts of dentures.

In loaded metal-plastic compounds, the metal be formed side connecting surface according to the invention, also in compounds of metal with Faserverbundwerkstof fen.

x-coordinate y coordinate | 0.0 | 0.0 5.0396264E-02 | 4.9018860E-04 9.7803771E-02 | 1.3618469E-03 0.14201444 | 3.3636093E-03 0.18345815 | 5.1E-03 0.22146857 | 8.2702637E-03 0.25692707 | 1.1E-02 0.28965676 | 1.41E-02 0.31945157 | 1.8515587E-02 0.34850132 | 2.2E-02 0.37649626 | 2.67E-02 0.40428942 | 3.2E-02 0.43124861 | 3.7380219E-02 0.45776540 | 4.2293549E-02 0.48353475 | 4.9386978E-02 0.50890476 | 5.6294441E-02 0.53324980 | 6.4815521E-02 0.55744958 | 7.2573662E-02 0.59044343 | 8.7E-02 0.62157142 | 0.10393333 0.65007830 | 0125 0.67788804 | 0.15171242 0.70273793 | 0.18212700

Claims (8)

1. Fatigue-resistant surface of implantable bone or dental prostheses or in loaded Metall-Kunststoffverbin applications, projecting from an otherwise smooth surface regularly shaped elevations with concave outer surfaces, characterized in that each side surface of a survey with a plane which is perpendicular to the otherwise smooth surface is, forms a cutting line in the normalized range between point ( 1 ) and ( 2 ), based on the smooth surface, between the values 0 to 0.7027 by the function F = 0.19433 x² - 0.25925 x⁴ + 1,2404 x⁶ is described, wherein the section line in the wider Be rich up to the middle of the survey at 1.303 can run ver. 2. Fatigue resistant surface according to claim 1, characterized marked records that the elevations a square base have and are arranged like a checkerboard. 3. fatigue-resistant surface according to claim 1, characterized in that the section line from the point ( 2 ) to the point ( 3 ) is a straight line with the slope of the function F in the point ( 2 ). 4. Fatigue-resistant surface according to claim 1 or one of the following, characterized in that the surfaces between the points ( 2 ) and ( 3 ) include grooves which run parallel to the smooth surface. 5. fatigue-resistant surface according to claim 1, 3 and 4, characterized characterized in that the elevations a circle as a plan and be as close together as possible. 6. fatigue resistant surface according to claim 1, 2, 3 or 4, since characterized in that the surveys are a regular Have polygon as a plan and as close as possible stand. 7. fatigue resistant surface according to claim 1 or one of following, characterized in that they serve as a surface on the metal side in metal and synthetic resin compounds is used. 8. fatigue resistant surface according to claim 1 or one of following, characterized in that they serve as a surface on the metal side in metal fiber composite used.