Electrolysis: processes – compositions used therein – and methods – Electrolytic coating – Forming nonmetal coating
Patent
1992-01-30
1994-01-04
Tufariello, T. M.
Electrolysis: processes, compositions used therein, and methods
Electrolytic coating
Forming nonmetal coating
C25D 1104
Patent
active
052757170
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to the processes for the manufacture of prosthetic elements, such as dental and maxillo-facial elements, and elements produced by such processes.
2. Discussion of Background Information
A number of materials were tested for the purpose of reconstructing or repairing hard biological tissues, namely bones or teeth. These materials, often called biomaterials, should have appropriate mechanical properties and not cause chemical reactions detrimental for tissues coming into contact with a prosthesis made with these materials.
In this respect, the qualities of metal oxides, in particular those of alumina, Al.sub.2 O.sub.3, the principal oxide of aluminum are known. Indeed, alumina is an extremely chemically stable compound, and is therefore considered as being inert in a biological medium. In addition, the hardness of alumina, four to five times higher, depending on its state, than the hardness of titanium alloys makes it a biomaterial which is mechanically superior to widely used titanium alloys. Moreover, the cost of titanium alloys is high compared with that of alumina. Therefore, alumina is particularly advantageous for the production of prostheses for use in a biological medium.
Known processes for manufacturing alumina prostheses, or prostheses coated with alumina, do however have serious disadvantages. Indeed, at present, it is now known how to use alumina except in the form of deposited or projected ceramics, i.e., the production of a layer of alumina either consists in the sintering of powders which are then amalgamated or in a thermal spraying process (by means of an electron torch, for example). These techniques, applied to the coating of prostheses or implants are described for example in the U.S. Pat. No. 4,556,389, in EP-211 676, in FR-2 318 617, and in International Application WO 87/00030.
However, these techniques are disadvantageous because:
either the layer of alumina deposited on the prosthesis is thin, and the porosity of the ceramic causes a risk of bacterial invasion which could lead to an infection,
or the layer is thick, around several tenths to several millimeters, and is fragile, and brittle, in spite of a porosity liable to promote the osteogenesis (regeneration of the bone around the prosthesis) without risk of infection.
Moreover, in both cases, the interface between the prosthesis and the layer of sintered or sprayed alumina is not unalterable since there only exists a mechanical retention between these two media. The layer of alumina is therefore not particularly adhesive.
Finally, should be noted that sintering and thermal spraying are not adapted to the deposit of ceramics on complex shapes, such as a threading, that occur frequently on prostheses or implanted prosthetic elements. These processes result in heterogeneous deposits of varying thickness covering the shapes. Moreover, even if it remains possible to reshape a profile in a layer of alumina ceramic which is sufficiently thick, the hardness of this oxide makes the work difficult and not very accurate.
SUMMARY OF THE INVENTION
The object of the invention is to remedy all these disadvantages by proposing a manufacturing process of elements for dental or maxillo-facial prostheses of the endo-osseous implants or pivot type, by which a layer of aluminum is deposited on a conductive substrate, notably a metal, for forming the core of a prosthesis or the core of a prosthetic element. The layer of aluminum is obtained by the electrochemical deposit of pure aluminum with a non-aqueous electrolyte base of the type which has an aluminum organic complex bath. This layer of pure aluminum is thereafter oxidized by anodization in a known manner until a layer of sealed and electrically insulating alumina is obtained separating the substrate and the biological tissue surrounding said prosthesis.
The process in accordance with the invention enables the use of all the previously known qualities mentioned of implanted alumina coated prostheses without the drawba
REFERENCES:
patent: 4145764 (1979-03-01), Suzuki et al.
patent: 4556389 (1985-12-01), Ueno et al.
patent: 4746532 (1988-05-01), Suzuki et al.
Blanc Jean
Cagniart Maurice
Gerard Catherine
Isnard Laurent
Prunier Pascal
LandOfFree
Process for the manufacture of prosthetic elements and elements does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for the manufacture of prosthetic elements and elements , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the manufacture of prosthetic elements and elements will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-304405