(Not Applicable)
(Not Applicable)
From WO 2004/041113 A1, a method for the production of fully ceramic tooth elements, by means of electrophoresis, is known, in which an electrically conductive chip placed, directly or at a distance on a working model or a structural element, for example, an implant-abutment, wherein the chip has different conductivities. Any desired spatial shape can be directly attained with the method with a corresponding selection of the chip and without a great deal of reworking. With this known method, power is supplied to the chip or chips by means of a cable.
After coating with slip, it is necessary to separate the cable from the chip. It should be obvious to the specialist that this cannot be done without a certain amount of effort, since a damaging of the applied slip layer is unavoidable. In order to produce satisfactory green bodies, a certain amount of reworking therefore is necessary.
Therefore, the goal of the invention indicated in claim 1 is to refine the electrophoresis method known from WO 2004/041113 A1 in such a way that a reworking is no longer required. This goal is attained with the method features of claim 1. Advantageous embodiments are described in the dependent claims.
The invention also concerns the constructive development of the chips that are particularly suitable for the claimed method.
For the terminology below, one should also note that the term “slip,” as used in dental practice, is understood to mean a paste of ceramic powder in a primarily aqueous suspension liquid. Furthermore, the term “working model” refers to the meaning common for a dental technician. Therefore, it is not a model duplicated by the working model. This statement is of importance in that other electrophoresis methods not developed by the inventor work only with duplicated models, since the specialist knows that aside from the additional work, any duplicating produces additional errors, which have to be removed in tedious reworking. It is obvious, however, that the claimed method can also be carried out on a duplicated model.
The invention is explained in more detail with the aid of
From the teeth of a patient, a working model is first prepared in the usual manner. From this working model, the section is sawed out, in which the restoration of the teeth is to take place.
Since, as a rule, a working model is made of gypsum or another nonconductive material, the surface of the tooth stumps must be rendered conductive. This is done by the application of a conducting lacquer, the conductivity of which is also attained by zinc powder. Silver conducting lacquers that are common in dental practice are less suitable, since they do not volatilize residue free during sintering. So that the green body can be removed without problems from the model after electrophoresis, coating of the model with a release agent is indicated, as is taught in DE 198 12 664 A1. In
The chip itself is preferably made of zinc. Here, the desired shape is cut out of zinc foil with a laser. Since zinc can easily be shaped in a lasting manner, a prefabricated chip is adapted to the local need by bending or by cutting the material. Thus, during electrophoresis, the desired spatial shape is already formed, and requires only a small amount of reworking, if any.
After drying and removing the model, the green body is sintered according to known methods. Here, another advantage of the zinc as material for the chip 1 and the adhesive wax 5 is shown, since it volatilizes residue free at the high sintering temperature.
In
From the preceding statements, it is clear that any structure is possible with the invention because of its versatility.
As all figures show, areas of different conductivities are produced in the chips by means of recesses 4. The chips also have a leg 7, which is used for better handling, but can also be used as a conductor for the electric current.
Number | Date | Country | Kind |
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10 2005 006 624.0 | Feb 2005 | DE | national |
This application is a submission to enter the national stage under 35 U.S.C. 371 for international application number PCT/DE2006/000002 having international filing date 3 Jan. 2006 for which priority was based upon patent application 10 2005 006 624.0 having a filing date of 12 Feb. 2005 filed in Germany.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/DE2006/000002 | 1/3/2006 | WO | 00 | 3/15/2007 |