EP1606436A1

EP1606436A1 - Device and the parts thereof for producing electrodeposited dental shaped pieces

Info

Publication number: EP1606436A1
Application number: EP04722179A
Authority: EP
Inventors: Alexander SCHRÖCK; Ralf Hornung; Jürgen Laubersheimer
Original assignee: Wieland Dental and Technik GmbH and Co KG
Current assignee: Wieland Dental and Technik GmbH and Co KG
Priority date: 2003-03-24
Filing date: 2004-03-20
Publication date: 2005-12-21
Anticipated expiration: 2024-03-20
Also published as: DE10313818A1; EP1606436B1; ATE480649T1; US20060131162A1; JP2006521465A; DE502004011639D1; WO2004085714A8; CN1791704A; CA2519519A1; WO2004085714A1

Abstract

The invention relates to an apparatus for electrodeposition, in particular for the electrodeposition of shaped dental parts. In addition to the standard components, this apparatus includes at least one magnetic connecting means for producing the electrical contact for the electrodeposition between at least one electrode and the current/voltage source of the apparatus. Furthermore, the invention describes an electrode which serves as a holding/contact element and has a magnet, and a component which interacts with this electrode and has a second magnet for providing the magnet contact-connection. This component is then assigned to the current/voltage source or a head or cover part of an electrodeposition appliance.

Description

description

Device and its parts for the galvanic deposition of dental molded parts

The invention relates to a device and its essential parts for the electroplating, in particular for the electroplating of dental molded parts such as frameworks for crowns, inlays, bridges and the like, according to the preamble of claim 1.

Galvanic deposition, i. H. the deposition under current flow, metallic layers has been known for a long time. If molded parts are formed, i.e. bodies that are stable in themselves, this is known as electroforming.

The use of galvanoforming in dental technology goes back to the early 1960s, when Rogers and Armstrong made inlays and onlays by electroplating. The then gold cyanide gold baths are still different, non-cyanide gold baths, such as. B. the sulfite gold bath of the applicant (EP 0 360 848).

Electroplated gold layers have a much higher hardness than cast ones, which is between 60-80 HV or between 100-130 HV depending on the electrolyte composition. These electroplated gold layers are usually free of voids, inhomogeneities and contaminants, which are inevitable when casting. Nevertheless, it can be caused by improper work and due to the introduction of contaminants or manufacturer-related process fluctuations in the separation process. These show up e.g. B. by electroplating impurities, bud formation, layer formation or holes in the layer. In the worst case, such disturbances can lead to loss of firing stability and thus make the layers / moldings obtained unsuitable for further processing in dental technology. The problem with the production of dental prostheses / dental molded parts by galvanic means lies in the sometimes complicated geometric shapes and the special precipitation properties that are required. For reasons of stability and processing technology, a uniformly homogeneous layer structure and a layer thickness distribution that is as uniform as possible are desirable. The current-controlled galvanic deposits, as z. B. in the AGC ^® devices of the applicant are significantly more reliable and deliver reproducible good properties.

For a number of years, various devices have been commercially available on the dental market, which are used in dental technology laboratories for the galvanic manufacture of dental prosthetic items or frameworks. Scaffolds are understood to mean the basic metallic structures such as crown caps or bridge caps, which the dental technician later veneered with ceramics, for example, and then fired to form the final denture. These scaffolds are made of fine gold for various reasons, in particular the biological compatibility for the patient. The devices mentioned are so-called small electroplating devices which, in contrast to industrial electroplating systems, do not work continuously, but rather discontinuously. The process times are - depending on the type and size of the device - usually a few hours, for example 1 to 16 hours. These devices can usually be placed and operated on a simple work table, usually with a usable volume of electrolyte from about a liter or less, and a capacity of a few dentures, e.g. B. crown caps, which can be produced in one process.

The users of such electroplating devices are generally employed in a dental laboratory, for example dental technicians - that is, not specially trained personnel for electroplating. It is therefore important that such electroplating devices are easy and risk-free to operate, both with regard to the quality of the dental prosthesis manufactured therein and with regard to the health hazard to the operator. Therefore, the manufacturers of such electroplating devices endeavor to offer devices with the greatest possible user friendliness and process reliability. Examples include the AGC ^® range of devices from the applicant, which covers, for example, capacities from 1 to 16 objects that can be galvanized simultaneously and process times from 1 to 16 hours.

Contacting should also be seen in connection with maximum user friendliness and process reliability. In the galvanic ele- ment "Galvanisiergerät" itself (for example, the AGC ^® gold bath of the applicant) is an electrolyte, an anode, and (at least) one provided with a conductive silver duplicate model of a tooth or the oral situation, which is connected as the cathode The duplicate model is connected to the current / voltage source in the device via a holding rod / wire, which mostly also functions as an electrical contact.This holding rod can be a stainless steel rod or a copper / titanium rod, for example, and can be designed to be simple or reusable Since a certain part of this type of contact rod is always immersed in the electrolyte during the process, it should be electrically insulated from the electrolyte so that it does not become gold-plated. This is usually done by means of a so-called shrink tube made of plastic or corresponding coatings. The contact rods / holding rods are then connected to the current / voltage source in the device using a plug contact (e.g. a socket), a metal collet or a crimp contact. It is also important for contact with the device that it has a long service life and, if it is inside the electroplating cell, that it is not susceptible to corrosion. Corrosion products can contaminate the electrolyte and endanger the entire function of the process. The operator establishes the contact, that is, equips the device with duplicate models and makes the electrical contact.

This places special demands on the contacting method, on the one hand to ensure process reliability and on the other hand to keep handling as simple as possible. For process security it is e.g. B. indispensable that the electrical contact remains reproducibly good permanently, ie over the entire process time.

A disadvantage of the types of contacts mentioned is that contact resistances always occur, which can be undefined and, under certain circumstances, prevent sufficient current flow to the duplicate model to be galvanized. In such cases, there may be a failure in the galvanizing process, which manifests itself in the fact that the galvanized gold framework is too thin and / or the layer structure is disturbed, or in the extreme case the galvanizing process is completely prevented. In addition, the above-mentioned contacts are sometimes difficult for the operator to handle and the parts connected to each other are difficult to adjust.

The object of the invention is therefore to avoid or to largely rule out the problems associated with contacting in the prior art. The parts to be galvanized or Models should be easily connectable to the current / voltage source, and this connection should be reliably maintained throughout the process time. Furthermore, the electrical contact should also be able to be broken again in a simple manner in order to be able to introduce new parts / models into the electroplating device.

This object is achieved by the device with the features of claim 1 and its important components, namely the electrode with the features of claim 12, the current / voltage source with the features of claim 19 and the head or cover part with the features of the claim 22. Preferred embodiments of this device or the corresponding parts are shown in the dependent claims 2 to 1 1, 13 to 18 and 20 and 21 and 23 and 24. The wording of all claims is hereby incorporated by reference into the content of this description.

The device according to the invention has at least one current / voltage source and electrodes which can be arranged in a vessel which can be filled with an electrolyte. At least one magnetic connecting means between at least one electrode and the current / voltage source is provided for producing the electrical contact for the galvanic deposition. The essence of the invention is based on the fact that a magnetic contact is provided for establishing the electrical contact between the electrode and the current voltage source. The magnetic adhesive force of two electrical metal magnetic parts causes an electrical circuit to be closed by the corresponding contact of these parts.

From the previous statements it follows that the magnetic connecting means provided according to the invention is preferably formed in two parts. Such a two-part design can a magnet as the first part and a second part made of a magnetizable metal. In a particularly preferred embodiment, the two-part magnetic connecting means consists of two magnets which, by their attraction, make the necessary contact. When using two magnets, a particularly good holding force and minimal contact resistance are achieved.

The magnets mentioned are preferably so-called permanent magnets, as are known from the prior art. These provide the required holding force on the magnetizable metal or on one another without the use of further aids. Furthermore, the magnets used preferably have a circular cross section. Such magnets can be referred to as round magnets.

In a further development, a magnet is assigned to the current / voltage source in the device according to the invention. If the invention is implemented in connection with the electroplating devices mentioned at the outset, such devices often have a so-called head or cover part which is arranged above the vessel which holds the electrolyte when the electrodeposition is carried out. In such designs, the magnet associated with the current / voltage source is preferably arranged on this head or cover part. In this way, contact with the electrodes can then be made particularly easily. In the above-mentioned embodiments, there is a sleeve in particular on the current / voltage source, preferably on the head or cover part, which receives the magnet. Such a particularly preferred embodiment will be explained later in connection with the drawing.

In further preferred embodiments, a magnet is assigned to the electrode or to a part of the electrode. As explained at the beginning, If the electrodes are expediently rod-like components, which can be referred to as contact rods / holding rods. Accordingly, in the last-mentioned embodiments, the magnet is preferably attached to these rod-shaped components. Such electrodes, in particular rods, then preferably have a sleeve-like receptacle into which the magnet is inserted. This will also be explained in more detail in connection with the drawing.

As is apparent from the previous description, the invention also includes a new electrode for the electrodeposition, in particular for the electrodeposition of dental molded parts. According to the invention, this electrode is designed such that it has at least one magnetic connecting means, in particular at least part of a two-part magnetic connecting means. This electrode preferably has the shape of a rod, as it basically corresponds to the shape of the previously known contact rods / holding rods.

According to the invention, the magnetic connecting means or a part thereof is provided at one end of the electrode in the new electrode. This is usually the end that is assigned to the current / voltage source in the electrodeposition after the electrical contact has been made.

The magnetic connecting means can be a magnetizable metal, which then interacts with a magnet that is assigned to the current-Z voltage source. However, the magnetic connecting means on the electrode is preferably a magnet, as has already been described above. Such a magnet is preferably a permanent or permanent magnet. Magnets with a round cross section (round magnets) are preferred. In further preferred embodiments of the electrode according to the invention, the magnet is located in a sleeve-like receptacle at one end of the (preferably rod-shaped) electrode. In order to protect the magnet from corrosion in this receptacle as well, this receptacle can preferably be closed with a cover part. This cover part is preferably flat. The upper side of the cover forms the contact surface which interacts with the other part of the magnetic connecting means associated with the current voltage source.

In principle, the electrode itself can be constructed from any conductive material. However, it is preferred if the electrode and also a cover part, if present, for closing the receptacle receiving the magnet are made of stainless steel. This material offers good protection against corrosion. If appropriate, the entire outer surface of the electrode, or preferably at least the upper side of a cover part forming the contact surface, can be coated with another metal. Such a metal coating can serve to further increase the corrosion resistance or the electrical conductivity. To be emphasized here are coatings made of gold or gold alloys, which can preferably be deposited galvanically on the electrode or only on the cover part.

The electrode according to the invention preferably has a smaller cross section at its “lower” end, which carries the parts / models to be coated during the electrodeposition, than at its “upper” end facing the current / voltage source or the head or cover part. The electrode preferably tapers at its “lower” end or tapers there. In this way, the parts / models to be coated can be attached more easily to the electrode, which also serves as a holding rod. Finally, it should be mentioned that the outer surface of the electrode can be provided with an electrically non-conductive coating, in particular with a plastic coating. This prevents galvanic metal from being deposited there and / or the electrode being attacked and damaged by corrosion. The “lower” end of the electrode is preferably free of such a coating in order to ensure simple contacting of the electrode on the parts / models to be coated.

As a further new component, the invention comprises a current / voltage source and a head or cover part (explained above) for the electrodeposition, in particular for the electrodeposition of dental molded parts. These components are also characterized in that they have at least one magnetic connecting means, in particular at least part of a two-part magnetic connecting means. This can be a magnetizable metal or preferably a magnet. Permanent or permanent magnets are particularly noteworthy here. The magnets preferably have a round cross section (round magnets).

With these two new components, too, the magnet is preferably located in a sleeve-like receptacle. To protect against corrosion, this receptacle is preferably provided with a cover part. Here, reference can be made to the more detailed description of the electrode according to the invention. Here, too, the contact surface is formed by the top of the cover part.

Finally, the essence of the invention can also be used as at least one magnetic connecting means for establishing the electrical contact between at least one electrode and one

Formulate current / voltage source in the galvanic deposition. This galvanic deposition is preferably one for the production of dental molded parts such as frameworks for crowns, inlays, bridges and the like.

The device according to the invention and the components according to the invention of this device have a whole series of advantages over those with the previously known contacts.

In the case of the invention, the required electrical contact is produced by means of a directed magnetic force. This is sufficiently strong that this contact is maintained throughout the galvanic deposition. If the preferred versions with two interacting parts of the magnetic connecting means, in particular the two mentioned magnets, are used, this advantage is particularly evident. The directed magnetic force inevitably pulls the two interacting parts into the correct position with respect to one another, so that the two parts, in particular the two magnets, are located one above the other. In this way it is ensured that there is always a defined contact area and a poor electroplating result due to undefined high contact resistance is virtually impossible.

Another advantage of the invention is that the electrical contact can be made quickly and easily by the operator. The electrode and the contact rod are easily exchangeable, which significantly increases the work efficiency for the operator. In addition, no maintenance of the components is necessary since, for example, contamination of the contact surfaces is largely excluded. Should a cleaning be necessary, then so. can be done simply by wiping. A further advantage of the embodiments according to the invention is evident when the process temperatures of conventional galvanic deposits, in particular in the dental field, are taken into account. Such process temperatures are usually in the range between 50 ° C and 70 ° C, usually around 65 ° C. As a result, condensation products from the electrolyte usually collect in the upper part of the vessel or the galvanizing cell. Due to their chemical composition, such condensation products can lead to corrosion on the parts that make the electrical contact. The products formed during the corrosion can then get into the electrolyte and contaminate it. Such impurities can then also be separated off, for example together with the gold, and in this way the quality of the electrodeposited molded parts, in particular the denture frameworks, deteriorate greatly. This can be almost certainly excluded by the contacting effected according to the invention. This applies in particular to the embodiments in which the magnets are located in a sleeve-like component which is securely closed with a cover part.

The advantages according to the invention emerge particularly clearly in the last-mentioned embodiments with a type of jacket construction for the magnets used to produce the electrical contact. With such designs, the magnet is completely protected by this jacket construction. Accordingly, a corrosion-resistant stainless steel is preferably used as the material for such constructions. Corrosion of the electrical contact is therefore excluded. If a layer of gold is additionally applied to the stainless steel electrode, at least on the contact surfaces such as the cover part, this corrosion resistance is further increased on the one hand, and excellent electrical conductivity is achieved on the other. With these versions, in combination with the other design features, an excellent the permanent and reproducible good electrical transition is created at the contact points between the electrode holding rod and the current / voltage source or head or cover part.

Finally, the electrode according to the invention or the holding Z contact rod according to the invention is permanently reusable. This applies in particular if it is additionally coated on its surface with a protective layer, preferably a non-conductive protective layer such as. B. a plastic is coated.

These and other features of the invention result from the examples and drawings described below in conjunction with the claims. The individual features can be implemented individually or in combination with one another.

The drawings show:

1 shows a schematic cross-sectional representation of an electrode according to the invention or of a holding Z contact rod according to the invention with inserted magnet, and

Fig. 2 is a schematic sectional view of a component according to the invention with inserted magnet, which can be assigned to a current-Z voltage source or a head or cover part of a device according to the invention.

Examples

A galvanizing device from the applicant of the type AGC ^® Speed is modified according to the invention. The single-cell version of this

Device, which is not shown in the figures, assumed. The

Device consists essentially of a housing that the current Z Voltage source and the controller takes. In addition, the device has an electrolyte container with a head or lid part, to which the anode and the cathode, which is provided with the part / model to be electroplated, are attached. With the AGC ^® Speed device from the applicant, the complete electrolyte container with head or lid part can be removed from the device. This simplifies the introduction of the parts / models to be coated into the electrolyte container and protects the other components of the device from contamination, for example by the electrolyte.

In the previous version of the applicant's AGC ^® speed device, plug-in contacts were used for fastening / contacting the anode, which is usually designed as a ring anode, and in particular the holding Z-contact rod connected as a cathode. The rod-shaped upper ends of these electrodes were inserted into corresponding receptacles in the head or cover part and locked, for example. However, this contacting, which in itself worked reliably, often did not allow for quick interchangeability. In addition, the contact surfaces had to be protected against corrosion by vapors rising from the electrolyte in a comparatively complex manner.

For the modification according to the invention of the device described by the applicant, the two components shown in FIGS. 1 and 2 are used.

Figure 1 shows an electrode 1 according to the invention in the manner of a holding or contact rod. This electrode 1 is made of stainless steel and has at its one end 2 a smaller cross-sectional area than at its other end 3. The end 2 is designed in the manner of a tip, which is used to fasten the electrode to a part or model not shown in FIG serves which is to be galvanically coated. This is explained in more detail below. At the other end 3, a sleeve-like receiving recess 4 is provided, into which a magnet 5 is inserted. This magnet 5 is a permanent magnet with a round cross-sectional area, ie a so-called round magnet. In order to protect this magnet 5 against corrosion, a cover part 6 is provided on the electrode 1, which is also made of stainless steel and seals the receptacle 4 tightly. Due to the construction of the end 3 of the electrode 1, the magnet 5 is thus fully encased.

According to the invention, the surface 7 on the outside of the cover part 6 forms the contact surface via which the magnet 5, as part of the two-part magnetic connecting means, can interact with a second part. To optimize the electrical contact made via the magnetic force, the surface 7 or, if appropriate, the entire outer surface of the electrode 1 can be gold-plated. This is not shown in more detail in FIG. 1. Likewise, the outer surfaces of the electrode 1, with the exception of the surface 7 serving as a contact surface, can be provided with a plastic coating. This then prevents an undesired galvanic deposition from taking place on the electrode itself. If the plastic coating is not present, the operator prevents this separation by other measures, for example by covering the electrode 1 with a shrink tube.

Figure 2 shows a sleeve-like component 1 1 with a round cross section, which is also made of stainless steel. This component 1 1 illustrates the counterpart serving as the holding ZKontaktstab electrode 1 of Figure 1. The component 11 may be introduced, for example in the above-explained head or cover part of the AGC ^® speed device of the applicant or in another construction of a Electroplating device can be assigned in another way to the current-Z voltage source. The component 11 has at one end 12 a receptacle / recess 13 into which a magnet 14 is inserted. Here, too, the magnet 14 is a permanent magnet with a round cross section, ie a round magnet. The receptacle 13 with the round magnet 14 is sealed with a cover part 15, which is also made of stainless steel. This also prevents the magnet 14 from being corroded by rising vapors from the electrolyte.

The outer surface 16 present on the cover part 15 represents in the component 11 the contact surface for the interaction of the magnet 14 with the other part of the two-part magnetic connecting means. Here, too, the surface 16 and possibly the entire outer surface of the component 11 can be gold-plated. Corresponding plastic coatings (with the exception of surface 16) are also possible.

If you now move the surface 7 of the electrode 1 in the direction of the surface 16 of the component 11 (with the correct orientation of the magnets 5 and 14 introduced), these become two

Surfaces are attracted by the magnetic force and positioned correctly in relation to each other. At the same time, the electrical contact required for galvanic deposition is established. The electrical current can then, for example, via the component 11 with the surface 16 in the

Surface 7 of the electrode 1 and thus also to one at its end

2 fixed model of a dental prosthetic item flow. In the same way, an electrical contact can of course also be used as a

Anode switched electrode can be produced. Such an anode will usually just be a metal rod. With an AGC ^® Speed device from the applicant, which was modified with the components according to Figures 1 and 2, dental prostheses are produced by electroforming. The component 11 (see FIG. 2) is introduced into the head or cover part of the device, and the electrode 1 (see FIG. 1) is used as a holding / contact rod for the tooth replacement part or the model.

In the two experiments presented below, a plaster stump is used, which is made conductive with silver in the usual way. On the other hand, a metallic primary crown is assumed, which is also coated with conductive silver to take account of the cement that will later connect the primary crown to the secondary crown (double crown technique). A sulfitic gold bath from the applicant is used as the electrolyte. However, the composition of the bath is not critical for the advantages according to the invention to occur.

The preparation and implementation of the galvanic deposition is summarized in the following table. In both examples, flawless molded parts made of fine gold with layer thicknesses of 300 μm are obtained. This shows that the “magnetic contact” according to the invention leads to the high-quality molded parts required in dental technology. If one takes into account the advantages compared to the previous contacts, as already mentioned in the introduction, the modification of the device according to the invention represents real progress.

Claims

claims

1 . Device for the electrodeposition, in particular for the electrodeposition of dental moldings such as frameworks for crowns, inlays, bridges and the like, with at least one current-Z voltage source and electrodes which can be arranged in a vessel which can be filled with an electrolyte, characterized in that for Production of the electrical contact for the galvanic deposition between at least one electrode and the current-Z voltage source, at least one magnetic connecting means is provided.

2. Device according to claim 1, characterized in that the magnetic connecting means consists of two parts which by

Magnetic force work together.

3. Device according to claim 2, characterized in that the magnetic connecting means consists of two magnets.

4. The device according to claim 2, characterized in that the magnetic connecting means consists of a magnet and a magnetizable metal part.

5. Apparatus according to claim 3 or claim 4, characterized in that the magnet has a round cross-sectional area.

6. Device according to one of claims 2 to 5, characterized in that one of the parts of the magnetic connecting means, in particular a magnet, is associated with the current-Z voltage source.

7. The device according to claim 6, characterized in that the part, in particular the magnet, is assigned to a head or cover part which is located in the electrodeposition above the vessel which can be filled with the electrolyte and on which the electrodes are preferably also arranged are.

8. Apparatus according to claim 6 or 7, characterized in that the magnet is arranged in a sleeve-like component.

9. Device according to one of claims 2 to 8, characterized in that part of the magnetic connecting means is assigned to an electrode or part of an electrode.

10. The device according to claim 9, characterized in that the electrode or the electrode part is rod-shaped.

1 1. Device according to claim 9 or claim 10, characterized in that the magnet is arranged in a sleeve-like receptacle in the electrode or in the electrode part.

12. Electrode for the electrodeposition, in particular for the electrodeposition of dental moldings such as frameworks for crowns, inlays, bridges and the like, characterized in that it has at least one magnetic connecting means, in particular part of a two-part magnetic connecting means.

13. Electrode according to claim 12, characterized in that it is rod-shaped.

14. An electrode according to claim 12 or claim 13, characterized in that the magnetic connecting means at one end the electrode is arranged, this end preferably being the end associated with the electrodeposition of a current-Z voltage source.

15. Electrode according to one of claims 12 to 14, characterized in that the magnetic connecting means is a magnet.

16. Electrode according to claim 15, characterized in that the magnet is arranged in a sleeve-like receptacle in the electrode, this receptacle preferably being closable with a cover part.

17. Electrode according to one of claims 12 to 16, characterized in that the end of the electrode without a magnetic connecting means has a smaller cross-sectional area than the end of the electrode with a magnetic connecting means, the end without a magnetic connecting means preferably tapering or tapering tapers.

18. Electrode according to one of claims 12 to 17, characterized in that it is provided with an electrically non-conductive coating, in particular a plastic coating, the end of the electrode preferably being free of such a coating without a magnetic connecting means.

19. Current / voltage source for the galvanic deposition, in particular for the galvanic deposition of dental molded parts such as frameworks for crowns, inlays, bridges and the like, characterized in that they have at least one magnetic connecting means, in particular at least part of a two-part magnetic connecting means, having.

20. Current-Z voltage source according to claim 19, characterized in that the magnetic connecting means is a magnet.

21. Current-Z voltage source according to claim 20, characterized in that the magnet is arranged in a sleeve-like receptacle, this receptacle preferably being closable with a cover part.

22. head or cover part for the electrodeposition, in particular for the electrodeposition of dental molded parts such as frameworks for crowns, inlays, bridges and the like, this head or cover part being arranged in the electrodeposition over a vessel that can be filled with an electrolyte, characterized in that there is at least one magnetic

Connecting means, in particular at least part of a two-part magnetic connecting means.

23. head or cover part according to claim 22, characterized in that it is a in the magnetic connecting means

Magnets.

24. Head or cover part according to claim 23, characterized in that the magnet is arranged in a sleeve-like receptacle, this receptacle preferably being closable with a cover part.

25. Use of at least one magnetic connecting means for establishing the electrical contact between at least one electrode and at least one current-Z voltage source in the electrodeposition, in particular in the galvanic deposition of dental molded parts such as frameworks for crowns, inlays, bridges and the like.