CH659383A5

CH659383A5 - Device for holding dental prosthetic telescope crowns together

Info

Publication number: CH659383A5
Application number: CH1619/82A
Authority: CH
Inventors: Herbert Dr Med Dent Spang
Original assignee: Herbert Dr Med Dent Spang
Priority date: 1982-03-16
Filing date: 1982-03-16
Publication date: 1987-01-30

Abstract

Device for holding dental prosthetic telescope crowns together, characterised in that a thin metal plate having one or more resilient lamellae is inserted into the wall of the secondary crown in the same direction of introduction as the secondary crown. This device occupies only a minimum of space because it does not much exceed the thickness of the resilient lamellae. Therefore, it can be built in without disturbing the anatomical shape of the crowns and without being conspicuous, and in addition it can easily be activated and exchanged. <IMAGE>

Description

       

  
 



   Beschreibung



   An Hand von Zeichnungen bevorzugter Ausführungsbeispiele soll im Folgenden die erfindungsgemässe Vorrichtung näher beschrieben werden:
Fig. 1 zeigt den Längsschnitt durch einen Zahnstumpf mit einem Doppelkronenelement, wobei a die Unterkrone, b  die Überkrone und c die Kammer zur Aufnahme des Federelements darstellen. d zeigt ein gefaltetes, ausgebuckeltes Federelement, das in eine Ausnehmung e in der Unterkrone eingreift.



   Fig. 2 zeigt den Schnitt durch eine Federkammer im Stadium der Modellation der Überkrone. a stellt einen aussäuerbaren Platzhalter aus Unedelmetall dar mit einer Ausnehmung b, in der ihn (in der hohlen Gussform) die Formmasse nach dem Ausschmelzen des Modellwachses festhält.



  c ist ein Teil der Wachsform der Überkrone und d ein verbrennbarer Kunststoffkörper, die als Platzhalter für den Boden der Federkammer dient.



   Fig. 3 stellt eine Ansicht einer Federkammer mit einer eingelegten Blattfeder mit U-förmiger Zunge dar. Die Fig. 4, 5, 6 zeigen verschiedene Schnitte dieser Kammer: Figur 4 zeigt einen Schnitt A - A, Fig. 5 einen Schnitt B - B und Fig. 6 einen Schnitt   C - C,    wobei a die Blattfeder, b die Uförmige Zunge,   c eine    Kerbe, in die ein Instrument zum Entfernen (beim Einlegen und Auswechseln) der Blattfeder eingreifen kann, darstellt. Die Fig. 7 a, b, c, und d zeigen andere Lamellen-Formen der Blattfeder.



   Fig. 8 zeigt den Wirkungsmechanismus der Federelemente zwischen Unter- und Überkrone während des Übereinandergleitens (Fig. 8) und in der Endlage (Fig. 9). Hier stellen dar: a den Kronenstumpf, b die Unterkrone, c die Uberkrone, d eine in die Kammer eingeschobene Blattfeder und e eine Ausnehmung in der Unterkrone, in die die federnden Lamellen in der Endlage eingreifen.



   Fig. 10 und 11 zeigen in Phantomzeichnungen eine vorgebogene Drahtfeder in einer runden Kammer.



   Fig. 12 zeigt in der Ansicht eine Federkammer, in die eine runde Blattfeder mit Kreisausschnitten eingelegt und zur Fixierung um   90O    gedreht wird.



   Fig. 13 eine ähnliche Form mit zusätzlichen Kreisausschnitten.



   Fig. 14 zeigt einen Schnitt durch eine Federkammer mit gefalteter Blattfeder.



   Fig. 15 eine solche mit in der Fläche gespaltener Feder.



   Fig. 16 zeigt die Ansicht einer Federkammer mit einer schmalen Blattfeder, die lediglich durch Zusammenbiegen in die Kammer eingelegt werden kann: Fig. 17 den Schnitt einer solchen Kammer.



   Anwendung
Am Beispiel einer der möglichen Anwendungen wird nun die grundsätzliche Anwendung der Federelemente demonstriert:
Bereits bei der Modellation wird eine Wand der Unterkrone für die Aufnahme des Federelements vorbereitet. in dem eine der Federkammer entsprechende ebene Fläche gestaltet wird, die so dick ist, dass eine Kerbe oder Nocke angebracht werden kann. Nach der Herstellung der Unterkrone wird in der Regel die Überkrone zunächst in Wachs oder Kunststoff modelliert. Zuvor wird an der vorgesehenen Wand der Unterkrone das Platzhalterelement aus Unedelmetall für die Federkammer so plaziert, dass die Ausbuchtung der federnden Lamellen in die Kerbe oder hinter die Nocke eingreifen kann.

 

   Die weitere Ausbildung der Überkrone erfolgt wie gewohnt, in dem durch Ausschmelzen einer Wachsform eine Hohlform aus einer feuerfesten Masse hergestellt wird, in die hinein das flüssige Gussmetall gegossen wird. Nach dem Guss wird das Platzhalterelement mittels einer geeigneten Säure ausgesäuert. Zurück bleibt ein Hohlraum, der genau dem Platzhalter und damit auch dem Federelement entspricht. In diesen Hohlraum wird das entsprechende Federelement eingeschoben oder eingedreht. Es wird durch die eigene Elastizität, durch unter sich gehende Wände oder die Ränder bedeckende Wände festgehalten. In dieser Lage kann es jederzeit durch Aufbiegen der Lamellen oder Drähte aktiviert oder nach Ermüdung ausgetauscht werden. 



  
 



   description



   The device according to the invention is to be described in more detail below with reference to drawings of preferred exemplary embodiments:
Fig. 1 shows the longitudinal section through a tooth stump with a double crown element, with a representing the lower crown, b the upper crown and c the chamber for receiving the spring element. d shows a folded, hunched-out spring element which engages in a recess e in the lower crown.



   Fig. 2 shows the section through a spring chamber at the stage of modeling the crown. a represents an acidic placeholder made of base metal with a recess b in which the molding compound (in the hollow mold) holds it after the model wax has melted out.



  c is part of the wax form of the crown and d is a combustible plastic body that serves as a placeholder for the bottom of the spring chamber.



   3 shows a view of a spring chamber with an inserted leaf spring with a U-shaped tongue. FIGS. 4, 5, 6 show different sections of this chamber: FIG. 4 shows a section A - A, FIG. 5 shows a section B - B and FIG. 6 shows a section C - C, in which a represents the leaf spring, b the U-shaped tongue, c a notch in which an instrument for removing (when inserting and replacing) the leaf spring can engage. 7 a, b, c, and d show other lamella shapes of the leaf spring.



   Fig. 8 shows the mechanism of action of the spring elements between the lower and upper crown during sliding over each other (Fig. 8) and in the end position (Fig. 9). Here are represented: a the crown stump, b the lower crown, c the upper crown, d a leaf spring inserted into the chamber and e a recess in the lower crown into which the resilient lamellae engage in the end position.



   10 and 11 show in phantom drawings a pre-bent wire spring in a round chamber.



   Fig. 12 shows in the view a spring chamber into which a round leaf spring with circular cutouts is inserted and rotated through 90 ° for fixation.



   Fig. 13 shows a similar shape with additional circular sections.



   14 shows a section through a spring chamber with a folded leaf spring.



   Fig. 15 such with a split spring in the surface.



   16 shows the view of a spring chamber with a narrow leaf spring, which can only be inserted into the chamber by bending it together: FIG. 17 shows the section of such a chamber.



   application
The basic application of the spring elements is now demonstrated using the example of one of the possible applications:
A wall of the lower crown is already prepared for the accommodation of the spring element during the modeling. in which a flat surface corresponding to the spring chamber is designed which is so thick that a notch or cam can be made. After the manufacture of the lower crown, the upper crown is usually modeled in wax or plastic. The base element made of base metal for the spring chamber is placed on the provided wall of the lower crown in such a way that the bulge of the resilient slats can engage in the notch or behind the cam.

 

   The further formation of the top crown takes place as usual, by melting a wax mold into a hollow form from a refractory mass into which the liquid cast metal is poured. After casting, the placeholder element is acidified using a suitable acid. What remains is a cavity that corresponds exactly to the placeholder and thus also to the spring element. The corresponding spring element is inserted or screwed into this cavity. It is held on by its own elasticity, by walls that go under it or walls that cover the edges. In this position, it can be activated at any time by bending the slats or wires or replaced after fatigue.

Claims

PATENT CLAIMS 1. Device for holding together dental prosthetic double crowns, characterized in that almost flat spring elements, which are inserted, inserted or screwed into a recess in the lower crown in a synchronized manner with the direction of insertion of the upper crown into a corresponding, partially open chamber in the upper crown.

2. Device according to claim 1, characterized in that a thin-walled chamber corresponding to the spring elements made of high-melting metal is poured into the wall of the upper crown.

3. Device according to claim 1, characterized in that the shape for the chamber for receiving the spring elements consists of a removable or acidifiable material such as base metal, graphite, boron nitride or ceramic material.

4. Device according to claims 1-3, characterized in that the chamber has wholly or partially or under-going side walls.

5. Device according to claims 1-3, characterized in that the spring elements consist of flat metal elements which are U-shaped, H-shaped or cross-shaped and are bent open so that one or more resilient slats are formed.

6. The device according to claim 5, characterized in that the resilient slats are humped.

7. Device according to claims 1-3, characterized in that the spring element consists of a flat metal element which is partially split parallel to its surface so that resilient slats are formed.

8. The device according to claims 1-3, characterized in that the spring elements consist of folded, thin metal plates.

9. The device according to claim 1-4, characterized in that the spring elements consist of preloaded flat springs.

10. The device according to claim 1-4, characterized in that the spring elements consist of prestressed wire elements.

State of the art In dental prosthetics, double crowns are used a lot for anchoring removable dentures. They are characterized by the fact that a metal top crown, which sits on a natural or artificial tooth stump, is pushed over an exactly top crown that adheres to one another due to static friction, wedging and / or restraint. Similar double constructions are also created using bars or root pin caps with superstructures.

Experience has shown that the static friction between the substructure and superstructure is lost over time due to the wear of the surfaces rubbing against each other or is reduced so that the initial cohesion is no longer present. This inevitable loss of static friction is countered by installing restrained resilient or lockable elements in the walls of the crowns from the outset, which hold the double crowns together in the end position and thus prevent harmful play. The elements of this type that have become known consist almost exclusively of resilient bolts which are inserted in a chamber lying perpendicular to the direction of insertion (and thus to the crown wall); in one case also from a rolled leaf spring; in another through resilient metal wires inserted (in holes made transversely to the direction of insertion).

task All these devices have in common that, despite their small size, they are relatively bulky and distort the anatomical shape of the crowns, since they are installed vertically or transversely to the crown axis from the inside or outside. For this reason, they are also difficult to use, since the bolts or other types of lock are difficult to access. If they are operated from the outside, they are usually covered by the replacement teeth and can only be operated after they have been removed. Operation from the inside of the crown is difficult because the necessary instruments cannot be placed vertically. The present invention seeks to remedy these circumstances - poor operation, excessive volume and falsification of the anatomical shape of the double crowns.

solution She sees the solution in that a resilient element is inserted instead of from the inside or outside and perpendicularly or transversely to the crown wall in the same direction as the insertion direction and the crown wall. This remains easily accessible from the crown edge for assembly, activation or eventual replacement. Instead of a resilient bolt or the like, which by its nature takes up a relatively large amount of space in the direction of action, in a preferred embodiment an almost flat resilient metal plate is inserted into a prepared flat chamber. This plate can be divided into resilient individual lamellae by slits and takes up little more space than its own thickness, which is less than one millimeter. Such a spring element is to be installed without significantly influencing the anatomical shape of the crowns.

To accommodate and fasten such a spring element, a precise chamber is required in the wall of the upper crown, the inner dimensions of which correspond to the outer of the spring elements. In contrast to other retention constructions, this is preferably produced by inserting a shaped piece into the wax form of the superstructure. This fitting can be made of base metal, ceramic material, drilling nitrite, graphite or a similar material that has a higher melting point than the cast metal. After the casting, the molding is removed by acidification or sandblasting.

What remains is a cavity corresponding to the fitting, into which a spring element can be inserted, inserted or screwed in. In addition, the chamber can also be produced by inserting a prefabricated hollow body made of high-melting metal, which is poured or soldered into the superstructure.

advantages The advantages of such constructions are obvious: the spring elements only require a minimum of space in the crown wall, are simple and inexpensive to manufacture, are not prone to repairs, are accessible at all times and can therefore be activated, deactivated and exchanged, and can therefore produce any desired restraint.