DE29911168U1 - Superstructure for anchoring a ceramic structure on a dental implant - Google Patents

Description

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Description

"Suprastructure for anchoring a ceramic structure on a metallic dental implant"

One or more missing teeth can be replaced dentally in two fundamentally different ways. In the conventional method, both removable and fixed dentures are anchored to the teeth bordering the gap, although this procedure always leads to damage to the tooth structure or the entire tooth.

Implantological prosthetic treatment is generally accepted as a possible alternative and is becoming increasingly important. In this case, metallic, artificial tooth roots (implants) are inserted (implanted) into the jawbone and provided with connecting structures (suprastructures) that serve as the basis for attaching the dentures. Alloys or ceramics can be used as the material for these suprastructures. By using tooth-colored ceramics for suprastructures and dentures, the highest requirements for biocompatibility and aesthetics can be met in comparison. Ceramic abutments currently on the market are the only alternative to this invention. However, ceramic components must be processed individually by the dental technician or dentist, which requires more work and can cause mechanical weakening of the component. Furthermore, the dentures must be attached by gluing or cementing, so that an irreversible connection is created, which, if complications arise (e.g. screws loosening, chipping of the ceramic), makes it necessary to destroy the entire denture in order to correct the errors.

The invention is based on the object of creating a material-appropriate construction for dental implantological abutments made of ceramic elements. With the construction presented here, it is possible to dismantle and reassemble this implant structure if necessary (without causing any damage).

Dr.-Ing. H. Fischer Thu. May 6, 1999 3/5

The design has four interfaces that differ from one another in terms of functionality. The direct connection to the implant is made via a metal spacer. A metal component can be easily adapted to the joint specified by the respective implant, which can be designed as an external hexagon (e.g. type Bränemark, Nobelbiocare, Gothenburg), internal polygon (e.g. type Semados, Bego, Bremen or type Frialit II, Friadent, Mannheim) and as a conical plug-in screw connection (e.g. type ITI Bonefit, Straumann, Switzerland or type Ankylos, Degussa, Frankfurt). The use of a metal component makes sense here both for manufacturing reasons during production and for fracture mechanics reasons during later use.

However, since the actual structure, which is translucent from the side in incident light, should consist of a tooth-colored ceramic (e.g. aluminum oxide or, due to mechanical advantages, preferably zirconium oxide) for the reasons mentioned above, the other interfaces take into account the problematic properties of ceramics to a large extent, such as susceptibility to brittle fracture and sensitivity to tensile and notch stress.

Since the superstructure must also be resistant to twisting in order to ensure that the occlusal surfaces involved mesh consistently and optimally, the interface between the metal and lower ceramic intermediate element is designed as a flat, V-shaped groove. In conjunction with the screw connection, the resistance to twisting is guaranteed. The groove should be designed to be as flat as possible (max. 10° inclination of the side surfaces compared to the horizontal) in order to minimize tensile stresses in the ceramic. A metal disk should be placed under the screw head so that there are no hard contact points with resulting tensile stress peaks that are unfavorable for the ceramic.

The lower ceramic intermediate element is clamped to the upper one via a conical seat. The conical angle should be in the range of 2° in order to achieve the best possible ratio of the contact force to the withdrawal force. The permanent connection via a conical seat has already proven itself in the medical field for femoral hip prostheses. Here, the artificial hip joint ball and prosthesis shaft are also reattached via a conical seat without micromotion and (non-destructively).

Dr.-Ing. H. Fischer Thu. May 6, 1999 4/5

detachably connected to each other.

Finally, the upper ceramic intermediate element is cylindrical on the outside. This allows a crown structure to be permanently bonded to the superstructure with good adhesion (see below for details).

The ceramic structure is divided into two parts. If this were not the case, a crown in the patient's mouth could only be cemented or adhesively attached using a composite in accordance with the clinically established procedure. This is also done with the ceramic abutments mentioned above for attaching a crown. It is of course no longer possible to dismantle the entire structure without causing damage once the crown has been attached.

However, this is guaranteed with the present invention. The crown can be temporarily removed without any problem so that, for example, the screw that connects the lower intermediate elements to the implant can be tightened. (This screw has already been reported to loosen in clinical use in connection with ceramic abutments in specialist publications.) The present two-part construction means that, for example, the metal intermediate element or the lower ceramic intermediate element can be replaced if necessary without having to destroy the entire structure. In addition, a crown can be renewed by simply removing the upper ceramic intermediate element from the clamping cone seat.

In particular, the split structure makes it possible to press a fully ceramic crown directly onto the upper ceramic intermediate piece in the dental laboratory, as is done with the hot-pressing process using the well-established dental ceramic materials IPS-Empress and Optec-OPC. This means that the use of a cement or composite is completely unnecessary. This is particularly important because the cement/composite intermediate layer is clinically problematic. Cements are washed out by saliva over long periods of time and composites age like all polymer materials. In both cases, this can lead to a deterioration in the bond between the crown and the superstructure or, in extreme cases, to the crown coming off completely.

Dr.-Ing. H. Fischer Thu. May 6, 1999 5/5

List of reference symbols: "^:>

1: artificial dental crown

2: upper ceramic intermediate element 3: screw

4: Washer

5: lower ceramic intermediate element 6: metallic intermediate element 7: implant

Views: ...._.._._. _—

left column: view from above middle column: exploded view,

View from the front in half section right column: View from below

Claims (9)

1. Suprastructure for anchoring a ceramic structure on a dental implant, characterized in that the construction consists of two ceramic intermediate elements and a metallic intermediate element located underneath. 2. Suprastructure according to claim 1, characterized in that the lower ceramic intermediate element is provided with an internal bore and can be connected to the metallic substructure in the implant by a screw. 3. Superstructure according to claim 1, characterized in that the connection between the lower ceramic intermediate element and the metallic intermediate element is designed to be torsion-proof. 4. Superstructure according to claim 3, characterized in that the anti-twisting device is designed by the combination of a screw connection and a flat groove. 5. Superstructure according to claim 1, characterized in that the lower ceramic intermediate element has an outer cone. 6. Superstructure according to protection claim 1, characterized in that the upper ceramic intermediate element has an inner cone adapted to the outer cone of the lower ceramic intermediate element. 7. Superstructure according to claim 1, characterized in that the two ceramic intermediate elements are joined via a conical seat. 8. Superstructure according to claim 1, characterized in that the upper ceramic intermediate element is cylindrical on the outside. 9. Suprastructure according to claim 1, characterized in that a dental crown can be built onto the upper ceramic connecting element.