A telescope-retained prosthesis based on Aurobase and XiVE implants

For patients with edentulous mandibles, treatment with overdentures attached on four osseointegrated implants has become a routine procedure. A variety of junction elements are in use for the support of overdentures by implants. The following case has been done using telescopes mounted on Xive® implants (Friadent®).

An 83-year old female patient complained about the unsatisfactory and unstable position of her mandibular denture. Both mandibular canines and a root of a premolar, all of them with poor prognosis, were still in place. She wore an insufficient partial prosthesis. Clinically and on X-ray investigation she was found to be suitable for treatment with four interforaminal implants without any additional augmentation. Concerning her maxillary total prosthesis, the patient was happy and did not want any changes.

At first, all residual teeth and roots were extracted and the old prosthesis adapted accordingly. Ten weeks after that four Xive® CellPlus®-implants (length 15mm, diameter 3.8mm) were inserted into the interforaminal region of the mandible. The implants were covered with mucoperiost. A healing time of three months was observed.

At re-entry gingiva formers were inserted to replace the cover screws. One week later an impression was made (Impregum®, Espe®) to cast a model. The dental technician (Dental laboratory: Zahnlabor Dieter Ribarich, Baden bei Wien) used AuroBase® abutments to fabricate the primary components for telescopic restorations. The secondary components then were fabricated on the primary AuroBase® abutments using an electroforming-technique. Such galvanised matrixes have a very high fitting precision. A tertiary frame of a cast CoCr alloy was modelled to form the basis of the new overdenture, enclosing the secondary galvanised matrixes, but not touching them. Thus, the cast frame did not cause any tension on the implants when laid onto the telescope construction. Finally, after the prosthesis was finished, the galvanised matrixes were cemented into it’s metal base. This was done intraorally, the secondary telescope crowns being in their place on the primary AuroBase® abutments, the respective basal parts of the prosthesis where filled with AGC® self curing compomer cement (Wieland®). In this way a perfect passive fit of the overdenture without any tension was achieved.

The use of telescope crowns is a well known technique in prosthetics. Combined with electroforming techniques, very good results can be achieved (1). When used for removable dentures on osseointegrated implants, a stable position of the prosthesis can be ensured (2,3). The "passive fit” method helps to avoid tension to the implants. This case shows that it is easily possible to establish the concept of overdentures on telescope abutments on implants in private practise.