Impression

PreparationThe fixation surfaces of Cercon restorations shall be sand-blasted before fitting (aluminium oxide, 110 µm, 3-4 bar). The stabbing of the surface causes better fixation for conventional and adhesive bonding.
Conventional and adhesiveThe zingoxyphospate and glassionomer cements are suitable for conventional fixation. The special conditioning of the stumps surface is not required with conventional cementing. On the basis of the provided studies the conventional dual cements are not suitable for adhesive bonding. The laboratory experiments with those products did not prove the steady bonding.
HintUnder the current experience only products Panavia 21 and Panavia F have proved their qualities in adhesive bonding of Cercon restorations.

Temporary fixation of Cercon restorations can be achieved with any temporary cement (e.g.: Temp Bond, Kerr GmbH, Karlsruhe). In case there is planned later adhesive bonding, it is recommended to use eugenolo-free temporary cements.

Adjustment
To adjust occlusive contact points there are recommended fine-grain diamond tools (e.g.: 8390.314.023 and 8860.314.012, Gebr. Brasseler, Lemgo), for polishing of worked ceramic surfaces there are suitable the following tools:

Dialite II-Set, Gebr.Brasseler, Lemgo Ng Keramik polisher, Identoflex AG, Schweiz




Odontotomy and selection
Odontotomy in two levelsThe odontotomy of Cercon restorations is carried out, with the correct selection of tools, without clinical problems and acceptable time frame. At preparation of the access cavity it is recommended to apply two-level procedure. Firstly the covering ceramics is removed by the diamond tool without framework perforation.

Secondly the framework shall be perforated in the required size by the diamond tool. The distance of 0.5 mm from the covering ceramics shall be kept. This prevents breaking of covering ceramics during the ceramic framework cutting.

HintThe framework steadiness of Cercon crowns remains unchanged also after the preparation of the access cavity thus leaving the restoration in place. There shall be applied a composite filling by adhesive to cover the odontotomy opening. Cercon restorations show comparable rtg-opacity as metal-ceramic restorations.
HintThe most suitable tools for odontotomy and removal of the crown include cylindrical rounded diamond tools with diamond granularity from 125 to 150 cm (e.g.: 6836.314.014 or 5836.314.016 Gebr. Brasseler, Lemgo) with bend with gear 4:1 and maximum cooling.
Restoration removalTo remove Cercon restorations they shall be slit-cut along the axial wall up to the half of the occlusive surface or incisional edge. The restoration is then stretched by means of the appropriate tool and it breaks. With restorations bonded by adhesive the remnants of cement from the stump can be removed by the ultrasonic tool.