Ivoclar Vivadent Zenostar - Manual (Page 36)

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Zenostar T/MO – Layering Technique
The following paragraphs will explain the most important steps in the veneering of Zenostar MO. For more detailed information on
the veneering ceramic and its processing, please refer to the respective Instructions for Use. The system indicated below is
recommended for veneering. Its components are optimally matched to Zenostar as far as the shade and physical properties are
concerned:
IPS e.max Ceram – Ivoclar Vivadent
For the assignment of the suitable framework shade (MO0 - MO5), please refer to the Table on page 52.
Finishing
Adjustment by grinding of the sintered Zenostar T restorations should be kept to a minimum.
Overheating must be avoided. If possible, the procedure should always be performed under water cooling, using low speed and
limited pressure.
Do not ’post-separate‘ the framework connectors. This may result in undesired predetermined breaking points, which will
subsequently compromise the stability of the all-ceramic restoration.
Please refer to page 25 for further notes on finishing.
Firing process for zirconium oxide-supported restorations
The following points need to be observed to achieve optimum firing results:
In order to ensure an even thickness of the veneer, the zirconium oxide framework must be designed in such a way that it provides
adequate support at the cusp area.
Since zirconium oxide is a poor heat conductor compared to other framework materials, a low temperature increase rate needs
to be selected. This ensures an even heat distribution within the framework and along the bonding interface between the veneer
and the framework. In addition to achieving an optimum bond, homogeneous sintering of the veneering material is ensured.
During cooling of the restorations after firing, stress occurs as a result of the different cooling speed at the outside and within the
material. By means of long-term cooling, particularly after the "final" firing cycle, thermally induced stress can be reduced and
the risk of delamination minimized.
Notes on cooling after completion of the firing program
In order to ensure controlled cooling of the restoration after firing, please observe the following notes:
Wait for the acoustic signal or optical indication of the furnace at the end of the firing cycle before removing the firing tray
with the fired objects.
Do not touch hot objects with metal tongs.
Allow the objects to cool to room temperature in a place protected from draft.
Do not blast or quench the objects.