Ivoclar Vivadent Zenostar - Manual (Page 46)

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General Information
Frequently asked questions
Do Zenostar restorations have to be pre-treated prior to sintering?
It is important to clean the restoration before sintering and remove any adhering milling dust. However, the restoration must not
be cleaned in an ultrasonic bath or with a steam cleaner and it must not be blasted with corundum or glass polishing beads. If the
restoration has come into contact with liquids, it must be dried before it is sintered.
Can moist frameworks be sintered?
The restorations must be fully dried before they are sintered. Moist frameworks must not be sintered. The drying time depends on
the temperature and the size of the restoration. When drying the objects, a temperature of 140 °C (284 °F) must not be exceeded.
If moist frameworks are sintered, the risk of cracking is considerably increased.
What needs to be observed when multi-unit restorations are sintered?
The sinter support structure to be used is dependent on the furnace model. More details on suitable sinter support structures can
be found in the Design and Production Guidelines. Sintering on so-called sinter beads is not recommended.
When is Regeneration firing required in conjunction with Zenostar restorations?
The need for a Regeneration firing procedure depends on the grinding instruments used for finishing the sintered Zenostar
restorations. Please observe the recommendation regarding the grinding instruments. Basic rule: The finer the grinding instrument,
the lower the risk of damaging the zirconium oxide restoration. We recommend conducting a Regeneration firing procedure after
diamond grinders with a grit size higher than 100 micron have been used. To remove the sinter support structures in multi-unit
bridges, the recommended grinding instruments must be used.
Why is it advisable to use Zenostar VisualiZr in combination with Zenostar Color Zr Liquids?
Zenostar VisauliZr helps to identify if and with which shade a framework was stained. Zenostar Color Zr Liquids are nearly colourless
and thus difficult to recognize on non-sintered zirconium oxide. For productivity-oriented laboratories in particular, this increases
the process reliability and helps to check the procedures. Handle the colouring liquids with care in order to avoid contamination of
the skin, clothes or laboratory equipment.
Can furnaces from other manufacturers also be used to sinter Zenostar restorations?
The Programat ® S1 sintering furnace and the furnaces of the Zenotec system have been tested with and approved for Zenostar.
Other high-temperature furnaces are thus suitable for sintering the restorations only to a limited extent.
Please contact Customer Services if you intend to use a furnace that is not a product of Ivoclar Vivadent or Wieland.
May Zenostar restorations be blasted with corundum prior to veneering?
Do not blast the restorations with corundum, as this may damage the ceramic surface and even initiate flaws within the bond
between the framework and the layering ceramic. In order to achieve a sound bond, the surface must be cleaned. Therefore, the
restorations should be cleaned under running water or with a steam cleaner. After cleaning, contamination of the restoration
surface (with e.g. skin oils, saliva) should be avoided.