6 tips: How to veneer large restorations
Would you like to know how large zirconium oxide (ZrO2) restorations can be veneered quickly and easily with IPS e.max Ceram? Here are six hot tips for you!
Tip 1: Framework design – the key to success
The framework design is key to the success of durable all-ceramic restorations.
- Make sure that the design supports the shape and cusps in order to achieve a veneering ceramic layer with an even thickness.
- Choose to apply a thin rather than a too thick veneering layer.
Advantages of a thin ceramic layer:
- less ceramic shrinkage
- less tension build-up
Remember: Even when applied in thin layers, highly esthetic results can be achieved with IPS e.max Ceram on a matched zirconium oxide framework (made from stained or unstained IPS e.max ZirCAD or Wieland Zenostar). Less is sometimes more!
Tip 2: Cleaning - avoid negative effects
Contamination of the framework may have a negative effect on the firing result and the bond to the veneer.
- Thoroughly remove all milling dust with oil-free compressed air and/or a dry, soft brush before sintering the zirconium oxide framework. Milling dust on the surface may be fired to the framework and compromise the fit and the bond to the veneer.
- Thoroughly clean the framework under running tap water or with the steam cleaner not only before the first firing (ZirLiner), but also prior to each subsequent firing. Any contamination after cleaning must be prevented. Use tweezers and clips to handle the framework.
Tip 3: ZirLiner firing - for a homogeneous bond
IPS e.max Ceram ZirLiner establishes a homogeneous and sound bond to the zirconium oxide framework. Moreover, it ensures that the framework shade is adjusted to the desired tooth shade and imparts the restoration with in-depth fluorescence.
Tips on applying ZirLiner:
- Apply ZirLiner in an even layer to the entire bonding surface of the restoration. Make sure to achieve a greenish shade effect. If the colour appears too pale, the layer is too thin.
- Ceramic ball instruments are particularly suitable for applying ZirLiner.
Tip 4: Wash firing - sintering to surfaces in a targeted fashion
Due to the low heat conductivity of zirconium oxide, a wash firing cycle is required. This allows the ceramic to be sintered to the framework surface in a controlled fashion. As a result, a homogeneous bond to the fired ZirLiner is achieved.
- For this purpose, mix IPS e.max Ceram Dentin or Deep Dentin material with the IPS Build-Up Liquid allround or soft. Apply this mixture in a thin coat to the entire fired ZirLiner. Then fire the restoration using the respective firing parameters.
Tip 5: Layering scheme - important for long-span restorations
The layering scheme plays an important role in the veneering of long-span restorations. Extensive build-ups and deep occlusal fossae influence the firing result.
In order to achieve the desired result, we recommend proceeding as follows:
- Conduct a separate Deep Dentin or Dentin firing throughout the entire surface in order to distribute the shrinkage over two firing cycles. This facilitates the placement of the Impulse materials for the second firing.
- Use a scalpel to separate the central fissure occlusally beyond the marginal ridge before the first firing. This allows the ceramic to be sintered to the framework surface in a controlled fashion. In the subsequent second Dentin and Incisal firing, the central fissure and the occlusal surface are supplemented.
Tip 6: Firing process - decisive for the firing result
The firing process chosen for large ZrO2 restorations decisively influences the firing result.
The following points should be strictly observed:
- Increase the drying time to be sure that the drying process is complete.
- Ensure long-term cooling to 450°C to avoid tension build-up in the ceramic.
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