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Case-study: Aesthetic rehabilitation in ALL ZIRCONIA by Giovanni Montironi Our lab was sent an impression for an aesthetic-functional job, 1.3 to 2.3, which included
two Branemark Replace implants corresponding to 1.1 and 2.1. 
The dentist wanted a temporary sectorial, with the two sectors weighing on the implants screwed to the fixtures. After creating the imprint, we made a first aesthetic evaluation, and immediately saw that the implant site tissues would be completely unlevelled.
Having to work on a temporary system, we would try to bring the gum levels to aesthetically acceptable levels.
We made a wax-up of the project by maintaining all the tissue positions and levels and disregarding the implants’ position – this wax-up is a guide for gum conditioning, discarding the plaster from the modelling limit to the tooth neck to the base of the equivalent laboratory sample. It was impossible to perform a programmed conditioning, as the two implants are not at the same level.
 Once the time necessary to condition the tissues was over, we took a new imprint for the final job and then, based on this new model, scanned both the model and the wax-up, thereby obtaining a digital map of our case which was extremely rich in details and references.
We were asked to design the final project with the same configuration as the temporary one, i.e. to connect elements 1.3-1.2 , 1.1-2.1, 2.2-2-3 with zirconia crowns and to create two stumps on the implants, again using zirconia.
To create the stumps we used the Procera technique – this implies the stumps are fashioned in wax or resin on a basis which replicates the anti-rotation gears. This is then contact scanned, and the file sent to the production centre. For the crowns, on the other hand, we used the Cad-Cam Cyrtina System, which implies scanning the model as well as each stump with a 3Shape optical scanner. The files can then be worked on using ScanManager 21 and CyrtinaCad21 software.
To deal with the management of spaces we used the mask obtained from the temporary system, since its shape was accepted both by the patient and by the medic and fit in quite well with the residual tooth morphology. When we received the Procera abutments, we saw that the emerging profile we had determined during waxing was not respected in production, because the technology adopted cannot replicate angles > 45° on the vertical axis. We were disappointed, but moved on, adapting our design to having the two centrals at different heights. Mesial and distal coulisse traces were added to the zirconia stump, in order to find a certain position in the crown.
 As fore mentioned, to create the crowns we used the Cyrtina Cad-Cam System technology. As with all Cad-Cam systems, this means it is necessary to prepare the stumps, highlighting the margins and performing a light undercut beyond the site limit. After feeding all the case files to the ScanManager21 software, the model is placed in the scanner – at the end of the procedure, a file is produced which can be worked on using the CyrtinaCad21 software.
This platform can manage all the design and modelling process with a few simple commands. In order to carry out a successful virtual modelling, a few parameters are necessary, such as a bite, obtained in silicone, or a complete wax-up, which the system will treat as antagonist. This last point allows us to clearly establish the thickness needed for the aesthetic coating, allowing for the structures to grow inside it.
It is important to note that using a software such as this one has in no way altered my way of designing structures – on the contrary, it was a valid ally to managing spaces in the way I have been doing for years.
Upon receiving the coping or fixed metal bridge we immediately appreciate the advantages of immediate-fit, which completely eliminates the need for the cumbersome passage of inserting the stump on plaster, which presented a constant risk of damaging the work.
 Ceramic coating is applied with the same techniques used and perfected through the years; zirconia’s photo-optical properties, by the way, are much superior to metal, but the material does not behave like a full (integral) ceramic, favoured, up to now, for use in aesthetic reconstruction.
 Giovanni Montironi
DentalPoint
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