When we first invested in the Sirona CBCT and CEREC system in the practice two years ago one of our main aims was to be able to provide surgical guides in the practice through our milling unit.
We finally achieved this in January 2016 when we started to routinely use CEREC Guide 2 in the practice for single unit cases (it can also be used for multiple unit cases with more than one guide being fabricated)
The workflow itself is really quite simple, let’s take for example an upper right first premolar for implant placement in a straightforward case with no grafting:
The patient attends for a CBCT scan of area two - three weeks before surgery (as close to surgery as possible to give you the most accurate information) at the same visit the patient undergoes intraoral CEREC scan to create a STL file. Both files are merged together on the system to provide a bony CBCT file which has a soft tissue and tooth overlay of the STL file. The STL file has the final restoration designed upon it. This means that the final implant crown is already designed in the STL file which lies on top of the CBCT file.
It’s then possible to place the implant in using the CBCT reporting software from Sirona (Galaxis) and this is verified clinically to be in the correct position. It is then just simple to export, design the guide and mill.
Perhaps one of the perceived disadvantages of the CEREC Guide 2 is that it does not provide large enough cross arch bracing for it to be entirely stable for a guided surgery guide but our experience so far is that is fits pretty well, is pretty stable and there is not a significant amount of obvious visible difference between that and a cross arch proprietary guide provided by SICAT in Germany.
The accuracy seems to be fantastic and although the guides are quite bulky they are impossible to bend and almost impossible to break; they are as rigid as rigid can be which adds increased accuracy.
In order to facilitate the correct vertical dimension you need to insert a metal Sirona key (this is included in the prescription provided in the planning process) which allows you to place the implant with a definitive stop. So far this has been entirely accurate although it can be a bit fiddly trying to hold so many things in the mouth at once.
You then have the option of using an ultra slow drilling protocol with no water or a slow drilling protocol with water, we would recommend you use a 20ml syringe at this stage to flush underneath the guide during placement to keep things as cool as possible. I would also suggest looking at ultra slow drilling protocols too.
Depending on how your guide is designed it is then possible to place the guided implant through the surgical guide but is not possible to match the exact vertical height on the guided placement as far as we can see. It is interesting to note here that you can use the CEREC Guide 2 in two ways: as a very accurate surgical guided without guided surgery (you can just mill all your implant surgical guides out like this) or you can use it as a truly guided preparation of the site without actual guided placement at the present time (we are looking into this to see how we can do it)
From a numbers point of view you have clearly got to invest in the system to get it going in the first place so around about £160,000 will do it (including VAT) but there are huge other applications for it to help pay off that whacking great cost. That said though, when you are well into your repayment schedule the guides themselves are coming out at about £35 + VAT with a minimal drill useage because they are quite soft material. The bottom line is, does it benefit your patient and make your surgery better? The answer in my practice has to be yes. I am putting implants into positions that I would never have dared to because I didn’t think they would be right when in fact they are much better than they ever used to be. From that point of view it has so far been a huge success.
Our next move is to investigate the possibility of using STL files for 3D printing, not to mention using the Omnicam from CEREC to take Invisalign ‘impressions’ so we’ll keep you updated
Blog Post Number: 844
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