Introduction to the case
In the time I’ve been around guided surgery, I’ve gotten to hear all the excuses why people don’t get on board. Some of them are very valid and I even used them myself at one time. One objection is it’s not accurate. It is accurate – far more accurate than what can be accomplished free hand.
But the much more valid arguments were that it was too cost prohibitive (which it was), that it was a lot of work (which it was), and that there were just too many moving parts making the process complex (which there were). Well, I’m pretty excited to share this because these concerns are now going to just evaporate.
The cost and complexity were due to the fact that you needed a CBCT, an optical scanner, an expensive printer, and expensive software to do it yourself, or you had to farm out different parts of the process like scanning or printing to 3rd parties. Now, you’ll be able to do the whole thing in house. The only barrier to entry is the CBCT which is necessary, but you can certainly refer it out to someone – you don’t have to own it.
But now, it’s gotten even better. Now, we can simply scan just an impression without even needing to pour it up. Blue Sky Plan allows us to turn that cone beam scan of the impression into an STL file which can then be “digitally poured” to create the actual STL. This digital pour is done in another free program currently but we’ll eventually have the entire functionality within Blue Sky Plan simplifying it even further. This is a workflow originally figured out by Dr. Rick Ferguson.
This is a notable improvement over scanning the stone models because you almost always have a little bubble in the stone that translates into an error in the guide built on it which will have to be adjusted out for proper fit in the mouth.
With an impression, you might possibly have a bubble, but that’s a positive error that would not affect the fit of the guide – when you “digitally pour” it, it would equate to a bleb on the model.
Also, I actually prefer getting the STL from a scan of PVS putty impression rather than getting the STL from an optical scanner or a CBCT scan of a stone model because the latter two can sometimes be TOO accurate. They pick up every little nook and cranny and then the guide gets built on that and it goes into every nook and cranny too. Then you have to adjust the guide a bit to prevent binding. By using PVS putty, the impression is slightly less detailed, it’s almost like what you would get if you lightly waxed out the embrasures.
So now, you get your STL and your cone beam data from just your CBCT machine. The second major development is that we’ve been testing the Cel Robox printer and the results have been great. This printer is $1500 and if all you’re doing is a guide or 2 a day, it’s sufficient for our purposes and uses food safe materials.
So now, it’s totally realistic to scan the patient and their impression in the morning, plan the case, and have the guide printed by lunch time.