If I said I Want Your Reference-Body, Would You Hold It Against Me? Verify the seating of the Thermoplast in CEREC Guide.

Here is a fun case that shows where some may have problems with Cerec-guide.  The two things that messed me up in the past was either not getting the drill body seated all the way or not placing the radiographic guide (thermoplast and reference body) correctly back in the mouth after fabricating on a model.  Here will show a little trick to visualize the radiographic guide in the scan.  The patient had endo a while back and a old composite crown. Looks like there may have been a perforation.  She started having sensitivity to heat and biting.  Gave the option of seeing an endodontist but with the perf, I did not think the success rate of the re-treat would be stellar.  She opted for extraction and implant. I cut to the chase, reduced the clinical crown and sectioned before the scan.       Learned the hard way that a brand new rubber bowl is not the “bowl of choice” for the thermoplast as it binds to it, so I have switched to stainless steel or ceramic.  Here is where we get some problems, fabricate the radiographic guide and seat in the mouth.  The problem is that the material is opaque and covers a lot of area and at times it is hard to verify seating.       Scanned and planned in the furcation for a 7mm Legacy 2.       In my classes I talk a lot about “clipping” and usually I clip away the opposing arch.  In this case we want to see if our radiographic guide is seated.  So I want to see a cross section tangentially (Mesio-Distally) to verify that.  Right click on the 3D and Clip Volume along Active Slice and then click on the Axial and scroll through until you are in the middle of the edentulous space.     Next select “Volumetric Mode with Contours” to display less dense objects than teeth and bone.  Go to the Configure Display option.  Play with ten opacity or just use my settings.  You should start to see the Thermoplast appear around the Reference Body.       Here is a comparison image of the Volumteric Mode vs our modified Volumteric Mode with Contours.  You can now turn that around in the 3D and check that the Radiographic Guide is seated.  Go ahead and plan and export the CEREC guide file and mill.       I use an acrylic bur from the occlusal to the apical in the space to make a hole.  If you go from the apical to the occlusal you push up thermosplast into the indentation made my the Reference body and that can mess with the seating of your Drill Body. When I get a free Friday I may sit down with a machinist and just make some keys to fit the implant direct drills in CEREC Guide, but for now buy the Nobel keys and just play around until you get the right combo.  The 2.3 is a little loose in the 2.8 but the subsequent keys correct for this.  If you are really a stickler you can just buy a 2.0 pilot from Nobel or Salvin and use that in the 2.0 key.     You know my deal by now right?  Drill through the furcation with the 2.3 (I cheated and pre drilled with my sectioning through the Dentin so I did not have to work that hard with the 2.3) Check to see that you are on course with the angulation pin. After the pilot, section the roots.  Sorry for the fuzzy shot but the pilot hole is in the middle of the furcal bone     Apparently this patient did not share my love of Dental Photography ;}         Crestal Bone drill non Guided.  I am loving these HA Coated implants and they are my default for D4-ish bone. I indexed this a little better after tis shot.  Placed DFDBA, membrane tacked down my cover screw.  Resorbable Villet sutures from ID.   Scan post in CEREC 4.2 Always like to try in the blue state Final, not my best stain work, but I think the patient will live ;}