Easy A: Common Errors in CEREC Guide with a Legacy 2 Case

 

 

“Easy A” is not my new rap name ;}, I titled this case that way due to some opinions I got from the awesome Sirona Drive Event, which was a Galileos users meeting in Charlotte last weekend.    As some of you may or may not know, I do a few CEREC Guides and am excited about having this option.  But when I talk to others who have tried it I get a range of opinions.  Some only use them for easy cases, others say that if its that easy they do it free hand.  Some have had great success, others have not and hate the thing. So I wanted to document an easy case and how I made it easy by following a few rules.  Patient has a nice wide ridge on #18, lots of good tissue and good access.  I tried in a large reference body which was too big, then switched ver to a medium. You should have at least 1mm of space inter proximally around the reference body.  You never want to alter the ref body as thats what cerec will mill to.  If you have to alter the teeth, but thats not recommended unless the adjacent teeth have rough or over contoured restorations.  Scanned in CEREC 4.3

 

 

As many that have tried CEREC Guide know, the real source of error comes from the Thermoplast.  So how you handle it is very important.  First we take an alginate, and warm up the thermoplastic in boiling hot water.  It should be uniformly clear when malleable.  If it looks like “boba” its not melted enough.  I like the beads over the ropes.  Let it cool in hot water, but before its fully set remove it.  It should be hard on the outside but still soft on the inside.  Place it back into the patient’s mouth.

 

 

I have the patient bite down but watch the thermoplastic, make sure it does not rock.  Now let it cool in the patients mouth and adapt.  Then scan the patient.

 

Another source of error in all guided surgery is having tunnel vision and just focusing on the screw access.  What I do first is plan the implant without the CEREC proposal.  You can draw your margin wrong, you can design your proposal wrong.  I love the PILOT DRILL PATH, that yellow tube to approximate the screw access, but take a few steps back and look at how the implant fits in the arch. Look at the curves of Wilson and Spee and make sure you have the appropriate angulation (I have at Atlas in Guided Impantology Made Easy that has these angles at www.implantsmadeeasy.com/shop/).  Then once you have that down you can concentrate on getting that yellow pole right in the central pit.  Then locate your reference body.

 

Another source of error is how you handle the drill body in the Thermoplast.  Remove the reference body first but DO NOT TOUCH THE THERMOPLAST, pop the Drill Body in there, THEN cut your hole on the underside. Remove all flash.  If you cut the hole first, the drill body may not seat.

 

 

A final source of error is taking the guide in an out and not seating it.  I have done cases where my initial working length film in right on, then my final implant was off.  Leave it in after popping it in!  You can still place your angulation pin and take your radiograph.

 

Final!  It was recently grafted bone, and I did not get 35 Ncm so no contour healer but will place one later, still used a healing abutment with this 5.2 by 10mm Legacy 2.  I use the Legacy 2 instead of the 4 as I will be doing a screw retained Emax and do not need the final abutment.  If you do a lot of stock abutments, the Legacy 4 is better.