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Proper Preparation Design for Anteriors with CEREC

Thomas Monahan Sameer Puri
11 years ago

I wanted to share this great case that was recently posted by one of our Mentors, Dr. Grant Olson.  You can read all about the case and the details of this young patient on this thread HERE .

  What I wanted to comment on this case in this blog was on two things.  The photography and documentation of the case and the preparation design of the tooth.    First the photography is absolutely exquisite.  If you look at the photos, all of them are perfectly exposed and cropped.  All three photos have the same amount of tooth structure showing which helps to compare the before and after.  There is nothing extra in the photos such as blood, lips, cheeks, or anything that will distract from the view of the photos.  Finally the tissue is healthy in the photos, especially the post op.  Too often, clinicians are in such a hurry to show off their great work that they take an immediate post op photo with the tissue still red.  I always advise doctors to wait. As excited as you may be to showcase that beautiful veneer that you just completed, have the patient back in a week or so to evaluate the final restoration and once the tissue has completely healed, then take the final photo.   Failing to do so will simply just result in viewers commenting on what a nice case you did, but not a great case as the red bloody tissue can distract from the porcelain work.   The case below by Dr. Olson follows all the criteria of a successful case not only from a clinical standpoint but also from a documentation standpoint.  I've blogged in the past about the type of flash to use with these anterior cases. You can find the blog here.   My favorite is the twin flash when photographing anterior cases. I use the one from Nikon personally but both Canon and Nikon have variations of this type of flash that will work.  The twin flash allows for a natural look and by having dual flashes, you end with a soft look to the photos without the harsh glare.  Typically with flash, the goal is to get the flash as far away from the lens as possible.  The further it is, the "softer" the flash.  You've seen point and shoot cameras where the flash is right next to the lens and you get a very harsh glare from the flash.  By moving the flash away from the lens, you minimize the glare and get much better photographs.    So congratulations to Dr. Olson for a great case and great documentation.   The second part of this blog, I want to concentrate on the dentistry itself.  As stated previously, its excellent.  The main thing I want you all to see is the preparation on the central incisor.  As you can see from the preoperative photo, the patient suffered a traumatic injury of the tooth, leaving very little tooth structure to restore.  Most dentists would prep for a full coverage crown with a build up which would only serve to further weaken the tooth.  With CEREC a build up is not necessary and a full coverage prep in the anterior should be avoided whenever possible.   One of the things that I stress in our Level 4 class is to save the cingulum whenever the clinician has an opportunity to do so. The cingulum is what imparts strength to the tooth and serves to keep the tooth's stiffness.  Without the cingulum, you lose a significant portion of the tooth's strength.     As you can see in the photos below, the cingulum was saved.  Studies by Andreasen have shown that anytime the cingulum can be saved, the tooth is stronger.   A build up is simply not necessary as build ups will lead to premature failure of the restorations.  Remember that we are doing CAD restorations, milled from a solid homogenous piece of porcelain.  This means that the old rule of unsupported porcelain more than 2mm does not apply.  With a milled CEREC restoration, there is no such thing as unsupported porcelain. If you imagine a  size 14 Empress block, that is 14mm of unsupported porcelain and it certainly has a tremendous amount of strength.   This case just goes to show that when doing bonded restorations, the traditional theories do not apply.  We don't need build ups for retention and resistance. We don't need to prep unnecessarily.  We can be conservative and provide a great service to patients.  Bravo to Grant Olson for a masterful case.  
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