CEREC World Douglas W. Voiers, DDS, FWCM Mark R. Morin DDS, FWCM

Previously, our CEREC World column focused on powder and optical impression. After the previous two stages are complete, the restoration is ready to be designed. Basic CEREC restorations can be designed quickly and easily with little computer knowledge. Several different methods for CEREC design are taught throughout the U.S. Our simplified techniques focus on streamlining all aspects of CEREC dentistry so that the clinician can move along through the process with minimal time and effort.

Inherent in producing fast, easy and accurate CEREC restoration designs is a faith in the camera accuracy and CEREC software program. This technology provides incredibly accurate restorations with a fit that rivals those fabricated by a laboratory technician. The information gleaned from the optical impression allows the software to automatically extrapolate and develop tooth morphology that fits into the arch form properly. Too often we find CEREC dentists second-guessing the machine, spending an inordinate amount of time during the design phase, only to find that the final result is no better off and perhaps even worse than if they would have trusted the CEREC system.

Dentists should strive to design an inlay, onlay or partial crown within about 3 minutes and fill a crown or veneer in 5 minutes using Extrapolation or Dental Database modes. Although many dentists are trained and adept at using another common mode called Correlation, we have found this method to be difficult and often ineffective in achieving satisfactory tooth shape and form. Another inefficient CEREC method involves taking an optical impression from a quadrant impression. This indirect method not only takes two additional steps, but it decreases the accuracy of the restoration since you are introducing two sources of distortion in the impression material and the poured model material. We always advocate taking the optical impression on the preparation intraorally in order to ensure that your computer design is done on a direct optical impression.

Our overarching philosophy of efficient CEREC design is to use a minimum number of design tools needed to get the job done. Assuming a simple posterior 3/4 crown is being designed in Extrapolation mode, first the clinician takes a few seconds to draw the Bottom Line of the planned restoration using the trackball and thumbpad. A green arrow then prompts the designer onto the next several steps, which are automatically designed by the computer system due to its library of morphological characteristics and information secured from the tooth on either side. CEREC computes the orientation of the restoration as well as the position and height of the cusps, then detects the contact points and proposes the marginal ridge and central fissure morphology, and the restoration design is concluded. The restoration can be “morphed” in any dimension using a pop-up cross-section window within less than a minute if the dentist wishes to change any aspect of the size and shape.

I am purchasing a CEREC 3 unit...please advise on appropriate insurance codes for inlays and onlays.
lovesadam, Official Townie

The codes are standard CDT-3 codes D2642, D2643, and D2644 for onlays. You will not find any insurance coverage for inlays, even though they do have a CDT-3 code (D2610, C2620 and D2630).
brian, Official Townie

If you have a CEREC question, please send it by fax to:480-598-3450 or send by email to: dwvdds@earthlink.net or carol@dentaltown.com

Mark Morin, DDS, FWCM, graduated from the University of Detroit in 1985 and immediately started his new practice in Southfield, MI. He became one of the first dentists in North America to begin using CEREC I technology. He currently places 10-15 CEREC restorations daily and continues to study CEREC technology extensively in Germany and Switzerland with inventor, Dr. Werner Mormann. Mark can be reached by email at: drmorin@earthlink.net or by calling 248-828-9989. Visit his website at www.drmorin.com.