A recent innovation available in the offices of some cosmetic dentists is a crown made using “Computer-Assisted Design-Computer-Assisted Manufacture” or “CAD-CAM.” The company that is foremost in this technology is CEREC. This crown is milled by a computer to fit your tooth precisely, thus eliminating the laboratory step in manufacturing the crown.
Without CEREC you must come into the office multiple times. On the first visit, you get an injection of anesthesia, your tooth is prepared, an impression is taken, and a temporary restoration is put on your tooth. At the second appointment – often several weeks later – you get another injection, have the temporary removed, and have a permanent restoration put on the tooth. With CEREC, the procedure is done in a single appointment, start to finish.
The CEREC Acquisition Unit is mobile and houses a computer and the CEREC camera. A digital camera is used to take an image of your prepared tooth. This picture is used instead of a traditional impression. The computer and CEREC 3D software converts the digital picture to a three dimensional virtual model of your prepped tooth. The doctor then uses the software to design your restoration on screen, while you wait. This software can assist with designing any single tooth restoration: crowns, inlays, onlays, and veneers. Once the doctor has designed your restoration (about 5 minutes), the data is communicated via a wireless radio signal to the CEREC Milling Unit. A ceramic block that matches the shade of the tooth being repaired is selected and inserted into the milling unit. The data from the acquisition unit is used to direct two diamond-coated burs to carve the block into the indicated shape of the restoration. This process usually takes 8 to 18 minutes depending on the size and type of restoration. After the milling is completed, the finished filling or crown is polished and bonded into place. The entire procedure is completed in one visit.