Abstract:

Introduction:
Tooth colored restoration using digital dentistry is growing worldwide. CAD/CAM technology are used in most of the dental schools in the United States. New York University college of dentistry have been using CAD/CAM technology since 1991. The combination of the accuracy of both machinable fabricated ceramic materials and the use of digital dentistry stimulate the student to succeed.
Learning CAD/CAM technology is very appealing to this generation. Student doctors are eager to learn this new technology which creates a positive effect on their performance and deliver a faster and better care to their patients.
Digital impression is more accurate, less time consuming and the restoration can be delivered to the patient the same day compared to a traditional impression which is less precise, more human error and a provisional restoration needed prior to deliver the restoration.

Objective:
Teaching the student doctors how to take a digital impression and familiarize them with the CEREC software in order to assess their own work and utilize the proper tooth colored materials.

Method:
Second year student Doctors are taught, in the simulation laboratory, to prepare inlays and onlays on typodont teeth. Each student take a digital picture of his/her preparation and self-evaluate his/her work. Using CAD/CAM technology students are able to magnify and rotate the virtual model 20 times, this will allow them to analyze their preparation.
Third and fourth year student doctors and trained in their respective group practices, to treat patient using CAD/CAM technology in addition to choose the proper material suitable for the procedure. Two different modes are taught at the school: Biogeneric individual for crown and Biogeneric copy for inlay and onlay. After getting the faculty approval for both biogeneric individual or biogeneric copy mode, the information is sent wirelessly to the milling chamber where the selected material (block, shade and size) is inserted and milled in approximately 10 to 15 minutes. The restoration is tried in the patient mouth, adjusted, and bonded to the tooth structure using resin cement.

Materials selection:
Materials used at NYU for CAD/CAM technology are: E-MAX CAD 9 (Lithium Disilicates) and Impress CAD by IVOCLAR VIVADENT or Sirona blocks (Aluminum, sodium and potassium oxide) by DENTSPLY Sirona.ceramic. Ceramic blocks have high physical and mechanical properties,better esthetic when compared to conventionally polymerized materials. The advantage of using lithium disilicate is that the restoration is adjusted in the patient mouth in a partially crystallized state, students are trained to stain, glaze and fully crystallize. The restoration generated from a Sirona block can be adjusted and polished chair side. In order to choose the proper material the student is asked to check the patient dentition of the opposing arch. The material should be compatible with the surrounding teeth to avoid the wear of the opposing tooth structure.

Conclusion:
The efficiency and accuracy of digital technology promote a huge benefit to dental education. Student doctors are capable to perform much better using digital technology which leads to a predictable outcome and superior patient’s experience. Selection of the proper material used in CAD/CAM is based on the type and location of the restoration planned. Proper selection of the material will promote excellent clinical result with long term success of the restoration.

Keywords:

CAD/CAM technology, digital impression ,materias selection