Accuracy of CAD/CAM Crown Fit with Infrared and LED Cameras

Purpose: The intraoral recording of digital images is a critical component of fabricating accurate Cerec restorations. This study evaluated the marginal fit and internal adaptation of Cerec ceramic crowns fabricated using different cameras, alternative powdering materials, and multiple image capture sequences. Materials and Methods: A master epoxy resin model was fabricated using a polyvinylsiloxane (PVS) impression of a typodont with an all-ceramic crown preparation on tooth 14. A titanium dioxide powder/mechanical sprayer and an aerosol contrast spray were used to create a uniformly reflective surface. An infrared laser Cerec 3/RedCam unit and LED Cerec AC/BlueCam unit were used to record images for crown fabrication. Three different image capture sequences were performed to record the data. Crowns were made for each test group using a Cerec AC unit with V3.80 software. The crowns were milled from blocks of IPS EmpressCAD. Marginal fit and internal adaptation of the crowns to the master model of the preparation was assessed with a measuring microscope at 20X. The data was analyzed using a two-way ANOVA. Results: No significant differences were found in the marginal fit, axial wall adaptation, or occlusal wall adaptation between any of the test groups (p 0.05). Conclusion: Within the confines of this in vitro study, there were no significant differences between the marginal fit and internal adaptation of Cerec CAD/CAM ceramic crowns fabricated with: 1) the infrared laser camera (RedCam) and the LED camera (BlueCam), 2) titanium dioxide powder or aerosol contrast spray, or 3) multiple imaging sequences for recording the preparation and adjacent teeth. Keywords: CAD/CAM, Cerec, all-ceramic, marginal fit, internal adaptation