Occlusal Accuracy and Reproducibility of CERC Digital Impression

Objectives: Evaluate the occlusal accuracy and reproducibility obtained using the Sirona CEREC 4.2.5 SW and digital impression in achieving proper occlusion eliminating the need for physical models.
Methods: Fifteen (N=15) three unit posterior fixed dental prostheses (FDPs) were fabricated on a standard preparation on ivorine teeth extending from 29-31 using Sirona 4.2.5 SW and direct digital impression. The prepared teeth were scanned using a Cerec blue cam. FPDs were divided into 3 groups (n=5/group) 1: full contour zirconia (Zr), 2: zirconia core veneered with milled Vita Triluxe Forte block using a split file technique (RLT) and 3: provisional material (Vita CAD Temp). Unprepared ivorine teeth were used as control. Occlusal contacts for all groups was measured and compared to that on control using a Faroarm machine.
Results: The occlusal contacts developed in all test groups when compared to that on control group shows differences in all three directions; Buccolingual (BL), Mesiodistal (MD) and Occlusalogingival (OG). RLT group shows the highest discrepancy and CADTemp the lowest. The table presents the average differences and direction between each test group and the control in µm.
Conclusions: FPD’s generated with Zr, RLT, and CADTemp using Sirona CEREC 4.2.5 SW showed deviation in all dimensions measured relative to the original unprepared teeth.