Influence of three different preparation designs on the marginal and internal gaps of CEREC3 CAD/CAM inlays

The aim of this study was to evaluate the marginal and internal gaps in CEREC3 CAD/CAM inlays of th ree different preparation designs. CEREC3 Inlays of three different preparation designs (n = 10) were fab-ricated according to Group I-conventional functional cusp capping/shoulder preparation, Group II-horizon-tal reduction of cusps and Group III-complete reduction of cusps/shoulder preparation. After cementation o f inlays, the bucco-lingual cross section was performed through the center of tooth. Cross section images of 20 magnifications were obtained through the stereomicroscope. The gaps were measured using the Leica ap plication suite software at each reference point. Statistical analysis was performed using one-way ANOVA and Tukey′s test (α< 0.05). The marginal gaps ranged from 80.0 to 97.8 μm for Group I, 42.0 to 194.8 μm for Group II, 51.0 to 80.2 μm for Group III. The internal gaps ranged from 90.5 to 304.1 μm for Group I, 80.0 to 274.8 μm for Group II, 79.7 to 296.7 μm for Group III. The gaps of each group were the smallest on the margin and the largest on the horizontal wall. For the CEREC3 CAD/CAM inlays, the simplified designs (groups II and III) did not demonstrate superior results compared to the traditional cusp capping design (group I). [J Kor Acad Cons Dent 34(3):177-183, 2009]