SEM Evaluation of the Marginal Fit of Cerec II and Cerec III Inlays

In response to the increased public demand for esthetic restorations CAD/CAM technology is being used to fabricate inlay/onlay, crown and laminate veneers. In order to keep up with the demand, Sirona Company (Charlotte, NC) has improved the software of Cerec II and released Cerec III. Objective: This study evaluated the fit at the gingival margin of two surface inlay restorations milled by the Cerec II and Cerec III. Method: Twenty freshly extracted intact human molars were prepared with Class II inlay preparations. Ten teeth were optically impressed and restorations were milled with Cerec II. The other ten teeth were optically impressed and the restorations were milled with Cerec III. All milled restorations were cemented occlusally. The teeth were cut one time horizontally 1.0mm below the CEJ and one time vertically half the mesial-distal width. The samples were prepared for viewing under the SEM. At 35X magnification the gingival margin of all samples was measured at 3 points. Result: The marginal fit of inlays milled by the Cerec III was better than those milled by the Cerec II (i.e. Cerec III 39-52 microns and Cerec II 43-59 microns). Oneway ANOVA tests revealed 89.9% confidence level. Statistical analysis of the results found p = 0.101. Conclusion: The difference in marginal fit of inlays milled by Cerec II and Cerec III was not statistically significant.