Evaluation of Influence of Finish line Design on Marginal Discrepancy of All-ceramics Lithium disilicate Crown restorations using μ-CT

Abstract

Purpose of this study was to evaluate influence of finish line design on marginal discrepancies of lithium disilicate crown restoration fabricated with CAD/CAM. 24 crown restorations (n=8 each group) were designed with three different finish lines: Shoulder finish line (SFLC), Round Shoulder finish line (RSFLC) and Deep Chamfer finish line. All dies were prepared with additive manufacturing whereas crowns were fabricated with CAD/CAM using these preparations. After fixation, restorations were scanned using SRμCT and obtained reconstructed 2D slices were used to measure marginal discrepancy (MD) and absolute marginal discrepancy (AMD) at four sites (buccal, lingual, mesial and distal) of each specimen with the help of Image J software. Finally, recorded data was analyzed by one way ANOVA and Tukey’s test. The mean marginal discrepancies (MD±SD) for three groups were as follow: SFLC (91.6 ±3.5), RSFLC (72.8 ±3.9) and DCFLC (65.9 ±5.2) whereas Mean absolute marginal discrepancies (AMD±SD) were as follow: SFLC (104.4 ±6.8), RSFLC (85.5 ±3.5) and DCFLC (78.7 ±5.3). According to results, marginal discrepancies as well as absolute marginal discrepancies of SFLC group were significantly higher than those of RSFLC and DCFLC groups. After all, MDs and AMDs of all three groups were below clinical acceptable value. For allceramics restorations, marginal discrepancies of lithium dislicate crown restorations were below clinical acceptable range and restorations designed with RSFLC and DCFLC demonstrated superior results compared to preparations designed with SFLC.