Clinical evaluation of all-ceramic crowns fabricated from intraoral digital impressions based on the principle of active wavefront sampling

Objectives: The aim of the present study was to compare the fit of all-ceramic crowns fabricated from intraoral digital impressions with the fit of all-ceramic crowns fabricated from silicone impressions. Methods: Twenty patients agreed to take part in the study to receive two Lava (TM) crowns each for the same preparation. One crown was fabricated from intraoral scans using the Lava (TM) Chairside Oral Scanner (Lava C.O.S.), and the other crown from a two-step silicone impression. Prior to cementation the fit of both crowns was clinically evaluated by two calibrated and blinded examiners; the marginal fit was also scored from replicas. Data from the replica scores were analysed by Anderson-Darling test, Levene's test and Mann-Whitney test. All tests were performed with alpha-level of 0.05. Results: Median marginal gap in the conventional impression group was 71 mu m (Q1:45 mu m; Q3:98 mu m), and in the digital impression group 49 mu m (Q1:32 mu m; Q3:65 mu m). Mann-Whitney test revealed a significant difference between the groups (p<0.05). No differences were found regarding the occlusion, and there was a trend for better interproximal fit for the digitally fabricated crowns. Conclusions: 1. Crowns from intraoral scans revealed significantly better marginal fit than crowns from silicone impressions. 2. Marginal discrepancies in both groups were within the limits of clinical acceptability. 3. Crowns from intraoral scans tended to show better interproximal contact area quality. 4. Crowns from both groups performed equally well with regard to occlusion. (C) 2010 Elsevier Ltd. All rights reserved.