Interface gap size of manually and CAD/CAM-manufactured ceramic inlays/onlays in vitro

Objectives: To determine the fit of ceramic inlays manufactured using a recently introduced CAD/CAM-system (Decim) and of two types of laboratory-made heat-pressed ceramics (IPS Empress and Opc). Materials and methods: Extracted human premolars were prepared to receive mesio-occlusodistal (MOD) ceramic inlays, for which 10 Denzir, 10 IPS Empress, and 10 Opc were fabricated. The Denzir restorations were produced by the manufacturer of the CAD/CAM-system, and the IPS Empress and Opc by student dental technicians. Results: Before luting the internal fit on the diestone models and on the premolars was determined using replicas. After luting on the premolars with a resin composite the marginal and internal fit were measured. The values were analyzed statistically using ANOVA and Scheffe's test at a significance level of p < 0.05. Results: Before luting there were no significant differences (p > 0.05) in the internal gap width between the three systems studied when placed on their matching diestone models. When placed on the premolars a significant difference (p < 0.01) in the internal fit was seen between Empress and Opc before luting, whereas there were no significant differences (p > 0.05) between Empress and Denzir and between Opc and Denzir. Between the diestone models and the premolars there were significant differences (p < 0.01) in the internal fit, except for IPS Empress. After luting there were no significant differences (p > 0.05) between IPS Empress and Denzir, whereas the marginal gap width was significantly wider (p < 0.001) for Opc than for IPS Empress and Denzir. The internal fit was significantly (p < 0.001) wider for Opc than for IPS Empress, whereas there were no significant differences (p > 0.05) between IPS Empress and Denzir or between Opc and Denzir. Conclusion: After luting there were only slight differences in the fit between the restorations fabricated using the three different manufacturing techniques and ceramics. Therefore, long-term follow-up studies, are needed to assess the clinical significance of the slight differences between the three systems. (C) 2002 Elsevier Science Ltd. All rights reserved.