Quintessence Int 49 (2018), No. 6 14. May 2018
Quintessence Int 49 (2018), No. 6 (14.05.2018)
Page 437-444, doi:10.3290/j.qi.a40354, PubMed:29756132
Comparison between five CAD/CAM systems for fit of zirconia copings
Habib, Syed Rashid / Al Otaibi, Asim Khaled / Al anazi, Talal Ali / Al anazi, Samer Mosleh
Objective: The aim of this in-vitro study was to investigate the marginal and internal fit of zirconia copings fabricated by five CAD/CAM (computer-aided design/computer-assisted manufacture) systems.
Method and Materials: A typodont mandibular right first molar was prepared according to ideal parameters for a zirconia crown, scanned digitally, and 100 identical resin dies fabricated by 3D printing. Samples were randomly divided into five groups and sent to CAD/CAM systems for zirconia copings (A, Ceramill-Motion 2, Amann Girrbach; B, Weiland, Ivoclar Vivadent; C, Cerec, Ivoclar Vivadent; D, Prettau Zirconia, Zirkonzahn; E, Cad4dent). CAD of the copings included standardized cement space of 30 µm and CAM was carried out. Copings were tried/adjusted on the respective dies and embedded under a standardized load of 20 N in self-curing resin. Samples were sectioned mesiodistally into two halves. Marginal and internal gap values were measured with a digital microscope at 50 to 200 × magnification at nine sites.
Results: The lowest and highest mean gap values of 46.93 ± 13.50 and 101.65 ± 35.56 μm were found for Group A and Group D, respectively. ANOVA showed a statistically significant difference between the mean values of all the groups (P = .000). Multiple comparisons with post hoc Tukey test indicated a statistically significant difference (P < .05) between: Group A and all groups except B; B with D; C with A; D with A; and B and E with A. Mean buccal/lingual gap value was found to be 51.54 ± 58.54 μm. Of the nine sites, the least gap resulted at the buccal axial wall and the greatest at the central groove. The overall mean gap recorded for the copings was 72.43 ± 57.56 μm.
Conclusion: Marginal and internal adaptations of CAD/CAM zirconia copings is influenced by manufacturing technique, and variations exist for different systems. Measurement sites showed different levels. CAD/CAM systems investigated showed a clinically acceptable level of gap values (< 120 µm).
Keywords: CAD/CAM, ceramic crown, dental crown, zirconia, zirconia crown