| ORIGINAL ARTICLE |
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| Year : 2016 | Volume
: 4
| Issue : 2 | Page : 32-36 |
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Evaluation of fit accuracy of computer-aided design/computer-aided manufacturing crowns fabricated by three different digital impression techniques using cone-beam computerized tomography
Noha M Salem, Sanaa H Abdel Kader, Fayza Al Abbassy, Amir S Azer
Department of Conservative Dentistry, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
Correspondence Address:
Dr. Noha M Salem
Department of Conservative Dentistry, Faculty of Dentistry, Alexandria University, Alexandria
Egypt
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/2347-4610.190609
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Purpose: The aim of this in vitro study was to evaluate the fit accuracy of computer-aided design (CAD)/computer-aided manufacturing lithium disilicate full contour crowns fabricated by three different digital impression techniques. Materials and Methods: An acrylic upper first molar was prepared to receive a full ceramic crown and used to fabricate ten ceramic master dies using lost wax and heat press techniques. Each ceramic die was seated in a typodont model and ten polyvinyl siloxane impressions were made for the dies and neighboring teeth to fabricate ten stone casts. Three groups of lithium disilicate crowns (n = 10) were fabricated; Group E: Crowns were fabricated by scanning the ten stone casts with in Eos X5 extraoral scanner. Group O: Crowns were fabricated by powder-free scanning of the ten ceramic dies in their typodont models with CEREC Omnicam. Group B: Crowns were fabricated by CEREC Bluecam optical impressions of the ceramic dies in their typodont models after titanium dioxide powder application. All the specimens were milled from IPS e-max CAD blanks. Each crown was evaluated on its die for fit accuracy using computerized cone-beam tomography at seventy measuring points. The variability among the three groups was evaluated using one-way ANOVA test at P < 0.05. Results: No statistically significant difference was found among the three groups for overall results at (P = 0.658), whereas Group E showed significantly better marginal fit with a mean value of 76 ± 39.0 μm at P = 0.047. Conclusions: All tested digital impression techniques showed clinically acceptable accuracy and extraoral scanning significantly enhanced the marginal fit. |
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