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Marginal gap and internal fit of CEREC e.max and Celtra Duo crowns

University of British Columbia

Objectives: To compare marginal and internal fit as well as marginal chipping of e.max (EM) and Celtra Duo (CD) all-ceramic crowns fabricated using chairside economical restoration of esthetic ceramics (CEREC) system. Material and Methods: Tooth # 15 was prepared for an all-ceramic crown on an ivorine typodont. A total of 15 CD and 15 EM crowns were designed and fabricated using CEREC Omnicam and CEREC MC XL milling chamber. Micro-computed tomography (micro-CT) was utilized to assess marginal and internal fit of crowns in both groups. Marginal gap (MG) measurements were done at 20 systematically selected points per crown. Internal gap (IG) was measured at 70 systematically selected points in each crown. Crowns with MG > 120 μm at more than five points were considered unacceptable. Clinical assessment was considered as an additional criterion for rejecting unacceptable crowns. Clinical assessment was done according to United States Public Health Service (USPHS) criteria that scores clinically acceptable restorations as Alpha and Bravo and unacceptable restorations as Charlie and Delta. A scanning electron microscope (SEM) was used to evaluate the extent and severity of marginal chipping. Results: CD crowns had significantly smaller MG (46 ± 25.42 µm) as compared to EM crowns (65 ± 29.08 µm) (p-values<0.05). CD crowns had smaller IG than did EM crowns (44 ± 36.94 μm and 54.9 ± 35.38 μm, respectively). Overall, two EM crowns were deemed unacceptable based on micro-CT assessment, while all crowns in the CD group were deemed acceptable. Based on clinical assessment, twelve crowns were clinically acceptable (eight Alpha and four Bravo), and three crowns were deemed unacceptable and scored Charlie in EM group. In the CD group, all crowns were clinically acceptable (twelve Alpha and three Bravo). Based on SEM assessment, the extent of chipping was larger in CD than in EM crowns while the severity of chipping was higher in EM crowns than in the CD group. Conclusion: While the mean MGs for crowns in both groups were clinically acceptable, there were three unacceptable crowns in the EM group. There were no significant differences in the internal fit nor in marginal chipping.

Text

2019-08-26

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/71449

Craniofacial Science

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/