Mrginal Accuracy of Hybrid and different Machinable Ceramic Crowns

Purpose: The aim of the present study was to evaluate marginal accuracy of hybrid and different ceramic crowns.
Material and Methods: Forty sound human maxillary central incisors were selected and received standardized preparation with shoulder finish line. They were divided into four groups according to the material of construction: Group I: VITA Enamic , Group II: E.max CAD, Group III Celtra-Duo ,Group IV: VIA Suprinity (n=10). The crowns were fabricated from blocks using CAD/CAM system. All crowns were cemented using self adhesive resin cement. Marginal discrepancy (pre and post cementation) was tested for all samples. Data were tabulated and statistically analyzed. The results were collected, arranged and tabulated to be statistically analyzed. Results: The highest mean value of marginal gap was found in E-max cad group, followed by Celtra-Duo group, followed by VITA Suprinity group while the lowest mean value was found in VITA Enamic group. The samples of VITA Enamic showed the lower marginal gap values compared to the other samples either before (29.5 μm ± 1.5) or after cementation 20.97 μm ± 1.45). The samples of E-max cad showed the highest marginal gap values compared to the other samples either before (33.8 μm ± 0.75) or after cementation (30.6 μm ±.0.6). Conclusion: Hybrid ceramics crowns introduced the highest marginal accuracy while E-max cad crowns introduced the lowest marginal accuracy. Zirconia reinforced Lithium silicate restorations, particularly the partially crystalline form, introduced better marginal accuracy than Hybrid ceramics restorations.