Internal Fit and Marginal Adaptation of Posterior CAD/CAM Crowns Fabricated from Fully Crystallized Lithium Disilicate Compared to Partially Crystallized Lithium Disilicate with Two Finish Line Thicknesses: An In Vitro Study.

AIM: This study aimed to evaluate internal fit and marginal adaptation of posterior CAD/CAM crowns fabricated from partially crystallized lithium disilicate and fully crystallized lithium disilicate with two finish line thicknesses (0.5 mm chamfer and 1 mm round shoulder). METHODOLOGY: In this in vitro study, 20 sound extracted human molar teeth were collected. The teeth were prepared using a dental surveyor. Teeth were divided into main groups: Group I partially crystallized e.max CAD (Em) and Group II fully crystallized Initial LiSi (Li). Each group was subdivided according to finish line thicknesses into 0.5 mm chamfer and 1 mm round shoulder finish lines. All samples were tested for internal fit by triple scanning technique and the marginal adaptation was measured by stereomicroscope before cementation. RESULTS: The results showed that the finish line thicknesses (0.5 mm chamfer,1 mm round shoulder) had no statistically significant effect on mean internal fit (p = 0.954). Ceramic types: Em and Li had no statistically significant effect on mean internal fit (p = 0.902). Regarding the marginal adaptation, Em showed statistically significantly higher mean marginal gap distance than Li (p < 0.001). CONCLUSION: The finish line thicknesses did not affect the internal fit or marginal adaptation values. Ceramic types did not affect the internal fit values. The marginal adaptation of Em was lower than Li. CLINICAL SIGNIFICANCE: GC Initial Lisi produced comparable results to the gold standard IPS e.max CAD, thus it can be used due to its clinically acceptable internal fit and marginal adaptation. How to cite this article: ElGendy M, Sherif R, Rabie K. Internal Fit and Marginal Adaptation of Posterior CAD/CAM Crowns Fabricated from Fully Crystallized Lithium Disilicate Compared to Partially Crystallized Lithium Disilicate with Two Finish Line Thicknesses: An In Vitro Study. J Contemp Dent Pract 2024;25(8):740-744.