Evaluation of Biaxial Flexural Strength and Shear Bond Strength of a Novel Chair-Side Cad/Cam Pre-crystalized Zirconia Reinforced Lithium Silicate (In-Vitro Study)

Abstract

Statement of problem. Lithium disilicate has been the gold standard for esthetic restorations, however several materials have been introduced to improve the strength without compromising esthetics. Purpose. The objective of this study was to perform a comparison between a newly introduced chair-side pre-crystalized zirconia reinforced lithium silicate material containing virgilite crystals (CEREC Tessera) and lithium disilicate ceramic material (LDS) regarding biaxial flexural strength and shear bond strength. Materials and Methods. For biaxial flexural strength, Twenty disc-shaped specimens, measuring 10 mm in diameter and 1.5 mm in thickness, were manufactured from both Tessera and LDS, with each group consisting of 10 specimens (n = 10The biaxial flexural strength was evaluated using the piston-on-ring method on a universal testing machine. For Shear Bond Strength, 20 cuboid specimens (3x3mm and 5 mm thickness) were fabricated from Tessera and LDS (n = 10). Specimens of both groups were bonded to natural human teeth with dual cured resin cement after appropriate surface treatment for both human natural teeth and specimen discs. The shear bond strength was assessed using a universal testing machine, and the testing was conducted at a cross-head speed of 1 mm/min. Results. The data obtained was statistically analyzed using appropriate tests. As for BFS, difference in results was statistically significant. The mean BFS value was higher for Tessera group (274.58 ± 22.26) compared to the LDS group (243.31 ± 24.98), however the difference in SBS values were not statistically significant between Tessera group (20.97 ± 1.59), although slightly higher, and LDS group (19.18 ± 2.99). The independent t test was used as the test of significance among the groups. Conclusion. Tessera material (zirconia reinforced lithium silicate material containing virgilite crystals) performed better overall than the more time-consuming e.max material ( lithium disilicate ceramic).