ABSTRACT
Aim: The goal of this study is to evaluate the impact of thermocycling on fracture strength and marginal adaptation of anterior endocrowns fabricated from two different types of lithium disilicate.
Material and Method: Twenty-four freshly extracted human maxillary upper central incisors were selected from the outpatients' clinic of the surgery department, Faculty of Dentistry, Minya University. The teeth were divided into two groups: Tessera and Emax CAD. The teeth were prepared for endo-crown restoration, and the endo-crowns were fabricated using CAD/CAM technology. A thermal cycling simulation device was utilized to subject all the study samples to 5000 cycles,cold water bath immersion for 30 seconds at 5 degrees the hot water bath immersion for 30 seconds at 55 degree dewll time 10 seconds to simulate temperature fluctuations in oral cavity. Marginal gaps were measured pre- and post-cementation using a stereomicroscope at various points. Fracture resistance was evaluated by subjecting the specimens to compressive loading until failure. Statistical analysis was performed to compare the marginal gaps and fracture resistance between the two groups.
Results: Both before and after cementation, the Tessera and Emax CAD groups' total marginal gaps did not differ significantly, according to the data. However, A considerable difference in fracture resistance was found., whereas Emax CAD exhibited more resistance in contrast to Tessera. The improved mechanical characteristics, chemical makeup, and microstructure of Emax CAD are responsible for its increased resistance to fracture.