Effect of Different Veneering Techniques on the Fracture Resistance of Bioceramic Lithium Disilicate Ceramics Crowns

Aim: The effect of three different veneering techniques (layering, press-over, and CAD/CAM techniques) on the fracture resistance of lithium disilicate crown (LDC). Material and Methods: Thirty lithium disilicate crowns were adhesively cemented on the standardized Epoxy die. LDC was fabricated according to the veneering materials and techniques into three groups (n = 10): group (LV) layering veneering technique, group (PV) pressed veneering technique, and group DV (CAD/CAM) technique. The specimen was artificially aged through dynamic loading and thermocycling. All specimens were tested for fracture resistance using compressive load. Descriptive statistics of frequency distribution mean and standard deviations were calculated and compared across different groups. ANOVA was used to evaluate the effect of the veneering technique on fracture resistance. Results: The highest load was demonstrated in the DV group (1057.26762±97.04401 N) and the lowest load was found in PV group (762.41229±102.56927 N). Similarly, the highest fracture resistance was observed in group DV (14.65171±1.34484 MPa), and the lowest was found in group PV group (10.56558±1.42141 MPa). Mean values of maximum loads and fracture resistance in veneers fabricated by digital, pressed, and layer veneering techniques showed a significant difference. Conclusion: The CAD/CAM veneered monolithic lithium disilicate crowns demonstrated superior fracture resistance compared to the lithium disilicate crowns fabricated by over-pressing and layering techniques.