Assessment of Fracture Force of CAD-CAM-fabricated Occlusal Veneer Restorations with Different Thicknesses

Purpose: To evaluate the fracture force of occlusal veneer restorations using ceramic material (Lithium di-silicate) and hybrid ceramic (VITA Enamic) Computer Aided Desingn/Computer Aided Manufacturer (CAD/CAM) material at different thicknesses after thermocycling. Material and Method: Thirty CAD/CAM occlusal veneer restorations were fabricated from group E (IPS e.max CAD), V (VITA Enamic) and divided into subgroups according to thickness 0.3, 0.6, 1 mm. The occlusal veneers were luted to epoxy dies (n=5). The specimens were subjected to thermocycling test then they were subjected to load until fracture using a computer controlled materials testing machine. Data were tabulated and statistically analyzed using Two-ways analysis of variance (ANOVA). Results: There was no significant difference in the fracture force between the two materials regardless the thickness. The fracture force increases with the increase of the thickness. Conclusion: VITA Enamic hybrid ceramic material is closer to IPS e.max CAD ceramic material in the fracture force. With the increase of thickness, it leads to increase of fracture force. Clinical Implication: Within the limitation of this in-vitro study, hybrid ceramic (VITA ENAMIC) and IPS e.max CAD are clinically applicable as occlusal veneer restoration with thickness 0.6 mm and more.