ABSTRACT
Background: Ceramic inlays have picked up prominence due to their superior esthetic characteristics and work-ability. In addition, they allow chair-side restorations to be completed in one appointment.
Objective: The aim of this study was to assess the in-vitro fracture resistance of three CAD/CAM ceramic materials.
Materials and Method: Mesio-occluso-distal (MOD) inlays (n=33) were fabricated from three CAD/CAM materials: Lithium disilicate glass ceramic (IPS-EMAX CAD), Zirconia-reinforced lithuim silicate (CELTRA-DUO) and hybrid composite filled with zirconium silicate particles (SHOFU HC BLOCK). Digital impressions of the inlay cavities prepared in the maxillary first premolar teeth were taken by CEREC scanner then the restorations were milled using CEREC MCXL milling machine.
Samples were cemented to MOD inlay cavities with resin cement (RelyX U200, 3M ESPE) and then fracture resistance test was performed by the Universal Testing Machine.
Results: The fracture resistance values of inlays fabricated from lithium disilicate EMAX CAD (1104.627) was higher than those from CELTRA DUO (937.024) followed by those of SHOFU (724.417). There was a statistical significance between group A (EMAX) and group C (SHOFU) p=0.005. The mode of failure of the restorations presented mixed types of failure (cohesive and catastrophic).
Conclusion: Strengthening with zirconia particles did not have a positive influence on the fracture resistance of neither the glass ceramic nor the composite resin materials tested.