Mechanical properties of zirconia reinforced lithium silicate glass-ceramic

Objective. The aim of this study was to assess the mechanical properties of recently introduced zirconia reinforced lithium silicate glass-ceramic. Methods. Two types of CAD/CAM glass-ceramics (Vita Suprinity (VS); zirconia reinforced lithium silicate and IPS e.max CAD (IC); lithium disilicate) were used. Fracture toughness, flexural strength, elastic modulus, hardness, brittleness index, and microstructures were evaluated. Data were analyzed using independent t tests. Weibull analysis of flexural strength data was also performed. Results. VS had significantly higher fracture toughness (2.31 +/- 0.17 MPa m(0.5)), flexural strength (443.63 +/- 38.90 MPa), elastic modulus (70.44 +/- 1.97 GPa), and hardness (6.53 +/- 0.49 GPa) than IC (P < 0.001). On the other hand, VS glass-ceramic revealed significantly a higher brittleness index (2.84 +/- 0.26 mu m(-1/2)) (lower machinability) than IC glass-ceramic (P < 0.05). VS demonstrated a homogeneous fine crystalline structure while, IC revealed a structure with needle-shaped fine-grained crystals embedded in a glassy matrix. The VS glass-ceramic revealed a lower probability of failure and a higher strength than IC glass-ceramic according to Weibull analysis. Significance. The VS zirconia reinforced lithium silicate glass-ceramic revealed higher mechanical properties compared with IC lithium disilicate glass-ceramic. (C) 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.