Mechanical properties of zirconia reinforced lithium silicate glass-ceramic

Abstract

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±0.17MPam(0.5)), flexural strength (443.63±38.90MPa), elastic modulus (70.44±1.97GPa), and hardness (6.53±0.49GPa) than IC (P<0.001). On the other hand, VS glass-ceramic revealed significantly a higher brittleness index (2.84±0.26μm(-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.

Keywords: Brittleness index; Lithium disilicate; Mechanical properties; Weibull analysis; Zirconia reinforced lithium silicate.