IN VITRO FRACTURE STRENGTH AND FAILURE OF ZIRCONIA-REINFORCED LITHIUM SILICATE GLASS CERAMICS

Objectives. To evaluate the in vitro fracture strength and failure of crowns made of zirconia-reinforced lithium silicate glass-ceramics, Suprinity. Materials and methods. 40 metal die replicas of the mandibular first molar were fabricated and distributed into two groups: control group (Zr), with porcelain veneered zirconia crowns, and test group (Sp), with crowns made with fully-sintered CAD/CAM blocks of zirconia-reinforced lithium silicate glass-ceramics, Suprinity. Results and discussion. The mean fracture strength of Suprinity crowns was 9300 +/- 545 N, which was statistically significantly higher than the porcelain veneered zirconia crowns, which fractured at a mean value of 4737 +/- 500 N (P=0.0001). Visual analysis of the failure mode showed that zirconia crowns have porcelain veneers chipping without core fracture, whereas Suprinity crowns have bulk fractures. Conclusions. Suprinity crowns are superior to zirconia crowns in terms of their static fracture strength.