Objective: the aim of this study was to evaluate the flexural strength (FS) of a commercially available Y-TZP zirconia (Lava, 3M ESPE) after grinding and heat treatment.
Method: Sixty-four bar-shaped specimens were obtained and randomly divided into 4 groups (n=16): control (C); control and heat-treated (CHT) (20 ✕ 4.0 ✕ 1.2 mm); ground (G); ground and heat-treated (GHT) (20 ✕ 4.0 ✕ 1.5 mm). The ground thickness (0.3 mm) was standardized by a custom-made device, and performed using a diamond bur (4Zr, Komet-Brasseler) in a high-speed handpiece, under constant water irrigation. CHT and GHT groups were heat-treated at 1000 °C during 30 min. Four-point bending test was conducted in artificial saliva at 37 °C in a MTS-810 machine (10 kN, 0.5 mm/min), according to ISO 6872. Data were analyzed by two-way ANOVA and Tukey’s test (α=.05).
Result: the FS of GHT group (848.7 MPa) was statistically similar to the G group (894.6 MPa). Moreover, only G group exhibits higher FS than the C (741.3 MPa) and CHT (810.1 MPa) groups.
Conclusion: FS increases with the grinding procedure, tending to diminish after heat-treatment of the ground specimens.