Efeitos de diferentes estratégias de usinagem com CAD/CAM no desempenho mecânico de uma vitro-cerâmica

Abstract

The objective of the present study was to evaluate the mechanical properties of the zirconia-reinforced lithium silicate glass-ceramic (ZLS - Vita Suprinity) produced by CAD/CAM technology. The specimens (CP) were produced in disk format with dimensions of 12 mm in diameter and 1.2 mm in thickness, using two machining protocols in CAD/CAM, one smooth (S) and one standard (N – normal) (n=17). The biaxial flexion test (piston-on-three-balls) was performed in a universal testing machine, in water at 37º C (n=5). Twelve PCs from each group were submitted to the cyclic fatigue test in a pneumatic mechanical cycler, with a load of 30 N and a frequency of 2Hz, in water at 37ºC. such as microstructure analyses. Flexion data were analyzed with ANOVA; fatigue data were analyzed with Kaplan-Meier (α=0.05). In the SEM analyses, it was observed that 4 had greater chipping on the edges of the PCs machined by the standard protocol, however, there was no difference in the surface of the samples in both groups, both before and after crystallization. There was no difference between groups for biaxial flexion (p=0.250). In the fatigue test, there was also no statistical difference for the survival curves between the groups (p=0.822). It is concluded that the type of CAD/CAM machining protocol does not affect the mechanical behavior of the ZLS.