Análise de diferentes protocolos de usinagem em CAD/CAM para zircônias policristalinas

Abstract

The objective of the study is to investigate the effect of different machining protocols in CAD/CAM on the behavior of polycrystalline zirconia. Two types of zirconia were studied, a conventional 3Y-TZP (3Y) and a translucent 5Y-PSZ (5Y). Disc-shaped specimens (n=15) were machined using three different CAD/CAM machining protocols: smooth (S), normal (N) and fast (R). The surface topography of the discs was analyzed with a rugosimeter and SEM. Five disks from each group were submitted to the resistance test to biaxial flexion (f). Ten disks from the 5Y-N and 5Y-R groups were submitted to the fatigue test using a pneumatic mechanical cycler. Roughness data were analyzed with Kruskal-Wallis test and Student-Newman-Keuls test (=0.05), f data were analyzed with two-way ANOVA (factor 1: material, factor 2: protocol machining) and Tukey's test (α=0.05). Fatigue data were analyzed with Kaplan-Meier (α=0.05). SEM analysis showed different surface patterns for different protocols. There was a difference between the groups for the roughness parameters, with the 3Y-S group having the highest median. 3Y showed greater f than 5Y. The S protocol resulted in higher f values than the R protocol. In the fatigue test, no difference was found between the survival curves of the 5Y specimens machined with the N and R protocol. the type of CAD/CAM machining protocol affects the properties of polycrystalline zirconia.