| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1427995 | Materials Science and Engineering: C | 2016 | 8 Pages |
•Two stimuli that Y-TZP monolithic restoration is submitted clinically were studied.•Grinding showed not to be detrimental to biaxial flexure strength of Y-TZP.•Low temperature aging did not promote deleterious impact at biaxial flexure strength of Y-TZP.•An increase in m-phase content was observed for control group (notable increase) and ground groups (less intense increase).•Low temperature aging did not affect roughness, while grinding promoted increase as function of grit size.
This study aimed to investigate the effects of grinding with diamond burs and low-temperature aging on the mechanical behavior (biaxial flexural strength and structural reliability), surface topography, and phase transformation of a Y-TZP ceramic for monolithic dental restorations. Disc-shaped specimens (Zirlux FC, Ivoclar Vivadent) were manufactured according to ISO 6872 (2008) and divided in accordance with two factors: “grinding — 3 levels” and “LTD — 2 levels”. Grinding was performed using a contra-angle handpiece under constant water-cooling with different grit-sizes (extra-fine and coarse diamond burs). LTD was simulated in an autoclave at 134 °C, under a pressure of 2 bar, over a period of 20 h. Surface topography analysis showed an increase in roughness based on surface treatment grit-size (Coarse > Xfine > Ctrl), LTD did not influence roughness values. Both grinding and LTD promoted an increase in the amount of m-phase, although different susceptibilities to degradation were observed. According to existing literature the increase of m-phase content is a direct indicative of Y-TZP degradation. Weibull analysis showed an increase in characteristic strength after grinding (Coarse = Xfine > Ctrl), while for LTD, distinct effects were observed (Ctrl < Ctrl LTD; Xfine = Xfine LTD and Coarse = Coarse LTD). Weibull moduli were statistically similar between all tested groups. Within the limits of this current study, it was feasible to notice that both aging in autoclave for 20 h (LTD) and grinding showed not to be detrimental to the mechanical properties of Zirlux FC Y-TZP ceramic.
