Mechanical behavior of a Y-TZP ceramic for monolithic restorations: effect of grinding and low-temperature aging

Made available in DSpace on 2019-09-12T16:53:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2016Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Netherlands Organization for International Cooperation in Higher Education (NUFFIC)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 degrees 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. (C) 2016 Elsevier B.V. All rights reserved.[Pereira, G. K. R.; Rippe, M. P.; Valandro, L. F.] Univ Fed Santa Maria, MDS PhD Grad Program Oral Sci, Floriano Peixoto 1184, BR-97015372 Santa Maria, RS, Brazil[Silvestri, T.; Camargo, R.] Univ Fed Santa Maria, Fac Odontol, Floriano Peixoto 1184, BR-97015372 Santa Maria, RS, Brazil[Amaral, M.] Universidade de Taubaté (Unitau), MDS PhD Grad Program Dent[Pereira, G. K. R.; Kleverlaan, C. J.] Univ Amsterdam, Acad Ctr Dent Amsterdam ACTA, Dept Dent Mat Sci, Amsterdam, Netherlands[Pereira, G. K. R.; Kleverlaan, C. J.] Vrije Univ Amsterdam, Amsterdam, Netherland