Effect of low-temperature aging on the mechanical behavior of ground Y-TZP

Made available in DSpace on 2015-10-22T06:28:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-05-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) This study evaluated the effects of low-temperature aging on the surface topography, phase transformation, biaxial flexural strength, and structural reliability of a ground Y-TZP ceramic. Disc-shaped specimens were manufactured and divided according to two factors: "grinding" - without grinding (as-sintered, Ctrl), grinding with an extra-fine diamond bur (25 mu m Xfine) and coarse diamond bur (181 mu m Coarse); and "low-temperature-aging" (absence or presence). Grinding was performed using a contra-angle handpiece under water-cooling. Aging was performed in an autoclave at 134 degrees C, under 2 bar, over a period of 20 h. Surface topography analysis showed an increase in roughness based on grit-size (Coarse>Xfine>Ctrl), and aging promoted different effects on roughness (Ctrl AgCoarse). Grinding and aging promoted an increase in the amount of m-phase, although different susceptibilities to degradation were observed. Weibull analysis showed an increase in characteristic strength after grinding (Coarse=Xfine>Ctrl); however, distinct effects were observed for aging (CtrlCoarse Ag). Weibull moduli were statistically similar. Grinding promoted an increase in characteristic strength as a result of an increase in m-phase content; when the Y-TZP surface was ground by coarse diamond burs followed by aging, characteristic strength was reduced, meaning the low-temperature degradation appeared to intensify for rougher Y-TZP surfaces. Copyright (C) 2014 Elsevier Ltd. All rights reserved. Univ Fed Santa Maria, Fac Odontol, PhD Grad Program Oral Sci, Prosthodont Unit, BR-97119900 Santa Maria, RS, Brazil Sao Paulo State Univ UNESP, Inst Sci &Technol, Fac Odontol, Sao Jose Dos Campos, Brazil Univ Sao Paulo, Fac Odontol, Dept Biomat &Oral Biol, BR-09500900 Sao Paulo, Brazil Indiana Univ, Sch Dent, Dept Restorat Dent, Div Dent Biomat, Indianapolis, IN USA Univ Amsterdam, Dept Dent Mat Sci ACTA, Amsterdam, Netherlands Vrije Univ Amsterdam, Amsterdam, Netherlands Univ Fed Santa Maria, Fac Odontol, MSD PhD Grad Programs Oral Sci, Prosthodont Unit, BR-97119900 Santa Maria, RS, Brazil Sao Paulo State Univ UNESP, Inst Sci &Technol, Fac Odontol, Sao Jose Dos Campos, Brazil