Subcritical crack growth and in vitro lifetime prediction of resin composites with different filler distributions
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
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Data(s) |
22/10/2013
22/10/2013
01/09/2012
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Resumo |
Objectives. Verify the influence of different filler distributions on the subcritical crack growth (SCG) susceptibility, Weibull parameters (m and sigma(0)) and longevity estimated by the strength-probability-time (SPT) diagram of experimental resin composites. Methods. Four composites were prepared, each one containing 59 vol% of glass powder with different filler sizes (d(50) = 0.5; 0.9; 1.2 and 1.9 mu m) and distributions. Granulometric analyses of glass powders were done by a laser diffraction particle size analyzer (Sald-7001, Shimadzu, USA). SCG parameters (n and sigma(f0)) were determined by dynamic fatigue (10(-2) to 10(2) MPa/s) using a biaxial flexural device (12 x 1.2 mm; n = 10). Twenty extra specimens of each composite were tested at 10(0) MPa/s to determine m and sigma(0). Specimens were stored in water at 37 degrees C for 24 h. Fracture surfaces were analyzed under SEM. Results. In general, the composites with broader filler distribution (C0.5 and C1.9) presented better results in terms of SCG susceptibility and longevity. C0.5 and C1.9 presented higher n values (respectively, 31.2 +/- 6.2(a) and 34.7 +/- 7.4(a)). C1.2 (166.42 +/- 0.01(a)) showed the highest and C0.5 (158.40 +/- 0.02(d)) the lowest sigma(f0) value (in MPa). Weibull parameters did not vary significantly (m: 6.6 to 10.6 and sigma(0): 170.6 to 176.4 MPa). Predicted reductions in failure stress (P-f = 5%) for a lifetime of 10 years were approximately 45% for C0.5 and C1.9 and 65% for C0.9 and C1.2. Crack propagation occurred through the polymeric matrix around the fillers and all the fracture surfaces showed brittle fracture features. Significance. Composites with broader granulometric distribution showed higher resistance to SCG and, consequently, higher longevity in vitro. (C) 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. federal grant agency CAPESMEC (Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior), Brazil federal grant agency CAPES-MEC (Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior), Brazil |
Identificador |
DENTAL MATERIALS, OXFORD, v. 28, n. 9, pp. 985-995, SEP, 2012 0109-5641 http://www.producao.usp.br/handle/BDPI/35520 10.1016/j.dental.2012.05.001 |
Idioma(s) |
eng |
Publicador |
ELSEVIER SCI LTD OXFORD |
Relação |
DENTAL MATERIALS |
Direitos |
closedAccess Copyright ELSEVIER SCI LTD |
Palavras-Chave | #RESIN COMPOSITES #DYNAMIC FATIGUE #SUBCRITICAL CRACK GROWTH #WEIBULL ANALYSIS #STRENGTH-PROBABILITY-TIME DIAGRAM #FRACTOGRAPHY #MECHANICAL-PROPERTIES #DENTAL COMPOSITE #RESTORATIVE MATERIALS #DYNAMIC FATIGUE #CLINICAL-PERFORMANCE #POSTERIOR COMPOSITES #NANOFILL COMPOSITE #FRACTURE-TOUGHNESS #ALUMINA CERAMICS #FOLLOW-UP #DENTISTRY, ORAL SURGERY & MEDICINE #MATERIALS SCIENCE, BIOMATERIALS |
Tipo |
article original article publishedVersion |