Fatigue stipulation of bulk-fill composites: An in vitro appraisal

Shruti A. Vidhawan, Adrian U. Yap, Barbara P. Ornaghi, Agnieszka Banas, Krzysztof Banas, Jennifer C. Neo, Carmem S. Pfeifer, Vinicius Rosa

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Abstract Objectives The aim of this study was to determine the Weibull and slow crack growth (SCG) parameters of bulk-fill resin based composites. The strength degradation over time of the materials was also assessed by strength-probability-time (SPT) analysis. Methods Three bulk-fill [Tetric EvoCeram Bulk Fill (TBF); X-tra fil (XTR); Filtek Bulk-fill flowable (BFL)] and a conventional one [Filtek Z250 (Z250)] were studied. Seventy five disk-shaped specimens (12 mm in diameter and 1 mm thick) were prepared by inserting the uncured composites in a stainless steel split mold followed by photoactivation (1200 mW/cm2/20 s) and storage in distilled water (37°C/24 h). Degree of conversion was evaluated in five specimens by analysis of FT-IR spectra obtained in the mid-IR region. The SCG parameters n (stress corrosion susceptibility coefficient) and σf0 (scaling parameter) were obtained by testing ten specimens in each of the five stress rates: 10-2, 10-1, 100, 101 and 102 MPa/s using a piston-on-three-balls device. Weibull parameter m (Weibull modulus) and σf0 (characteristic strength) were obtained by testing additional 20 specimens at 1 MPa/s. Strength-probability-time (SPT) diagrams were constructed by merging SCG and Weibull parameters. Results BFL and TBF presented higher n values, respectively (40.1 and 25.5). Z250 showed the highest (157.02 MPa) and TBF the lowest (110.90 MPa) σf0 value. Weibull analysis showed m (Weibull modulus) of 9.7, 8.6, 9.7 and 8.9 for TBF, BFL, XTR and Z250, respectively. SPT diagram for 5% probability of failure showed strength decrease of 18% for BFL, 25% for TBF, 32% for XTR and 36% for Z250, respectively, after 5 years as compared to 1 year. Significance The reliability and decadence of strength over time for bulk-fill resin composites studied are, at least, comparable to conventional composites. BFL shows the highest fatigue resistance under all simulations followed by TBF, while XTR was at par with Z250.

Original languageEnglish (US)
Article number2577
Pages (from-to)1068-1074
Number of pages7
JournalDental Materials
Issue number9
StatePublished - Sep 1 2015


  • Dynamic fatigue
  • Resin composites
  • Strength degradation
  • Strength-probability-time diagram
  • Subcritical crack growth
  • Weibull analysis

ASJC Scopus subject areas

  • Materials Science(all)
  • Dentistry(all)
  • Mechanics of Materials


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