title: Flexural strength of a composite resin light cured with different exposure modes and immersed in ethanol or distilled water media.
abstract: OBJECTIVE
  The aim of this in vitro study was to evaluate the flexural strength of a composite resin polymerized with three different modes of light exposure.
  
  
  METHODS
  The three different modes of light exposure were conventional, 600 mW/cm2/40s; soft start, 300 mW/cm2/10s + 600 mW/cm2/30s; pulse delay, 600 mW/cm2/1s + 60 s of waiting time + 600 mW/cm2/39s). Twenty samples were prepared for each polymerization method. Flexural strength (FS) tests were carried out with a 2 kN load at a speed of 0.5 mm/ min. All tested groups were submitted to analysis of variance (one-way-ANOVA) and Tukey's test (P < 0.05).
  
  
  RESULTS
  When stored in water, conventional and pulse delay groups presented higher FS values which were statistically different from the soft start group. When stored in 100% ethanol, conventional and soft start groups presented higher FS values which were statistically different from the pulse delay group.
  
  
  CONCLUSIONS
  Different polymerization modes and immersion media can affect the physical properties (flexural strength) of composite resin.
authors.affiliation: Department of Restorative Dentistry, Dental School of Três Corações, Vale do Rio Verde University, UNINCOR, Três Corações, Brazil.
authors.forename: Saulo Galvão
authors.initials: SG
authors.lastname: Dos Santos
authors.forename: Marcos Ribeiro
authors.initials: MR
authors.lastname: Moysés
authors.forename: Carlos Eduardo Pinto
authors.initials: CE
authors.lastname: Alcântara
authors.forename: José Carlos Rabelo
authors.initials: JC
authors.lastname: Ribeiro
authors.forename: João Gustavo Rabelo
authors.initials: JG
authors.lastname: Ribeiro
keywords: Composites resins; flexural strength; polymerization modes; storage media