title: Influence of filler addition, storage medium and evaluation time on biaxial flexure strength and modulus of adhesive systems.
abstract: OBJECTIVE
  This study evaluated the effects of filler addition, storage medium and time on biaxial flexural strength and flexural modulus of six adhesive systems.
  
  
  METHODS
  The adhesives were either unfilled resins: Single Bond, Prime&Bond 2.1 and One-Step; or filled resins: Single Bond Plus, Prime&Bond NT and One-Step Plus. Resin discs of each product (0.5 mm thick × 6.0 mm diameter) were prepared using silicon molds (n = 10). The discs were stored dry, in water, mineral oil or ethanol for 1 week or 3 months before biaxial flexural testing. Data were statistically analyzed by 3-way ANOVA and Tukey's post-hoc test (α = 0.05). The specimens were tested in a universal testing machine at 1.27 mm/min until failure occurred.
  
  
  RESULTS
  In general, the storage in ethanol led to significantly lower flexural strength and flexural modulus values than the other storage conditions for all adhesives in both storage periods. Filler addition increased flexural strength and flexural modulus for Prime&Bond NT, when it was stored dry or in water for 1 week. For Single Bond Plus, the filler addition resulted in higher flexural modulus, when it was stored for 1 week in oil and in ethanol. No significant differences in flexural modulus were observed between One-Step and One-Step Plus in any storage medium.
  
  
  CONCLUSIONS
  Results suggested that filler addition does not necessarily have to increase the flexural strength and flexural modulus. Ethanol and oil storages tended to yield opposite effects.
authors.affiliation: Department of Restorative Dentistry, Operative Dentistry Division, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil. giannini@fop.unicamp.br
authors.forename: Marcelo
authors.initials: M
authors.lastname: Giannini
authors.forename: Michele Santana
authors.initials: MS
authors.lastname: Liberti
authors.forename: César Augusto Galvão
authors.initials: CA
authors.lastname: Arrais
authors.forename: André Figueiredo
authors.initials: AF
authors.lastname: Reis
authors.forename: Donald
authors.initials: D
authors.lastname: Mettenburg
authors.forename: Frederick Allen
authors.initials: FA
authors.lastname: Rueggeberg
mesh_terms: D000704:Analysis of Variance; D003738:Dental Cements; D008422:Materials Testing
chemical_list: D003738:Dental Cements