title: Shear Bond Strength of Two Types of Glass Ionomer to Bleached Dentin: Effect of Delayed Bonding and Antioxidant Agent.
abstract: BACKGROUND
  Studies have shown a reduction in bond strength of composites and glass ionomer to bleached enamel and dentin. Several methods have been proposed to reverse compromised bond strength.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the effect of delayed bonding and application of antioxidant agent on the bond strength of reinforced self-cured (Fuji IX) and light-cured glass ionomers (Fuji II LC) to bleached dentin.
  
  
  METHODS
  Eighty extracted third molars were randomly divided into 8 groups. Buccal dentin surfaces received different treatments: Two control groups: no treatment + bonding Fuji IX or Fuji II LC. Two immediate bonding groups: bleaching + bonding Fuji IX or Fuji II LC. Two delayed bonding groups: bleaching + 7 days delay + bonding Fuji IX or Fuji II LC. Two sodium ascorbate application groups: Bleaching + application of 10% sodium ascorbate + bonding Fuji IX or Fuji II LC. All samples were tested for shear bond strength. Two-way analysis of variance (ANOVA) was used to compare the mean and standard deviations among groups, followed by the Tukey's test for significant interaction.
  
  
  RESULTS
  No statistically significant difference was detected in shear bond strength of Fuji IX to bleached or normal dentin. Although a significant reduction was found shear bond strength values of Fuji II LC to bleached dentin, no significant difference was observed between no bleaching group and those treated with 10% sodium ascorbate or 7 days of delay in bonding for both types of glass ionomer.
  
  
  CONCLUSIONS
  Bleaching had no significant effect on shear bond strength of Fuji IX to dentin; this type of GI can be used immediately after bleaching.
authors.affiliation: Department of Operative Dentistry, Dental Students Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Ladan Ranjbar
authors.initials: LR
authors.lastname: Omrani
authors.affiliation: Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Siences, Tehran, Iran.
authors.forename: Parastoo
authors.initials: P
authors.lastname: Sabouri
authors.affiliation: Department of Operative Dentistry, School of Dentistry, Tehran University of Medical Siences, Tehran, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Abbasi
authors.affiliation: Department of Operative Dentistry, Dental Students Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Elham
authors.initials: E
authors.lastname: Ahmadi
authors.affiliation: Department of Dental School, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Ghavam
keywords: Antioxidant agent; Bleaching; Bond Strength; Dentine; Glass ionomer