title: Effect of Intermediate Agents and Preheated Composites on Repair Bond Strength of Silorane-Based Composites.
abstract: OBJECTIVE
  Repairing composite restorations is a challenging procedure especially when two different types of composites are used. This study aimed to compare the repair strength of silorane-based composite (SC) (Filtek P90) with that of preheated SC, methacrylate composite (MC)(Z250), flowable MC (Filtek Supreme Plus) and different adhesive/composite combinations.
  
  
  METHODS
  Eighty-four SC specimens were fabricated and randomly divided into seven groups (G). In the control group (G7), SC was bonded immediately to SC. The other specimens were water-aged for two months and were then roughened, etched and repaired with the following materials: G1) Silorane Adhesive Bond (SAB)/SC; G2) Preheated SC; G3) SAB/MC; G4) Adper Single Bond (SB)/MC; G5) Flowable MC/MC; G6) Preheated MC. After water storage and thermocycling, the repaired specimens were subjected to shear bond strength testing. The data were analyzed using ANOVA and Tukey's test.
  
  
  RESULTS
  Preheated SC and MC, flowable MC and SAB/SC resulted in bond strength comparable to that of the control group. Preheated SC showed significantly higher bond strength when compared to SAB/MC (P=0.04) and SB/MC (P<0.001). Bond strength of SB/MC was significantly lower than that of the other groups (P<0.05), except for SAB/SC and SAB/MC.
  
  
  CONCLUSIONS
  All repairing materials except for SB/MC resulted in bond strength values comparable to that of the control group. Repair with preheated SC yielded the highest bond strength.
authors.affiliation: Professor, Prevention of Oral and Dental Disease Center, Department of Operative Dentistry, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Fereshteh
authors.initials: F
authors.lastname: Shafiei
authors.affiliation: Assistant Professor, Department of Operative Dentistry, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Sahar
authors.initials: S
authors.lastname: Akbarian
authors.affiliation: Undergruduate Student, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Marzieh
authors.initials: M
authors.lastname: Daryadar
keywords: Composite Resins; Dental Restoration Repair; Shear Strength; Silorane Composite Resin