title: Effect of an Extra Hydrophobic Resin Layer on Repair Shear Bond Strength of a Silorane-Based Composite Resin.
abstract: OBJECTIVE
  Composite repair is a minimally invasive and conservative approach. This study aimed to evaluate the effect of an additional hydrophobic resin layer on the repair shear bond strength of a silorane-based composite repaired with silorane or methacrylate-based composite.
  
  
  METHODS
  Sixty bar-shaped composite blocks were fabricated and stored in saline for 72 hours. The surface of the samples were roughened by diamond burs and etched with phosphoric acid; then, they were randomly divided into three groups according to the repairing process: Group 1: Silorane composite-silorane bonding agent-silorane composite; group 2: Silorane composite-silorane bonding agent-hydrophobic resin-silorane composite, and group 3: Silorane composite-silorane bonding agent-hydrophobic resin methacrylate-based composite. Repairing composite blocks measured 2.5×2.5×5mm. After repairing, the samples were stored in saline for 24 hours and thermocycled for 1500 cycles. The repair bond strength was measured at a strain rate of 1mm/min. Twenty additional cylindrical composite blocks (diameter: 2.5mm, height: 6mm) were also fabricated for measuring the cohesive strength of silorane-based composite. The data were analyzed using One-way ANOVA and the post hoc Tukey's test (α=0.05).
  
  
  RESULTS
  Cohesive bond strength of silorane composite was significantly higher than the repair bond strengths in other groups (P<0.001). The repair bond strength of group 3 was significantly higher than that of group 1 (P=0.001).
  
  
  CONCLUSIONS
  Application of an additional hydrophobic resin layer for repair of silorane-based composite with a methacrylate-based composite enhanced the repair shear bond strength.
authors: Associate Professor, Department of Operative Dentistry, Dental Faculty, Tabriz University of Medical Sciences, Tabriz, Iran.
authors: Narmin
authors: N
authors: Mohammadi
authors: Assistant Professor, Dental and Periodontal Research Center, Dental Faculty, Tabriz University of Medical Sciences, Tabriz, Iran; Assistant Professor, Department of Operative Dentistry, Dental Faculty, Tabriz University of Medical Sciences, Tabriz, Iran.
authors: Mahmoud
authors: M
authors: Bahari
authors: Professor, Department of Operative Dentistry, Dental Faculty, Tabriz University of Medical Sciences, Tabriz, Iran.
authors: Soodabeh
authors: S
authors: Kimyai
authors: General Practitioner, Department of Operative Dentistry, Dental Faculty, Tabriz University of Medical Sciences, Tabriz, Iran.
authors: Behnam
authors: B
authors: Rahbani Nobar
keywords: Dental Restoration Repair; Hydrophobic and Hydrophilic Interactions; Shear Strength; Silorane Composite Resin