title: Effect of surface treatment on micro shear bond strength of two indirect composites.
abstract: OBJECTIVE
  To determine the effect of surface treatment on micro shear bond strength of two indirect composites.
  
  
  METHODS
  Blocks of 2 × 7 × 20 mm dimensions were made from two kinds of resin composites, Gradia and Signum plus. Samples were subjected to secondary curing to complete polymerization. They were divided into five groups: control without any preparation, second group sandblasted with aluminum oxide, third, fourth and fifth groups were lased under a beam of 0.5, 1 and 2 W respectively. Panavia resin cement was placed on the composite blocks using tygon tubes and cured and micro shear bond strength was measured. One sample of each group was observed under electronic microscope. Data was analyzed by two-way ANOVA and Tukey's multiple comparison tests.
  
  
  RESULTS
  For Gradia composite, the sandblasted group showed highest strength (25.7±2.9 MPa) followed by the laser beam of 1 W group (with 23.6± 2.8 MPa). In Signum composite, the laser beam of 1 W (21.4±4.2 MPa) showed the highest strength followed by the sandblasted group (with 19.4±3.2 MPa).
  
  
  CONCLUSIONS
  Surface treatments using sandblast and laser beam of 1W power along with silane are two effective methods to increase the bond strength of composites.
authors.affiliation: Department of Operative Dentistry, School of Dentistry, Shaheed Beheshti University of Medical Sciences, Dental College, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Moezizadeh
authors.forename: Zahra Jaberi
authors.initials: ZJ
authors.lastname: Ansari
authors.forename: Fatemeh Matin
authors.initials: FM
authors.lastname: Fard