title: Effect of combinations of surface treatments and bonding agents on the bond strength of repaired composites.
abstract: BACKGROUND
  Enhancement of bond strength between new and old composite usually requires increasing the surface roughness to promote mechanical interlocking and coating of old composite with unfilled resin bonding agents to advance surface wetting and chemical bonding.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the effect of combinations of surface treatments and bonding agents on the shear bond strength between new and old composite.
  
  
  METHODS
  Six surface treatments, two bonding agents, and an untreated control comprised 18 different subgroups.
  
  
  RESULTS
  The use of unfilled resin, alone or combined with silane, was the most effective procedure to enhance the shear bond strength of the repaired composite specimens, irrespective of the surface pretreatment processes. Silanation and unfilled resin slightly but not significantly improved the repair strength compared with unfilled resin alone.
  
  
  CONCLUSIONS
  Different combinations of surface treatments and bonding agents affect shear bond strength differently. The highest shear bond strength values were achieved by grinding the surface with green Carborundum stone or sandblasting, whereas the lowest values were obtained with hydrofluoric acid as the surface treatment agent.
authors.affiliation: Section of Oral Rehabilitation, Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel.
authors.forename: T
authors.initials: T
authors.lastname: Brosh
authors.forename: R
authors.initials: R
authors.lastname: Pilo
authors.forename: N
authors.initials: N
authors.lastname: Bichacho
authors.forename: R
authors.initials: R
authors.lastname: Blutstein
mesh_terms: D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods*; D003775:Dental Polishing; D017269:Dental Prosthesis Repair / Q000379:methods; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D006858:Hydrofluoric Acid; D008422:Materials Testing; D012821:Silanes; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D003188:Composite Resins; D012821:Silanes; D017438:Bisphenol A-Glycidyl Methacrylate; D006858:Hydrofluoric Acid