title: Two-year interfacial bond durability and nanoleakage of repaired silorane-based resin composite.
abstract: OBJECTIVE
  To investigate the effect of silane primer application, intermediate adhesive agent/repair composite, and storage period on the interfacial microtensile bond strength (μTBS) of repaired silorane-based resin composite compared with unrepaired composites and on the nanoleakage.
  
  
  METHODS
  Forty-eight 1-month-old substrate specimens from Filtek P90 were roughened, etched, and distributed over two groups (n=24) based on receiving silane (Clearfil Ceramic Primer) or not. Then, half of the specimens (n=12) were repaired with P90 System Adhesive/Filtek P90 and the other half with Adper Scotchbond Multipurpose adhesive/Filtek Z250 resin composite. Within each repair category, repaired specimens were stored in artificial saliva at 37°C for either 24 hours (n=6) or two years before being serially sectioned into sticks (0.6 ± 0.01 mm(2)). From each specimen, two sticks were prepared for nanoleakage determination and four sticks were used for μTBS testing. Additional unrepaired specimens from each composite (n=12) were made to determine the cohesive strength at 24 hours and two years. Mean μTBS were calculated and statistically analyzed. Modes of failure were also determined.
  
  
  RESULTS
  General linear model analysis revealed no significant effect for the silane priming, intermediate adhesive agent/repair composite, and storage period or for their interactions on the μTBS values of the repaired specimens. There was no significant difference between the cohesive strength of Filtek P90 and Filtek Z250; both were significantly higher than all repaired categories. At 24 hours, nanoleakage was not detected when silorane-based composite was repaired with the same material. However, after two years, all repair categories showed nanoleakage.
  
  
  CONCLUSIONS
  Silane application has no effect on μTBS and nanoleakage. Durability of the interfacial bond of repaired silorane-based resin composite appeared successful regardless of the chemistry of the intermediate adhesive agent/composite used for repair. However, nanoleakage was detected early when a different repair intermediate adhesive agent/composite was used.
authors.affiliation: Cairo University, Restorative, Cairo, Egypt. enasmobarak@hotmail.com
authors.forename: E
authors.initials: E
authors.lastname: Mobarak
authors.forename: H
authors.initials: H
authors.lastname: El-Deeb
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods; D003763:Dental Leakage / Q000145:classification*; D003764:Dental Materials / Q000737:chemistry*; D018130:Diamond / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012464:Saliva, Artificial / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D062047:Silorane Resins / Q000737:chemistry*; D016622:Silver Staining; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors
chemical_list: D017554:Carbon Compounds, Inorganic; D003188:Composite Resins; D003764:Dental Materials; C444701:Filtek Z250; D010756:Phosphoric Acids; D019279:Resin Cements; D012464:Saliva, Artificial; C084018:Scotchbond Multi-Purpose; D012821:Silanes; D017655:Silicon Compounds; D062047:Silorane Resins; C544925:filtek P90; D018130:Diamond; C030242:phosphoric acid; C022088:silicon carbide