title: Durability of composite repair using different surface treatments.
abstract: OBJECTIVE
  To evaluate the surface treatment and hydrophilicity of the bonding agent on the composite repair strength (RS), silver nitrate uptake (SNU), surface roughness (SR) and estimation of surface area (SA).
  
  
  METHODS
  Fifty resin blocks (Opallis, FGM) were polished and divided in 5 groups: no treatment (NT); roughening with a fine (FDB); medium (MDB); coarse-grit (CDB) and 50-μm aluminium oxide sandblasting (AO). A hydrophobic (Adhesive, Scotchbond Multi-Purpose Plus, 3M ESPE) or hydrophilic (Adper Single Bond 2, 3M ESPE) adhesive was applied, followed by composite placement (Opallis, FGM). Composite-composite bonded sticks (0.9 mm2) were tested in tension (1.0mm/min) immediately [IM] or after 6 months [6M] of water storage. Two sticks from each tooth, at each time, were immersed in a 50% silver nitrate solution and evaluated by SEM. A profilometer was used to measure SR. SEM images were used to estimate the SA using the Image J software. Data were analysed by ANOVA and Tukey's tests.
  
  
  RESULTS
  The AO showed the highest CR strength for both adhesives, whilst the NT group showed the lowest, irrespective of the storage period. The diamond burs had intermediate performance. Silver nitrate deposits were seen after 6M for the hydrophilic adhesive. The ranking of SR values (Ra) from the lowest to the highest was: NT<FDB<MDB<AO≤CDB. A higher SA was produced by AO treatment.
  
  
  CONCLUSIONS
  The AO treatment provides the highest CR strength likely due to the high SA produced. The bonding agent did not seem to affect the CR strength after 6M, although early signs of degradation were detected for the hydrophilic system.
  
  
  CONCLUSIONS
  Polished composite should be preferred roughened with aluminium oxide followed by the application of a hydrophobic intermediate agent before composite repair.
authors.affiliation: School of Dentistry, State University of Ponta Grossa, School of Dentistry, Av. General Carlos Cavalcanti, 4748 Ponta Grossa, Paraná CEP 84030-900, Brazil.
authors.forename: Thays Regina Ferreira
authors.initials: TR
authors.lastname: da Costa
authors.forename: Alexandra Mena
authors.initials: AM
authors.lastname: Serrano
authors.forename: Allbens Picardi Faria
authors.initials: AP
authors.lastname: Atman
authors.forename: Alessandro Dourado
authors.initials: AD
authors.lastname: Loguercio
authors.forename: Alessandra
authors.initials: A
authors.lastname: Reis
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003738:Dental Cements / Q000737:chemistry; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D058250:Dental Restoration Repair; D018130:Diamond / Q000737:chemistry; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D016622:Silver Staining; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: C554641:Adper single bond 2; D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; D019279:Resin Cements; C425844:Scotchbond Multi-Purpose Plus; D014867:Water; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; C041979:2,2-bis-(4-(2-methacryloxyethoxy)phenyl)propane; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D018130:Diamond; D000537:Aluminum Oxide