title: Can the method of primer application influence adhesion to Er:YAG-laser irradiated dentin?
abstract: OBJECTIVE
  The aim of this study was to evaluate how cavity preparation and primer application methods influence the adhesion of composite resin to dentin using a self-etching system.
  
  
  METHODS
  Forty-eight extracted, sound human molars were divided into six groups (n=8) according to the method used for the surface preparation of the teeth (#600-grit paper disc, diamond bur, and Er:YAG laser) and the primer application method utilized (active or passive). Following the adhesive procedure using a self-etching system, 5 mm high composite buildups were created with Z-250 composite resin. After storage in water at 37 degrees C for 24 hours, the specimens were vertically sectioned into serial 1 mm2 sticks and tested for microtensile strength (micro-TBS). Nine additional molars were prepared for morphological analysis using scanning electron microscopy (SEM).
  
  
  RESULTS
  Statistical analysis showed surface preparation technique (p < 0.00) and primer application methods (p < 0.001) do influence bond strength of the self-etching system tested. The best adhesion was achieved with specimens having the dentin ground with sandpaper followed by those ground with diamond burs. The worst bonding was obtained with Er:YAG laser ablated dentin. The active primer application method increased bonding performance compared to the passive method.
  
  
  CONCLUSIONS
  Within the limitations of the study, it can be stated surface treatment can influence the bond strength of the self-etching system tested and the active primer application method is more effective in achieving success in bonding to dentin compared with the passive application method.
  
  
  CONCLUSIONS
  Clinicians should use the active application method to apply a mild acidic self-etching primer along with an appropriate tooth surface preparation to facilitate the bond strength between dentin and composite resin.
authors.affiliation: Department of Dentistry, School of Dentistry, University of São Paulo, São Paulo, Brazil. sbbotta@usp.br
authors.forename: Sergio B
authors.initials: SB
authors.lastname: Botta
authors.forename: Samuel N
authors.initials: SN
authors.lastname: Vieira
authors.forename: Rosely
authors.initials: R
authors.lastname: Cordon
authors.forename: Marcia M
authors.initials: MM
authors.lastname: Marques
authors.forename: Adriana B
authors.initials: AB
authors.lastname: Matos
mesh_terms: D003188:Composite Resins; D001840:Dental Bonding / Q000379:methods*; D003737:Dental Cavity Preparation / Q000295:instrumentation / Q000379:methods*; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents; D006801:Humans; D053844:Lasers, Solid-State; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008963:Molar; D019279:Resin Cements; D016369:Smear Layer; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: C438313:Clearfil SE Bond; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; D019279:Resin Cements