title: Influence of Er:YAG laser surface treatment and primer application methods on microtensile bond strength self-etching systems.
abstract: OBJECTIVE
  The aim of this in vitro study was to evaluate how surface preparation and primer application technique can influence the microtensile bond strength of self-etching system.
  
  
  BACKGROUND
  One of the possible applications of dental lasers includes increasing the quality of bond strength.
  
  
  METHODS
  12 extracted, sound human molars were ground flat to expose occlusal dentin and were then divided into six groups (G1-G6)(n = 30-36) according to surface preparation and primer application (active or passive): G1-diamond bur (DB) + active primer (AP); G2-DB + passive primer (PP); G3-Er:YAG laser (EL) + AP; G4-EL + PP; G5-#600-grit paper disc (PD) + AP; G6-PD + PP. After adhesive procedure, 5-mm high composite buildups were created with Z 250. After storage in water at 37 degrees C for 24 h, teeth were vertically sectioned into serial 1- mm2 sticks. Samples were tested for tension in an Instron machine at 0.5 mm/min. Nine additional molars were prepared to morphological analysis. Regular grit diamond bur, Er:YAG laser, or #600-grit SiC paper was used for SEM observations of dentin surfaces of each group before and after treatment with self-etching primers. Microtensile data were submitted to statistical analysis.
  
  
  RESULTS
  G1-43.85 +/- 9.60 MPa; G2-24.28 +/- 8.90 MPa; G3-24.11 +/- 4.05 MPa; G4-23.30 +/- 4.21 MPa; G5-55.64 +/- 8.50 MPa; G6-56.45 +/- 12.05 MPa.
  
  
  CONCLUSIONS
  (1) Er:YAG laser and diamond burs are able to create distinct smear layers; however the resistance of dentin/adhesive interface is similar. In this way, we can use both instruments clinically without diminishing bond strength; (2) the #600-grit sandpaper disc least affects resistance and is highly recommended for in vitro studies to achieve standard preparation of dentinal surface; (3) active primer application is the method most recommended, despite the type of dentin preparation instrument used.
authors.affiliation: Campos School of Dentistry, Operative Dentistry Department, Rio de Janeiro, Brazil.
authors.forename: Lussaraazevedo
authors.initials: L
authors.lastname: Manhães
authors.forename: Denise Cerqueira
authors.initials: DC
authors.lastname: Oliveira
authors.forename: Márcia Martins
authors.initials: MM
authors.lastname: Marques
authors.forename: Adriana Bona
authors.initials: AB
authors.lastname: Matos
mesh_terms: D045662:Dental Etching; D006801:Humans; D007834:Lasers; D008855:Microscopy, Electron, Scanning