title: Self-etch bonding agent beneath sealant: Bond strength for laser-irradiated enamel.
abstract: OBJECTIVE
  This study evaluated the in vitro shear bond strength (SBS) of a resin-based pit-and-fissure sealant (Fluroshield [F], Dentsply/Caulk) associated with either an etch-and-rinse (Adper Single Bond 2 [SB], 3M/ESPE) or a two-step self-etch adhesive system (Adper SE Plus [SE], 3M/ESPE) on Er: YAG laser-irradiated enamel.
  
  
  METHODS
  Seventeen sound third molar crowns were embedded in acrylic resin, and the mesial-distal enamel surfaces were flattened. The enamel sites were irradiated with a 2.94-μm wavelength Er: YAG laser (120 mJ, 4 Hz, noncontact mode/17 mm, 20 s). The specimens were randomly assigned to three groups according to the bonding technique: I - 37% phosphoric acid etching + SB + F; II - SE + F and III - F applied to acid-etched enamel, without an intermediate layer of bonding agent. In all of the groups, a 3-mm diameter enamel-bonding site was demarcated and the sealant cylinders were bonded. After 24 hours in distilled water, the shear bond strength was tested at a crosshead speed of 0.5 mm/minute. The data were analyzed by one-way ANOVA and Tukey's test. The debonded specimens were examined with a stereomicroscope to assess the failure modes.
  
  
  RESULTS
  The mean SBS values in MPa were I = 6.39 (±1.44); II = 9.50 (±2.79); and III = 5.26 (±1.82). No statistically significant differences were observed between groups I and III; SE/F presented a significantly higher SBS than that of the other groups (P = 0.001). With regard to the failure mode, groups I (65%) and II (75%) presented adhesive failures, while group III showed 50% adhesive failure. Cohesive failure did not occur.
  
  
  CONCLUSIONS
  The application of the two-step self-etch bonding agent (Adper SE Plus) beneath the resin pit-and-fissure sealant placement resulted in a significantly higher bond strength for the Er:YAG laser-irradiated enamel.
authors.affiliation: Department of Pediatric Clinics, Preventive and Community Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Borsatto
authors.affiliation: Department of Pediatric Clinics, Preventive and Community Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil.
authors.forename: Jackelline de Lemes
authors.initials: JL
authors.lastname: Giuntini
authors.affiliation: Department of Pediatric Clinics, Preventive and Community Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil.
authors.forename: Marta Maria Martins Giamatei
authors.initials: MMMG
authors.lastname: Contente
authors.affiliation: Department of Pediatric Clinics, Preventive and Community Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil.
authors.forename: Jaciara Miranda
authors.initials: JM
authors.lastname: Gomes-Silva
authors.affiliation: Department of Pediatric Clinics, Preventive and Community Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil.
authors.forename: Carolina Paes
authors.initials: CP
authors.lastname: Torres
authors.affiliation: Department of Dental Materials and Prostheses, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-904, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Galo
keywords: Adhesive system; Er:YAG laser; pit and fissure sealant; shear bond strength