title: Shear bond strength of self-etching and total-etch adhesive systems to Er:YAG laser-irradiated primary dentin.
abstract: OBJECTIVE
  The purpose of this study was to assess in vitro the shear bond strength of self-etching and total-etch adhesive systems to Er:YAG laser-irradiated primary dentin.
  
  
  METHODS
  Forty crowns of primary canines were embedded in acrylic resin and mechanically ground to expose a flat dentin surface. The specimens were randomly assigned to 2 groups (N=20), according to the adhesive system: (A) Single Bond (SB); and (B) Adper Prompt (AP). Each group was divided into 2 subgroups (N=10), depending on the surface treatment: (1) conventional bonding protocol, as recommended by the manufacturers; and (2) irradiation of the dentin site with a 2.94-microm wavelength Er:YAG laser, with a 300-mJ pulse energy and a 2-Hz repetition rate followed by the bonding protocol. In both groups, a 3-mm diameter dentin bonding site was demarcated, the adhesive systems were applied, and resin composite cylinders were bonded. After 24 hours in distilled water, shear bond strength was tested at a crosshead speed of 0.5 mm/minute.
  
  
  RESULTS
  Means (in MPa) were: group A1=14.14(+/-1.7); group A2=8.41(+/-1.04); group B1=6.88(+/-1.12); and group B2=4.19(+/-0.7). Data were submitted to statistical analysis using 2-way analysis of variance and t test at 5% significance level.
  
  
  CONCLUSIONS
  Irradiation of primary dentin with the Er:YAG laser decreased the bond strength of total-etch and self-etching adhesive systems.
authors.affiliation: Department of Pediatric Clinics, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Carolina Paes
authors.initials: CP
authors.lastname: Torres
authors.forename: Jaciara Miranda
authors.initials: JM
authors.lastname: Gomes-Silva
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Borsatto
authors.forename: Juliana Machado
authors.initials: JM
authors.lastname: Barroso
authors.forename: Jesus Djalma
authors.initials: JD
authors.lastname: Pécora
authors.forename: Regina Guenka
authors.initials: RG
authors.lastname: Palma-Dibb