title: Bond strength of self-etching primer to bur cut, Er,Cr:YSGG, and Er:YAG lased dental surfaces.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the tensile bond strength of a self-etching primer system to enamel and dentin surfaces treated with Er:YAG and Er,Cr:YSGG lasers.
  
  
  BACKGROUND
  The recently introduced self-etching primer systems have been shown to adhere better to dental surfaces with thin or no smear layers. Moreover, there have been no previous reports on the bond strength of these adhesives to Er,Cr:YSGG laser-irradiated enamel and dentin, which have been shown to be free of a smear layer.
  
  
  METHODS
  Thirty samples of enamel and thirty of dentin were divided into three groups. The first group of each substrate served as a control with a standardized bur cut, and the other two groups were conditioned with Er:YAG (350 mJ, 10 Hz, 20 J/cm(2) for enamel; 300 mJ, 6 Hz, 17 J/cm(2) for dentin) and Er,Cr:YSGG laser (125 mJ, 20 Hz, 16 J/cm(2) for both substrates). After the bonding procedure, samples were restored with composite resin, and the tensile bond strength test was performed.
  
  
  RESULTS
  The ANOVA two-way analysis and the Tukey test at 5% significance level showed that for enamel and dentin, the bond strength values were statistically higher in Er:YAG-laser treated than in Er,Cr:YSGG-laser treated surfaces (p = 0.0001). However, bond strength means for both laser-irradiated groups were statistically lower than for the bur cut group (Er:YAG: p = 0.0281 and Er,Cr:YSGG: p < 0.0001). SEM observation of laser-irradiated surfaces revealed a roughened aspect and absence of smear layer.
  
  
  CONCLUSIONS
  The self-etching system adhesion was influenced by the type of erbium laser used, and the bond strength was higher in the Er:YAG-laser irradiated than in the Er,Cr:YSGG-laser irradiated surfaces.
authors.affiliation: Department for Conservative Dentistry, Periodontology and Preventive Dentistry (ZPP), RWTH Aachen University, Pauwelsstr. 30, Aachen, Germany. marcella@usp.br
authors.forename: Marcella
authors.initials: M
authors.lastname: Esteves-Oliveira
authors.forename: Denise M
authors.initials: DM
authors.lastname: Zezell
authors.forename: Christian
authors.initials: C
authors.lastname: Apel
authors.forename: Miriam L
authors.initials: ML
authors.lastname: Turbino
authors.forename: Ana Cecília Corrêa
authors.initials: AC
authors.lastname: Aranha
authors.forename: Carlos de Paula
authors.initials: Cde P
authors.lastname: Eduardo
authors.forename: Norbert
authors.initials: N
authors.lastname: Gutknecht
mesh_terms: D000268:Adhesiveness; D001840:Dental Bonding; D003743:Dental Enamel / Q000528:radiation effects* / Q000648:ultrastructure; D045662:Dental Etching / Q000379:methods*; D017220:Dentin-Bonding Agents; D006801:Humans; D066298:In Vitro Techniques; D053844:Lasers, Solid-State; D028022:Low-Level Light Therapy; D013718:Tensile Strength
chemical_list: D017220:Dentin-Bonding Agents