title: Shear bond strength and SEM morphology evaluation of different dental adhesives to enamel prepared with ER:YAG laser.
abstract: BACKGROUND
  Early observations of enamel surfaces prepared by erbium lasers motivated clinicians to use laser as an alternative to chemical etching.
  
  
  OBJECTIVE
  Evaluate shear bond strength (SBS) values of different dental adhesives on Erbium:Yttrium Aluminum Garnet (Er:YAG) laser prepared enamel and to evaluate possible etching patterns correlations between dental adhesives and SBS values.
  
  
  METHODS
  One hundred bovine incisors were randomly assigned to SBS tests on enamel (n = 15) and to enamel morphology analysis (n = 5) after Er:YAG laser preparation as follows: Group I - 37% phosphoric acid (PA)+ ExciTE(®); Group II - ExciTE(®); Group III - AdheSE(®) self-etching; Group IV - FuturaBond(®) no-rinse. NR; Group V - Xeno(®) V. Teeth were treated with the adhesive systems and subjected to thermal cycling. SBS were performed in a universal testing machine at 5 mm/min.
  
  
  METHODS
  One-way ANOVA and post-hoc tests (P < 0.05). For the morphology evaluation, specimens were immersed in Ethylenediamine tetraacetic acid (EDTA) and the etching pattern analyzed under Scanning Electron Microscope (SEM).
  
  
  RESULTS
  Mean bond strengths were Group I - 47.17 ± 1.61 MPa (type I etching pattern); Group II - 32.56 ± 1.64 MPa, Group III - 29.10 ± 1.34 MPa, Group IV - 23.32 ± 1.53 MPa (type III etching pattern); Group V - 24.43 MPa ± 1.55 (type II etching pattern).
  
  
  CONCLUSIONS
  Different adhesive systems yielded significantly different SBSs. Acid etching significantly increased the adhesion in laser treated enamel. No differences in SBS values were obtained between AdheSE(®) and ExciTE(®) without condition with PA. FuturaBond(®) NR and Xeno(®) V showed similar SBS, which was lower in comparison to the others adhesives. No correlation between enamel surface morphology and SBS values was observed, except when PA was used.
authors.affiliation: Department of Operative Dentistry, Faculty of Dentistry, University of Porto, Porto, Portugal.
authors.forename: Patrícia T
authors.initials: PT
authors.lastname: Pires
authors.forename: João C
authors.initials: JC
authors.lastname: Ferreira
authors.forename: Sofia A
authors.initials: SA
authors.lastname: Oliveira
authors.forename: Alvaro F
authors.initials: AF
authors.lastname: Azevedo
authors.forename: Walter R
authors.initials: WR
authors.lastname: Dias
authors.forename: Paulo R
authors.initials: PR
authors.lastname: Melo
keywords: Adhesion; Er-YAG laser; SEM morphology; dental enamel; enamel-surface preparation; laser conditioning; self-etch; shear bond strength