title: Er,Cr:YSGG laser dentine conditioning improves adhesion of a glass ionomer cement.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the bond strength (BS) of different surface treatments, including laser irradiation, between conventional glass ionomer cement (GIC) and dentine.
  
  
  METHODS
  Eighty-five human third molars were divided into five groups with one of the following treatments: G1- control group, had no treatment; G2, G3, and G4 were treated with Er,Cr:YSGG laser irradiation at 0.5 W, 20 Hz, 25 mJ, 9 J/cm(2) (G2); 1.0 W, 20 Hz, 50 mJ, 18 J/cm(2)(G3); and 1.5 W, 20 Hz, 75 mJ, 27 J/cm(2) (G4); and G5 was treated with GIC liquid, which contains polyacrylic acid. Scanning electron microscopy (SEM) evaluation (n=2) and micro-shear bond strength test (n=15) using the GIC bonded to dentine were performed after 24 h of water immersion. The data were analyzed by one way analysis of variance (ANOVA), according to irradiation protocol (p<0.001).
  
  
  RESULTS
  G2 specimens presented the highest BS results (in MPa) (10.50±0.84), followed by G1 (4.77±0.59) and G5 (4.26±1.02), which were statistically similar. G3 (3.32±0.39) and G4 (2.94±0.50) demonstrated the lowest BS values, and the difference between these groups was not statistically significant (p>0.001). SEM analysis of G1 revealed that the smear layer covered the entire dentine surface, whereas in G2, G3, and G4, irregular dentine was detected with open dentinal tubules and protruded peritubular dentine. Laser pulses could easily be distinguished in G2 but not in G3 and G4. G5 revealed a thin smear layer with dentinal tubule apertures clearly detectable.
  
  
  CONCLUSIONS
  Dentine treatment with an Er,Cr:YSGG laser irradiation at a power of 0.5 W increased the BS of conventional GIC.
authors.affiliation: 1 Operative Dentistry Department, School of Dentistry, University of Sao Paulo , São Paulo, SP, Brazil .
authors.forename: Bruna Uglik
authors.initials: BU
authors.lastname: Garbui
authors.forename: Cynthia Soares
authors.initials: CS
authors.lastname: de Azevedo
authors.forename: Denise Maria
authors.initials: DM
authors.lastname: Zezell
authors.forename: Ana Cecília Correa
authors.initials: AC
authors.lastname: Aranha
authors.forename: Adriana Bona
authors.initials: AB
authors.lastname: Matos
mesh_terms: D001840:Dental Bonding / Q000379:methods*; D003804:Dentin / Q000528:radiation effects*; D005899:Glass Ionomer Cements / Q000494:pharmacology*; D006801:Humans; D053844:Lasers, Solid-State; D008855:Microscopy, Electron, Scanning; D008963:Molar; D013499:Surface Properties
chemical_list: D005899:Glass Ionomer Cements