title: Influence of pulse frequency Er:YAG laser on the tensile bond strength of a composite to dentin.
abstract: OBJECTIVE
  To evaluate the influence of different pulse frequencies of Er:YAG laser on the tensile bond strength of a composite to dentin.
  
  
  METHODS
  The dentin surface treatment was performed by Er:YAG laser at 1, 2, 3 and 4Hz pulse frequencies and 80 mJ, for 20 seconds, followed by etching. The control group was etched by phosphoric acid solely. The Single Bond/Z250 system was used. The specimens were subjected to tensile strength tests in a testing machine (0.5mm/minute) after water storage (37 degrees C/24 hours).
  
  
  RESULTS
  The averages in MPa were: 1Hz: 13.45 (+/- 5.31); 2Hz: 9.54 (+/- 2.13); 3Hz: 7.29 (+/- 1.26); 4Hz: 7.41 (+/- 2.44) and control group: 16.95 (+/- 2.57). The Kruskal-Wallis test revealed statistically significant difference. The increased frequency of the Er:YAG laser decreased the composite bond strength.
authors.affiliation: Department of Dental Materials and Prosthesis, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, Av. do Café, S/N MonteAlegre, Ribeirão Preto--Cep: 14040-904, SP, Brazil. ane.gon@netsite.com.br
authors.forename: Mariane
authors.initials: M
authors.lastname: Gonçalves
authors.forename: Silmara A Milori
authors.initials: SA
authors.lastname: Corona
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Borsatto
authors.forename: Jesus Djalma
authors.initials: JD
authors.lastname: Pécora
authors.forename: Regina G Palma
authors.initials: RG
authors.lastname: Dibb
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods*; D003799:Dental Stress Analysis; D003804:Dentin / Q000187:drug effects / Q000528:radiation effects; D003806:Dentin Permeability / Q000187:drug effects / Q000528:radiation effects; D003808:Dentin Solubility / Q000187:drug effects / Q000528:radiation effects; D017220:Dentin-Bonding Agents; D004871:Erbium; D006801:Humans; D007834:Lasers; D008422:Materials Testing; D008963:Molar; D010756:Phosphoric Acids; D013718:Tensile Strength
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; D010756:Phosphoric Acids; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate; D004871:Erbium; C030242:phosphoric acid