title: Bond strength of adhesive systems to Er,Cr:YSGG laser-irradiated dentin.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effects of Er,Cr:YSGG laser irradiation and different adhesive procedures on bond strength of two bonding agents to dentin.
  
  
  BACKGROUND
  Studies have shown that laser-irradiated dentinal tissue yields lower bond strengths than does nonirradiated dentin. In this study, different treatment methods of laser irradiating dentin were studied to enhance the bond strength of bonding agents to nonirradiated dentin.
  
  
  METHODS
  Third molars were wet ground with SiC until the occlusal flat dentin surface was exposed, and the teeth were randomly assigned to six groups (n=5). A two-step self-etching primer (Clearfil SE Bond, G1) and a two-step etch-and-rinse adhesive (Single Bond Plus, G2) were applied to the nonirradiated dentin surface according to manufacturer's instructions, as control groups. In G3 and G4, the same adhesives were applied after Er,Cr:YSGG laser irradiation, whereas in G5 and G6 adhesives were applied after Er,Cr:YSGG laser irradiation, phosphoric acid etching, and NaOCl deproteinization of etched dentin. The Er,Cr:YSGG laser worked at 2.78??m and the repetition rate was fixed at 20?Hz. Composite blocks were built on bonded surfaces and the teeth were stored for 24?h at 37?C. Restored teeth were vertically and serially sectioned to obtain bonded specimens for the bond strength test. Data were analyzed by two-way ANOVA and Tukey test (?=5%).
  
  
  RESULTS
  Laser irradiation reduced bond strengths for the two adhesives, regardless of acid etching and deproteinization of dentin post-irradiation (p<0.05). The self-etching primer system showed higher bond strengths to laser irradiated dentin than did Single Bond Plus (p<0.05). The adhesive systems applied to normal dentin yielded higher bond strengths than when they were applied to laser irradiated dentin (p<0.05).
  
  
  CONCLUSIONS
  The self-etching primer seemed to be less affected by dentin irradiation with Er,Cr:YSGG laser. The additional etching and NaOCl solution did not overcome the effects of laser irradiation on dentin.
authors.affiliation: Department of Restorative Dentistry, Piracicaba Dental School, Campinas State University, SP, Brazil.
authors.forename: Adriana Oliveira
authors.initials: AO
authors.lastname: Carvalho
authors.forename: Andr Figueiredo
authors.initials: AF
authors.lastname: Reis
authors.forename: Marcelo Tavares
authors.initials: MT
authors.lastname: de Oliveira
authors.forename: Patr Cia Moreira
authors.initials: PC
authors.lastname: de Freitas
authors.forename: Ana Cec Lia Corr A
authors.initials: AC
authors.lastname: Aranha
authors.forename: Carlos de Paula
authors.initials: Cde P
authors.lastname: Eduardo
authors.forename: Marcelo
authors.initials: M
authors.lastname: Giannini
mesh_terms: D001840:Dental Bonding; D003804:Dentin / Q000528:radiation effects; D017220:Dentin-Bonding Agents / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007834:Lasers; D053844:Lasers, Solid-State; D011897:Random Allocation
chemical_list: D017220:Dentin-Bonding Agents