title: Evaluation of Intra Root Canal Er,Cr:YSGG Laser Irradiation on Prosthetic Post Adherence.
abstract: OBJECTIVE
  In clinical prosthetics procedures, including endodontics and post fixation, the presence of a smear layer can reduce the post bond strength. An Er,Cr:YSGG laser, which emits at 2780 nm, can promote a smear-layer-free surface due to the ablation process. Considering these aspects, the purpose of this work was to evaluate the influence of Er,Cr:YSGG laser irradiation using either a radial or an axial fiber tip on the bond strength of three resin cements to the fiber-reinforced composite posts.
  
  
  METHODS
  Ninety recently extracted single rooted human teeth had their root canal instrumented and were randomly distributed into nine experimental groups, in which three resin cements (total-etching Variolink II, self-etching Panavia F, and self-adhesive RelyX Unicem Aplicap) and three root canal treatments (no treatment, laser irradiation using the radial fiber tip, laser irradiation using the axial fiber tip) were used. Specimens were then sectioned into three sections (cervical, middle, and apical thirds) with two slices on each section. A push-out test was performed on each slice, and the values were recorded as MPa. The push-out data were analyzed by a Ryan-Joiner normality test followed by a two-way ANOVA test and Tukey pairwise comparison. The statistical analysis was performed on each third section separately, with a 5% significance level.
  
  
  RESULTS
  Laser irradiation with axial fiber tip significantly increased the post bond strength of RelyX Unicem Aplicap on middle third of specimens (p < 0.001) when compared to other root canal treatments (unlased or irradiated with radial tip). Considering the Panavia resin cement, laser irradiation with either axial or radial tips promoted a significant increase on the post bond strength of middle third when compared to unlased specimens (p < 0.001); however, laser irradiation did not influence the post bond strength of Variolink resin cement.
  
  
  CONCLUSIONS
  The use of the Er,Cr:YSGG laser for clinical prosthetics procedures enhances the post bond strength of Panavia and RelyX Unicem Aplicap resin cements, mainly at middle third of roots, and does not interfere with the bond strength of Variolink resin cement. For the RelyX Unicem Aplicap system, the use of axial tip is most advantageous and can be recommended for future clinical application.
authors.affiliation: Laboratory of Biophotonics, Center for Lasers and Applications, São Paulo, Brazil.
authors.forename: Jose
authors.initials: J
authors.lastname: Quinto
authors.affiliation: Laboratory of Biophotonics, Center for Lasers and Applications, São Paulo, Brazil.
authors.forename: Marcello Magri
authors.initials: MM
authors.lastname: Amaral
authors.affiliation: Faculdade de Odontologia da Universidade de São Paulo, Brazil.
authors.forename: Carlos Eduardo
authors.initials: CE
authors.lastname: Francci
authors.affiliation: Laboratory of Biophotonics, Center for Lasers and Applications, São Paulo, Brazil.|Centro de Engenharia, Modelagem e Ciências Sociais Aplicadas, Universidade Federal do ABC (UFABC), São Bernardo do Campo, Brazil.
authors.forename: Patricia Aparecida
authors.initials: PA
authors.lastname: Ana
authors.affiliation: Medical University of Vienna, Bernhard Gottlieb School of Dentistry, Division of Conservative Dentistry & Periodontology, Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Moritz
authors.affiliation: Laboratory of Biophotonics, Center for Lasers and Applications, São Paulo, Brazil.
authors.forename: Denise Maria
authors.initials: DM
authors.lastname: Zezell
mesh_terms: D001840:Dental Bonding / Q000379:methods*; D045662:Dental Etching / Q000379:methods; D003786:Dental Pulp Cavity / Q000528:radiation effects; D003799:Dental Stress Analysis; D005898:Glass; D006801:Humans; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D008422:Materials Testing; D011176:Post and Core Technique / Q000295:instrumentation; D011829:Radiation Dosage; D019279:Resin Cements / Q000737:chemistry* / Q000528:radiation effects*; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods; D012390:Root Canal Therapy / Q000295:instrumentation* / Q000379:methods*; D055116:Self-Curing of Dental Resins; D013314:Stress, Mechanical; D014092:Tooth Root / Q000528:radiation effects*
chemical_list: C438843:Panavia-Fluoro; C483701:Rely X Unicem; D019279:Resin Cements; C009753:fiberglass; C103502:Variolink
keywords: Er,Cr:YSGG laser; bond strength; fiber post; self-adhesive; self-etching; total-etching