title: Influence of cyclic loading on the adhesive effectiveness of resin-zirconia interface after femtosecond laser irradiation and conventional surface treatments.
abstract: OBJECTIVE
  The aim of this study was to evaluate the influence of cyclic loading on the shear bond strength (SBS) of a self-adhesive resin cement to zirconia surfaces after femtosecond laser irradiation at different steps and several conventional surface treatments.
  
  
  METHODS
  One hundred fifty square-shaped zirconia samples were divided into five groups according their surface treatment: NT Group-no surface treatment; APA25 Group-airborne abrasion with 25 μm alumina particles; TSC Group-tribochemical silica coating; FS20 Group-femtosecond laser irradiation (800 nm, 4 mJ, 40 fs/pulse, 1 kHz, step 20); and FS40 Group-femtosecond laser irradiation (same parameters except step 40). Self-adhesive resin cement cylinders were bonded at the centre of the zirconia surface. For each experimental group, half of the specimens were subject to cyclic loading under 90 N (50.000 cycles, 3 cycles/sec) and the rest of the specimens were stored in distilled water at 37°C. All subgroups were tested for SBS with a universal testing machine at a crosshead speed of 0.5 mm/min, until fracture. The results were analyzed statistically.
  
  
  RESULTS
  When cyclic loading was applied, all surface treatments had lower SBS values, except APA25. The four surface treatments had the same SBS values when cyclic loading was employed.
  
  
  CONCLUSIONS
  Use of femtosecond laser irradiation could be an alternative to conventional surface treatments to achieve suitable adhesion zirconia and resin cements. Femtosecond laser irradiation at step 40 is preferable because it is more efficient and faster.
authors.affiliation: Dental Clinic (Faculty of Medicine), University of Salamanca. Paseo Universidad de Coimbra, s/n, 37007, Salamanca, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Vicente
authors.affiliation: Dental Clinic (Faculty of Medicine), University of Salamanca. Paseo Universidad de Coimbra, s/n, 37007, Salamanca, Spain.
authors.forename: Ana L
authors.initials: AL
authors.lastname: Gomes
authors.affiliation: Contracted Professor of Dental Clinic (Faculty of Medicine), University of Salamanca. Paseo Universidad de Coimbra, s/n, 37007, Salamanca, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Montero
authors.affiliation: Dental Clinic (Faculty of Odontology), University of Granada. Colegio Máximo, Campus Universitario de Cartuja, 18011, Granada, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Rosel
authors.affiliation: Dental Clinic (Faculty of Medicine), University of Salamanca. Paseo Universidad de Coimbra, s/n, 37007, Salamanca, Spain.
authors.forename: Vicente
authors.initials: V
authors.lastname: Seoane
authors.affiliation: Contracted Professor of Dental Clinic (Faculty of Medicine), University of Salamanca. Paseo Universidad de Coimbra, s/n, 37007, Salamanca, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Albaladejo
mesh_terms: D007834:Lasers; D008422:Materials Testing; D019279:Resin Cements / Q000528:radiation effects*; D033081:Shear Strength / Q000528:radiation effects*; D015040:Zirconium / Q000528:radiation effects*
chemical_list: D019279:Resin Cements; C095998:Adhesive cement; D015040:Zirconium; C028541:zirconium oxide
keywords: adhesion; ceramics; shear bond strength; surface treatment