title: Evaluation of Mechanical Properties of Glass Fiber Posts Subjected to Laser Surface Treatments.
abstract: OBJECTIVE
  The aim of this study was to evaluate the influence of laser irradiation on flexural strength, elastic modulus, and surface roughness and morphology of glass fiber posts (GFPs).
  
  
  BACKGROUND
  Laser treatment of GFPs has been introduced to improve its adhesion properties.
  
  
  METHODS
  A total of 40 GFPs were divided into 4 groups according to the irradiation protocol: GC-no irradiation, GYAG-irradiation with erbium:yttrium-aluminum-garnet [Er:YAG], GCR-irradiation with erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG), and GDI-irradiation with diode laser. The GFP roughness and morphology were evaluated through laser confocal microscopy before and after surface treatment. Three-point bending flexural test measured flexural strength and elastic modulus. Data about elastic modulus and flexural strength were subjected to one-way ANOVA and Bonferroni test (p < 0.05). The effect of roughness was evaluated using the linear mixed effects model and Bonferroni test (p < 0.05).
  
  
  RESULTS
  Laser treatment changed surface roughness in the groups GCR (p = 0.000) and GDI (p = 0.007). The mean flexural strength in GYAG (995.22 MPa) was similar to that in GC (980.48 MPa) (p = 1.000) but different from that in GCR (746.83 MPa) and that in GDI (691.34 MPa) (p = 0.000). No difference was found between the groups GCR and GDI (p = 0.86). For elastic modulus: GYAG (24.47 GPa) was similar to GC (25.92 GPa) (p = 1.000) but different from GCR (19.88 GPa) (p = 0.002) and GDI (17.20 GPa) (p = 0.000).
  
  
  CONCLUSIONS
  The different types of lasers, especially Er,Cr:YSGG and 980 ηm diode, influenced the mechanical properties of GFPs.
authors: School of Dentistry, University of Ribeirão Preto , Ribeirão Preto, Brazil .
authors: Carolina
authors: C
authors: Barbosa Siqueira
authors: School of Dentistry, University of Ribeirão Preto , Ribeirão Preto, Brazil .
authors: Natália
authors: N
authors: Spadini de Faria
authors: School of Dentistry, University of Ribeirão Preto , Ribeirão Preto, Brazil .
authors: Walter
authors: W
authors: Raucci-Neto
authors: School of Dentistry, University of Ribeirão Preto , Ribeirão Preto, Brazil .
authors: Vivian
authors: V
authors: Colucci
authors: School of Dentistry, University of Ribeirão Preto , Ribeirão Preto, Brazil .
authors: Erica
authors: E
authors: Alves Gomes
mesh_terms: D005898:Glass / Q000528:radiation effects*; D007834:Lasers; D053844:Lasers, Solid-State; D008422:Materials Testing; D011176:Post and Core Technique; D013499:Surface Properties
chemical_list: C009753:fiberglass