The effect of Er : YAG laser and various surface treatment protocols on surface topography an mechanical properties of glass fiber posts / Dina Mohamed Elgedawi ; Supervised Mostafa Esam Gheith , Mai Hisham Abdelrahman

Thesis (M.Sc.) - Cairo University - National Institute of Laser Enhanced Sciences - Department of Laser Applications in Oral Surgery

Objective: The aim of this study was to evaluate morphology, surface roughness and mechanical properties of glass fiber Posts (GFPs) after different surface treatment protocols. Materials and methods: A total of forty GFPs with maximum diameter were be divided into four groups (n=10): GC- no surface treatment (control), GSB- sandblasted, GHF- hydrofluoric acid etched, GE- Er:YAG laser irradiated. The GFPs surface morphology was evaluated through scanning electron microscope (SEM), surface roughness was measured using surface profilometer and the 3-points bending flexural test measured flexural strength and elastic modulus. Results: SEM showed alternation of post surfaces after all surface treatments. Analysis of surface roughness demonstrated significant difference between the tested groups at p{u2264}0.001. GSB (5.5±0.6) showed the highest roughness followed by GHF (3.9±0.3), GE (3.2±0.2), then GC (2.1±0.4). The 3 points bending test results were calculated and recorded insignificant difference between the tested groups at p=0.481 for maximum flexure load (N) as for the flexure stress at the maximum Flexure load (MPa) it was shown significant difference between the tested groups at p=0.009. GSB (697.1±96.9 N) showed the highest flexure stress (MPa) compared to GE (548±112.7 N) and GHF (572.9±102.6 N). Modulus of elasticity (GPa) showed significant difference between the tested groups at p=0.003. GSB (28.9±2.9 MPa) showed the highest modulus of elasticity (GPa) compared to GE (23±4.6 MPa) and GHF (23.6±4 MPa). GC showed insignificant difference with all tested treatments

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