Effect of Er: YAG laser and different surface treatment methods on the push-out bond strength of glass fiber post to self adhesive resin cement

To compare the push-out bond strength of adhesive resin cement and glass fiber posts (GFP) at different root levels after exposure to Er: YAG laser irradiation compared to other conventional surface treatment procedures. A total of 24 mandibular premolars were decoronated, root canal treatment was done, post spaces were prepared, and roots were mounted in acrylic resin blocks. Fiber posts were divided into four groups (n = 6) according to surface treatment methods: (1) silane only (control group), (2) Er: YAG laser 1.5 W + silane, (3) 30% hydrogen peroxide + silane, (4) sandblasting with 50 μm aluminum oxide particles + silane. GFP were cemented using self-adhesive resin cement. Scanning electron microscope images with 500x magnification were taken for all groups. Push-out test was performed using a universal testing machine at different root levels. The difference between groups was statistically significant with laser group recording the highest mean ± SD value of push-out bond strength (5.668042 ± 1.16 MPa), followed by the H2O2 group, then the control group, meanwhile the lowest value was recorded with Sand-blasting group. There were no statistically significant differences between the Control group and Er: YAG group; Control group and sandblasted group. The difference between the radicular regions was not statistically significant, with the middle region recorded the highest push-out bond strength (4.746851 ± 0.73 MPa). GPF surface treatment using an Er: YAG laser is effective as it increases the retention to resin cement, while sandblasting decreases fiber post retention to resin cement. The hydrogen peroxide and the control groups give similar bond strength. The middle and apical regions of GFP have better retention to resin cement than the coronal one.