Evaluation of Various Pretreatments to Fiber Post on the Push-out Bond Strength of Root Canal Dentin.

INTRODUCTION: The aim of this in vitro study was to compare the effect of different pretreatments (fiber post) with the laser-activated irrigation (LAI) technique (for removal of the smear layer) on root canal dentin in terms of push-out bond strength (PBS) in a fiber post.

METHODS: Fifty freshly extracted mandibular single-rooted premolars were prepared, and LAI was applied to all roots (17% EDTA was 5 mL for 120 seconds with an erbium, chromium:yttrium-scandium-gallium-garnet laser [0.50 W, 20 Hz, 25 mJ]). In addition, 50 quartz fiber posts were randomly assigned to 5 groups (n = 10) according to the surface treatments as follows: group S (sandblasting), group N1 and group N2 (neodymium:yttrium-aluminum-garnet laser irradiation [2 W, 200 mJ, 10 Hz, with pulse durations of 180 or 320 microseconds), group HF (9.7% hydrofluoric acid etched), and group C (control with no treatment). Dual-cure resin cement was adhered onto the fiber posts after they were covered with a silane agent, and then the posts were placed into the canal space using a Lentulo spiral. The PBS test was performed after all specimens were transversally sectioned (root slices of 1-mm thickness). Data were analyzed with 1-way analysis of variance/Tukey post hoc test (α = 0.05).

RESULTS: The highest PBS value was observed in group S (middle part), and the lowest value was observed in group C (apical part). There were no statistical differences among the groups regardless of the part. Furthermore, when the PBS values of the different parts of dentin were compared within treated groups, significant differences were observed in all groups except group N2 (P < .05).

CONCLUSIONS: Within the limitations of this study, it can be concluded that the LAI technique when used with 17% EDTA had a significant effect on the amount of smear layer removed from the root canal dentin, which was also detected in the fracture pattern (adhesive failure [resin-post interface]). However, the various treatments of the fiber post did not improve the PBS of the root dentin.