Impact of laser-assisted and different pre-treatment modalities on dentin surface interface and bond strength of fiber posts (In-vitro study).

Abstract

Background: Dentin-cement interface can be considered a critical point in fiber post cementation. Post-space preparation may leave a smear layer and sodium hypochlorite remnants on root dentin, which can compromise bonding between fiber posts and self-adhesive resin cement. This study evaluated the effect of different post-space dentin pretreatment modalities on dentin surface characteristics and push-out bond strength of fiber posts.

Methods: Forty-five extracted single-rooted mandibular second premolars were endodontically treated and assigned to five groups according to post-space dentin pretreatment (n = 9): 2.5% chitosan (CH), 5% apple vinegar (AV), Er,Cr:YSGG laser (ErCr), 970 nm diode laser (DL), and 0.9% saline as control group (CG). Fiber posts were cemented using self-adhesive resin cement. Specimens were sectioned into coronal, middle, and apical slices for push-out bond strength testing and failure mode analysis. One additional specimen from each group was examined by scanning electron microscopy (SEM).

Results: Push-out bond strength was significantly influenced by surface treatment. The ErCr laser group showed the highest mean bond strength, followed by the chitosan, diode laser, and apple vinegar groups, all of which demonstrated significantly higher values than the control group. Differences between root regions were not statistically significant. Mixed failure was the predominant mode in all experimental groups. SEM revealed superior smear layer removal in the ErCr laser and chitosan groups, whereas the diode laser and apple vinegar groups showed only partial dentinal tubules exposure, and the control group retained a dense smear layer.

Conclusions: Post-space dentin pretreatment improved fiber post bond strength and interfacial adaptation compared with saline treatment. ErCr laser and 2.5% chitosan showed the most favorable outcomes and may represent promising conditioning strategies before fiber post cementation.