Effect of Hydrogen Peroxide, Ytterbium Fiber Laser, and Phthalocyanine-Mediated Low-Level Laser Therapy on Surface Characteristics, Flexural Strength, and Push-out Bond Strength of Glass Fiber Posts to Root Dentin

Abstract

Objective: Assessing the impact of different surface conditioners (Hydrogen peroxide (H₂O₂), Ytterbium fiber laser (YFL), Low‑level laser therapy (LLLT)-Phthalocyanine (Pc) on the surface characterization, flexural strength (FS), surface roughness (Ra) and push-out bond strength (POBS) of glass fiber post (GFP) bonded to root dentin using conventional resin cement (CRC) and self-adhesive resin cement (SARC).

Methodology: This in-vitro study included eighty single-rooted mandibular premolar teeth, and subsequently, crowns were decoronated. Ethical approval was obtained from Dar Al Uloom University (COD/IRB/2025/91; Dated February 15, 2025). The study duration was six months. 120 GFP were allocated to four groups according to the conditioning protocol. Group-1 (No conditioning), Group-2 (H2O2), Group-3 (YFL), and Group-4 (1% Pc‑LLLT). Scanning Electron Microscopy (SEM) was performed to assess the surface topography. Ra was measured using a profilometer. The three-point bending test was used to evaluate the flexural strength (FS). Root canal procedure was performed, followed by post space preparation. Twenty GFPs were distributed into two subgroups based on the bonding technique- Subgroup A: CRC via total etch (TE); Subgroup B: SARC. POBS and bond failure assessment were performed using a universal testing machine and a stereomicroscope. Two-way ANOVA and Tukey post hoc test were applied for all comparisons.

Results: The highest Ra and lowest FS were seen in Group-2 (H₂O₂). The lowest Ra and the highest FS were observed in Group-1 (No conditioning) samples. The highest POBS was observed in the cervical third of Group-2A (H2O2+CRC). Conversely, the lowest bond strengths were observed in the apical section of Group-4A (1% Pc-LLLT+CRC).

Conclusion: The yttrium fiber laser demonstrated satisfactory Ra, FS, and POBS for the glass fiber post. Self-adhesive resin cement outperformed conventional luting cement.