In Vitro Comparison of Ascorbic Acid, Erbium Yag Laser, and Non-Thermal Atmospheric Nitrogen Plasma on Shear Bond Strength of Immediate Composite Restorations After Bleaching Publisher



G Tayebi GOLNAZ ; S Shahabi SIMA ; S Saberi SOGOL ; S Varmazyari SHABNAM ; Mr Khani Mohammad REZA ; P Pedram PARHAM ; S Valizadeh SARA
Source: Plasma Medicine Published:2025

Abstract

This study compares the effects of 10% ascorbic acid (AA), Er:YAG laser (LA), and non-thermal atmospheric nitrogen plasma (NANP) on the micro-shear bond strength (μSBS) of post-bleaching composite restorations. Fifty third molars (wisdom teeth) were allocated into five groups (n = 10): negative control (NC) (bonding/restoration without bleaching), positive control (PC) (bleaching followed by bonding/restoration), AA (bleaching followed by 10% AA for 10 min), LA (bleaching followed by Er:YAG laser irradiation at 20 Hz, 2 W, for 1 min), and NANP (bleaching followed by NANP at 70 W and 3000 cc/min for 1 min). Bleaching was done using 35% hydrogen peroxide gel. μSBS was evaluated using a universal testing machine, with one-way ANOVA and Tukey’s post-hoc serving for analysis (α = 0.05). The NANP group achieved the highest μSBS (37.5 ± 8.0 MPa), surpassing all other groups. The PC group had the lowest bond strength (7.5 ± 4.4 MPa). NC group values (18.7 ± 3.7 MPa) were higher than those of LA and AA (MD = 1.2 MPa, P < 0.001, and MD = 6.3 MPa, P < 0.001, respectively), with no differences between LA and AA (MD = 5.1 MPa, P = 0.20). NANP significantly enhanced immediate bond strength after bleaching, surpassing even pre-bleaching levels. While LA and AA treatments also mitigated bleaching effects, they performed weaker in comparison, with no difference in their efficacy. NANP’s superior performance suggests its potential to improve same-day restorative outcomes post-bleaching. Further studies and clinical validation are needed to refine this method’s protocols and ensure long-term bond stability. © 2025 Elsevier B.V., All rights reserved.