Laser-Activated Irrigation via Photon-Induced Photoacoustic Streaming and Shock Wave Enhanced Emission on Smear Layer Removal Efficacy, Pushout Bond Strength, and Sealer Adaptation: A SEM Assessment

Abstract

The study aims to assess the effectiveness of four different root canal disinfection techniques: passive ultrasonic irrigation (PUI), photon induced photoacoustic streaming (PIPS), and shock wave enhanced emission photoacoustic streaming (SWEEPS) on the smear layer (SL) removal, pushout bond strength (PBS) and sealer adaptation to the radicular dentin. Root canal treatment of 64 human mandibular premolars was initiated. Disinfection was performed. Group 1 (2.5% NaOCl (SI) + EDTA), Group 2 (2.5% NaOCl (PUI) + EDTA), Group 3 (2.5% NaOCl (PIPS) + EDTA), and Group 4 (2.5%NaOCl (SWEEP) + EDTA). This was followed by obturation and sectioning at three different thirds of the canal. Universal testing machine (UTM) and stereomicroscope assessed the PBS and failure mode. Residual SL and sealer dentin interface were assessed via SEM. To compare the mean scores among tested groups, one-way ANOVA and post hoc Tukey test were applied (p < 0.05) The lowest residual SL (1.22 ± 0.11) and highest PBS (11.27 ± 0.09 MPa) were observed in the cervical third of Group 3 (2.5% NaOCl + PIPS). However, the highest remaining SL (2.51 ± 0.08) and lowest bond strength (8.11 ± 0.12 MPa) were observed in the apical third of Group 1 (2.5% NaOCl + SI) Laser-activated irrigation (PIPS, SWEEPS) presents a promising approach for improving the efficacy of SL removal and enhancing the adhesion and bond strength of root canal sealers to root dentin.