Eur Endod J. Ahead of Print: EEJ-69926 | DOI: 10.14744/eej.2025.69926

Antimicrobial Effectiveness of High-Power Sonic and Ultrasonic Devices Combined with Stepwise Intraoperative or Final Activation of Sodium Hypochlorite

Flaviana Bombarda De Andrade¹, Maricel Rosario Cardenas Cuellar¹, Victor Feliz Pedrinha¹, Márcia Sirlene Zardin Graeff², Gianluca Plotino^3
1Department of Operative Dentistry, Endodontics and Dental Materials, University of São Paulo, Bauru School of Dentistry, São Paulo, Brazil
²Integrated Research Center, University of São Paulo, Bauru School of Dentistry, São Paulo, Brazil
³Private Practice, Grande Plotino and Torsello – Studio di Odontoiatria, Rome, Italy

Objective: This study investigated the intratubular decontamination promoted by high-power sonic and ultrasonic devices using either a stepwise intraoperative activation (SIA) technique or a final conventional activation (CA) approach during root canal chemomechanical preparation.
Methods: Fifty human lower premolars were contaminated with Enterococcus faecalis and assigned into five groups (n=8): conventional syringe irrigation (CSI); final ultrasonic activation (FUA) using the ultrasonic insert 25/25 IRRI S; final sonic agitation (FSA) using the high-power sonic insert 20/28 Eddy system (both CA techniques); stepwise ultrasonic activation (SUA); and stepwise sonic agitation (SSA) using the same devices during and after canal preparation (SIA techniques). Remaining specimens served as controls. Root canal preparation was performed with the Reciproc system and 5.25% NaOCl, followed by final irrigation with 17% EDTA. Bacterial viability was assessed via confocal microscopy with Live/Dead technique. Statistical analysis was employed using non-parametric tests (α=0.05).
Results: SUA showed the lowest bacterial viability, followed by FSA, both statistically similar. SSA and FUA were similar but less effective than SUA and FSA (p < 0.05). The CSI group had significantly higher bacterial viability compared to all other groups (p < 0.05).
Conclusions: High-power sonic agitation and ultrasonic activation enhanced intratubular decontamination against E. faecalis. The SIA technique, using IRRI S or Eddy systems, effectively reduced bacterial viability and represents a promising approach for root canal disinfection. (EEJ-2024-11-185)

Keywords: Endodontics, Enterococcus faecalis, root canal irrigants, root canal preparation, ultrasonics

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