Evaluation of bacterial biofilm, smear layer, and debris removal efficacy of a hydro-dynamic cavitation system with physiological saline using a new ex vivo model: a CLSM and SEM study.

Introduction: To evaluate the bacterial biofilm, smear layer and debris removal efficacy of a hydro-dynamic cavitation system with physiological saline using a new ex vivo model.
Methods: Seventy-five dentin discs were prepared from fifty-four extracted teeth. Seventy-five artificial root sockets were prepared. Sixty dentin discs were used to grow 3-week-old bacterial biofilms, while smear layer and debris were produced on fifteen dentin discs. These dentin discs were adhered to the middle third of the artificial root canals. The sixty ex vivo models with biofilm-covered dentin discs were divided into six groups: control, needle with physiological saline, ultrasonic with physiological saline, Odne™ Clean with physiological saline, needle with 3% NaOCl, and ultrasonic with 3% NaOCl. Biofilm removal efficacy was evaluated using confocal laser scanning microscopy. The fifteen ex vivo models with smear layer and debris-covered dentin discs were divided into three groups: control, Odne™ Clean with physiological saline, and 5% NaOCl followed by 17% EDTA. Smear layer and debris removal efficacy was evaluated using scanning electron microscopy. Statistical analysis was performed using one-way analysis of variance for comparisons involving more than two groups. Post-hoc pairwise comparisons were conducted using the Tukey test.
Results: Odne ^TM Clean with physiological saline (98%) performed significantly better than needle irrigation (47%) or ultrasonic activation (54%) with physiological saline (P < 0.05). Odne ^TM Clean with physiological saline removed biofilms as effectively as needle irrigation (97%) or ultrasonic activation (98%) with 3% NaOCl (P > 0.05). Additionally, 5% NaOCl followed by 17% EDTA (score: 1.33) removed the smear layer significantly better than Odne ^TM Clean with physiological saline (score: 4.47) (P < 0.05). However, Odne ^TM Clean with physiological saline (score: 1.27) removed debris as effectively as 5% NaOCl followed by 17% EDTA (score: 1.13) (P > 0.05).
Conclusions: Odne ^TM Clean with physiological saline can effectively remove bacterial biofilm and debris from the dentin surface but cannot effectively remove the smear layer. Utilizing Odne ^TM Clean during the final irrigation may enhance root canal cleaning efficacy.
Competing Interests: Declarations. Ethics approval and consent to participate: The clinical Research Ethics committee of the University of British Columbia (certificate H1202430) approved the protocol of this study. All participants provided signed informed consent, authorizing the use of their extracted premolars for research purposes. The authors ensure that all procedures were conducted in line with relevant guidelines and regulations. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.
(© 2025. The Author(s).)