OR30 - Synchronized-microbubble-photodynamic Activation to Disinfect Minimally Prepared Root Canals

Abstract: Introduction: The purpose of this study was to evaluate the antimicrobial efficacy of a novel irrigation strategy using synchronized-microbubble-photodynamic-activation (SYMPA) in a minimally prepared single canal. Methods: Fifty single canal mandibular incisors were inoculated with Enteroccocus faecalis for 3 weeks, and randomly allocated to 5 groups based on different irrigation protocols: control (saline), conventional needle irrigation (CI), ultrasonic irrigation (UI), SYMPA following NaOCl, and SYMPA following saline. First three groups were instrumented to size 25.07v (WaveOne Gold Primary) and SYMPA groups were minimally prepared to size 20.07v (WaveOne Gold Small, Dentsply Sirona, Tulsa, OK). The apical 5mm was resected for microbiological assessment using culture technique (colony-forming-unit (CFU)), ATP-based viability assay (relative luminescence units (RLU)), and percentage of live bacteria using confocal-laser-scanning-microscopy (CLSM). Results: Log CFU from UI (2.37 ± 0.66), SYMPA following NaOCl (2.21 ± 0.86), and SYMPA following saline (3.55 ± 0.41) showed significant reduction compared to control and CI (p< .05). RLU reduction was significant in UI (619.08 ± 352.78) and SYMPA following NaOCl (415.25 ± 329.51) compared to control (1213.2 ± 880.03) (p < .05). The percentage of live bacteria was significantly lower in UI, SYMPA following NaOCl, and SYMPA following saline, compared to control and CI. Although higher microbial reduction was observed in SYMPA following NaOCl when compared to UI, there was no statistical significance (p>.05). Conclusion: SYMPA activation in minimally prepared canals showed significant antimicrobial efficacy. The novel irrigation protocol using SYMPA could be an effective disinfection strategy for minimally prepared root canals.