SWEEPS-Assisted Antibacterial Photodynamic Therapy Against Dual-Species Biofilms in Mandibular Molars: An In Vitro Study.

: The synergistic effect of shock wave-enhanced emission photoacoustic streaming (SWEEPS) and antimicrobial photodynamic therapy (aPDT) in mandibular molar root canal disinfection remains underexplored, particularly against dual-species biofilms that better simulate clinical conditions. This study evaluates their combined antimicrobial efficacy against and biofilms and assesses potential tooth discoloration caused by riboflavin and nano-curcumin. : The mesiobuccal canals of 57 extracted mandibular molars were inoculated with and biofilms. The antimicrobial effects were assessed using riboflavin or nano-curcumin with a 450 nm diode laser (BDL), SWEEPS, or their combinations, compared to 5.25% NaOCl (positive control) and saline (negative control). Biofilm reduction was quantified by colony-forming units (CFUs/mL), and discoloration was evaluated using the ΔE metric in the CIE Lab* color space. : Both microorganisms showed a significant decrease in colony numbers in all experimental groups compared to the negative control ( < 0.001), except for , where no significant difference was observed between the riboflavin/nano-curcumin groups and the negative control. Combining riboflavin or nano-curcumin with SWEEPS or BDL significantly enhanced antimicrobial efficacy compared to individual treatments ( < 0.001). The combined photodynamic therapy and SWEEPS groups showed the lowest colony counts. The ΔE values were, on average, 1.81 for riboflavin and 1.09 for nano-curcumin. : The combination of SWEEPS and aPDT effectively reduces and biofilms in molars, supporting its potential as an adjunct in endodontic disinfection. Minimal discoloration further highlights its clinical applicability.