Background: To evaluate the sterilization effect of photon-initiated photoacoustic streaming (PIPS) in different widths or different tapers root canal systems.
Methods: Artificial root canal samples (n=480) were randomly divided into 3 groups (n=160/group). The canals were prepared into size #10/.02, #25/.02 or #25/.06. Four different irrigation solutions were activated with conventional needle irrigation (CNI) or laser-activated irrigation (LAI). Bacterial suspensions and biofilms were assessed with adenosine 5'-triphosphate (ATP) assay kit and fluorescent microscopy.
Results: When the root canal taper is 0.02, size #10 with LAI had a significant reduction of the bacteria than #25 with CNI (P < .05). When the apical width is 25, taper 0.02 with LAI had a significant reduction of the bacteria than taper 0.06 with CNI (P < .05). 5.25% NaOCl attained superior antibacterial and bacteriostatic effects as compared to the other irrigants, followed by 2% NaOCl. 2% and 5.25% NaOCl combined with PIPS can effectively enhance the long-term antibacterial effect of root canal after incubation for 6 hours.
Conclusions: Compared with CNI, PIPS have stronger ability to remove bacteria in root canals with a small preparation width and a small taper. PIPS with 2% and 5.25% NaOCl can have superior antibacterial and bacteriostatic effects.