Bacteria debridement efficacy of two sonic root canal irrigant activation systems.

ABSTRACT

OBJECTIVE: To evaluate the bacteria debridement efficacy of two generations of sonic root canal irrigant activation systems EndoActivator (Dentsply Sirona), the first generation, and SmartLite Pro EndoActivator, the second generation. METHODS: Instrumented, autoclaved, single-rooted human premolars were inoculated with Enterococcus faecalis (ATCC-29212) for 21 days. The bacteria biofilm-containing teeth were randomly divided into 5 groups (N=8) Group 1 Syringe-side-vented needle (S-N) delivery of saline for 1 min; Group 2 S-N delivery of 2% NaOCl for 1 min; Group 3 S-N delivery of 2% NaOCl for 5 min; Group 4 EndoActivator activation of 2% NaOCl for 1 min; Group 5 SmartLite Pro EndoActivator activation of 2% NaOCl for 1 min. The teeth were evaluated for bacterial reduction using CFU counts, and the percentages of dead bacteria within the dentinal tubules using confocal laser scanning microscopy. RESULTS: Activation of NaOCl with EndoActivator or SmartLite Pro EndoActivator significantly reduced the overall intracanal bacterial load, compared with S-N irrigant delivery (P<0.05), with no significant difference between the two agitation devices (P>0.05). Nevertheless, S-N delivery of 2% NaOCl for 5 min produced better bacteria debridement than either sonic agitation system. Different degrees of bacteria kill were identified in the coronal-middle portions and apical portion of the canal space. CONCLUSION: Delivery time of NaOCl affects the efficacy of bacteria disinfection. Activation for 1 min with the EndoActivator or SmartLite Pro EndoActivator demonstrated comparable canal wall biofilm and intracanal bacteria reduction efficacy when 2% NaOCl was used as irrigant for disinfecting E. faecalis in single-rooted teeth. CLINICAL SIGNIFICANCE: Although the sonic root canal irrigant activation devices investigated do not completely eliminate live bacteria biofilms from the canal space, they help reduce bacteria load during irrigant activation.