(PR13) In Vitro Evaluation of Efficacy of Two Endodontic Sonic-Powered Irrigant Agitation Systems in Killing Single-Species Intracanal Biofilms

Objective: The aim of this study was to compare the efficacy of two sonic-powered irrigation systems, EDDY^TM and EndoActivator^TM, in killing intra-canal biofilm. Materials and methods: 83 instrumented, autoclaved single-rooted human premolars were inoculated with E. faecalis for 21 days to generate mature, single-species biofilms. The teeth were divided into four groups: irrigation with saline (N = 11); irrigation with 2% NaOCl without agitation (N = 24); irrigation with 2% NaOCl with agitation by the EndoActivator^TM (N = 24); and irrigation with 2% NaOCl with agitation by the EDDY^TM (N = 24). Colony-forming unit counts and XTT assay were used to evaluate bacterial load. Additional teeth were split into root-halves for staining to examine the percentages of live/dead bacteria in the dentinal tubules present in different canal locations.

Results: Agitation reduced bacterial load more than lack of agitation (p < 0.05). No significant difference was detected between agitation systems (p>0.05). Both devices had better intra-tubular bacteria killing efficacy than the use of irrigant only in all parts of the canal (p < 0.05), with no significant difference detected between systems (p>0.05). Elimination of intra-canal and intra-tubular bacteria were less efficient in the apical portion of the canal for all groups.

Conclusion: Using 2% NaOCl as an irrigant, the EDDY^TM and EndoActivator^TM demonstrated improved and equivalent intra-canal bacteria reduction efficacy, but are incapable of completely killing all bacteria that resided within the dentinal tubules of root canals.