The effectiveness of three different irrigant activation methods in removal of enterococcus feacalis from root canals

This thesis study aimed to compare the intracanal Enterococcus faecalis (E. Faecalis) reduction promoted by final irrigation using conventional needle irrigation and three different irrigant activation method. Root canals of extracted premolar teeth were instrumented with rotary instruments in a crown-down manner. Sodium hypochlorite (NaOCl) was used for irrigation at each file change during the biomechanical shaping procedures. The smear layer was removed by consecutive use of ethylenediaminetetraacetic acid (EDTA) and NaOCl. Following the completion of root canal preparation, root canals were contaminated with E. faecalis and incubated for three weeks. Specimens were randomly allocated to 4 experimental groups of 15 teeth each, according to the final irrigation method to be used: group 1, conventional irrigation with needle; group 2, passive ultrasonic irrigation (PUI); group 3, activation with XP-Endofinisher; and group 4, laser activated irrigation (LAI). The overall irrigation time and total irrigant volume used were kept constant for the groups. Bacterial samples were taken before and after final irrigation procedures were cultured, the colony-forming units were counted, and reduction percentages were calculated. Kruskal-Wallis and Dunnet tests were used for statistical analysis. Results showed that the reduction in the rate of the bacterial count was highly significant for all groups. All irrigant activation methods were significantly more effective than the conventional needle irrigation group. Although LAI group generated more negative samples, there was no statistically significant difference between LAI and PUI. LAI was significantly more effective than XP-Endofinisher, whereas PUI and XP-Endofinisher was statistically similar. Under the conditions of this study, final irrigation with LAI and PUI showed the best reductive effect on E. faecalis colonies. Considering that LAI group had more negative samples in the count, it may be an alternative to enhance root canal disinfection.