An in vitro comparison of the antimicrobial efficacy of positive pressure and negative pressure irrigation techniques in root canals infected with Enterococcus faecalis

AIM: The aim of this in vitro study was to compare the efficacy of irrigation with the negative pressure and the traditional positive pressure in eradicating Enterococcus faecalis from the root canal. MATERIALS AND METHODS: A total of 40 extracted mandibular premolars were sterilized and divided into four groups with 10 samples each. Then, they were prepared to apical size #35 (Group 1, 3) and 45 (Group 2, 4) and inoculated with E. faecalis for 7 days and then irrigated with 3% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. The positive pressure irrigation was performed in Group 1 and Group 2 while the negative pressure irrigation (NPI) using the Endovac in Group 3 and Group 4. Samples taken after the root canal irrigation procedures were cultured and the colony-forming units were counted. Data were statistically analyzed using the Fisher's exact test. RESULTS: Results were statistically significant when comparing apical negative-pressure irrigation size 45 (Group 4) to positive-pressure irrigation size 35 (Group 1). CONCLUSION: The results of this in vitro study showed that the apical NPI method (Endovac) was more effective in removing E. faecalis from the root canal at the larger apical preparation size.