Inconclusive results were reported about the cleaning and disinfection accomplished by the two irrigation methods .
There is insufficient evidence to cl aim general superiority of any one of these methods .
The aim of this study was to systematic ally review and critically analyse the published data on the treatment outcome ( primary outcome ) and on the  cleaning and disinfection of root canals  ( secondary outcomes ) achieved by negative pressure irrigation as compared to syringe irrigation .
Comparative evaluation of canal isthmus debridement efficacy of modified EndoVac technique with different irrigation systems.
INTRODUCTION The purpose of this study was to evaluate the canal isthmus debridement efficacy of a new modified EndoVac ( Discus Dental , Culver City , CA ) irrigation protocol in comparison with EndoVac , passive ultrasonic irrigation ( PUI ) , and conventional needle irrigation in mesial roots of m and ibular molars . METHODS The mesial roots of 64 extracted m and ibular molars mounted in resin using Kuttler 's endodontic cube , sectioned at 2 and 4 mm from the working length , were r and omly divided into 4 groups ( n = 16 ) : group 1 : Max-I-Probe ( Dentsply Tulsa Dental , York , PA ) , group 2 : EndoVac ( EVI ) , group 3 : modified EndoVac , and group 4 : PUI . The specimens were reassembled and instrumented . A st and ard irrigation protocol was used during cleaning and shaping and final irrigation with the 4 irrigation/agitation techniques . Images of the isthmus region were taken before and after cleaning and shaping and after final irrigation . The percentage reduction of debris in the isthmus region was calculated by using the software program Image J ( v1.43 ; National Institutes of Health , Bethesda , MD ) . Intergroup analysis was performed using the Kruskal Wallis and Mann-Whitney U tests . Intragroup analysis was performed using Friedman and Wilcoxon signed rank tests . The level of significance was set at P < .05 . RESULTS Intragroup analysis revealed a statistically significant difference in the percentage reduction of debris after cleaning and shaping and after final irrigation protocol in all the groups ( P < .001 ) . The final irrigation protocol produced significantly cleaner canal isthmuses in all the groups ( P < .001 ) . On intergroup analysis , the modified EVI group performed significantly better than the other groups . The EVI and PUI groups performed better than the Max-I-Probe group . There was no statistical significance between the EVI and PUI groups . CONCLUSIONS Canal isthmuses were significantly cleaner with the modified EndoVac irrigation technique when compared with the cleanliness seen with the other irrigation systems
Inconclusive results were reported about the cleaning and disinfection accomplished by the two irrigation methods .
There is insufficient evidence to cl aim general superiority of any one of these methods .
The aim of this study was to systematic ally review and critically analyse the published data on the treatment outcome ( primary outcome ) and on the  cleaning and disinfection of root canals  ( secondary outcomes ) achieved by negative pressure irrigation as compared to syringe irrigation .