Influence of an Irrigation System Utilizing Apical Negative Pressure on Bacterial Elimination during Endodontic Therapy: a prospective randomized clinical study

The rationale of endodontic therapy is obtaining a microbe-free root canal system, in which irrigation plays a critical role. Previous investigations of irrigants and the efficacy of delivery systems have yielded mixed results in obtaining microbe-free (MF) root canals. Recent in-vitro studies evaluating root canal debridement using an apical negative pressure irrigation system, EndoVacTM (EVI), have demonstrated promising results canals. We conducted a randomized, controlled, prospective in-vivo clinical investigation comparing the efficacy of EVI to standard needle irrigation (SNI) in obtaining MF canals. Forty-eight patients with single rooted teeth with apical periodontitis, requiring routine endodontic therapy were recruited to the study. Teeth were randomly assigned to either SNI (n=24) or EVI (n=24) groups, and endodontic therapy was performed over two clinical visits, using 0.5% NaOCl as the primary irrigant. Surface microbial cultures (S1) (obtained prior to access), and 2 intra-canal microbial cultures (S2 and S3) were obtained before and after chemomechanical preparation for each irrigation method. The samples were cultivated in anaerobic conditions for 1 week. Three cases were excluded from either group. Evaluation of S3 cultures revealed that 9.1% of teeth treated with SNI (2/ 22) and 17.4% with EVI (4/23) demonstrated microbial growth. Fisher’s Exact Test revealed no statistically significant difference in the antimicrobial efficacy of either SNI or EVI. Also, there was no significant association between any study variables and the irrigation systems’ antimicrobial efficacy. We conclude from our clinical investigation that EVI provides no added advantage over SNI, in producing microbe-free root canals