Infection Control in Retreatment Cases: In Vivo Antibacterial Effects of 2 Instrumentation Systems

R.C. Rodrigues, H.S. Antunes, M.A. Neves, J.F. Siqueira Jr., I.N. Rôças

Journal of Endodontics. 2015 October; 41(10):1600-5


INTRODUCTION: This in vivo study compared the antibacterial effects of 2 instrumentation systems in root canal-treated teeth with apical periodontitis.

METHODOLOGY: Forty-eight teeth with a single root and a single canal showing post-treatment apical periodontitis were selected for this study. For retreatment, teeth were randomly divided into 2 groups according to the instrumentation system used: Self-Adjusting File (SAF; ReDent-Nova, Ra'anana, Israel) and Twisted File Adaptive (TFA; SybronEndo, Orange, CA). In both groups, 2.5% sodium hypochlorite was the irrigant. Bacteriological samples were taken before (S1) and after chemomechanical preparation (S2). In the TFA group, passive ultrasonic irrigation (PUI) was performed after instrumentation, and samples were also taken after this supplementary step (S2b). DNA was extracted from the clinical samples and subjected to quantitative real-time polymerase chain reaction to evaluate the levels of total bacteria, streptococci, and Enterococcus faecalis. Statistical analyses from quantitative real-time polymerase chain reaction data were performed within groups using the Wilcoxon matched pairs test and between groups using the Mann-Whitney U test and the Fisher exact test with the significance level set at P < .05.

RESULTS: Bacteria were detected in S1 samples from 43 teeth, which were then included in the antibacterial experiment. Both SAF and TFA instrumentation protocols showed a highly significant intracanal bacterial reduction (P < .001). Intergroup quantitative comparisons disclosed no significant differences between TFA with or without PUI and SAF (P > .05). PUI did not result in significant improvement in disinfection (P > .05). 

CONCLUSIONS: Both instrumentation systems/treatment protocols were highly effective in significantly reducing the intracanal bacterial counts. No significant difference was observed between the 2 systems in disinfecting the canals of teeth with post-treatment apical periodontitis.


Additional Info

  • ReDent Nova’s note:

    This clinical research has found the SAF to provide satisfactory results, despite not following the clinical guidelines for the SAF System.

    In re-treatment, the use of a guttapercha solvent (chloroform) is highly recommended, as it helps remove the obturation material and reach a higher level of cleanliness, as shown in previous research (Abramovitz et al., Int Endod J 2012; Solomonov et al, J Endod 2012).

    Furthermore, using a NiTi rotary instrument after the SAF is unnecessary and creates further debris, and the use of EDTA was only done after the rotary instrument. Had the recommendation to use EDTA as part of the irrigation protocol with the SAF, the results would have most likely been better.

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  • View abstract on PubMed. PMID: 26234543