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The antimicrobial effects of the agitational irrigation on single- and multispecies biofilms in dentin canals

University of British Columbia

Introduction: Endodontic treatments aim to prevent or heal apical periodontitis. Some infections are persistent, which are mainly caused by bacterial invasion and colonization in canal walls and dentinal tubules. Some of these bacteria have the ability to form biofilms. Eradicating biofilms play a critical role in endodontic treatment. Mechanical instrumentation alone cannot eliminate biofilms. Because they render areas that cannot be touched by rotary files such as lateral canals, fins, and isthmuses, other chemical aids are necessary to maximize bacterial reduction. The most commonly used root canal irrigant is sodium hypochlorite (NaOCl). Studies have shown supplementing NaOCl with contemporary different agitation devices may optimize endodontic treatment outcomes. Objective: The aim of this study was to compare the antibacterial effects of different agitation devices on single and multispecies biofilms in dentin canals using confocal laser scanning microscopy (CLSM). Hypotheses: There are no differences between root canal agitation devices in eliminating single and multispecies biofilms in dentin canals. Methods: Dentin blocks were prepared from human root dentin. To form biofilms, Enterococcus faecalis and plaque were introduced into dentinal tubules using centrifugation and incubation. After three weeks, two infected dentin samples were placed at 8 mm and 16 mm in a customized model. Samples were randomly divided into eight groups according to the agitation device used: Syringe needle irrigation (SNI), EndoActivator (EA), passive ultrasonic irrigation (PUI), and EDDY, with 2.5% and 6% NaOCl concentrations. Samples were stained and observed using CLSM to quantify the proportions of killed bacteria in dentin canals. Results: There were no significant differences (p > 0.05) between single- and multispecies biofilms. The killing of biofilms in dentin tubules was more effective when NaOCl was agitated. NaOCl concentration, location of infected dentin and agitation device used each played a role in the killing efficacy. There were no significant differences between the killing efficacies of EDDY and PUI. Conclusions: EDDY was as effective as PUI when used with concentrated NaOCl and demonstrated enhanced antibacterial effects against mono- and multispecies biofilms in the dentinal tubules. Apical portion with low antimicrobial efficiency remains a concern.

Text

2020-11-05

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/76461

Craniofacial Science

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/