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Effect of ethylenediaminetetraacetic acid pre-treatment on biofilm dissolution by sodium hypochlorite Ananthan, Joshua


Introduction: Endodontic treatment is aimed at the management and treatment of pathoses caused by bacterial colonization of the root canal system; this is primarily achieved through mechanical and chemical means. Various irrigants have been introduced in varying degrees, concentrations and combinations to optimize bacterial eradication, however, there is no well established optimal protocol nor a recommended procedure by a regulatory body. The present study aims to evaluate the effect of ethylenediaminetetraacetic acid (EDTA) pre-treatment on sodium hypochlorite’s ability to dissolve biofilm. Materials and Methods: Hydroxyapatite discs were inoculated with subgingival plaque and biofilm was grown in brain-heart infusion broth for three weeks in anaerobic conditions. Samples were exposed to a pre-treatment of either sterile water or 17% EDTA for 30 or 60 seconds, washed with an intermediate sterile water rinse, and subjected to either 2% or 6% sodium hypochlorite. Samples were examined under stereomicroscopy for complete dissolution of the biofilm; time was recorded from initial exposure to sodium hypochlorite to complete dissolution. Results: Biofilm dissolution time was decreased by increasing the concentration of sodium hypochlorite from 2% to 6% for all matched groups. Pre-treatment with 17% EDTA for 30 seconds decreased the time for biofilm dissolution by sodium hypochlorite while pre-treatment with 17% EDTA for 60 seconds increased the time for biofilm dissolution; this effect was conserved between both 2% and 6% concentrations of sodium hypochlorite. Discussion: Overall, pre-treatment of biofilms with 17% EDTA will alter sodium hypochlorite’s dissolution ability. Shorter exposure times may augment NaOCl biofilm dissolution while long exposure times may be detrimental to sodium hypochlorite’s dissolution ability. Regardless, of length of pre-treatment time, sodium hypochlorite at both 2% and 6% concentrations was eventually able to complete dissolve all biofilm in all samples.

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