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Effect of NaOH solutions on planktonic bacteria, biofilms, and lipopolysaccharide

University of British Columbia

Background: Eradicating bacteria, biofilms and harmful by-products such as LPS from the root canal system is important in providing successful endodontic treatment. To date no irrigant or medicament used in endodontics has been able to completely eradicate bacteria in the root canal system or detoxify all LPS. Aim: It is proposed that a novel solution containing NaOH (Sodium hydroxide), Sodium dodecyl sulfate (SDS) and an alcohol may have unique disinfective properties against bacterial factors highly relevant in endodontic treatment. Materials and Methods: Combinations of the proposed solution were tested and compared to NaOCl (sodium hypochlorite) against 1- Planktonic E. faecalis in direct contact and quantified by CFU counts 2 - Polymicrobial biofilms in an open model exposed to solutions and visualized with CLSM (Confocal Laser Scanning Microscopy) 3 – LPS using a biofunctional assay, stimulating IL-1ß production in RAW 264.7 macrophages with treated LPS aliquots and analyzed by ELISA. Results: Planktonic killing tests with E. faecalis showed that NaOCl was more effective than NaOH solutions. With potency from highest to lowest as follows: 6% NaOCl, 2% NaOCl, NaOH/SDS/Propanol, NaOH/Propanol. Biofilm tests showed that NaOCl killed more biofilm bacteria, however NaOH/SDS combinations removed more biofilm mass. Results showed that LPS samples treated with either 6% or 2% NaOCl produced no IL-1ß. Samples treated with NaOH/SDS combinations produced inconsistent results regarding IL-1ß release due to inefficient dialysis removal of toxic irrigants. Conclusions: Results suggest that NaOCl remains the irrigant of choice as it is most effective in killing bacteria either planktonically or within biofilm systems. The results of this study suggest that NaOCl is indeed effective in LPS detoxification which is contrary to suggestions by several previous studies. NaOH/SDS combinations while less effective in killing, appear to remove more biofilm mass when compared to NaOCl. This may be attributed to the surfactant properties of SDS.

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2016-06-29

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/58354

Craniofacial Science

University of British Columbia

UBCV

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