A New Nano-Chitosan Irrigant with Superior Smear Layer Removal and Penetration

Our primary objective was to measure root canal penetrations of aqueous antibacterial nano-chitosan (Nano-CS), for the first time. The second objective was to compare and contrast such penetrations to those of chitosan (CS) itself, as well as sodium hypochlorite (NaOCl), chlorhexidine (CHX) and ethylenediamintetraacetic acid (EDTA), at the routinely used concentrations. Molar roots were split longitudinally by a rotary diamond saw. Nano-CS was made by dissolving CS in acetic acid and adding tripolyphosphate (TPP), followed by a freeze-drying process. Dentin penetrations are estimated through measurements of sessile contact angles. Penetrations of the probed irrigants were assessed as inverse functions of their sessile contact angles. Accordingly, all Nano-CS solutions showed smaller sessile angles compared to those of NaOCl, CS, and EDTA samples. Hence, Nano-CS appeared to be a superior irrigant for demonstrating a higher penetration than the latter three. It fell only behind CHX, yet, the superb chelating ability of Nano-CS enabled it to remove smear layer to a larger extend than all of our other irrigants including CHX. Nano-CS could be considered as a new irrigant. Higher penetration was its main advantage over CS, and commercial NaOCl, and EDTA. This was verified by  the smaller sessile contact angle of Nano-CS. Anticipated chelating effect of Nano-CS could anchor more efficient removal of smear layer. This was another advantage of Nano-CS over other irrigants including CHX. Other advantages of Nano-CS included its reported biocompatibility, biodegradability and antibacterial effects. Commercialization of Nano-CS was deemed in the near horizon.