Fig. (4) SEM micrograph of each sample representative: final irrigation using 0.2% chitosan nanoparticles exhibited a few areas covered by a smear layer and debris, with most tubules cleaned and opened (A and B), 17% EDTA revealed no smear layer and debris at all, with all tubules cleaned and opened (C and D), and 2.5% NaOCl showed smear layer and debris covering almost all of the surface (E and F). Original magnification X1000 (A, C and E), and X 2000 (B, D, F).