A compar investigati hand K-Fle

n: The most important aims of root canal preparation are the removal of vital emaining necrotic debris and infected dentin, eliminating the bulk of bacteria root canal system. The aim of this study was to compare the cleaning efficacy of files and rotary RaCe and K3 instruments in root canal preparation. and Methods: A total of 60 single rooted teeth with maximum curvature of cted and divided into three groups of 20 teeth each. Canals were prepared with Kand RaCe instruments using crown down preparation technique, up to size #30. entation, the root canals were flushed with 5 mL of 2.5 % NaOCl solution. The bris and smear layer was quantified on the basis of Hulsmann method using a ron microscope. The data were statistically analyzed with one-way ANOVA test ce level of P<0.05. ne of the three groups achieved completely debrided root canals.. In general, Ke able to achieve cleaner canals compared to K3 and RaCe instruments (P<0.05). significant differences between three groups in smear layer removal throughout walls (P<0.05). : K-Flexofiles group had less remained debris when compared to K3 and RaCe