Efficacy of F file compared to ultrasonic techniques using scanning electron microscopy.

: A study was undertaken to compare the debridement efficacy of the F file with ultrasonics. Thirty mandibular premolars were instrumented with the Protaper file series using a crown-down technique. All the canals were irrigated using 2 ml of 5.25% sodium hypochlorite and 2 ml of 17% EDTA for one minute, alternating each instrument. The teeth were then divided into three groups of 10 each. In Group I, a final flush with only 5.25% NaOCl concluded the preparation (control group). Group II underwent 5.25% NaOCl and ultrasonic irrigation for one minute. Group III, 5.25% NaOCl and F-file for 30 seconds. Smear layer and debris scores were examined under a scanning electron microscope. In a blind manner, two investigators scored the presence or absence of smear layer and debris. Significantly higher smear layer and debris scores were found at the apical level compared to the middle and coronal levels in all the three groups. In the end, the F file proved more beneficial in removing smear layer and debris than ultrasonics.