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.

Comparison of the canal centring ability of K3, Liberator and EZ Fill Safesiders by using spiral computed tomography.

The purpose of the study was to compare the canal centring ability of K3, Liberator and EZ Fill Safesiders by using spiral computed tomography (SCT). Forty curved mandibular premolars were selected. Before and after instrumentation teeth were scanned by spiral computed tomography and nine cross-sectional views of each tooth were obtained at 1.5 mm intervals from the apex. Canal centring ratio was calculated. Mean values were compared between different study groups by using one-way ANOVA followed by Tukey - HSD procedure. At 1st, 2nd and 3rd levels, there was no statistical difference between groups. From 4th to 9th levels Safesider showed higher centring ratio, followed by Liberator and K3. Safesider showed better canal centring ability followed by Liberator and K3.