RESUMO
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.