background and aims. the superiority of rotary systems has been reported in several clinical studies on permanent teeth. this study consisted of radiographic assessment and chair time of rotary instruments in the pulpectomy of primary second molar teeth. materials and methods. in this randomized controlled clinical study, 46 children, 3-6 years of age, were selected. the patients were divided r...

use of rotary nickel-titanium (niti) instruments for endodontic preparation has introduced a new era in endodontic practice, but this issue has undergone dramatic modifications in order to achieve improved shaping abilities. cone-beam computed tomography (cbct) has made it possible to accurately evaluate geometrical changes following canal preparation. this study was carried out to compare cana...

The aim of this study was to examine the lifespan or number of cycles to failure of tapered rotary nickel-titanium (Ni-Ti) endodontic instruments. Simulated root canals with different curvatures were used to determine a relation between canal curvature and instrument lifespan. Using a novel mathematical model for the deformation of pseudoelastic Ni-Ti alloy, it was shown that maximum stress nee...