, vol. 39, issue 7, pp. 906-909, 2013.
Introduction: This study evaluated the effects of 2
different kinematics rotary nickel-titanium (NiTi)
systems, Twisted File (TF), a continuous rotation fullsequence
system, and WaveOne (WO), a reciprocating
single-file system, on transportation, curvature, and
volumetric changes of curved root canals by using
cone-beam computed tomography. Methods: Forty mesiobuccal
canals of mandibular molars with angle of
curvature ranging from 25–35 were divided according
to the NiTi rotary system used in canal preparation into 2
groups of 20 samples each, TF group and WO group.
Canals were scanned by using an i-CAT cone-beam
computed tomography scanner before and after instrumentation
to evaluate canal transportation at coronal,
middle, and apical thirds, canal curvature, and volumetric
changes. The significance level was set at P #
.05. Results: TF system recorded significantly lower
mean of canal transportation than WO group at all canal
thirds (apical P = .034, middle P = .003, and coronal P =
.012). In both groups the apical third recorded the significantly
least amount of transportation (P < .05). There
was no significant difference between the 2 groups in
canal curvature and volumetric changes after instrumentation
(P > .05). Conclusions: Both TF and WO NiTi
systems can be safely used to the full working length,
resulting in satisfactory preservation of the original
canal shape
