Abstract
Objectives This in vivo study evaluated the operative torque and preparation time of ProTaper NEXT (Dentsply
Maillefer; Ballaigues, Switzerland) and EdgeFile X7 (EdgeEndo; Albuquerque, New Mexico,
United States) rotary systems during root canal preparation of maxillary premolars.
Materials and Methods Ten double-rooted maxillary premolars with independent canals were selected. Each
canal in each tooth was prepared with one of the rotary systems (n = 10), ProTaper NEXT or EdgeFile X7. The instruments were rotated at 300 rpm with
maximum torque set at 2 N.cm using an electric motor (KaVo; Biberach, Germany) that
automatically recorded torque values at every 1/10th of a second (ds).
Statistical Analysis Operative torque (N.cm) and preparation time (s) of the first shaping instrument
(size 17/.04) of both rotary systems were recorded and statistically compared using
the Mann–Whiney U test with a significance level set at 5%.
Results No instrument exhibited flute deformation or underwent intracanal failure. No differences
were found between the instruments regarding the maximum (peak) torque values (p > 0.05). EdgeFile X7 17/.04 required significantly less preparation time (3.75 seconds
interquartile range [IQR]: 3.2–9.0) than ProTaper NEXT X1 (15.45 seconds IQR: 8.35–21.1)
(p < 0.05). The median operative torque values of ProTaper NEXT X1 (0.26 N.cm; IQR:
0.18–0.49) were significantly higher compared with EdgeFile X7 17/.04 (0.09 N.cm;
IQR: 0.05–0.17) (p < 0.05).
Conclusions Although no difference was found between the median peak torque values of ProTaper
NEXT X1 and EdgeFile X7 17/.04 instruments, the operative torque and instrumentation
time results were impacted by their different designs and alloys during clinical preparation
of root canals.
Keywords
EdgeFile - nickel-titanium - ProTaper NEXT - rotary instruments - torque
