ABSTRACT
Context: This study evaluated and compared the shaping ability of ProTaper Gold (PG) (PG; Dentsply, Tulsa Dental Specialties, Tulsa, OK, USA) system with ProTaper Universal (PU) (PU; Dentsply Maillefer, Ballaigues, Switzerland) using cone‑beam computed tomography (CBCT) imaging. Materials and Methods: Forty mesiobuccal canals of mandibular first molars with curvatures of 25−30° were divided into two experimental groups (n = 20) according to the rotary nickel–titanium (NiTi) file system used in canal instrumentation as follows: Group PG and group PU. Canals were scanned before and after instrumentation using CBCT scanner to evaluate root canal transportation and centering ratio at 3, 5, and 7 mm from the apex and volumetric changes. Data were statistically analyzed using independent t‑tests and the significance level was set at P < 0.05. Results: There was no significant difference between PG and PU systems in the mean volume of removed dentine, canal transportation, and centering ratio (P > 0.05). Conclusions: The PG and PU NiTi rotary systems showed similar root canal shaping abilities in the preparation of mesial canals of mandibular first molars.