Research Article Comparison of Canal Transportation, Separation Rate, and Preparation Time between One Shape and Neoniti (Neolix): An In Vitro CBCT Study Maryam Kuzekanani , 1 Faranak Sadeghi, 2 Nima Hatami , 1 Maryam Rad , 3 Mansoureh Darijani , 4 and Laurence James Walsh 5 1 Endodontology Research Center, Department of Endodontics, Kerman Dental School, Kerman University of Medical Sciences, Kerman, Iran 2 Student Research Committee, School of Dentistry, Kerman University of Medical Sciences & Health Services, Kerman, Iran 3 Oral and Dental Diseases Research Center and Kerman Social Determinants on Oral Health Research Center, Kerman University of Medical Sciences, Kerman, Iran 4 Department of Oral & Maxillofacial Radiology, School of Dentistry, Kerman University of Medical Sciences & Health Services, Kerman, Iran 5 UQ Oral Health Centre, e University of Queensland School of Dentistry, 288 Herston Road, Herston 4006, Australia Correspondence should be addressed to Maryam Kuzekanani; maryamk2325@gmail.com Received 30 April 2021; Revised 19 July 2021; Accepted 10 August 2021; Published 8 September 2021 Academic Editor: Sivakumar Nuvvula Copyright © 2021 Maryam Kuzekanani et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Purpose. is in vitro study compared root canal preparation in curved mesiobuccal canals of molar teeth using either the One Shape ™ or the Neoniti (Neolix) rotary NiTi single-file systems, assessing canal transportation, instrument separation and time required for preparation. Methods. Extracted maxillary and mandibular human molar teeth with mesiobuccal canals having apical angles of curvature between 25 and 35 o were selected and embedded in acrylic resin blocks, and an initial CBCTwas taken. e teeth were divided into two equal groups (n � 20), and the canals were cleaned and shaped using either Neoniti ™ or One Shape ™ engine-driven NiTi rotary files. Each individual instrument was used to prepare 5 canals. e time required for the preparation of each canal was recorded. Post- preparation CBCTscans were taken and used to determine the extent of canal transportation at levels of 2, 4, 6, and 8 mm from the apex. e Kolmogorov–Smirnov test for normality was applied, and then, datasets were compared using independent t-tests, with a threshold of P < 0.05. Results. Neoniti rotary files caused significantly less canal transportation of the curved canals (P � 0.0001). On the other hand, the time required for canal preparation was significantly shorter for One Shape (P � 0.0001). No instrument separation was recorded in both groups. Conclusion. Based on these results, the Neoniti ™ rotary file system is preferred because it maintains the original shape of curved root canals better than One Shape ™ ; even though this benefit comes at the cost of an increase in preparation time in clinical practice, the better technical performance may be more important than a difference in procedural time. 1.Background Development of nickel-titanium (NiTi) rotary instruments has improved the overall quality of canal preparation in endodontics, with fewer procedural errors, such as ledges, zipping perforations, and transportation [1]. ird- and fourth-generation files include Neoniti ™ (Neolix, Chatres- La-Foret, France) and One Shape ™ (Micro-Mega, Besançon, France), respectively. ese both employ a single file used in continuous rotating motion to clean and shape the whole root canal system [2]. e main advantages of such single rotary NiTi file systems are ease of use and high efficiency, reducing the time required, which benefits both the clinician and the patient. Neoniti ™ files are available in three different sizes (20/0.08, 25/0.08, and 40/0.08). According to the manufacturer, they Hindawi International Journal of Dentistry Volume 2021, Article ID 6457071, 6 pages https://doi.org/10.1155/2021/6457071