Research of the major clinical findings of the use of reciprocant files: a systematic review

Abstract

Introduction: In the context of root canal treatments, nickel-titanium endodontic rotary instruments fracture due to torsional overload or cyclic fatigue. Channels with bends located closer to the channel orifice and channels with double bends (S-shaped channels) have been shown to increase the risk of fatigue failure of rotating instruments. Thus, Yared was the first to report the use and effectiveness of reciprocating motions for rotary files, as he demonstrated that a single reciprocating file was sufficient to replace several files used in continuous rotation. Objective: A concise systematic review was carried out on the main results of clinical studies on the use of reciprocating files, to externalize the scientific evidence of these files to files used in continuous rotations. Methods: The present study followed the model of systematic literature review (PRISMA). The research was carried out from January 2022 to March 2022 and was developed based on Google Scholar, Scopus, PubMed, Scielo, and the Cochrane Library. The quality of scientific evidence of the studies was based on the GRADE instrument. The risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 85 articles were found. After the process of analyzing the quality of scientific evidence, 32 articles were selected. After analyzing the risk of bias, 8 recent clinical studies, from 2019 to 2022, were selected to compose this systematic review. Based on the clinical studies presented in the present study, it was evidenced that there is a significant statistical difference in the number of cycles in and out movement and wear time to failure between reciprocating and continuous rotary files. Furthermore, an endodontic treatment combining a single reciprocating file with a single cone showed similar clinical efficacy to treatment with hand file instrumentation and lateral compaction obturation. However, randomized clinical studies have shown that reciprocating instruments have less resistance to cyclic fatigue when operated in canals with curvatures in the coronal and middle thirds when compared with curvatures in the apical thirds.