Microtomographic Evaluation of Canal Centralization and Dentine Removal after Canal Preparation with Two Rotary Systems: HyFlex EDM and ProTaper Next.

Marília Fagury Videira Marceliano-Alves,Eduardo Fagury Videira Marceliano,Carlos Eduardo Da Silveira Bueno,Ricardo Tadeu Lopes,Thais Machado De Carvalho Coutinho,Paula Avelar Da Silva Ribeiro Goulart,Alexandre Sigrist De Martin,Karin Zuim,Vivian Ronquete

doi:10.1055/s-0041-1739440

Abstract

Objective This study compared the ProTaper Next (PTN; Dentsply Sirona, Tulsa, Oklahoma, United States) and HyFlex EDM (HEDM; Coltene/Whaledent AG, Alstätten, Switzerland) systems using micro–computed tomography (CT). Materials and Methods Twenty-one mesial roots classified as Vertucci's type IV from extracted mandibular first molars with curvatures between 20 and 40 degrees were selected. The teeth were scanned using a micro-CT before and after root canal preparation by both systems, applied to the same root, in alternating canals. The following parameters were analyzed: canal centering, apical transportation, root canal diameter/root diameter. Results No statistically significant differences between both systems were observed for any of the assessed morphological parameters ( p > 0.05). All canals presented diameter enlargement of more than 40% in relation to root diameter in the cervical and middle segments. No statistically significant difference was noted between the HEDM and PTN groups. The wear percentage for the HEDM group in the cervical and middle thirds were 49.66 ± 8.65 and 46.48 ± 14.29, respectively, and 51.02 ± 11.81 and 45.48 ± 10.79 for the PTN group, respectively. Conclusion Both systems displayed similar mandibular molar mesial canals preparation, with no differences noted for any of the assessed parameters. Both groups showed increased canal diameter in the cervical and middle thirds by more than 40%.

Highlights

Understanding the anatomy of tooth canals is an essential step for effective endodontic therapy
No statistically significant difference was noted between the HyFlex EDM (HEDM) and ProTaper Next (PTN) groups
These difficulties in preparation may predispose the root canal to persistent infection, as bacteria may remain in unprepared areas, adhered to canal walls or in areas inaccessible to the chemical–mechanical preparation, which can lead to failures in endodontic treatment.[4]

Summary

Introduction

Understanding the anatomy of tooth canals is an essential step for effective endodontic therapy. Studies report changes to root canal morphology during canal preparation, which may vary according to applied instrumentation technique.[1] In addition, root curvature introduces a complexity that influences the ability of instruments to prepare and clean all root canal walls, regardless of the applied instrumentation system.[2,3] These difficulties in preparation may predispose the root canal to persistent infection, as bacteria may remain in unprepared areas, adhered to canal walls or in areas inaccessible to the chemical–mechanical preparation, which can lead to failures in endodontic treatment.[4]. Automated instruments made from a nickel–titanium (NiTi) alloy have become widely applied in clinical practice. The NiTi alloy presents a lower elasticity modulus than stainless steel, allowing for easy and efficient preparation of curved root canals.[5,6] errors in iatrogenic procedures, such as deviations, perforations, or root canal transportation, may occur due to the applied instrumentation technique, in curved canals, culminating in deviations of the original root canal pathway.[7,8]

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Results

Discussion

Conclusion