Centering ability, canal transportation and surface modifications of ProTaper F2 and F3 used in continuous rotation and reciprocating motion in curved root canals

Jader Vinicius Andreazza,Fabiana Soares Grecca,Miguel Assis Martins Dos Santos,Júlia Eick Iglesias ,Fernanda Ulmann Lopez ,Lucas Siqueira Pinheiro

doi:10.22456/2177-0018.86208

Jader Vinicius Andreazza, Fabiana Soares Grecca + Show 4 more

Open Access

https://doi.org/10.22456/2177-0018.86208

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Abstract

Aims: To evaluate the centering ability, canal transportation and surface modifications of F2 and F3 ProTaper Universal (PT) instruments used in continuous rotation (CR) and reciprocating motion (RM) for the preparation of curved root canals. Material and methods: sixty mesiobuccal root canals of upper molars with curvatures between 25º and 35° were divided into three groups: I - PT in CR up to F3; II - PT in RM up to F3; III - F2 and F3 PT instruments in RM. Cone Beam Computed Tomography images were obtained before and after instrumentation. The scans were superimposed to determine the centering ability and canal transportation in apical, medium and cervical thirds. The apical 6 mm of the F2 and F3 files were evaluated under Scanning Electron Microscope before and after 1, 3 and 6 uses to assess distortion, surface wear and fracture. The statistical analysis of centering ability and canal transportation were performed by Kruskal–Wallis and ANOVA, respectively. The scores for deformation and surface wear were compared using ANOVA. Fisher’s exact test was used for the evaluation of instrument fracture. Results: there were no significant differences between groups regarding centering ability and canal transportation, as well as, for distortion, surface wear and fracture (p>.05). Conclusion: F2 and F3 instruments can be used for curved canals instrumentation. However, when used for entire canal preparation, F2 and F3 should be discarded after single use.

Highlights

A successful outcome in endodontics is directly dependent on the cleaning and shaping of the root canal system[1]
The increased flexibility of nickel-titanium (Ni–Ti) instruments have significantly improved the quality of root canal shaping[2] with less canal transportation, dentin preservation and reduced risk of zipping or stripping curved canals[3]. Despite these advantages, when used in continuous rotation (CR), instrument fracture by torsional failure or cyclic fatigue can occur[4], and these problems can be attributed to the continuous rotation[5]
Roots were randomly divided into 3 groups (n=20): Group I: twenty canals were prepared with the ProTaper Universal (PT) full-sequence (Dentsply Maillefer, Ballaigues, Suíça) in CR up to F3

Summary

Introduction

A successful outcome in endodontics is directly dependent on the cleaning and shaping of the root canal system[1]. There is a continuous search to improve instruments performance and techniques, in terms of root canal wall cleanness and maintenance of its original shape. The increased flexibility of nickel-titanium (Ni–Ti) instruments have significantly improved the quality of root canal shaping[2] with less canal transportation, dentin preservation and reduced risk of zipping or stripping curved canals[3]. Despite these advantages, when used in continuous rotation (CR), instrument fracture by torsional failure or cyclic fatigue can occur[4], and these problems can be attributed to the continuous rotation[5]. The single use of these instruments is desirable in order to reduce fracture and avoid cross-contamination

Methods

Results

Conclusion