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CC BY 4.0 · Eur J Dent
DOI: 10.1055/s-0045-1814775
Original Article

Cleaning Efficacy, Debris Extrusion, and Instrument Separation during Root Canal Filling Removal using Continuous Rotation, Reciprocation, and Optimum Torque Reverse Motions: An In Vitro Study

Authors

  • Tarek Abboud 

    1   Department of Operative and Endodontic Dentistry, Faculty of Dentistry, Damascus University, Damascus, Syria

  • Mouhammad Al-Tayyan 

    2   Department of Endodontics, Faculty of Dentistry, Damascus University, Damascus, Syria

  • Hassan Achour 

    1   Department of Operative and Endodontic Dentistry, Faculty of Dentistry, Damascus University, Damascus, Syria

  • Yasser Alsayed Tolibah 

    3   Department of Pediatric Dentistry, Faculty of Dentistry, Damascus University, Damascus, Syria

Funding This research is funded by Damascus University (Grant Number 501100020595).
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Abstract

Objectives

This study aims to address the Optimum Torque Reverse (OTR) efficacy in root canal obturationmaterials removal, the amount of apically extruded debris, and separating instruments (SI) as a complication compared to continuous rotational motion (CRM) and reciprocating motion (RM).

Materials and Methods

The sample involved 45 straight mandibular first premolars. The crowns were decoronated to standardize the length to 16 mm. The root canals were prepared up to a size 25 taper 0.06, obturated using the lateral compaction technique with a resin-based sealer, stored for 7 days, and divided according to the motion type used during retreatment into three groups (each group consisted of 15 samples); Group 1: CRM using Protaper Universal Retreatment system (D3 20 0.07 last file reach apical third), Group 2: RM using WaveOne Gold system Medium 25 0.07 variant taper, and Group 3: OTR motion using Protaper Universal Retreatment system (D3 20 0.07 last file reach apical third). The extruded debris weight was measured using an analytical balance. Samples were sectioned longitudinally and photographed at 20X magnification using an optical microscope. The images were analyzed in ImageJ to assess the percentage of residual obturation material. The number of SI during retreatment was recorded. Statistical Analysis Data were statistically analyzed using one-way analysis of variance (ANOVA) and chi-square tests at an α = 0.05 significance level.

Results

The results indicate that the incidence of SI during retreatment in the OTR motion group was higher than the CRM group and the RM group (p = 0.001). There were no significant differences among the groups regarding the amount of apically extruded debris and the percentage of residual obturation material (p >0.05).

Conclusion

The effectiveness of root canal obturation material removal and the amount of extruded debris during retreatment do not depend on the motion used. However, the OTR motion is associated with an increased risk of SI during retreatment.

Keywords

endodontic retreatment - OTR motion - continuous rotational motion - reciprocating motion

Authors' Contributions

T.A. conceptualized the idea, provided the laboratory work, and contributed to the writing, documenting, and interpretation of data. M.A-T. conceptualized the idea and supervised the research. H.A. was the project admin. Y.A.T contributed to writing the main manuscript, made the revision, formatting, and re-editing of the manuscript. All authors have read and agreed to the published version of the manuscript.


Note

The presented article is a part of the MCS's study of author T.A., approved by the IRB, Damascus University College of Dentistry, Damascus, Syria (UDDS-76-20122021/SRC-1428).


Institutional Review Board Statement

The study was conducted according to the guidelines of the Declaration of Helsinki and was approved by the Institutional Review Board of Damascus University (UDDS-76-20122021/SRC-1428).


Informed Consent

Informed consent was obtained from all subjects/caregivers involved in the study.


Data Availability Statement

De-identified data are available upon reasonable request to the corresponding author.




Publication History

Article published online:
20 January 2026

© 2026. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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