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VOLUME 18 , ISSUE 6 ( June, 2017 ) > List of Articles


Comparative Evaluation of Stress developed on Rotary Retreatment Instruments during Retrieval of Gutta-percha

Sushmita Shivanna, Dhanasekaran Sihivahanan, T Vinay Kumar Reddy, Anchu Rachel Thomas, Natarajan Senthilnathan, Murali Sivakumar

Citation Information : Shivanna S, Sihivahanan D, Reddy TV, Thomas AR, Senthilnathan N, Sivakumar M. Comparative Evaluation of Stress developed on Rotary Retreatment Instruments during Retrieval of Gutta-percha. J Contemp Dent Pract 2017; 18 (6):484-489.

DOI: 10.5005/jp-journals-10024-2070

Published Online: 01-10-2017

Copyright Statement:  Copyright © 2017; The Author(s).



The aim of the study is to compare the maximum stress distribution on the rotary retreatment instruments within the root canal at cervical, middle, and the apical one-third during retreatment of gutta-percha.

Materials and methods

A human mandibular premolar was scanned, and three-dimensional geometry of the root was reconstructed using finite element analysis (FEA) software package (ANSYS). The basic model was kept unchanged; tooth models were created using the same dimensions and divided into two groups as follows: Group I: ProTaper Universal retreatment system and group II: Mtwo rotary retreatment system. The stress distribution on the surface and within the retreatment files was analyzed numerically in the FEA package (ANSYS).


The FEA analysis revealed that the retreatment instruments received the greatest stress in the cervical third, followed by the apical third and the middle third. The stress generated on the ProTaper Universal retreatment system was less when compared with the Mtwo retreatment files.


The study concludes that the retreatment instruments undergo higher stress in the cervical third region, and further in vivo and in vitro studies are necessary to evaluate the relationship between instrument designs, stress distribution, residual stresses after use, and the torsional fracture of the retreatment instrument.

Clinical significance

The stress developed on the rotary retreatment instruments during retrieval of gutta-percha makes the instrument to get separated. There is no instrument system, i.e., suitable for all clinical situations and it is important to understand how the structural characteristics could influence the magnitude of stresses on the instrument to prevent its fracture in use.

How to cite this article

Sihivahanan D, Reddy TVK, Thomas AR, Senthilnathan N, Sivakumar M, Shivanna S. Comparative Evaluation of Stress developed on Rotary Retreatment Instruments during Retrieval of Gutta-percha. J Contemp Dent Pract 2017;18(6):484-489.

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