Effect of rotational speed of Protaper™ rotary file on the change of root canal configuration

Article information

Restor Dent Endod. 2006;31(3):179-185

Publication date (electronic) : 2006 May 31

doi : https://doi.org/10.5395/JKACD.2006.31.3.179

Min-Chul Seo , Yoon-Jeong Jeon , In-Chol Kang ¹, Dong-Jun Kim , Yun-Chan Hwang , In-Nam Hwang , Won-Mann Oh

Department of Conservative Dentistry, School of Dentistry, Dental Science Research Institute, Chonnam National University, Korea.

¹Department of Oral Microbiology, School of Dentistry, Dental Science Research Institute, Chonnam National University, Korea.

Corresponding Author: Won-Mann Oh. Department of Conservative Dentistry, School of Dentistry, Chonnam National Universtiy, 8 Hak-dong, Dong-gu, Gwangju, Korea, 501-757. Tel: 82-62-220-4431, Fax: 82-62-225-8387, wmoh@chonnam.ac.kr

Received 2005 October 13; Revised 2006 January 16; Accepted 2006 January 20.

Abstract

This study was conducted to evaluate canal configuration after shaping by ProTaper™ with various rotational speed in J-shaped simulated resin canals.

Forty simulated root canals were divided into 4 groups, and instrumented using by ProTaper™ at the rotational speed of 250, 300, 350 and 400 rpm. Pre-instrumented and post-instrumented images were taken by a scanner and those were superimposed. Outer canal width, inner canal width, total canal width, and amount of transportation from original axis were measured at 1, 2, 3, 4, 5, 6, 7 and 8 mm from apex. Instrumentation time, instrument deformation and fracture were recorded. Data were analyzed by means of one-way ANOVA followed by Scheffe's test.

The results were as follows

Regardless of rotational speed, at the 1~2 mm from the apex, axis of canal was transported to outer side of a curvature, and at 3~6 mm from the apex, to inner side of a curvature. Amounts of transportation from original axis were not significantly different among experimental groups except at 5 and 6 mm from the apex.
Instrumentation time of 350 and 400 rpm was significantly less than that of 250 and 300 rpm (p < 0.01).

In conclusion, the rotational speed of ProTaper™ files in the range of 250~400 rpm does not affect the change of canal configuration, and high rotational speed reduces the instrumentation time. However, appearance of separation and distortion of Ni-Ti rotary files can occur in high rotational speed.

Keywords: Rotational speed; Canal configuration; Image analysis

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This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Figure 1

Pre-instrumentation image. Working length was 16 mm, the round circles were the landmark for getting the superimposed image.

Figure 2

The diagram indicates the points at which the canal width was measured after superimposition of pre-instrumentation and post-instrumentation image.

Table 1

Mean values (± SD) of outer, inner, total canal width, and amount of transportation after shaping with various rotational speed (mm)

Minus value indicates that axis of canal was transported to inner side curvature after canal preparation.

The different letter means significant difference between groups (p < 0.05).

Table 2

Instrumentation time for the canal preparation with various rotational speed

^*^*: significant difference (p < 0.01).