J Korean Acad Conserv Dent. 2005 Jul;30(4):303-311. Korean.
Published online Jul 30, 2005.
Copyright © 2005 Korean Academy of Conservative Dentistry
Original Article

The change of canal configuration after instrumentation by several nickel-titanium files in the simulated canal with abrupt curvature

Jung-Jang Lim, Dong-Jun Kim, Yun-Chan Hwang, In-Nam Hwang and Won-Mann Oh
    • Department of Conservative Dentistry, School of Dentistry, DSRI, Chonnam National University, Korea.
Received November 11, 2004; Revised December 29, 2004; Accepted February 15, 2005.

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.

Abstract

The purpose of this study was to evaluate which type of Ni-Ti files are able to maintain canal configuration better in the simulated canal with abrupt curvature near it's apex.

Ninety six simulated root canals were made in epoxy resin and #15 finger spreader was used as root canal templates. The simulated root canals were made with radius of curvature of 1.5 mm, 3.0 mm, 4.0 mm, 6.0 mm respectively and the angle of curvature of all simulated canals were adjusted to 90 degree. The simulated canals were instrumented by ProFile, ProTaper, Hero 642, and K3 at a 300 rpm using crown-down pressureless technique. Pre-instrumented and post-instrumented images were taken by digital camera and were superimposed with Adobe Photoshop 6.0 program. Images were compared by image analysis program.

The changes of canal width at the inner and outer side of the canal curvature, canal transportation were measured at 9 measuring point with 1 mm interval. Statistical analysis among the types of Ni-Ti files was performed using Kruskal-Wallis test and Mann-Whitney U-test.

The result was that ProFile maintain original canal configuration better than other engine driven Ni-Ti files in the canals above 3.0 mm radius of curvature, and in the 1.5 mm radius of curvature, most of Ni-Ti flies were deformed or separated during instrumentation.

Keywords
Ni-Ti file; Canal curvature; ProFile; ProTaper; Hero 642; K3

Figures

Figure 1
4.0 mm radius of curvature of finger spreader

Figure 2
Pre- and Post-image of root canal and Measuring points were measured with 1 mm interval from 1 mm to 9 mm.

Figure 3
Change of total canal width of the curvature in 3.0 mm radius group (Unit: mm).

*significant difference among Ni-Ti files at each measuring point (p < 0.05).

Figure 4
Change of total canal width of the curvature in 4.0 mm radius group (Unit: mm).

*significant difference among Ni-Ti files at each measuring point (p < 0.05).

**significant difference among Ni-Ti files at each measuring point (p < 0.01).

Figure 5
Change of total canal width of the curvature in 6.0 mm radius group (Unit: mm).

*significant difference among Ni-Ti files at each measuring point (p < 0.05).

**significant difference among Ni-Ti files at each measuring point (p < 0.01).

Figure 6
Canal transportation of 3.0 mm radius group (Unit: mm).

*significant difference among Ni-Ti files at each measuring point (p < 0.05).

**significant difference among Ni-Ti files at each measuring point (p < 0.01).

Negative value means inside transportation from central axis of original root canal.

Figure 7
Canal transportation of 4.0 mm radius group (Unit : mm).

*significant difference among Ni-Ti files at each measuring point (p < 0.05).

**significant difference among Ni-Ti files at each measuring point (p < 0.01).

Negative value means inside transportation from central axis of original root canal.

Figure 8
Canal transportation of 6.0 mm radius group (Unit : mm).

*significant difference among Ni-Ti files at each measuring point (p < 0.05).

**significant difference among Ni-Ti files at each measuring point (p < 0.01).

Negative value means inside transportation from central axis of original root canal.

Tables

Table 1
The number of ledge formation and File fracture

Table 2
Deformation and separation of Ni-Ti files

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