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A comparison of the shaping ability of four rotary nickel-titanium files in simulated root canals

A comparison of the shaping ability of four rotary nickel-titanium files in simulated root canals

Article information

Restor Dent Endod. 2010;35(2):88-95
Publication date (electronic) : 2010 March 31
doi : https://doi.org/10.5395/JKACD.2010.35.2.088
Department of Conservative Dentistry, Division of Dentistry, Graduate of Kyung Hee University, Seoul, Korea.
Corresponding Author: Gi-Woon Choi. Department of Conservative Dentistry, Division of Dentistry, Graduate of Kyung Hee University, 1, Hoegi-dong, Dongdaemun-Gu, Seoul, 130-702, Korea. Tel: 82-2-958-9336, gwchoi@khu.ac.kr
Received 2009 October 14; Revised 2010 January 06; Accepted 2010 March 10.

Abstract

The purpose of this study was to compare the root canal shaping ability of 4 rotary NiTi instruments in simulated root canals.

For the preparation of thirty two curved root canals, Mtwo instruments using "single length"technique, and Profile, ProTaper Universal, and K3 using crown-down technique (N = 8) were used. All canal samples were prepared by reaching an apical canal size of #30. Pre- and post-instrumentation digital images were recorded and an assessment of canal shape was determined using a computer image analysis program SigmaScan Pro (Systat Software Inc., San Jose, CA, USA). The changes of the dimension of inner walls of canals, (2) the changes of the dimension of outer walls of canals, and (3) the centering ratio were measured at 7 measuring points, and then data were statistically analyzed using one-way ANOVA and Duncan's test. The results were as below;

  1. The root canal shaping ability of Profile was significantly faster than that of other rotary NiTi instruments (p < 0.05).

  2. The deformation and fracture of all instruments used for this study were not experienced.

  3. In the degree of changes of the dimension of inner walls of canals, Profile demonstrated the lowest changes of the dimension of inner walls of canals except at the measuring points of the 1 and 2 mm (p < 0.05). However, the ProTaper Universal showed the highest changes of the dimension of inner walls of canals at all measuring points (p < 0.05).

  4. In the degree of changes of the dimension of outer walls of canals, Mtwo demonstrated the lowest changse of the dimension of outer walls of canals except at the measuring point of the 1 mm (p < 0.05). However, Profile exhibited the highest changes of the dimension of outer walls of canals at the measuring points of 3 and 4 mm and ProTaper Universal and K3 showed the largest changes of the dimension of outer walls of canals at the measuring points of 1, 2, 6, and 7 mm (p < 0.05).

  5. In degree of centering ratio, Profile demonstrated the least centering ratio comparing with the centering ratio shown by other NiTi instruments at the measuring points of 1, 4, 5, and 6 mm.

Results suggest that in the coronal part of canal preparation, active cutting files such as ProTaper Universal may efficiently flare the canal orifice and form a better taper, and in the apical part of the canal, files which have a better centering ability such as Profile may maintain the original canal curvature and reduce the shaping time.

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Article information Continued

Figure 1

a. The image of block before canal preparation. b. The image of block after canal preparation. c. Superimposed images of the pre-and post-instrumentations.

Figure 2

Mean working time and total working time of four rotary NiTi file.

Table 1

Mean preparation time (sec) with four rotary Ni-Ti files

Table 1

PT: preparation time. WT: working time. TWT: total instrumentation time.

Different superscript letter indicates significant difference (p < 0.05).

Table 2

Comparison of the amount of resins removed (1/100 mm) from inner canal walls at different measurement sites after preparation

Table 2

Different superscript letter indicates significant difference (p < 0.05).

Table 3

Comparison of the amount of resins removed (1/100 mm) from outer canal walls at different measurement sites after preparation

Table 3

Different superscript letter indicates significant difference (p < 0.05).

Table 4

Deviation of centering ratio at different measurement sites of four rotary Ni-Ti files

Table 4

Different superscript letter indicates significant difference (p < 0.05).

A positive valu indicates an effect in the measured direction, while a negative valus indicates a shift in the opposite direction