J Korean Acad Conserv Dent.  2003 Jan;28(1):41-49. 10.5395/JKACD.2003.28.1.041.

Effect of various canal preparation techniques using rotary nickel-titanium files on the maintenance of canal curvature

• Lee CH
• Cho KM
• Hong CU

• KMID: 2117429
• DOI: http://doi.org/10.5395/JKACD.2003.28.1.041

Abstract

There are increasing usage of Nickel-Titanium rotary files in modern clinical endodontic treatment because it is effective and faster than hand filing due to reduced step. This study was conducted to evaluate the effect of canal preparations using 3 different rotary Nickel-Titanium files that has different cross sectional shape and taper on the maintenance of canal curvature. Simulated resin block were instrumented with Profile(Dentsply, USA), GT rotary files(Dentsply, USA), Hero 642(Micro-Mega, France), and Pro-Taper(Dentsply, USA). The image of Pre-instrumentation and Post-instrumentation were acquired using digital camera and overspreaded in the computer. Then the total differences of canal diameter, deviation at the outer portion of curvature, deviation at the inner portion of curvature, movement of center of the canal and the centering ratio at the pre-determined level from the apex were measured.
Results
were statistically analyzed by means of ANOVA, followed by Scheffe test at a significance level of 0.05. The results were as follows; 1. Deviation at the outer portion of curvature, deviation at the inner portion of curvature were showed largest in Pro-Taper, so also did in the total differences of canal diameter(p<0.05). 2. All the groups showed movements of center. Profile combined with GT rotary files and Hero 642 has no difference but Pro-Taper showed the most deviation(p<0.05). 3. At the 1, 2, 3mm level from the apex movements of center directed toward the outer portion of curvature, but in 4, 5 mm level directed toward the inner portion of curvature(p<0.05). As a results of this study, it could be concluded that combined use of other Nickel-Titanium rotary files is strongly recommended when use Pro-Taper file because it could be remove too much canal structure and also made more deviation of canal curvature than others.

Keyword

Rotary Ni-Ti file; Protaper file; GT file; Hero 642; Curvature; Transportation

MeSH Terms

Hand
Transportation

Figure

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  Fig. 1 A transluscent Endo-training block used in study that has single 35° - curvature measured by Schneider method.

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  Fig. 2 The image of the fixed block before canal shaping.

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  Fig. 3 A focused canal image from the image before canal shaping.

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  Fig. 4 The image of fixed block afer canal shaping in the same way.

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  Fig. 5 A piled image on the image after canal shaping and transluscency change.

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  Fig. 6 The extent of the change toward outer portion of canal curvature is the area from the line before canal shaping to the outer line, and the area below the line is the extent of the change toward inner part.

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