J Korean Acad Conserv Dent.  2007 Jan;32(1):61-68. 10.5395/JKACD.2007.32.1.061.

A comparison of canal centering abilities of four root canal instrument systems using X-ray micro-computed tomography

• Ko HS
• You HM
• Park DS

• KMID: 1986931
• DOI: http://doi.org/10.5395/JKACD.2007.32.1.061

Abstract

The purpose of this study was to compare the centering abilities of four root canal instrument systems and the amounts of dentin removed after root canal shaping using them. The mesial canals of twenty extracted mandibular first molars having 10 - 20degrees curvature were scanned using X-ray micro-computed tomography (XMCT)-scanner before root canals were instrumented. They were divided into four groups (n = 10 per group). In Group 1, root canals were instrumented by the step-back technique with stainless steel K-Flexofile after coronal flaring. The remainders were instrumented by the crown-down technique with Profile (Group 2), ProTaper (Group 3) or K3 system (Group 4). All canals were prepared up to size 25 at the end-point of preparation and scanned again. Scanned images were processed to reconstruct three-dimensional images using three-dimensional image software and the changes of total canal volume were measured. Pre- and post-operative cross-sectional images of 1, 3, 5, and 7 mm from the apical foramen were compared. For each level, centering ratio were calculated using Adobe Photoshop 6.0 and image software program. ProTaper and K3 systems have a tendency to remove more dentin than the other file systems. In all groups, the lowest value of centering ratio at 3 mm level was observed. And except at 3 mm level, ProTaper system made canals less centered than the other systems (p < 0.05).

Keyword

X-ray micro-computed tomography; ProFile; Protaper; K3; Centering ratio; Three dimensional image software

MeSH Terms

Dental Pulp Cavity*
Dentin
Imaging, Three-Dimensional
Molar
Stainless Steel
Tooth Apex
X-Ray Microtomography*
Stainless Steel

Figure

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  Figure 1 Examples of superimposed images. Dark gray: Cross section of root after canal shaping Light gray: Cross section of root before canal shaping

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  Figure 2 The drawing representing superimposed image of pre-and post-instrumentation canal shapes for measurement of centering ratio. T': Maximum extent of canal movement in one direction T: Movement in the opposite direction D: Diameter of the final canal preparation

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