(PO30) In Vitro Assessment of Geometric Characteristics in Canal Preparation Using Nickel-Titanium Files Generated With Increased RPM

Abstract: The objective of this study was to assess geometric characteristics in canal preparation using nickel-titanium files generated with increased RPM. Thirty J-shaped canals in resin blocks were divided into three groups (n=10) and instrumented with Trunatomy (TR, Size 26, Medium; 500 rpm, 1.5 N), EndoRoad (ER, Size 25, RG25; 600 rpm, 0.6 N), and Protaper Ultimate (PTU, Size 25, F2; 400 rpm, 4.0 N). Samples were scanned using microcomputed tomography. Scanned images were reconstructed, and the surface area of the canal was measured from 0.5 to 6.5 mm from the apex in the resin block. 3D representative models of each group were rendered. The data were statistically analyzed by one-way ANOVA and Kruskal-Wallis test (p < .05). In 3D representative models, the TR group showed a superior ability to maintain the center of mass. The ER group tended to prep the canal more towards the inner side of the curvature, while the PTU group tended to prep the canal more towards the outside of the curvature. In the surface area instrumented using each nickel-titanium file, at levels other than 0.5 mm, 2.0 mm, and 3.5 mm from the apex, there was a statistically significant difference among the three groups (p < .05). At a level of 0.5 mm from the apex, there was no statistically significant difference between the TR group and the PTU group (p > .05). At levels of 2.0 and 3.5 mm from the apex, there was no statistically significant difference between the TR group and the ER group (p > .05). Understanding these geometric characteristics of nickel-titanium files in canal preparation enables clinicians to make informed choices when faced with various clinical situations.