Oral Health and Dental Management

Abstract

The effects of rotary ni-ti canal instruments on canal curvature in the preparation of curved canals

This study compared the effects of Hero 642 and Profile Ni-Ti canal instruments, to which a file is
attached, on the original canal curvature.
This study was performed on the mesiobuccal canals of 20 extracted human mandibular first and
second molar teeth. The teeth were embedded in clear acrylic resin and separated into two test
groups. Pre- and postoperative radiographs of the teeth were made using a special apparatus. The
radiographs were digitized and transferred to a computer. Using the program Free Hand, the preand
postoperative angular and linear values of each tooth were determined, and then the curved
canals were evaluated using AutoCAD R12.
In the teeth prepared using the Profile system, no statistically significant difference was found
between the pre- and postoperative canal access angle (CAA), Schneider angle, or AC distance (p >
0.05). However, in the samples prepared with the Hero 642, the postoperative CAA decreased significantly
(p < 0.01). Furthermore, there was also a significant decrease in the postoperative AC distance.