Force and vibration generated in apical direction by three endodontic files of different kinematics during simulated canal preparation: An in vitro analytical study

Abstract

During root canal shaping, pain could result from the high level of force or vibration generated. This could be related to file kinematics or geometry. In the present study, a comparison is made between forces and vibrations generated by endodontic files having three different kinematics. Square pillar resin blocks were used as simulated root canals to study forces and vibrations generated by the file having reciprocating motion (WaveOne Gold), transline motion (Self-Adjusting File), and rotary motion (2Shape). The forces and vibrations were measured using the dynamometer and accelerometer, respectively. Recorded time domain signals were processed in MATLAB to calculate the root mean square value. A one-way analysis of variance and Tukey’s test for post hoc comparison at 95% confidence interval were applied over the root mean square data of different files. From a statistical analysis of the file systems, the null hypotheses could not be accepted ( P < 0.05) as 95% of the confidence interval. Differences between the means were statistically significant. The root mean square values of force and vibration for WaveOne Gold significantly exceeded those of Self-Adjusting File, 2Shape1, and 2Shape2 while the root mean square values of vibration for 2Shape1 and 2Shape2 were significantly less than the Self-Adjusting File; however, the root mean square value of force for the 2Shape2 was significantly more than for the Self-Adjusting File. Under the present experimental conditions, significant differences in the root mean square values of force and vibration of the three endodontic files of different kinematics have been observed. The WaveOne Gold file system generated higher apical force and vibration than the transline and rotary file system.

Force and vibration analysis in biomechanical preparation of root canals using reciprocating endodontic file system: In vitro study

“…It was evident from the responses that as the force increases, the maximum amplitude of the vibration also increases. Some of the previous authors 19,26,27,42 have reported the same observation as observed in this study.…”

“…Force signals were sampled at 7.1 kHz, and vibration signals at 51.2 kHz. 19,27 The accelerometer and dynamometer were connected to the data acquisition system, which converts voltage signal and current signal into the respective value of vibration and force. DAQ system was connected to the desktop and laptop for transferring the data.…”

“…22 At present, real-time measurement of the mechanical signals in the in vitro operation has focused signal characteristics upon simulated model, 23 endo turbine with handpiece, 24 endodontic motor and handpiece 18 and endo motors with different motions. 25 A few of the literature deals with the force and vibration analysis in the simulated root canal with endo-training blocks, 26,27 plastic block with curved canal, 28 and simulated resin block 29 for obtaining the uniform root canal geometry and uniform surface. These studies utilized the simulated root canal with the help of endodontic blocks which is not the real-world practice.…”

On comprehensive analysis of root canal shaping ability of three endodontic files of different kinematics

“…A complete rotation of the endodontic file leads the screwing force in an apical direction. While the reciprocating motion of the WoG helps to eliminate the screwing force, the alternating offset cross-section of the WoG, 22 which is shaped like a parallelogram, limits the engagement of the file only at 1 or 2 points at any cross-section. 23 This reduces the taper lock and screwing effect.…”

Comparison of vibration characteristics of file systems for root canal shaping according to file length

“…Comparison of the taper range of D0 to D3 showed a larger taper for PTG, with tapers of 0.07 and 0.06 for PTG and PTN, respectively. It is suspected that the PTG files were associated with greater vibration acceleration because the cutting force increases when cutting at a greater depth, generating stronger vibrations [19].…”