Nayak Ankit, Kankar Pavan Kumar, Jain Niharika, Jain Prashant Kumar
CAD/CAM Lab, Mechanical Engineering Discipline, PDPM, Indian Institute of Information Technology, Design and Manufacturing Jabalpur, Madhya Pradesh 482005, India.
Department of Conservative Dentistry and Endodontics, Triveni Institute of Dental Science, Hospital and Research Centre, Bilaspur, Chhattisgarh 495001, India.
J Dent Sci. 2018 Sep;13(3):184-189. doi: 10.1016/j.jds.2018.01.002. Epub 2018 Mar 26.
BACKGROUND/PURPOSE: The focus of this study was to find a correlation between the forces and vibrations during root canal shaping. This can be used to predict the fracture of the self-adjusting file (SAF) in root canal shaping.
Forty J-shaped resin blocks were used in this study. Simulated root canals of resin blocks were prepared with the SAF. Force and vibration during root canal shaping were measured by dynamometer and accelerometer respectively. The recorded time domain signal of force and vibration were transformed to frequency domain signals. Frequency domain signals had been used for correlation study between force and vibration amplitude. The root mean square (RMS) value of force and vibration signature for new file and file just before failure were statistically compared using t-test at 95% confidence interval (CI).
Vibrations generated during root canal shaping exhibited positive linear correlation ( = 0.9173) with force exerted by the SAF on the root canal. It means vibration has strong correlation with force. The RMS values of force and vibration increase significantly ( < 0.05) just before the fracture.
From force and vibration analysis of SAF it was concluded that the vibration is well associated with force applied by the SAF on root canal. Therefore, the trend of force variation was reflected in the vibration signature. The sudden increment in vibration was the symptom of bulge formation and the end of useful life of the SAF.
背景/目的：本研究的重点是找出根管预备过程中力与振动之间的相关性。这可用于预测根管预备中自调式锉（SAF）的折断情况。
本研究使用了40个J形树脂块。用SAF对树脂块制备模拟根管。分别用测力计和加速度计测量根管预备过程中的力和振动。将记录的力和振动的时域信号转换为频域信号。频域信号用于力与振动幅度之间的相关性研究。使用t检验在95%置信区间（CI）对新锉和即将折断前的锉的力和振动特征的均方根（RMS）值进行统计学比较。
根管预备过程中产生的振动与SAF施加在根管上的力呈正线性相关（r = 0.9173）。这意味着振动与力有很强的相关性。在折断前，力和振动的RMS值显著增加（P < 0.05）。
通过对SAF的力和振动分析得出，振动与SAF施加在根管上的力密切相关。因此，力变化趋势反映在振动特征中。振动的突然增加是SAF形成凸起和使用寿命结束的征兆。
