Evaluation of the efficiency of a new file removal system in comparison with two conventional systems

A novel file-removal system (FRS) was designed to address weak points of conventional file-removal methods. The purpose of this study was to compare fileremoval time and dentin removal rates among the FRS, the Masserann kit (Micro-Mega, Besancon, France), and an ultrasonic file-removal method. Ninety extracted mandibular incisors with separated nickel titanium files were divided into 3 groups of 30 teeth each. Groups 1, 2, and 3 had file-removal attempts made by using the Masserann kit, a CPR-7 titanium ultrasonic tip (Obtura-Spartan Corp., Fenton, MO), and the FRS, respectively. Each group had three operators removing the separated files. Pre-/postoperative digital radiographs were downloaded into image analyzing software that calculated the amount of dentin removed. The FRS needed less time and had less dentin loss than the others (p < 0.05). There were statistical differences between the experienced operator and less experienced operators regarding the file-removal time and the dentin removal rates (p < 0.05).