Evaluating the cutting efficiency of NiTi instruments with reciprocating motions

Abstract

Aim: This study tested a setup for in vitro experimental analysis of axial forces and torque during the preparation of artificial canals using nickel-titanium reciprocating endodontic files. Methods: The cutting efficiency of Reciproc (RC) and WaveOne (WO) reciprocating size 25/.08 instruments (n = 10) was evaluated, taking into account their dimensional and geometrical features. Measurements of the diameter at each millimeter from the tip, pitch length, helical angle, and cross-sectional design and area were assessed. Cutting efficiency tests were carried out on a specific bench device by measuring the torque and axial force required during artificial canal shaping. Statistical analysis was performed using one-way ANOVA (α = 0.05). Results: The WO samples showed larger A3 mean values than did the RC instruments (P <.0001), despite having equal diameters at 3mm from the tip (D3) (P = .521). The mean values of pitch length were higher for RC than for WO instruments (P <.0001), with consequently smaller helical angles (P <.0001). For the cutting efficiency tests, the required torque was lower for the RC group when compared to the WO group, but it was significant only in the first stage of insertion in the artificial canals (P = .008). Regarding the apical force, the RC instruments reached higher values when compared to the WO instruments (P = .04) in the second stage of cutting action. Conclusion: Reciproc instruments demonstrated statistically higher cutting efficiency when compared to WaveOne instruments.Uniterms: cutting efficiency; M-Wire; reciprocating motion; Reciproc; WaveOne