A comparative finite analysis of the mechanical behavior of ProTaper NEXT and WaveOne rotary files

Abstract

Finite element analysis was used to evaluate the stress distribution, estimate the residual stresses, bending, and amount of displacement of two nickel-titanium instruments manufactured by the same M-wire technology but with different cross-section. Materials and methods: Two brands of Ni-Ti instruments ProTaper NEXT (Dentsply Maillefer), and WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) were scanned with stereomicroscope to produce a two-dimensional model for each file using computer-aided design programs (CAD) (SolidWorks software package), which then was converted into stereolithographic extension to be readable by programming software (MATLAB software) to produce three-dimensional models. The mathematical analysis of files was performed on SolidWorks software package. The mechanical behavior of the two files was analyzed numerically in a SolidWorks package to simulate and measure torsion, bending, and file displacement. Application of a shear moment (torsion) 2.5 N/mm moment of force was applied to the shaft in a clockwise direction, while the last 4 mm of the tip was rigidly constrained to evaluate the stress distribution on each file. As for Cantilever bending, a concentrated load of 1 N at the tip of the file with its shaft rigidly held in place was applied for the finite element models. The vertical displacement was measured and the von Mises stress distribution was evaluated. Results: The WaveOne file showed higher torsional stresses accumulation than those accumulated in the ProTaper NEXT. While the ProTaper NEXT showed more bending and file displacement than those showed by WaveOne file. Conclusions: The two files rotary models highlighted the different mechanical properties of the files although they share the same manufactured technology M-wire. The ProTaper NEXT showed less torsional stress accumulation and more bending properties.

Computerized Generation and Finite Element Stress Analysis of Endodontic Rotary Files

“…Although metallurgical properties and metallurgical treatments have been shown to influence the properties of NiTi endodontic rotary instruments, geometrical design has been highlighted to be directly related to the stiffness [41], clinical efficiency and cutting performance of endodontic rotary files [29,42]. The cross-section design of endodontic rotary files has experienced a continuous development; Versluis et al reported that increasing the cross-sectional surface area lead to a decrease in the flexibility of endodontic rotary files by a stress accumulation at the upper and lower edges of the cross section during bending tests, compared with smaller cross-sectional surface areas [17].…”

The Influence of Single and Multiple NiTi Rotary File Systems on Prevalence of Postoperative Pain Following Root Canal Instrumentation Using Mechanical or Manual Glide Path Techniques

“…On the other hand, the PTN system was used in continuous rotation movement that was reported to enhance the coronal carriage of dentine debris and chips via acting as a screw conveyor (23) . Besides, the WOG has a parallelogram cross section (4) , while PTN has a rectangular cross section (24) .…”