Finite Element Study on Continuous Rotating versus Reciprocating Nickel-Titanium Instruments

Abstract

In the present study, GTX and ProTaper as continuous rotating endodontic files were numerically compared with WaveOne reciprocating file using finite element analysis, aiming at having a low cost, accurate/trustworthy comparison as well as finding out the effect of instrument design and manufacturing material on its lifespan. Two 3D finite element models were especially prepared for this comparison. Commercial engineering CAD/CAM package was used to model full detailed flute geometries of the instruments. Multi-linear materials were defined in analysis by using real strain-stress data of NiTi and M-Wire. Non-linear static analysis was performed to simulate the instrument inside root canal at a 45° angle in the apical portion and subjected to 0.3 N.cm torsion. The three simulations in this study showed that M-Wire is slightly more resistant to failure than conventional NiTi. On the other hand, both materials are fairly similar in case of severe locking conditions. For the same instrument geometry, M-Wire instruments may have longer lifespan than the conventional NiTi ones. In case of severe locking conditions both materials will fail similarly. Larger cross sectional area (function of instrument taper) resisted better to failure than the smaller ones, while the cross sectional shape and its cutting angles could affect instrument cutting efficiency.

Cutting efficiency of conventional and heat‐treated nickel–titanium rotary or reciprocating glide path instruments

“…However, in agreement with the present findings, it has been reported that the pulsating action of the reciprocating motion of the cutting edge of file increases the applied load on the substrate to cut, and thus, it could increase the cutting efficiency of reciprocating files (El‐Anwar et al . ).…”

Torsional fatigue resistance of pathfinding instruments manufactured from several nickel‐titanium alloys

“…Previous reports have stated that instruments with small cross-sectional areas generally have lower torsional strength (Turpin et al 2000, Baek et al 2011, Kim et al 2012, Ninan & Berzins 2013, Pedull a et al 2016. Moreover, the cross-sectional design modified the stress distribution under torsion, which affected the torsional strength and susceptibility to fracture (Turpin et al 2000, Zhang et al 2011, El-Anwar et al 2016.…”

Advanced Computational Methods in Bio-Mechanics

“…Recent numerical studies of rotary and reciprocating instruments proved that modelling of the instrument with equivalent circular cross-sectional area did not affect results quality, while the cross-sectional shape and its cutting angles could affect instrument cutting efficiency [ 13 ] [ 14 ]. The reciprocating system has great advantages over other root therapy instruments.…”