Sarah Isaac El Mankabadi, Geraldine Mohamed Ahmed And Heba Ahmed ElAsfouri,

ABSTRACT


Aim: To Compare The Cyclic Fatigue Resistance Of Three Thermomechanically Treated Rotary NiTi Instruments 2Shape (TS; Micro-Mega, Besancon, France), ProTaper Gold (PTG; Dentsply Maillefer, Baillagues, Switzerland) And Vortex Blue (VB; Dentsply; Tulsa Dental Specialties, Tulsa, OK, USA) Under Intracanal Conditions.

Materials and Methods: A Total Of 36 Rotary NiTi Instruments Of TS (25/0.06), PTG (25/0.08) And VB (25/0.06) (n=12) Were Rotated In A Custom Made Model Having A 60? Angle Of Curvature And 5mm Radius Of Curvature Until Fracture Occurred. The Model Was Immersed In An Acrylic Container Filled With 2.5% Sodium Hypochlorite (NaOCl) Solution Set At Intracanal Temperature (35?C ? 2?C). Time To Fracture Was Recorded Followed By Calculating The Number Of Cycles To Failure (NCF). The Length Of The Fractured Segments Was Measured Using A Digital Caliper And Scanning Electron Microscope (SEM) Examination Was Also Performed. The Data Were Statistically Analyzed Using Kruskal-Wallis And Dunn?s Tests With The Significance Level Set At P ? 0.05.

Results: The PTG Group Showed The Highest Statistically Significant NCF Followed By The VB And TS Groups Respectively (P < 0.001). Both The PTG And TS Groups Exhibited No Statistical Significant Difference Regarding The Length Of The Fractured Segment (P > 0.05). However, They Had Statistically Significant Longer Fragment Compared To The VB Group (P < 0.007). SEM Analysis Revealed Typical Features Of Cyclic Fatigue Failure.

Conclusions: The Gold Treatment Had The Highest Cyclic Fatigue Resistance Followed By The Blue Treatment. The T.wire Technology Of The TS System Showed The Lowest Resistance To Cyclic Fatigue.