Influence of Heat Treatment of Nickel–Titanium Instruments on Cyclic Fatigue Resistance in Simulated Curved Canals

Abstract

Objective The aim of this study was to compare the cyclic fatigue of heat-treated and non-treated instruments. Materials and Methods Twenty instruments with and without heat treatment from Bassi Logic were evaluated (n = 10). All instruments were subjected to dynamic cyclic fatigue through continuous rotations inside a stainless-steel tube (1.4-mm diameter, 9-mm curvature with 6-mm radius, and 90° angle) using a custom-made device, which performed 1 axial oscillation every 2 seconds with an amplitude of 3 mm, powered by a torque-controlled motor (Silver Reciproc, VDW, Germany), with speed adjusting to 950 rpm and torque to 4 N, according to manufacturer's guidance. The groups were compared using the Mann–Whitney test. Result The fracture time of the heat-treated instruments (97.20 ± 39.94 second and non-treated instruments (14.30 ± 6.78 seconds had statistical differences [p < 0.05]). Heat-treated instruments were 6.8 times more resistant to fatigue than non-treated instruments (p < 0.05). Conclusion Heat treatment provides increased fatigue resistance of NiTi alloy with the same design.

A Comprehensive Multimethod Analysis of Mechanical Properties of two different heat treatments for endodontic Nickel-titanium instruments

“…Authors contributing to Annali di Stomatologia agree to publish their articles under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which allows third parties to copy and redistribute the material providing appropriate credit and a link to the license but does not allow to use the material for commercial purposes and to use the material if it has been remixed, transformed or built upon. A Comprehensive Multimethod Analysis of Mechanical Properties of two different heat treatments for endodontic Nickel-titanium instruments they are proprietary and not disclosed by manufacturers (3)(4)(5).It has been shown that many mechanical properties can be influenced by the heat treatments, even if overall performance is still a combination of instruments' design, dimensions, motions and alloy (6)(7)(8) Currently the heat treatment of endodontic NiTi instruments has become a crucial aspect of their manufacturing process, playing a pivotal role in enhancing their mechanical properties and overall performance in root canal procedures. Heat treatment involves subjecting the NiTi alloy to specific temperature and time conditions to modify its microstructure.…”

“…Heat treatment involves subjecting the NiTi alloy to specific temperature and time conditions to modify its microstructure. The primary goals of heat treatment for endodontic NiTi instruments are to enhance their flexibility, resistance to fracture, and to es-t0ablish a balanced combination of hardness and toughness (5)(6)(7)(8). The process typically involves a sequence of steps, including solution treatment, quenching, and aging.…”