Xiangya Huang1, Ya Shen2, Xi Wei3, Markus Haapasalo4. 1. Department of Conservative Dentistry and Endodontics, Guanghua School of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-Sen University Guangzhou, China; Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, Vancouver, Canada. 2. Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, Vancouver, Canada; Department of Materials Engineering, The University of British Columbia, Vancouver, Canada. 3. Department of Conservative Dentistry and Endodontics, Guanghua School of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-Sen University Guangzhou, China. 4. Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, Vancouver, Canada. Electronic address: markush@dentistry.ubc.ca.
Abstract
INTRODUCTION: The purpose of this study was to introduce a new fatigue test model that simulates the clinical situation for evaluating the corrosion effect of 5.25% sodium hypochlorite (NaOCl) on nickel-titanium (NiTi) files and to evaluate the effect of 3 different temperatures (22°C, 37°C, and 60°C) on the cyclic fatigue of these files. METHODS: Three NiTi files (size 25/.04), K3 (SybronEndo, Orange, CA), K3XF (SybronEndo), and Vortex (Dentsply Tulsa Dental Specialties, Tulsa, OK), were subjected to cyclic fatigue tests inside a novel artificial ceramic canal with a curvature of 60° and a 5-mm radius. A 19-mm-long file segment from the tip was introduced into the canal and immersed in water or 5.25% NaOCl at 3 different temperatures, and the number of revolutions to fracture (Nf) was recorded. The fracture surface of all fragments was examined by a scanning electron microscope. Data were analyzed using univariate analysis of variance with the significance level at 0.05. RESULTS: The Nf of Vortex files was the highest followed by K3XF and K3 (P < .05) at all conditions. The Nf of all files was highest at 22°C and lowest at 60°C (P < .05). However, no difference in Nf was detected in Vortex files between 22°C and 37°C. The Nf of all files in 5.25% NaOCl was shorter than that in water although there was no statistically significant difference. No pitting or crevice corrosion was observed on the fracture surface. CONCLUSIONS: NaOCl, 5.25%, does not significantly affect the fatigue behavior of NiTi files. The fatigue resistance should be tested under specific temperature conditions. The austenite finish temperature of a file is important in determining the fracture risk at body temperature.
INTRODUCTION: The purpose of this study was to introduce a new fatigue test model that simulates the clinical situation for evaluating the corrosion effect of 5.25% sodium hypochlorite (NaOCl) on nickel-titanium (NiTi) files and to evaluate the effect of 3 different temperatures (22°C, 37°C, and 60°C) on the cyclic fatigue of these files. METHODS: Three NiTi files (size 25/.04), K3 (SybronEndo, Orange, CA), K3XF (SybronEndo), and Vortex (Dentsply Tulsa Dental Specialties, Tulsa, OK), were subjected to cyclic fatigue tests inside a novel artificial ceramic canal with a curvature of 60° and a 5-mm radius. A 19-mm-long file segment from the tip was introduced into the canal and immersed in water or 5.25% NaOCl at 3 different temperatures, and the number of revolutions to fracture (Nf) was recorded. The fracture surface of all fragments was examined by a scanning electron microscope. Data were analyzed using univariate analysis of variance with the significance level at 0.05. RESULTS: The Nf of Vortex files was the highest followed by K3XF and K3 (P < .05) at all conditions. The Nf of all files was highest at 22°C and lowest at 60°C (P < .05). However, no difference in Nf was detected in Vortex files between 22°C and 37°C. The Nf of all files in 5.25% NaOCl was shorter than that in water although there was no statistically significant difference. No pitting or crevice corrosion was observed on the fracture surface. CONCLUSIONS:NaOCl, 5.25%, does not significantly affect the fatigue behavior of NiTi files. The fatigue resistance should be tested under specific temperature conditions. The austenite finish temperature of a file is important in determining the fracture risk at body temperature.
Authors: Daiane Nogueira; Carlos Eduardo Da Silveira Bueno; Augusto Shoji Kato; Alexandre Sigrist De Martin; Rina Andréa Pelegrine; Ana Grasiela Da Silva Limoeiro; Daniel Guimarães Pedro Rocha; Carlos Eduardo Fontana Journal: J Conserv Dent Date: 2021-02-11
Authors: Javier Nino-Barrera; Jose Sanchez-Aleman; Manuel Acosta-Humanez; Luis Gamboa-Martinez; Carlos Cortes-Rodriguez Journal: Sci Rep Date: 2021-06-21 Impact factor: 4.379