Gustavo De-Deus1, Emmanuel João Nogueira Leal Silva2, Victor Talarico Leal Vieira2, Felipe Gonçalves Belladonna3, Carlos Nelson Elias4, Gianluca Plotino5, Nicola Maria Grande6. 1. Department of Endodontics, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil. Electronic address: endogus@gmail.com. 2. Department of Endodontics, Grande Rio University, Duque de Caxias, Rio de Janeiro, Brazil. 3. Department of Endodontics, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil. 4. Department of Biomaterials, Military Institute of Engineering, Duque de Caxias, Rio de Janeiro, Brazil. 5. Grande Plotino & Torsello - Studio di Odontoiatria, Rome, Italy. 6. Department of Endodontics, Catholic University of Sacred Heart, Rome, Italy.
Abstract
INTRODUCTION: The aim of the present study was to evaluate the influence of Blue thermal treatment on the bending resistance and cyclic fatigue of conventional M-Wire Reciproc files (VDW, Munich, Germany). The roughness pattern and the microhardness of the files were also assessed. METHODS: Flexibility of standard Reciproc R25 files and the corresponding Blue prototypes was determined by 45° bending tests according to the ISO 3630-1 specification. Instruments were also subjected to cyclic fatigue resistance, measuring the time to fracture in an artificial stainless steel canal with a 60° angle and a 5-mm radius of curvature. The fracture surface of all fragments was examined with a scanning electron microscope. The roughness of the working parts was quantified by using a profilometer, and the microhardness test was performed using the Vickers hardness tester. Results were statistically analyzed using the Student t test with a level of significance set at P < .05. RESULTS: Reciproc Blue instruments presented a significantly longer cyclic fatigue life and significantly lower bending resistance than the original Reciproc instrument (P < .05). Regarding the roughness pattern, there was no significant difference between Reciproc Blue and the original Reciproc instruments (P > .05), whereas Reciproc Blue revealed significantly lower microhardness than the original Reciproc instrument (P < .05). CONCLUSIONS: Reciproc Blue nickel-titanium showed improved all-around performance when compared with conventional M-Wire superelastic nickel-titanium, demonstrating improved flexibility and fatigue resistance, and reduced microhardness while maintaining similar characteristics of the surface.
INTRODUCTION: The aim of the present study was to evaluate the influence of Blue thermal treatment on the bending resistance and cyclic fatigue of conventional M-Wire Reciproc files (VDW, Munich, Germany). The roughness pattern and the microhardness of the files were also assessed. METHODS: Flexibility of standard Reciproc R25 files and the corresponding Blue prototypes was determined by 45° bending tests according to the ISO 3630-1 specification. Instruments were also subjected to cyclic fatigue resistance, measuring the time to fracture in an artificial stainless steel canal with a 60° angle and a 5-mm radius of curvature. The fracture surface of all fragments was examined with a scanning electron microscope. The roughness of the working parts was quantified by using a profilometer, and the microhardness test was performed using the Vickers hardness tester. Results were statistically analyzed using the Student t test with a level of significance set at P < .05. RESULTS: Reciproc Blue instruments presented a significantly longer cyclic fatigue life and significantly lower bending resistance than the original Reciproc instrument (P < .05). Regarding the roughness pattern, there was no significant difference between Reciproc Blue and the original Reciproc instruments (P > .05), whereas Reciproc Blue revealed significantly lower microhardness than the original Reciproc instrument (P < .05). CONCLUSIONS: Reciproc Blue nickel-titanium showed improved all-around performance when compared with conventional M-Wire superelastic nickel-titanium, demonstrating improved flexibility and fatigue resistance, and reduced microhardness while maintaining similar characteristics of the surface.
Authors: Murilo Priori Alcalde; Marco Antonio Hungaro Duarte; Clovis Monteiro Bramante; Bruno Carvalho de Vasconselos; Mario Tanomaru-Filho; Juliane Maria Guerreiro-Tanomaru; Jader Camilo Pinto; Marcus Vinicius Reis Só; Rodrigo Ricci Vivan Journal: Clin Oral Investig Date: 2017-12-09 Impact factor: 3.573