Cyclic fatigue and torsional strength of three different thermally treated reciprocating nickel-titanium instruments

• Published in: Clinical oral investigations 2018-05, Vol.22 (4), p.1865-1871
• Main Authors: Alcalde, Murilo Priori, Duarte, Marco Antonio Hungaro, Bramante, Clovis Monteiro, de Vasconselos, Bruno Carvalho, Tanomaru-Filho, Mario, Guerreiro-Tanomaru, Juliane Maria, Pinto, Jader Camilo, Só, Marcus Vinicius Reis, Vivan, Rodrigo Ricci
• Format: Article
• Language: English
• Subjects: Dental equipment; Dentistry; Endodontics; Fractures; Materials fatigue; Medicine; Nickel; Original Article; Root canals; Scanning electron microscopy; Stainless steel
• ISSN: 1432-6981; 1436-3771
• DOI: 10.1007/s00784-017-2295-8

Objectives The aim of this study was to evaluate the cyclic and torsional fatigue resistance of the reciprocating single-file systems Reciproc Blue 25.08 (VDW GmbH, Munich, Germany), Prodesign R 25.06 (Easy Dental Equipment, Belo Horizonte, Brazil), and WaveOne Gold 25.07 (Dentsply/Tulsa Dental Specialties, Tulsa, OK, USA). Materials and methods Sixty reciprocating instruments of the systems Reciproc Blue R25 (RB #25 .08 taper), Prodesign R (PDR #25 .06 taper), and WaveOne Gold (WOG #25 .07 taper) ( n  = 20) were used. Cyclic fatigue resistance testing was performed by measuring the time to failure in an artificial stainless steel canal with a 60° angle of curvature and a 5-mm radius located 5 mm from the tip ( n  = 10). The torsional test (ISO 3630-1) evaluated the torque and angle of rotation at failure of new instruments ( n  = 10) in the portion 3 mm from the tip. The fractured surface of each fragment was also observed using scanning electron microscopy (SEM). In addition, a supplementary examination was performed to measure the cross-sectional area of each instrument 3 and 5 mm from the tip. The data were analyzed using one-way ANOVA and Tukey’s test, and the level of significance was set at 5%. Results The cyclic fatigue resistance values of PDR 25.06 were significantly higher ( P