Cyclic fatigue of new nickel-titanium instruments in artificial canals with single and double curvature [Fatica ciclica di nuovi strumenti al nichel-titanio in canali artificiali a singola e doppia curvatura]

Objectives: Aim of this study was to evaluate the cyclic fatigue resistance of two types of new nickel-titanium endodontic instruments Materials and methods: 80 instruments divided into 4 groups (20 each group), GTX 30/.06, GTX 40/.04, Twisted Files 30/.06, Twisted Files 40/.04. All the instruments were tested in two different artificial canals, one with a single curvature and the other with a double curvature. All instruments were rotated until fracture and the number of cycles to fracture (NCF) was then calculated, Results: Twisted Files instruments resisted longer in rotation in the different canals. The size of the instrument (30.06, 40.04) did not have a statistically significant influence. Conclusions: The instruments Twisted Files were more resistant to cyclic fatigue compared to the GTX. © 2012 Società Italiana di Endodonzia.