2015-04-242015-04-242013-04PESSOA, Oscar Faciola; SILVA, Juliana Melo da; GAVINI, Giulio. Cyclic fatigue resistance of rotary niti instruments after simulated clinical use in curved root canals. Brazilian Dental Journal, Ribeirão Preto, v. 24, n. 2, p. 117-120, abr. 2013. Disponível em: <http://www.scielo.br/pdf/bdj/v24n2/0103-6440-bdj-24-02-117.pdf>. Acesso em: 22 abr. 2015. <http://dx.doi.org/10.1590/0103-6440201302164>.0103-6440https://repositorio.ufpa.br/handle/2011/6572The aim of this study was to assess cyclic fatigue resistance in rotary nickel-titanium instruments after simulated clinical use in curved root canals (40-degree, 5-mm radius curve). Thirty-six RaCe rotary NiTi files, size #5, taper 0.04, were divided into 3 groups: Groups A, B and C with one, three and five cycles of use, respectively. Time to failure was recorded with a stopwatch in seconds and subsequently converted to number of cycles to fracture. The data were analyzed statistically by ANOVA and Tukey's test (α=0.05). Five sets of clinically used files (group C) reached significantly lower cycle-numbers before fracture (mean=197.5 cycles) when compared with one set of clinically used files (mean=309.2) and three sets (mean=287.5). Results showed that the number of simulated clinical uses of RaCe instruments for shaping curved canals affects adversely the fatigue resistance of these instruments after five uses.engAcesso AbertoEntodontiaFadiga cíclicaNíquel-titânioCavidade pulparInstrumentos odontológicosInstrumentos rotatóriosArtigo de Periódico