Effect of autoclave cycles on cyclic fatigue resistance of control memory NiTi files observed by scanning electron microscopy

• Autor(a) principal: Vieira, Victor Talarico Leal
• Data de Publicação: 2017
• Outros Autores: Lopes, Hélio Pereira, Elias, Carlos Nelson, Souza, Leticia Chaves de, Silva, Emmanuel João Nogueira Leal da, Prata, Daniel Brito, Moreira, Edson Jorge Lima, Vieira, Marcia Valeria B.
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Revista Brasileira de Odontologia
• Texto Completo: https://revista.aborj.org.br/index.php/rbo/article/view/799
• topic: DENTAL MEDICINE (DENTISTRY); Endodontics; Autoclavage; Electron microscopy; Fatigue resistence; Control memory NiTi files; MEDICINA DENTÁRIA (ODONTOLOGIA); Endodontia; Autoclavagem; Microscópio eletrônico; Resistência à fadiga; Controle de arquivos NiTi da memória

Objective: Hyflex CM instruments were developed for debridement of the root canal system. The control-memory alloy recovers its shape on sterilization, thereby allowing instrument reuse. This study investigated the effect of shape recovery by sterilization on the fatigue life and crack formation of Hyflex CM NiTi instruments. Material and Methods: the cyclic fatigue test was performed in two groups: In the first, it was continuously performed to establish the fatigue life (group 1, n = 10); in the second, it was performed with outages of 30s to evaluate cracks’ nucleation and propagation (group 2, n = 10). The test was performed using a stainless steel canal that was 1.5mm in diameter and 3.5mm in depth, with an arc of 9.42mm and radius of curvature of 6mm. The instruments were driven at 300 rpm. The fatigue time was recorded using a digital stopwatch (Technos). An electronic microscope (Quanta 250) was used to observe the crack formation and growth during the cyclic fatigue. Results: the autoclaved instruments endured 1196.67+214.63 cycles, and the non-autoclaved endured 1000+199.42 cycles until the occurrence of fracture. The t-student test (?=5%) revealed a significant difference. The cyclic fatigue test with pauses demonstrated a significantly longer cyclic fatigue life than the continuous cyclic fatigue test (p