Influence of the curved root canal segments length on the fatigue fracture of rotatory NiTi instruments

Hélio Pereira Lopes, Márcia Valéria Boussada Vieira, Carlos Nelson Elias, Victor Talarico Leal Vieira, Letícia Chaves de Souza, Carlos Estrela

Introduction: The aim of this study was to evaluate the influence of the curved root canal segments length on the number of cycles needed to induce fatigue fracture of a rotatory nickel-titanium (NiTi) instrument. Methods: The instruments used in this study were Mtwo with 0.35 mm D0 diameter, 0.02 mm/mm taper and 25 mm length. The instruments were used in two artificial metallic root canals with curved segments under 300 rpm speed. The curvatures were located in the root canals extremities and had different curved segments lengths. The device used in the rotating bending test of the selected endodontic instruments was described previously by Lopes et al.1 Results: The number of cycles needed to cause fatigue fracture was influenced by the artificial root canal curved segments length. Conclusion: The number of cycles needed to induce fatigue fracture on the instruments used at rotating bending in artificial root canals of same radius sizes decreased with the curved segments length increasing.

Keywords: Curved segments length. Fatigue. Fracture.

How to cite: Lopes HP, Vieira MVB, Elias CN, Vieira VTL, Souza LC, Estrela C. Influence of root canal curved segments length on the fatigue fracture of rotatory NiTi instruments. Dental Press Endod. 2012 July-Sept;2(3):32-5.

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