Avaliação da fratura por fadiga de rotação de instrumentos de níquel titânio tratados termicamente.

Abstract

Introduction: Endodontic files suffer from two types of fractures. The torsion fracture occurs when the extremity remains immobile and the remainder rotates along its long axis. The fatigue fracture of rotation is due to wear and tear with the use of the instrument, where it undergoes tension and compression on its surface over and over again. Aim: the present study evaluated the fatigue fracture strength of reciproc Blue® (VDW, Munich) endodontic files used in reciprocating motion. Methods: Twelve # 25/06 21 mm files were selected, divided into 2 groups (n = 6) with angles of 45º and 60º and with reciprocating kinematics of the Reciproc® System (VDW, Munich, Germany). The groups were submitted to the test with devices that simulate the root canal, with a radius of 6 mm and angles of curvature of 45 ° and 60 °. The time to fracture was measured, in seconds. The number of cycles until the fracture was calculated and the data tabulated. Results: the results were statistically analyzed using the Tukey HSD test, with a 95% confidence interval. When comparing the 45º and 60º angulations in reciproc reciprocal kinematics, it was observed that there was no statistically significant difference between the results (p> 0.05). Conclusion: It can be concluded that, with respect to the rotation fatigue fracture resistance, the Reciproc Blue® files at 45 ° and 60 ° angles presented similar performance.