Investigation of cyclic fatigue of rotary endodontic instruments

Aim. To study the properties and resistance to cyclic loading of nickel-titanium files with a martensitic phase. The use of nickel-titanium instruments is an integral part of the endodontic treatment of root canals. During endodontic treatment, nickel-titanium instruments experience a huge load, which is manifested by fatigue of nickel-titanium instruments, in the form of a fracture. Purpose. To determine the resistance of nickel-titanium files to mechanical, chemical and temperature stress. Materials and methods. A nickel-titanium file with a martensitic S-flexi phase from Geosoft was selected as a study. Cyclic fatigue was determined using a simulation endodontic unit. Photo and video fixation was carried out as a calculation of the revolutions and breakage time of the tool in the process of determining cyclic fatigue. To assess changes in the structure of nickel-titanium instruments with a martensitic phase, electron scanning microscopy and determination of the elemental composition of the alloy were carried out. Results. In the course of the study, tests were carried out to determine the cyclic load, close to the clinical reception. After a series of cyclic load detection tests, S-flexi files showed different resistance to cyclic load. The results of cyclic fatigue are summarized in Table 1. Conclusion. High-quality and safe mechanical treatment of root canals is possible when using nickel-titanium S-flexi files. Due to the high resistance to mechanical, chemical and thermal stress.