METHODS FOR DETERMINING CYCLIC FATIGUE OF NICKEL-TITANIUM FILES AND A SIMULATION ENDODONTIC UNIT FOR THEIR IMPLEMENTATION Russian patent published in 2023 - IPC G09B23/28 G01N3/00 A61C5/42 

FIELD: medicine.

SUBSTANCE: group of inventions relates to medicine, namely to methods for determining cyclic fatigue of endodontic tools and a simulation endodontic unit for their implementation. The nickel-titanium file is subjected to a mechanical load by rotating it in the channels of a simulation endodontic unit, which includes five groove-shaped channels that can be filled with NaOCl solution. Three channels have each one bending angle with values of 30°, 45° and 90°. The fourth channel has two bending angles with magnitudes of 45°, and the fifth channel has four bending angles with magnitudes of 45°. The file is rotated in alternately replaceable channels with the application of a mechanical load in the corresponding channel for no longer than 40 seconds. After completing the full cycle of mechanical loading in all five channels, the nickel-titanium file is subjected to a chemical load stage, and then to a temperature load stage. Next, the mechanical load cycle is resumed until the nickel-titanium file breaks off, or several mechanical load cycles are alternated with chemical and temperature load stages until the file breaks off at one of the mechanical load cycles. Video recording of the process is used to calculate the time and number of revolutions of the file. The data of the received video material is processed, according to the result of which the limit of cyclic fatigue of the nickel-titanium file is determined.

EFFECT: increase in the accuracy of assessing the fatigue characteristics of NiTi files and the safety of machining complex root canals is achieved due to the possibility of optimal selection of tools taking into account their strength characteristics.

7 cl, 3 dwg, 1 tbl