A comparative evaluation of the sterilization-based cyclic fatigue of four different nickel titanium file system with reciprocal movements

The aim of this thesis study is to examine the effect of sterilization and temperature difference on cyclic fatigue resistance of WaveOne Gold, Reciproc, Reciproc Blue and Twisted File Adaptive rotary file systems. Within the scope of the study, a total of 160 files were used, 40 of which from 4 different file systems. In each file system, freshly unpacked materials and materials sterilized once were used. At the same time, this study was repeated in two different temperature environments as 20 ° C and 39 ° C. The artificial channel designed in the AutoCAD program was obtained by etching from stainless steel blocks with CNC (computer numerical control) machines. An artificial channel made of stainless steel with an inner diameter of 1.5 mm, a curvature of 60 ° and a curvature radius of 5 mm was used for the static cyclic fatigue mechanism. The curvature of the artificial canal is located in the 5 mm coronal part where the canal ends. The files were fixed at 19 mm and standardized and processed. Time to fracture of the files was recorded using a digital stopwatch and the number of laps was obtained numerically by multiplying by the rotation speed. The number of turns until fracture occurs for each file was calculated according to the following formula: Breaking Turns Number (KTS) = [Rotation speed (rpm) x Time (sec)] / 60 SPSS 22 program was used for statistical analysis. Number (%) was used in the display of categorical data, and the median and interquartile distance (IQR) were used in displaying the measurable data. Whether the data showed normal distribution was evaluated using the Shapiro Wilk test. The Mann-Whitney U test was used in paired groups and the Kruskal-Wallis tests in groups with more than two variables were used to compare the data that were found to be incompatible with normal distribution, and Tukey's test for post-hoc analysis was used to see where the differences originated. p <0.05 was considered statistically significant. When the fracture length of the file was compared according to the type of file, it was observed that there was a statistically significant difference between the groups (p <0.001). It was found that this difference was caused by the difference between all groups except Twisted File Adaptive and Reciproc Blue. According to the result, the broken piece lengths are listed as Reciproc> WaveOne Gold> Reciproc Blue = Twisted File Adaptive. When the temperature and the broken piece length are compared, the broken piece length of the files at 20 ° C was found to be significantly higher than the files at 39 ° C (p = 0.012). When evaluated separately for four different files; The broken piece length at 20 ° C was found to be significantly higher than the broken piece length at 39 ° C. For the Reciproc and Reciproc Blue file groups, the fracture length of the sterilized files was significantly higher than the non-sterilized files. When the number of turns of the file was compared according to the file type, it was seen that there was a statistically significant difference between the groups (p <0.001). This difference is due to the difference between Reciproc Blue and the other three files. According to the values in the study in terms of the number of breaking turns parameter, it is listed as Reciproc Blue> Reciproc = WaveOne Gold = Twisted File Adaptive. When the temperature and the number of breaking turns were compared, the number of breaking turns of the files at 20 ° C was found to be significantly higher than the files at 39 ° C (p <0.001). When evaluated separately for four different files, the CTS at 20 ° C was found to be significantly higher than the CTS at 39 ° C. For the Reciproc and Reciproc Blue file groups, the CTS values of the sterilized files were significantly higher than the non-sterilized files. As a result, it was found that the cyclic fatigue resistance of the Reciproc Blue file was higher than the other files. Low temperature has been shown to increase resistance to cyclic fatigue. Key Words: WaveOne Gold, Reciproc, Reciproc Blue and Twisted File Adaptive, Cyclic Fatigue