eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-12-22 13 4 2037 2044 10.13005/bbra/2362 17408 article Correlation of the Material Composition and Transistional Phases During Stress, on Cyclic Fatigue of Three Different Ni-Ti Rotary File System V. Prakash 1 P. Dinesh 1 V. G Sukumaran 1 A. Subbiya 1 P. Vivekanandhan 1 Sherin Banu 1 Department of Conservative dentistry and Endodontics, Sree Balaji Dental College and Hospital, Bharath University, Chennai- 600100, Tamilnadu, India. A correlation between the material composition and phase changes during cyclic fatigue of three different(K3, K3XF, HYFLEX CM) rotary instruments were studied using DSC (Differential Scanning Calorimetry) and ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy). To determine the role of composition and phase changes present in different types of  NiTi rotary instruments during cyclic fatigue. ICP-OES was done by mixing 0.5g of sample with 20 ml of 1:1 ratio of water and 98% sulphuric acid. Samples were then heated upto 250oC to dissolve and then they were made upto 100 ml by adding distilled water. The samples were sent in the ICP-OES machine, where the samples get converted into different ions of characteristic intensity, from which the compostion is determined. DSC was done by heating/cooling the sample at the rate of 10oC/min increase in temperature. The sample is first heated to +130oC from room temperature and then cooling down to -150oC to obtain the cooling curve and then heated back to +130oC to obtain heating curve. The number cycles to failure were tested by Universal Testing machine and results were tabulated. One way ANOVA and Tukey tests were used to analyze the data. Enthalphy of HYFLEX CM was found to be highest followed by K3XF enthalpy and K3 found to be having Least Enthalpy. Comparing time taken for fracture of HYFLEX and K3XF there was statistically significant difference. Within the limitation of this study, it may be concluded that HYFLEX is the preferred instrument of choice in curved canals due to its controlled shape memory and longer time for phase transformation. https://www.biotech-asia.org/vol13no4/correlation-of-the-material-composition-and-transistional-phases-during-stress-on-cyclic-fatigue-of-three-different-ni-ti-rotary-file-system/ HYFLEX; K3; Cyclic fatigue; phase change; Differential Scanning Calorimetry; Inductively Coupled Plasma Optical Emission Spectroscopy