Comparison of the Cyclic fatigue & the Cutting Efficiency of two Rotary NiTi Systems

Purpose: This study compares cyclic fatigue and cutting efficiency of two types of NiTi Rotary files, namely AF one files with a constant 4% taper and Hyflex EDM Files with a variable taper. Materials and Methods: Forty files, twenty of each brand, were examined under a microscope to ensure their integrity before testing. The evaluation focused on cyclic fatigue and cutting efficiency. Cyclic fatigue testing utilized a specialized block simulating dental canals, following Grande et al.’s prescribed design. Lubricating oil flooded the artificial canals, and files were tested at specified RPM and torque until breakage, with recorded breakage times. Cutting efficiency testing involved using plexiglass blocks, and measuring the length of cut during 1 minute. A dedicated device facilitated testing, including an air compressor for debris clearance. Results: Data from both tests were collected and analyzed, revealing that Hyflex EDM files demonstrated superior resistance to cyclic fatigue compared to AF one files(p<0.001). However, AF one files exhibited higher cutting efficiency than Hyflex EDM (p= 0.001), with statistically significant differences in both results. These findings are crucial for dentists in making informed decisions about the choice of files for root canal treatment in their practice.