Comparison of surface defects in Protaper Next and Hyflex EDM files after single clinical use: A stereoscopic evaluation

Objective: To compare the surface defects created on the ProTaper Next files versus HyFlex Electrical Discharge Machining files after single clinical use in molars. Methods: The cross-sectional study was conducted in the dental department of the Aga Khan University Hospital, Karachi, from December 2018 to June 2019, and comprised Nickel-Titanium files belonging to HyFlex Electrical Discharge Machining and ProTaper Next to perform complete root canal treatment of molar teeth. The files were first visually examined and then analysed under 25.6x magnification using a stereomicroscope for the evaluation of surface defects. A photographic record was maintained and studied. Data was analysed using SPSS 23.0. Results: Of the 114 files, 38(33.3%) each were ProTaper Next X1, ProTaper Next X2 and HyFlex Electrical Discharge Machining. The number of files showing defects under microscopic evaluation were 17(14.9%). Deformation of the cutting edge was the most frequently seen defect type, found in 9(7.9%) files. The frequency of fractured files was 4(3.5%). The odds of microscopic defects in HyFlex Electrical Discharge Machining files was 2.64 times that of ProTaper Next files. Conclusion: Even after single clinical use, HyFlex Electrical Discharge Machining files were more likely to get microscopic defects on their surface compared to ProTaper files.