Comparison of shaping ability of two different rotary nickel-titanium preparation systems and two different hand preparation systems in curved root canals

Purpose: The purpose of this study was to compare shaping ability of Quantec LX and Profile 29 rotary NiTi instruments and Nitiflex and stainless steel hand instruments in curved canals. Material and Methods: In this present study, mesial canals of 48 mandibular molar teeth possesing 25-40° of curvature angle were separated into 4 groups in a manner each group including 12 canals. The preparation groups were Nitiflex and H hand instruments, Profile 29 and Quantec LX rotary NiTi instruments. At the end of the study, changes of canal curvature and working lenght, instrument fractures and perforations were recorded. Data were analysed statistically using Wilcoxon, Kruskal-Wallis and Mann-Whitney U tests. Results: More changes of canal curvature and working lenght were observed in the rotary NiTi preparation systems than stainless steel files. In the stainless steel and Nitiflex files, no instrument fracture was found. Stainless steel files group was occured strip perforations, while rotary NiTi preparation systems were occured lateral preforations. Conclusion: In conclusion, rotary NiTi preparation systems were found to prepare curved root canals more effective than hand preparation systems.