Clinical evaluation of nickel-titanium rotary instruments in preparation of curved root canals

Objective To study the clinical application of Nickel-titanium(NiTi) rotary instruments,namely ProFile,ProTaper and Mtwo,to preparation of curved root canals.Methods A total of 72 teeth with curved root canals were prepared by ProFile,ProTaper and Mtwo rotary instruments in test groups and by stainless steel K files in control group.All teeth were obturated with lateral condensation technique.The efficiency of preparation and obturation was analyzed.Results Three NiTi rotary instruments could keep the curvature and flow of cured canals very well,and the continuously tapered root canal shape was achieved.There were no transportation and ledge in all test groups.The operative time was shorter for ProTaper and Mtwo than ProFile.Conclusion With the NiTi rotary instruments,ProFile,ProTaper and Mtwo,curved root canals can be prepared effectively and quickly.Meanwhile,the problem of instrument fracture should be prevented.