Clinical evaluation of two types of nickel-titanium rotary instruments in preparation of molar root canals in the elderly

Objective:This research aimed to study and evaluate clinical application of the using of two Nickel-titanium(NiTi)rotary instruments Mtwo and ProTaper,in preparation of molar root canals.Methods:60 molar root canals were instrumented by Mtwo or ProTaper rotary instruments in test groups and by stainless steel K files in control group.All teeth were obturated with lateral condensation method.The efficiency of preparation was analyzed by radiographs before and after treatment.The operating time and the incidence of complications were recorded.Results:Two NiTi rotary instruments could keep the curvature and flow of curved canals very well,and the continuously tapered root canal shape was achieved.There were no transportation,apical blockage,and ledge in all test groups.The operative time of Mtwo was shorter than that of ProTaper.Two ProTaper rotary instruments fractured in canals.Conclusion:With the NiTi rotary instruments,Mtwo instruments can be prepared as effectively and quickly as ProTaper instruments.Meanwhile,Mtwo instruments was as safe as ProTaper instruments.