Comparison of Three Nickel-titanium File Systems for C-shaped Root Canal Preparation

Objective To compare the effectiveness of three different nickel-titanium file systems(ProTaper,Mtwo and Hero642) in C-shaped root canal preparation.Methods Forty C-shaped root canals in 40 mandibular second molars were randomly divided into four groups of 10 specimens each.Root canals in group A,B,C and D were prepared by hand stainless steel K files,ProTaper nickel-titanium instruments,Mtwo nickel-titanium instruments and Hero642 nickel-titanium instruments,respectively.The canals were filled using lateral condensation technique.The time for root canal preparation,effectiveness of root canal obturation,and reaction following root canal obturation were observed.Results The time for root canal preparation was(12.30±2.23),(5.81±0.95),(6.13±1.12) and(5.91±1.01) minutes in group A,B,C and D,respectively.The rate of pain reaction was 30%,10%,10% and 10% in group A,B,C and D,respectively.The proper filling rate was 80% for all four groups.Compared with group A,the time for root canal preparation and proper filling rate significantly decreased in group B,C and D(P0.05).Conclusion Non-ISO nickel-titanium rotary files are effective for preparation of C-shaped root canals in mandibular second molars with advantages of simple operation,saving time,good formability and safety,and high efficiency and practicality.