The comparative study of the root canal offset in the work of three kinds of root canal preparation instruments

Objective To investigate root canal offset in the work of three kinds of root canal preparation instruments and evaluate the security of preparation types. Methods Curved root canals were prepared by Rotary NiTi file of Mt-wo,Rotary NiTi file of ProTaper and Hand NiTi files of ProTaper.The offset value of the root canal before and after preparation were analysed by CBCT. Results Bending of Rotary NiTi file of ProTaper and Hand NiTi files of ProTaper were smaller than that of Rotary NiTi file of Mtwo,comparative differences between groups was statistically significant (P0.05).In relatively flat ab segment of root canal among three preparation root canal were not statistically significant (P0.05);The bc segment with relatively bigger bending of Hand NiTi files of ProTaper was smaller than that of other preparation types,comparative differences between groups was statistically significant ( P0.05). Conclusion Hand Pro-Taper NiTi file is recommended in root canal preparation for curved root canals .