ABSTRACT
Objective:To investigate the shaping and cleaning ability of Reciproc(RE),OneShape(OS)and ProTaper(PT)in oval-shaped root canal preparation.Methods:The canals of 57 distal roots of mandibular first molars were randomly divided into 3 groups and prepared by RE,OS and PT respectively.The preparation time was recorded.After instrumentation,all root canal walls were examined under SEMand evaluated by scores of debris and smear layer.The 3D data and images of the roots of pre-and post-preparation were con-structed by Micro-CT scanning.Results:Group RE and OS showed lower scores of debris and smear layer than those in group PT at the apical level(P <0.05),and less preparation time (P <0.05).Before and after preparation,the changes of root canal morphological pa-rameters (including volume,surface,area,major diameter and minor diameter)in OS group were less than those in group RE and PT(P<0.05).The changes of canal curvature in group PT was larger than that in group RE and OS (P <0.05).Conclusion:RE and OS are more effective than PT in debridement and faster in root canal preparation.RE and OS can maintain the centering of original canal better than PT in the apical part of the root canal.The shaping ability of OS is weaker than that of RE and PT.