Aim: to Evaluate Surface defects in new reciproc and reciproc blue rotary nickel-titanium files and after thee and six canals preparation using Scanning Electron Microscopy.
Methodology: Sixty human mandibular molars were selected for the study, with moderate angle of curvature between (25o-35o). Mesial canals of the sixty molars were classified according to the file used for canal preparation into two groups. Group I: 60 MB canals were prepared using 10 Reciproc files. Group II: 60 ML canals were prepared using 10 Reciproc blue files. Each group divided into two subgroups A & B. in each group, these 10 files were used to prepare 30 canals so that each file was used to prepare 3canals (subgroub A). Then the same 10 files were further used to perpare another 30 canals ending up that each file was used to prepare 6 canals (subgroup B). Scanning Electron Microscopy was used to evaluate surface defects before and after three and six canals preparation.
Results: There was no statistically significant difference between reciproc and reciproc blue. In reciproc blue There was a significant difference between new and after three and six canals used in disruption of cutting edge, debris and scraping.
Conclusions: Different surface defects appeared to be present in all reciproc and reciproc blue new files with various incidence rates. By use for three and six times, reciproc blue files presented increased disruption of cutting edge, debris and scraping.