OBJECTIVETo establish a new evaluation system of curved root canal deviation by the technique of micro-CT.

METHODSCurved simulated root canals were prepared with ProTaper NiTi-hand files by crown-down technique. After root canals were scanned by micro-CT and analyzed by image processing software, the planar area and centers' transportation of each cross-section were compared to evaluate the prepare effect of ProTaper, and a three-dimensional model about it were established.

RESULTSThe same cross-section's area of the root canals which was prepared with ProTaper NiTi-hand files were essentially consistent. With the data analysis of micro-CT, a system of combining planar and three-dimensional index to evaluate the root canal deviation were established. The shapes of root canal before and after prepared with ProTaper showed less deviation, which proved the shaping ability of ProTaper could meet the requirements for clinical use.

CONCLUSIONA three-dimensional root canal central axis model is established using micro-CT. It provides a new method to analyze the shaping ability of the instrumentation after root canal preparation. It will give us a more direct view to analyze the situation of the root canal deviation combining the two-dimensional image and the three-dimensional model.