Correlating cutting efficiency and debris retention of endodontic files to their design features using AutoCAD measurements

This study aims at evaluating the deformation changes on three types of root canal rotary instruments with different designs; the Pro-Taper Universal, the V-Taper, and the Liberator systems after clinical use. Measurements were made before and after the instruments were used for treating four human root canals by developing stereo-microscopic images for a number of instruments from the three systems at the same position. All images were transformed to AutoCAD to evaluate changes in measurements before and after use. The results showed that the majority of the tested instruments were subjected to significant deformations along the length of the working parts of the instruments. These deformations were only detected by the AutoCAD program but went unnoticed by either visual or microscopic examinations. The results suggest that AutoCAD could be a ground of developing a chair side “computer image analysis program” to predict and justify discarding of a piece before or during operation. In addition, considerations should be given to the material of construction and new approaches of ion implants, such as electro-polishing, that could improve or at least assist in enhancing the wear resistance of the instruments against the dentine surface.