| 摘要 |
An endodontic instrument including an elongate member having a longitudinal axis, a proximal end, a distal end and a working length between the proximal and distal ends. The working length is formed with a plurality of surface portions cut from the outer surface thereof along paths extending along at least partially around the longitudinal axis. The cut surface portions are then physically twisted to form helical cutting and/or debris removal edges extending around the longitudinal axis. The instrument may be a file or reamer used in root canal procedures and may have three, four or more longitudinally extending surface portions and corresponding edges. The cutting edges define grind angles that vary along the working length. Flexibility of the instrument may also be easily varied according to the invention. Methods of manufacturing the instrument may include grinding flats on the outer surface of a wire blank, with the flats partially twisting around the longitudinal axis. The blank with the partially twisting flats is then physically twisted to form the helical cutting and/or debris removal edges. |
