| 摘要 |
Each of a set of files 57 has a handle 48 and a shank which tapers from the handle towards a rounded tip and has a series of cutting edges. Along one side of the shank the cutting edges are removed at 62 to provide a safe edge which will enable perforation of the root canal to be avoided. A flat 64 on the handle corresponds in position with the safe edge 62. The files of the set are used in a sequence of progressively increasing taper to create an increasingly tapered aperture in the root canal. |
