| 摘要 |
An endodontic reamer or file instrument for cleaning and shaping root canals includes a shank having a tapered working portion extending along a section of the shank length to a leading end. A pilot is attached to the working portion adjacent the leading end and is smaller in diameter than is the working portion at the leading end. The working portion includes at least one continuous helical flute which spirals along its length and a helical land at the periphery of the working portion which extends between adjacent flutes. The working portion also includes at least one lip adjacent the pilot which has a cutting edge which lies generally in a radial plane of the shank, and each flute which spirals along the length of the working portion toward the leading end terminates at the cutting edge of a corresponding lip so that as the instrument is moved longitudinally through a root canal, root canal tissue disposed to one side of the pilot is exposed to the cutting edge of the working portion.
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