| 摘要 |
An endodontic file (200) is provided particularly adapted for the removal of tooth structure, decayed or damaged nerve tissues or dentine material on the interior walls of a root canal or dentine and/or enamel from the external tooth wall. The endodontic instrument includes a shaft (202) having a shank portion (204) and a generally elongated working portion (206). The working portion preferably includes cutting or abrading features (232) adapted upon rotation and/or reciprocation of the instrument to cut, abrade or remove tissue from the interior walls of a root canal or dentine and/or enamel from the external tooth wall. The working portion extends from a proximal end (207) adjacent the shank portion to a distal end (208) terminating at a tip (250). The entire instrument and/or at least the working portion thereof is formed of an amorphous or essentially amorphous material having no or essentially no detectable crystalline structure and/or from a nanocrystalline material having an average crystalline grain size less than about 1 μm. The instrument may be formed by conventional grinding operations or by direct casting, forging or molding, in a manner producing an integral as-molded instrument having one or more sharp cutting edges. The instrument is inexpensive to manufacture and exhibits improved cutting-edge sharpness, wear resistance, lubriciousness and resistance to breakage.
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