| 摘要 |
An improved endodontic instrument includes a tapered working portion defined on a flexible shaft. The working portion includes a plurality of spiral rotationally bi-directional cutting edges thereon. The instrument includes a tapered tip defined on the flexible shaft and intersecting an end of each of the cutting edges of the working portion. The tapered tip has a greater angle of taper than does the tapered working portion. The tapered tip is shaped such that the sharp cutting points which are normally present at an intersection between the ends of the cutting edges and a standard 75 DEG included angle conically tapered tip are substantially eliminated so that lateral transportation of the instrument when cutting a curved root canal is reduced as compared to an otherwise similar instrument having a standard 75 DEG included angle conically tapered tip.
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