| 摘要 |
A dental instrument for cleaning and shaping a root canal of a tooth includes a working portion having three helical flutes and a guide tip with a first, second, and third face surface. A portion of the guide tip is removed so that each of the first and second surfaces are contiguous to a lateral surface of a conical-shaped envelope defining the original tip but a portion of the third surface is not contiguous to a lateral surface of the conical-shaped envelope. The intersection of the first and second surfaces, however, remains at the center point of the guide tip. The removed portion of the guide tip may result in an arcuate-shaped face surface, an angular-shaped face surface, or some combination of the two. |
