| 摘要 |
PURPOSE: A file of the combining form for root canal treatment is provided, which can apply the gradation of the radial land to the single file structure longitudinally, and improve the maintenance of the center of root canal end and the cutting efficiency of the upper part of root canal at the same time. CONSTITUTION: A file of the combining form for root canal treatment includes: a radial landing portion in which the width(41) of the radial land diminishes in the file shaft direction, while the width of the radial land is the largest in the end part of the file; a transform unit in which the width of the radial land becomes 0; and a blade portion formed from the transform unit in the file shaft direction. The transform unit is located in the position of 30-60% of the file total length. The transform unit is located in the position distanced 6-10mm from the end part of file. The size of the pitch(31) increases gradually from the radial landing portion toward the blade portion. |
