| 摘要 |
The invention relates to an instrument for boring dental root canals, comprising a thin rod (1) having, at least over part of the length thereof, called the active part (1b), a polygonal section (4) forming at least two cutting edges (5a, 5b), said active part (1b) ending in a tip (3) and being defined by a cylindrical or conical envelope, the longitudinal axis of which merges with the rotational axis (A) of the instrument. Said active part (1b) has a first portion (1c) extending from the tip (3) and a second portion (1d) following on from the first portion (1c) towards the rear of the active part (1b). Every section (4a) of the first portion (1c) has a centre of mass (ma) located on the rotational axis and said cutting edges (5a, 5b) defined by said section (4a) are located on the envelope (7). Every section (4b) of the second portion (1d) has a centre of mass (mb) that is offset in relation to the rotational axis and at least one cutting edge (5a) defined by said section (4b) is set back inside the envelope (7). |
