| 摘要 |
An endodontic file for a motorized rotary handpiece includes a coupler element for coupling to the handpiece, a central longitudinal flexible core including a central flexible cable supported by the coupler element, and a helical wire surrounding the core and extending toward a tip of the core opposite the handle end. The flexible core includes a first plurality of inner strands twisted together in a first direction and surrounded by a second plurality of outer strands twisted in an opposite direction. The tip of the core is chamfered and unbonded and protrudes beyond the helical wire at the tip whereby in use reversing a direction of rotation of the endodontic file after the tip of the core reaches the apex of the root canal, unwinds the outer strands, which operate as a brush during removal of the endodontic file from the root canal. |
