A dental reamer root canal instrument has a working area that is substantially cylindrical or conical along a longitudinal axis, the instrument including X helical flutes forming X lips of helical cuts, a cut lip being formed by the intersection of two consecutive flutes, wherein X is equal to or greater than three. Over a cross-section of the instrument, the angles (αI, βI, γI) between two consecutive cut lips, measured relative to the longitudinal axis of the instrument, are all different. A method for producing the root canal instrument in a cylindrical or conical rod is also disclosed. The rod is made of a metal or metal alloy material selected for the mechanical bending strength and shape memory properties thereof. The method includes steps for using a grinding wheel to machine a flute to a predefined depth and steps for rotating the rod in front of the machining wheel.
