The present invention provides a system for the endodontic treatment of a root canal, comprising(i) an endodontic instrument；(ii) an endodontic handpiece having a drive motor for rotating the endodontic instrument releasably attached to the handpiece；(iii) a control unit for controlling the rotation of the endodontic instrument according to one or more predetermined rotational sequences；the rotational sequences comprising reciprocating the endodontic instrument by continuously sequentially rotating the endodontic instrument in a first direction followed by reversing the direction of rotation so that0.5×Ψ≦α<；Ψ and 3≦α/β≦20,wherein α represents a rotational angle in a direction in which the rotating endodontic instrument removes debris from the root canal, β represents a rotational angle in the opposite direction, and Ψ represents the elastic angle of the endodontic instrument at which plastic deformation occurs in the direction of α.
