Patent ID: 8496476

Claim:
An endodontic instrument for preparing an endodontic cavity space, comprising: a shank configured for attachment to a motor to rotate the endodontic instrument about an axis of rotation; and a body extending from the shank, the body having a shank end where the body extends from the shank and a longitudinal length extending from the shank end to a tip, the body and tapering from the shank end toward the tip so that the tip has a diameter that is less than a diameter of the shank end, the body having a cutting surface extending between the shank end and the tip, with the axis of rotation extending from the shank end toward the tip, the body being substantially straight without bends along the longitudinal length when at rest, wherein the body has centers of mass at each transverse cross-section and the centers of mass at each consecutive transverse cross-section lie along straight line to define a mass axis, wherein the mass axis is off the axis of rotation with a center of mass of a transverse cross-section at the tip being further from the axis of rotation than a center of mass of a transverse cross-section at the shank end and with the center of mass of the transverse cross-section at the tip located no further from the axis of rotation than the diameter of the shank end such that, when the body is rotated, the body is configured to form a helical envelope of motion that displaces the body of the instrument from being substantially straight to being substantially helical.