An Optical Fiber-Based Curvature Sensor for Endodontic Files Inside a Tooth Root Canal

Fatigue fracture of rotary file inside the root canal of teeth is one of the important equipment failure modes in endodontic treatment. Knowing the curvature of a file in a root canal allows its bending strain and fatigue life to be estimated. This can help to avoid the highly undesirable fracture. Although the canal geometry can be revealed by X-ray radiograph, its 2-D nature may not correctly reflect the true curvature. Moreover, canal curvature is not equivalent to the curvature of an inserted file.