Force Sensor Design and Measurement for Endodontic Therapy

To assist endodontic therapy, in this paper, a force sensor is designed and fabricated for measuring the axial force and the bending moment simultaneously. By detecting the bending moment, we can know the severity of bending. Axial force detection is also desired, as excessive axial forces may result in instrument buckling or even root canal perforation. This paper installs three sensing cells in each of two planes to detect the bending direction. Each sensing cell consists of a pressure-sensitive electric conductive rubber and an electrode. The size of the force sensor is 1.4-mm wide and 6-mm high for matching the size of endodontic instruments and making it feasible in the endodontic treatment. Experimental results on accuracy, repeatability, and nonlinearity are presented to validate the proposed sensor.