Abstract: Device for continuous auscultation of the motion and positions of a patient mandible including means for sensing the motion and positions of the mandible at the rear of the condyle inside the external auditory duct with the help of strain gauges connected with a Wheatstone bridge, and means for amplifying the output signal which is finally applied to a reading device. Such a device is usable for real and accurate determination of any mandibular motion, centric relation and rest position in making dental prosthesis.