ROOT PIPE LENGTH MEASURING DEVICE AND ROOT PIPE REMEDIAL DEVICE

PURPOSE:To enhance the improvement in measuring sensitivity without causing pain to the patient by detecting the change of a peak voltage generated between a measuring electrode and a mouth electrode at the time of applying an impulse measuring signal between both the electrode, and measuring a root pipe length. CONSTITUTION:A rectangular wave pulse (a) is converted into a fixed impulse signal (b) having a fixed peak current value by a voltage converting part 5. Thus, the peak voltage of the terminal voltage of a primary coil 11a is proportional to the impedance between a measuring electrode 2 and a mouth electrode 3, and this voltage is detected by a signal detector 6 and peak-held by a peak hold circuit 7. The thus-obtained peak hold signal (d) becomes small with the impedance being lowered as the measuring electrode 2 is introduced into a root pipe more deeply, and on the other hand, the output signal (e) of an amplifier 8 becomes large. As the measuring signal has impulse form, and the impedance is detected by its peak voltage, the peak value can be increased to a value easy to detect while suppressing the average current value to about 5mum or less which never causes pain to a patient.