Method and apparatus for apical detection with complex impedance measurement

摘要

An apical position detector for use in dental endodontics includes an electronic controller coupled to a conductive probe and a lip electrode. The probe is positioned in a root canal and the lip electrode contacts another location on the patient's body. The controller produces a test signal as a combination of signals at selected frequencies. The controller then monitors a voltage of the probe and extracts the amplitude and phase of each of the frequency components of the voltage at the probe. Test scores are generated from summations of the amplitudes and/or phases of the various frequency components to determine when the impedance between the probe and the lip electrode changes from a primarily reactive impedance to a primarily resistive impedance. A first test score is displayed to indicate when the impedance changes from a reactive to a resistive impedance. The second test score indicates when the measurement conditions are unsatisfactory. The test scores are displayed in bar graph or similar form.