Digital apical foramen locating apparatus with linear graphic display

摘要

The digital apical foramen locating apparatus of the present invention utilizes the recognized fact that the conductance from the apical foramen to a patient's lip is not only equal to the conductance from the sulcus to the lip but is also constant from patient to patient. It further utilizes the recognition that there is a linear correspondence in the change of the conductance as the apical foramen is approached in root canal therapy. Utilizing this knowledge, the present invention employs a pair of fixed resistors to calibrate a single oscillator. This same oscillator is then used in the actual measurement and a comparison is made between the measured values and the stored reference values. In addition to a digital readout in 0.1 mm increments, there is an audible display whose cadence increases as the apex is approached and a graphical display which graphically illustrates to the dentist the location of the reamer in the canal and also the status of the probe's reliability.