Abstract: A secondary caries detection device includes a current generating device configured to generate a current having the form of a sinusoidally varying signal with a frequency chosen from the range of frequencies from 200 Hz to 100 kHz and a chosen amplitude from the range of 50 mV to 5 V. The secondary caries detection device also includes a plurality of preamplifiers of high sensitivity and linearity with phase-sensitive measuring components sensitive to the chosen frequency and integral multiples of the chosen frequency. The secondary caries detection device further includes a microprocessor control unit connected to the current generating device and the plurality of preamplifiers.

Abstract: A device for secondary caries detection characterized in that it contains a current generating block in its casing (6), advantageously equipped with the high linearity amplifiers, the current having the form of sinusoidally varying signal, advantageously with one frequency chosen from the range of frequencies from 200 Hz to 100 kHz and amplitude from 50 mV to 5 V; a block of preamplifiers (4), advantageously of high sensitivity and linearity with phase-sensitive detectors measuring components, advantageously with one frequency chosen from the range of frequencies from 200 Hz to 100 kHz as well as its multiples, advantageously integral in principle; microprocessor control unit (5), advantageously with a miniature keyboard and display unit, and at least one fixed electrode (2) placed on mucous membrane of the oral cavity and at least one moveable electrode to be mounted on a tooth (1).

Abstract: A method of analysing the structure of bone tissue comprises placing first and second electrodes in electrical contact with the bone tissue to be analysed such that the bone tissue forms at least part of an electrical circuit between the first and second electrodes. Alternating electrical signals are applied to the circuit and the electrical response of the circuit is monitored. The monitored response is processed to generate output data representative of the structure of the bone tissue.

Abstract: There is described a method o monitoring the structure of a tooth comprising:—placing an electrode carrier, having at least three electrodes, adjacent the tooth such that the electrodes contact at least one of the occlusal, approximal or free smooth surfaces of the tooth; selecting pairs of the carrier electrodes, one electrode of each selected pair to act as a contact electrode, and the other as a counter electrode; for each selected pair of electrodes, passing an alternating electrical current between the electrodes so as to form a circuit from the electrodes and a respective part of the tooth at least between the electrodes, and monitoring the electrical response for the circuit; and processing the monitored response for each pair of electrodes so as to determine structural information relating to the respective parts of the tooth. Apparatus for carrying out the method is described. The method is preferably an impedance spectroscopy technique, for caries detection and monitoring.