Patent ID: 8734151
Filing Date: 2014-05-27
Classification: A61B,A61C

Abstract:
1. Apex-locating device for determining the depth position of the apical constriction in a dental root canal, the device comprising: a terminal for connection to a first conductive endodontic probe electrode able to be inserted into the root canal or one of the root canals of a tooth, a second electrode shaped to be brought into electrically conductive contact with an oral mucous membrane, one or more frequency-generating means able to produce alternating electrical signals at at least two frequencies, means for measuring the electrical magnitude of the alternating signals in a circuit comprising the frequency-generating means, the first electrode inserted into the root canal of the tooth and the second electrode in contact with the oral mucous membrane, frequency selection control means for exciting the circuit at a first lower frequency and at a second higher frequency so that the means for measuring the electrical magnitude of the alternating signals in the circuit respectively measures a first level and a second level of magnitude of the alternating electrical signals in the said circuit and means for detecting a point of coincidence where the first level measured at the first lower frequency and the second level measured at the second higher frequency meet and are substantially equal.