Method and device for determining the apical position in a dental root canal

Apex-locating method for determining a measurement (M) of the depth position of the apex in a root canal of a tooth (α, β, γ, Δ), using a device comprising a first conductive electrode (E1) forming an endodontic probe (S) able to be inserted into the root canal (CR) of a tooth, a second electrode (E0) shaped to be brought into electrically conductive contact with an oral mucous membrane, frequency-generating means (GF) able to produce alternating electrical signals at a number of frequencies, and means (AM) for measuring the magnitude of alternating electrical signals in a circuit comprising said frequency generator, the first probe electrode inserted into the root canal and the second electrode in contact with the oral mucous membrane, said method comprising the steps of:

• exciting the circuit and measuring the levels of magnitude (I) of the alternating electrical signals in the circuit, respectively at a lower frequency (f) and at a higher frequency (F);
• and
• detecting a point of coincidence (C) where two respective levels (If, IF) of the electrical magnitude (I) measured at said lower and higher frequencies (f, F) meet and are substantially equal, said lower and higher frequencies (f, F) being sufficiently far apart for such a point of coincidence (C) to exist, said point of coincidence (C, M) corresponding to the position (X) of the apex.