| 摘要 |
The invention concerns a method and a device for measuring and/or locating the apex (14) of the root canal (12) of a tooth (10), by measuring the variations in the time constants of resistance/capacity encountered in the canal, between a file forming an electrode (18) inserted in the root canal and a second electrode (22) provided in the mouth, characterised in that it consists in: applying to the electrode terminals, a direct current signal or a squarewave current signal of predetermined frequency for repeating the measurements; carrying out at the electrode terminals at least two measurements of predetermined alternation; computing with a ratiometer the measurements obtained to eliminate the interference effects such as those produced by medicinal liquids and the like; processing the computed result so as to convert it into a distance which represents the distance separating the distal end of the file (18) from the apex (14).
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