Method and improved device for measuring and locating a tooth apex
OwnerRoger Heraudinventor
Life of this patent
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Abstract
A process and a device for measuring and locating the apex of a root canal of a tooth, by measuring, between a rasp forming an electrode inserted in the root canal and a second electrode disposed in the mouth, the variations of time constants of resistances and capacitances encountered in the canal, includes applying to the terminals of the electrodes a continuous current signal or a square signal of current of predetermined frequency for repeating the measurements and carrying out at the terminals of the electrodes at least two measurements for a given alternation so that a radiometric computation of the measurements can be obtained which result represents a distance separating the distal end of the rasp from the apex.
Claims16
A process for locating and measuring an apex of a tooth root canal by measuring variations of time constants of resistances and capacitances encountered between a measuring electrode forming the first electrode inserted in the root canal and a second electrode disposed in contact with mouth tissues, comprising the steps of:
- applying to the first and second electrodes a square wave signal of a predetermined frequency;
- establishing a measurement baseline at a level obtained at a beginning of an alternation of the square wave signal;
- making two electrical measurements, A and B, in time during the alternation,
- computing a result M of a ratio of the two measurements with a known constant K1;
- and
- converting the result M by a coefficient to a value representing the distance separating a distal end of the first electrode from the apex.
Device for locating and measuring an apex of a tooth root canal by measuring variations of time constants of resistances and capacitances encountered between a measuring electrode forming the first electrode inserted in the root canal and a second electrode disposed in contact with mouth tissues, comprising:
- a first electrode adapted for insertion in the root canal;
- a second electrode adapted for disposed in a patient's mouth;
- a square wave signal source operatively connected to terminals of the first and second electrodes;
- a measuring means for obtaining at least two values of voltage, A and B, over one alternation of the square wave signal;
- a computational module connected to the measuring means and determining the distance between the distal end of the first electrode when inserted in the canal and the apex of the canal by computing a result M of a ratio of the two measurements A and B with a known constant K1 and converting the result M by a coefficient to a value representing the distance separating a distal end of the first electrode from the apex;
- and
- a display operatively connected to said computational module and displaying the determined distance.
Dependencies are inferred from the claim text.