Method and apparatus for apical detection with complex impedance measurement
First Claim
1. An apical detection apparatus, comprising:
- a first electrode, the first electrode including a conductive probe shaped for penetrating a root canal of a tooth;
a second electrode configured to electrically contact a patient'"'"'s body;
a phase detector coupled to the first and second electrodes, the phase detector being operative to detect a phase of a complex impedance having a real component and a reactive component;
a user interface coupled to the phase detector to provide an indication to a user of a parameter that is a function of the detected phase;
an electronic controller coupled to the phase detector, the controller being operative to produce a signal indicating location of the probe at an apex of the root canal as a function of the detected phase; and
an amplitude detector operative to detect the magnitude of the complex impedance, wherein the controller is operative to produce the signal indicating location of the probe at an apex of the root canal as a function of both the detected phase and the magnitude.
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Abstract
An apical position detector for use in dental endodontics includes an electronic controller coupled to a conductive probe and a lip electrode. The probe is positioned in a root canal and the lip electrode contacts another location on the patient'"'"'s body. The controller produces a test signal as a combination of signals at selected frequencies. The controller then monitors a voltage of the probe and extracts the amplitude and phase of each of the frequency components of the voltage at the probe. Test scores are generated from summations of the amplitudes and/or phases of the various frequency components to determine when the impedance between the probe and the lip electrode changes from a primarily reactive impedance to a primarily resistive impedance. A first test score is displayed to indicate when the impedance changes from a reactive to a resistive impedance. The second test score indicates when the measurement conditions are unsatisfactory. The test scores are displayed in bar graph or similar form.
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Citations
32 Claims
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1. An apical detection apparatus, comprising:
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a first electrode, the first electrode including a conductive probe shaped for penetrating a root canal of a tooth; a second electrode configured to electrically contact a patient'"'"'s body; a phase detector coupled to the first and second electrodes, the phase detector being operative to detect a phase of a complex impedance having a real component and a reactive component; a user interface coupled to the phase detector to provide an indication to a user of a parameter that is a function of the detected phase; an electronic controller coupled to the phase detector, the controller being operative to produce a signal indicating location of the probe at an apex of the root canal as a function of the detected phase; and an amplitude detector operative to detect the magnitude of the complex impedance, wherein the controller is operative to produce the signal indicating location of the probe at an apex of the root canal as a function of both the detected phase and the magnitude.
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2. An apical detection apparatus, comprising:
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a first electrode, the first electrode including a conductive probe shaped for penetrating a root canal of a tooth; a second electrode configured to electrically contact a patient'"'"'s body; a phase detector coupled to the first and second electrodes, the phase detector being operative to detect a phase of a complex impedance having a real component and a reactive component; a user interface coupled to the phase detector to provide an indication to a user of a parameter that is a function of the detected phase; and a signal source coupled to the first and second electrodes, the signal source providing a testing signal to the first and second electrodes, the testing signal including a plurality of test frequencies, wherein the phase detector is operative to detect the phase of the complex impedance at each of the test frequencies. - View Dependent Claims (3)
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4. An apparatus for detecting contact with a body tissue of a first type in a patient, comprising:
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a first electrode coupleable to the patient'"'"'s body; a second electrode movable to contact the tissue of the first type, the second electrode including a probing member for contacting the patient'"'"'s body; and a complex impedance sensor coupled to the first and second electrodes and configured to detect a plurality of amplitude relationships among at least three different frequencies and a plurality of relationships between real and reactive components of impedances at at least three different frequencies between the first and second electrodes. - View Dependent Claims (5, 6, 7)
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8. A method of detecting an apical location in a root canal of a patient comprising the steps of:
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electrically coupling to the patient at a first location; probing the root canal at a second location; detecting a complex impedance between the first location and the second location, the complex impedance having a first phase component and a first magnitude component; and producing an indicator of the second location as a function of the first phase component; the step of detecting a complex impedance between the first and second locations comprising the steps of; detecting a first impedance at a first frequency; and detecting a second impedance at a second frequency different from the first frequency, wherein the first phase component corresponds to the first impedance and a second phase component corresponds to the second impedance. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of indicating apical position, comprising the steps of:
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probing a root canal with a probe;
detecting a complex component of a complex impedance between the probe and a location on a patient'"'"'s body;producing a first test score as a function of the complex component; and
displaying the first test score to a user; andproducing a second test score indicating testing conditions based upon a selected component of the complex impedance; and
producing a visible indication of the testing conditions in response to the second test score. - View Dependent Claims (18, 19)
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20. A method of indicating apical position, comprising the steps of:
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probing a root canal with a probe; detecting a complex component of a complex impedance between the probe and a location on a patient'"'"'s body; producing a first test score as a function of the complex component; displaying the first test score to a user; identifying undesirable measuring conditions in response to a selected component of the complex impedance; and providing an audible indication of the undesirable measuring conditions.
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21. A method of determining a probe location, comprising the steps of:
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applying the probe to a patient'"'"'s body; applying a multifrequency signal to the probe, the multifrequency signal having spectral components at a plurality of more than two frequencies; detecting a response signal produced in response to the applied multifrequency signal; extracting more than two selected spectral components of the response signal; and in response to the extracted spectral components, producing an output indicating the probe location based on a sum of amplitude ratios and of phase angles of the extracted spectral components. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification