Tooth vitality probe and process

• US 5,259,761 A
• Filed: 09/10/1990
• Issued: 11/09/1993
• Est. Priority Date: 08/06/1990
• Status: Expired due to Fees

• Current Assignee: Jenifer M. Schnettler
• Original Assignee: Jenifer M. Schnettler
• Inventors: Schnettler, Jenifer M., Wallace, James A.
• Primary Examiner(s): O'Connor, Cary E.
• Assistant Examiner(s): CHERICHETTI, CINDY
• Application Number:
  US07/579,810
• Time in Patent Office: 1,156 Days
• Field of Search: 433/25, 433/215, 433/229, 433/29, 128/633
• US Class Current: 433/215
• CPC Class Codes: A61B 2562/0238 Optical sensor arrangements for performing transmission measurements on body tissue
• CPC Class Codes: A61B 5/0088 for oral or dental tissue
• CPC Class Codes: A61B 5/0534 for testing vitality of teeth
• CPC Class Codes: A61C 19/04 Measuring instruments specially adapted for dentistry A61C5/44 takes precedence; testing vitality of teeth A61B5/0534; radiation diagnosis specially adapted for dentistry A61B6/51

Abstract

The present invention relates to the use of pulse oximeter technology, and particularly, a pulse oximeter-like probe for diagnosing the pulpal vitality and vascular integrity of a subject tooth. The present invention does not require a reaction by the patient to pain caused by stimulation of a tooth. Thereby, the present invention is not as susceptible to false negatives or positives as were past methods for determining tooth vitality which were dependent on obtaining a neuronal response. As described herein, lack of neuronal response does not always indicate pulpal death. Both the apparatus and method of the present invention allow an immediate, objective diagnosis of tooth vitality without inducing painful stimulation.

Claims

1. An apparatus for non-invasively determining the vitality of a tooth, said apparatus comprising:

means for obtaining a blood oxygen saturation measurement of blood contained in a portion of at least one of the pulp chamber or root canal of said tooth, said means for obtaining comprising means for detecting a pulsatile component in said blood and means for determining said oxygen saturation measurement based on said pulsatile component; and

means for comparing said oxygen saturation measurement to a predetermined criteria in order to determine said vitality of said tooth.

2. The apparatus of claim 1, wherein said predetermined criteria comprises two separate ranges, a first range consisting of values of oxygen saturation predetermined to represent a vital tooth, and a second range of values predetermined to represent a non-vital tooth.

3. The apparatus of claim 2, wherein said first range comprises the values of 85 to 100 percent blood oxygen saturation, and said second range comprises the values of 0 to 84 percent blood oxygen saturation.

4. The apparatus of claim 2, wherein said predetermined criteria comprises a third range including values predetermined to represent various intermediate pathological stages of said tooth, said stages being between vital and non-vital.

5. The apparatus of claim 4, wherein said first range comprises the values of 85 to 100 percent blood oxygen saturation, said second range comprises the values of 0 to 10 percent oxygen saturation, and said third range comprises the values of 11 to 84 percent oxygen saturation.

6. The apparatus of claim 1, wherein said means for obtaining a blood oxygen saturation measurement comprises:

a photoelectric sensor, said sensor comprising;

light source means for providing light to be transmitted through said portion of said tooth;

detector means for receiving at least part of said transmitted light and for producing an output signal which is indicative of the degree of absorption of said received light due to said blood within said portion of said tooth; and

a sensor body for maintaining said light source and detector means in fixed, facing relation on generally opposite sides of said tooth so as to provide a source to detector path which intersects said portion of said tooth; and

processing means for converting said output signal into said oxygen saturation measurement.

7. The apparatus of claim 6, wherein said light from said light source means comprises light of first and second wavelengths, said first wavelength being a wavelength for which hemoglobin and hemoglobin oxide in a patient'"'"'s blood each have approximately the same light absorption coefficient, and said second wavelength being a wavelength for which said hemoglobin and hemoglobin oxide have differing light absorption coefficients.

8. The apparatus of claim 7, wherein said first wavelength is in the infrared region of the light spectrum, and said second wavelength is in the visible region of the light spectrum.

9. An apparatus for non-invasively determining the vitality of a tooth, said apparatus comprising:

means for detecting the presence of a pulse in said tooth; and

means for indicating that the tooth is vital in the event a pulse is detected, and for indicating that the tooth is non-vital in the event said pulse is not detected.

10. The apparatus of claim 9, wherein said means for detecting the presence of a pulse comprises a photoelectric sensor, and wherein said sensor comprises:

light source means for providing light to be transmitted through a portion of at least one of the pulp chamber or root canal in said tooth;

first detector means for receiving at least part of said transmitted light and for producing an electrical output signal which is indicative of the degree of absorption of said light due to blood within said portion of said tooth; and

second detector means for detecting the presence of an alternating current component of said output signal which is indicative of the presence of said pulse.

11. An apparatus for non-invasively determining the vitality of a tooth, said apparatus comprising:

means for detecting an interchange of arterial and venous blood in at least one of the pulp chamber or root canal in said tooth; and

means for indicating that the tooth is vital in the event said interchange is detected, and for indicating that the tooth is non-vital in the event said interchange is not detected.

12. The apparatus of claim 11, wherein said means for detecting said interchange comprises a photoelectric sensor, and wherein said sensor comprises:

light source means for providing light to be transmitted through a portion of at least one of the pulp chamber or root canal in said tooth;

first detector means for receiving at least part of said transmitted light and for producing an electrical output signal which is indicative of the degree of absorption of said light due to both the arterial and venous blood within said portion of said tooth; and

second detector means detecting a variation in said output signal which is indicative of said interchange.

13. The apparatus of claim 12, wherein said light from said light source means comprises light of first and second wavelengths, said first wavelength being a wavelength for which hemoglobin and hemoglobin oxide in a patient'"'"'s blood each have approximately the same light absorption coefficient, and said second wavelength being a wavelength for which said hemoglobin and hemoglobin oxide have differing light absorption coefficients.

14. The apparatus of claim 13, wherein said first wavelength is in the infrared region of the light spectrum, and said second wavelength is in the visible region of the light spectrum.

15. A method for diagnosing the vitality of a patient'"'"'s tooth, said method comprising the steps of:

non-invasively measuring the oxygen saturation level of blood contained in at least one of the pulp chamber or root canal of said patient'"'"'s tooth;

comparing said oxygen saturation level to a predetermined criteria which comprises a first set of oxygen saturation values representing a vital tooth, and a second set of oxygen saturation values which represent a non-vital tooth; and

determining the vitality of said patient'"'"'s tooth based on said comparison step, wherein said first set of oxygen saturation values comprises the values of 85 to 100 percent, and said second set comprises the values of 0 to 84 percent.

16. A method for diagnosing the vitality of a patient'"'"'s tooth, said method comprising the steps of:

non-invasively measuring the oxygen saturation level of blood contained in at least one of the pulp chamber or root canal of said patient'"'"'s tooth;

comparing said oxygen saturation level to a predetermined criteria which comprises a first set of oxygen saturation values representing a vital tooth, and a second set of oxygen saturation values which represent a non-vital tooth; and

determining the vitality of said patient'"'"'s tooth based on said comparison step, wherein said predetermined criteria further includes a third set of oxygen saturation values which represent various pathological stages of said tooth between vital and non-vital.

17. The method of claim 16, wherein said step of measuring said oxygen saturation comprises the steps of:

transmitting first and second wavelengths of light through at least a portion of said at least one of the pulp chamber or root canal contained within said patient'"'"'s tooth;

detecting the relative intensities of said first and second wavelengths of light after having been transmitted through said portion of said patient'"'"'s tooth;

comparing the relative intensities of said detected first and second wavelengths of light in order to arrive at said oxygen saturation measurement.

18. The method of claim 16, further comprising the step of calibrating said oxygen saturation measurement for known error prior to performing said step of comparing said measurement to said predetermined criteria.

19. A method for determining the vitality of a tooth, said method comprising the steps of:

non-invasively testing for the presence of a pulse in at least one of the pulp chamber or root canal in said tooth; and

determining said tooth to be vital in the event said pulse is detected and to be non-vital in the event said pulse is not detected.

20. The method of claim 19, wherein said step of testing for the presence of a pulse comprises the steps of:

transmitting light through a portion of said at least one of the pulp chamber or root canal in said tooth;

receiving at least part of said transmitted light and producing an electrical output signal which is indicative of the degree of absorption of said light due to blood within said portion of said tooth; and

detecting the presence of an alternating current component of said output signal which is indicative of the presence of said pulse.

21. A method for determining the vitality of a tooth, said method comprising the steps of:

non-invasively testing for an interchange of arterial and venous blood in at least one of the pulp chamber or root canal in said tooth; and

determining that the tooth is vital in the event said interchange is detected, and that the tooth is non-vital in the event said interchange is not detected.

22. The method of claim 21, wherein said step for testing for said interchange comprises the steps of:

transmitting light through a portion of said at least one of the pulp chamber or root canal in said tooth;

receiving at least part of said transmitted light and producing an electrical output signal which is indicative of the degree of absorption of said light due to both the arterial and venous blood within said portion of said tooth; and

detecting a variation in said output signal which is indicative of said interchange.

23. A photoelectric sensor for use in the non-invasive diagnosis of tooth vitality, said sensor comprising:

light source means for providing light to be transmitted through at least a portion of a tooth;

detector means for receiving at least part of said transmitted light and for providing an output signal indicative of the amount of said light absorbed by the blood within said tooth;

a sensor body for maintaining said light source and detector means in fixed relation to said tooth;

said light source means and said detector means being capable of being fixedly positioned below a patient'"'"'s gum line about the root section of said tooth, and

wherein said light source means comprises a first and second light source and said detector means comprises a first and second detector, said first light source and first detector being positioned on said sensor body such that when engaged to said tooth, a first source-to-detector path through the crown section of said tooth is formed, and said second light source and second detector being positioned on said sensor body such that when engaged to said tooth, a second source-to-detector path through the root section of said tooth is formed.