Caries detection using timing differentials between excitation and return pulses

• US 20060099548A1
• Filed: 08/12/2005
• Published: 05/11/2006
• Est. Priority Date: 08/13/2004
• Status: Active Grant

• Current Assignee: Biolase Incorporated
• Original Assignee: Biolase Technology Inc
• Inventors: Rizoiu, Ioana M., Boutoussov, Dmitri
• Granted Patent: US 7,303,397 B2
• Time in Patent Office: Days
• US Class Current: 433/29
• CPC Class Codes: A61B 1/00121 Connectors, fasteners and adapters, e.g. on the endoscope handle
• CPC Class Codes: A61B 5/0088 for oral or dental tissue
• CPC Class Codes: A61C 1/0046 Dental lasers surgical lasers A61B18/20; working by laser beam in general B23K26/00; lasers per se H01S3/00
• CPC Class Codes: A61C 1/10 Straight hand-pieces
• CPC Class Codes: G01N 21/64 Fluorescence; Phosphorescence

Abstract

A laser device is disclosed that directs light to a tooth and analyzes scattered light reflected from the tooth. The device measures a time delay between excitation and reflections of light. Reflected light is analyzed to determine a presence and extent of dental caries on the tooth.

Claims

1. A method of detecting dental caries, comprising:

directing at least one excitation pulse of laser energy toward a surface of a tooth;

receiving at least one corresponding return pulse of fluorescent radiation responsive to the electromagnetic energy; and

determining at least one time delay between the at least one excitation pulse and the at least one corresponding returned pulse.

2. The method as set forth in claim 1, further comprising determining a relative time delay according to the at least one time delay.

3. The method as set forth in claim 2, wherein the determining of a relative time delay comprises:

maintaining a running average of time delays between excitation pulses and corresponding returned pulses;

receiving a time delay; and

comparing the time delay with the running average.

4. The method as set forth in claim 1, further comprising comparing a returned pulse with a corresponding excitation pulse according to at least one of intensity, time delay, and spectral distribution.

5. The method as set forth in claim 1, comprising receiving an indication of a depth of caries according to the time delay.

6. The method as set forth in claim 1, further comprising directing electromagnetic energy toward caries to perform caries therapy.

7. An apparatus for detecting dental caries, comprising:

an electromagnetic energy device capable of generating at least one excitation pulse of electromagnetic energy;

a delivery system capable of directing the at least one excitation pulse toward a surface of a tooth;

a detector capable of receiving at least one return pulse of fluorescent radiation corresponding to the at least one excitation pulse; and

a controller capable of measuring a time delay between the transmitting of the at least one excitation pulse and the receiving of the at least one return pulse.

8. The apparatus as set forth in claim 7, wherein the detector comprises:

an electromagnetic radiation receiver;

a splitter;

at least one filter; and

at least one photo detector.

9. The apparatus as set forth in claim 8, wherein the at least one filter comprises a first narrow band filter.

10. The apparatus as set forth in claim 9, wherein the first narrow band filter passes electromagnetic radiation having wavelengths of about 636 nm.

11. The apparatus as set forth in claim 9, wherein the at least one filter further comprises a second narrow band filter.

12. The apparatus as set forth in claim 11, wherein the second narrow band filter passes electromagnetic radiation having wavelengths of about 550 nm.

13. The apparatus as set forth in claim 12, wherein:

the at least one photo detector comprises a first photo detector and a second photo detector;

the first photo detector is capable of generating a first electrical signal according to electromagnetic radiation received from the first narrow band filter;

the second photo detector is capable of generating a second electrical signal according to electromagnetic radiation received from the second narrow band filter;

the controller is capable of determining a quotient by dividing a magnitude of the first electrical signal by a magnitude of the second electrical signal; and

the controller is capable of comparing the quotient with a stored threshold and of providing an indication on a display device according to the result of the comparison.

14. An apparatus capable of detecting dental caries, comprising:

an electromagnetic energy device capable of directing electromagnetic energy to a surface of a tooth;

a detector capable of receiving reflected electromagnetic radiation from the tooth according to the electromagnetic energy; and

a controller capable of measuring a time delay according to the electromagnetic energy and the reflected electromagnetic radiation.

15. The apparatus as set forth in claim 14, wherein the electromagnetic energy device is further capable of generating a pulse of electromagnetic energy.

16. The apparatus as set forth in claim 15, wherein:

the controller is capable of controlling a timer according to a time of generating the pulse of electromagnetic energy; and

the controller is capable of controlling the timer according to a time of receiving a pulse of reflected electromagnetic radiation according to the generated pulse of electromagnetic energy.

17. The apparatus as set forth in claim 16, wherein the controller is capable of determining a running average of time delays, receiving a time delay, and comparing the time delay with the running average.

18. The apparatus as set forth in claim 17, further comprising:

an electromagnetic radiation receiver;

a splitter;

a first narrow band filter;

a second narrow band filter;

a first photo detector; and

a second photo detector.

19. The apparatus as set forth in claim 18, wherein:

the first narrow band filter passes electromagnetic radiation having wavelengths of about 636 nm;

the second narrow band filter passes electromagnetic radiation having wavelengths of about 550 nm;

the first photo detector is capable of generating a first electrical signal according to an intensity of electromagnetic radiation received from the first narrow band filter; and

the second photo detector is capable of generating a second electrical signal according to an intensity of electromagnetic radiation received from the second narrow band filter.

20. The apparatus as set forth in claim 19, further comprising a controller configured to receive the first electrical signal and the second electrical signal, and to determine a quotient by dividing a magnitude of the second electrical signal by a magnitude of the first electrical signal.