Caries detection using real-time imaging and multiple excitation frequencies

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.

21 . The method as set forth in claim 1 , wherein the return pulse is received as a viewable two-dimensional image.

22 . The apparatus as set forth in claim 7 , wherein the detector comprises a camera.

23 . The apparatus as set forth in claim 14 , wherein the detector comprises a camera.