Caries detection using timing differentials between excitation and return pulses
View Patent ↗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.
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 carries 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, the detector comprising an electromagnetic radiation receiver, a splitter, at least one filter which comprises a first narrow band filter and at least one photo detector; 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 first narrow band filter passes electromagnetic radiation having wavelengths of about 636 nm.
9. The apparatus as set forth in claim 7 , wherein the at least one filter further comprises a second narrow band filter.
10. The apparatus as set forth in claim 9 , wherein the second narrow band filter passes electromagnetic radiation having wavelengths of about 550 nm.
11. The apparatus as set forth in claim 10 , 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.
12. An apparatus capable of detecting dental caries, comprising:
an electromagnetic energy device capable of generating a pulse of electromagnetic energy and directing the electromagnetic energy to a surface of a tooth;
a detector capable of receiving returned 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 returned electromagnetic radiation, the controller being capable of controlling a timer according to a time of generating the pulse of electromagnetic energy and a time of receiving a pulse of returned electromagnetic radiation.
13. The apparatus as set forth in claim 12 , 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.
14. The apparatus as set forth in claim 13 , 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.
15. The apparatus as set forth in claim 14 , 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.
16. The apparatus as set forth in claim 15 , 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.