Systems for detecting carious lesions in teeth using short-wave infrared light

1. A system for detecting carious lesions on a tooth, the system comprising:

an optical interrogator including:

a light engine for emitting light in a light beam;

a scanning mirror assembly positioned to reflect the light beam;

a single-pixel photodetector; and

a double-clad optical fiber coupler positioned to direct the light beam to the scanning mirror assembly and to direct scattered light to the single-pixel photodetector; and

a controller operatively coupled to the optical interrogator including logic that, upon execution by the controller, causes the system to perform operations including:

causing the light engine to emit the light having wavelengths in a range of about 900 nm to about 1,700 nm;

selectively directing the light beam over different portions of the tooth with the scanning mirror assembly to provide scattered light; and

correlating scattered light signals generated by the single-pixel photodetector in response to the scattered light with the portion of the tooth.

2. The system of claim 1 , wherein the light engine comprises a plurality of light sources, the system further comprising a wavelength division multiplexer coupled with the light engine to combine light emitted by the plurality of light sources to provide a combined light beam; wherein one or more of the plurality of light sources emit light having a different emission spectrum than other light sources of the plurality of light sources.

3. The system of claim 1 , wherein the single-pixel photodetector is a single-pixel indium-gallium-arsenide (InGaAs) photodetector having a single InGaAs photodiode.

4. The system of claim 1 , wherein the scanning mirror assembly further includes a micro-electromechanical system for selectively altering an orientation of the scanning mirror assembly.

5. The system of claim 1 , wherein the optical interrogator further includes an output, and wherein the operations further include generating, with the output, one or more carious lesion signals indicative of a suspected carious lesion responsive to one or more scattered light signals above a predetermined level.

6. The system of claim 5 , wherein the output is configured to display an image representative of the tooth and an area on the tooth suspected of having a carious lesion.

7. The system of claim 1 , wherein the optical interrogator further includes a collimating lens positioned to collimate the light beam.

8. The system of claim 1 , wherein the optical interrogator further includes a scan lens positioned to focus the light beam on the portion of the tooth.

9. The system of claim 1 , wherein the optical interrogator further includes a filter configured to filter wavelengths of light in the scattered light that are outside the range of about 900 nm to about 1,700 nm.

10. The system of claim 1 , wherein the scattered light signals include one or more analog signals, and wherein the optical interrogator further comprises a converter configured to generate digital signals in response to the one or more analog signals for receipt by the controller.

11. The system of claim 2 , wherein one or more of the plurality of light sources is configured to emit light having wavelengths in a range of about 1,400 nm to about 1,700 nm.

12. The system of claim 1 , wherein portions of the optical interrogator including the scanning mirror assembly are disposed within a probe shaped to be held and manipulated by a hand of a person.

13. A method of detecting a carious lesion on a tooth comprising:

emitting, from a light engine, light in a light beam having wavelengths in a range of about 900 nm to about 1,700 nm;

selectively directing the light beam with a scanning mirror assembly optically coupled to a double-clad optical fiber coupler over different portions of the tooth to provide scattered light;

generating scattered light signals with a single-pixel photodetector in response to the scattered light received from the double-clad optical fiber coupler; and

generating one or more carious lesion signals indicative of a suspected carious lesion when the scattered light signals are above a predetermined level.

14. The method of claim 13 , wherein the light engine includes a plurality of light sources, and wherein one or more of the plurality of light sources emit light having a different emission spectrum than other light sources in the plurality of light sources.

15. The method of claim 14 , wherein the relative emission intensity of each of the plurality of light sources is determined by a machine learning process comprising:

generating a training data set by a process including:

annotating, by one or more dental care professionals, a plurality of carious lesions and a plurality of areas of intact tooth enamel; and

generating hyperspectral reflectance spectra from the plurality of carious lesions and the plurality of areas of intact enamel to provide the training data set; and

training a linear support vector machine on the training data set to generate a classifying vector having coefficients, wherein the coefficients define at least in part the relative emission intensity of the plurality of light sources.

16. The method of claim 13 , further comprising correlating the scattered light signals and the portions of the tooth.

17. The method of claim 13 , wherein the single-pixel photodetector is a single-pixel InGaAs photodetector having a single InGaAs photodiode.

18. The method of claim 13 , further comprising displaying an image representative of the tooth and an area on the tooth suspected of having a carious lesion.

19. The method of claim 13 , wherein the scanning mirror assembly includes a micro-electromechanical system, and wherein selectively directing the light beam onto a portion of the tooth with the scanning mirror assembly includes selectively altering an orientation of the scanning mirror assembly with the micro-electromechanical system.