All-optical photoacoustic imaging and detection of early-stage dental caries

Ashwin Sampathkumar, David A. Hughes, Chris Longbottom, Katherine J. Kirk

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Dental caries remain one of the most common oral diseases in the world. Current detection methods, such as dental explorer and X-ray radiography, suffer from poor sensitivity and specificity at the earliest (and reversible) stages of the disease because of the small size (< 100 microns) of early-stage lesions. We have developed a fine-resolution (480 nm), ultra-broadband (1 GHz), all-optical photoacoustic imaging (AOPAI) system to image and detect early stages of tooth decay. This AOPAI system provides a non-contact, non-invasive and non-ionizing means of detecting early-stage dental caries. Ex-vivo teeth exhibiting early-stage, white-spot lesions were imaged using AOPAI. Experimental scans targeted each early-stage lesion and a reference healthy enamel region. Photoacoustic (PA) signals were generated in the tooth using a 532-nm pulsed laser and the light-induced broadband ultrasound signal was detected at the surface of the tooth with an optical path-stabilized Michelson interferometer operating at 532 nm. The measured time-domain signal was spatially resolved and back-projected to form 2D and 3D maps of the lesion using k-wave reconstruction methods. Experimental data collected from areas of healthy and diseased enamel indicate that the lesion generated a larger PA response compared to healthy enamel. The PA-signal amplitude alone was able to detect a lesion on the surface of the tooth. However, time- reversal reconstructions of the PA scans also quantitatively depicted the depth of the lesion. 3D PA reconstruction of the diseased tooth indicated a sub-surface lesion at a depth of 0.6 mm, in addition to the surface lesion. These results suggest that our AOPAI system is well suited for rapid clinical assessment of early-stage dental caries. An overview of the AOPAI system, fine-resolution PA and histology results of diseased and healthy teeth will be presented.
Original languageEnglish
Title of host publicationLasers in Dentistry XXI
EditorsPeter Rechmann, Daniel Fried
PublisherSociety of Photo-Optical Instrumentation Engineers
Volume9306
ISBN (Print)9781628413960
DOIs
Publication statusPublished - Feb 2015

Publication series

NameProceedings of SPIE
PublisherSociety of Photo-Optical Instrumentation Engineers (SPIE)
Volume9306
ISSN (Print)1605-7422

Keywords

  • Photoacoustic microscopy
  • interferometric detection
  • early-stage dental caries
  • lesion detection

Cite this

Sampathkumar, A., Hughes, D. A., Longbottom, C., & Kirk, K. J. (2015). All-optical photoacoustic imaging and detection of early-stage dental caries. In P. Rechmann, & D. Fried (Eds.), Lasers in Dentistry XXI (Vol. 9306). [93060E] (Proceedings of SPIE; Vol. 9306). Society of Photo-Optical Instrumentation Engineers. https://doi.org/10.1117/12.2079765
Sampathkumar, Ashwin ; Hughes, David A. ; Longbottom, Chris ; Kirk, Katherine J. / All-optical photoacoustic imaging and detection of early-stage dental caries. Lasers in Dentistry XXI. editor / Peter Rechmann ; Daniel Fried. Vol. 9306 Society of Photo-Optical Instrumentation Engineers, 2015. (Proceedings of SPIE).
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Sampathkumar, A, Hughes, DA, Longbottom, C & Kirk, KJ 2015, All-optical photoacoustic imaging and detection of early-stage dental caries. in P Rechmann & D Fried (eds), Lasers in Dentistry XXI. vol. 9306, 93060E, Proceedings of SPIE, vol. 9306, Society of Photo-Optical Instrumentation Engineers. https://doi.org/10.1117/12.2079765

All-optical photoacoustic imaging and detection of early-stage dental caries. / Sampathkumar, Ashwin; Hughes, David A.; Longbottom, Chris; Kirk, Katherine J.

Lasers in Dentistry XXI. ed. / Peter Rechmann; Daniel Fried. Vol. 9306 Society of Photo-Optical Instrumentation Engineers, 2015. 93060E (Proceedings of SPIE; Vol. 9306).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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N2 - Dental caries remain one of the most common oral diseases in the world. Current detection methods, such as dental explorer and X-ray radiography, suffer from poor sensitivity and specificity at the earliest (and reversible) stages of the disease because of the small size (< 100 microns) of early-stage lesions. We have developed a fine-resolution (480 nm), ultra-broadband (1 GHz), all-optical photoacoustic imaging (AOPAI) system to image and detect early stages of tooth decay. This AOPAI system provides a non-contact, non-invasive and non-ionizing means of detecting early-stage dental caries. Ex-vivo teeth exhibiting early-stage, white-spot lesions were imaged using AOPAI. Experimental scans targeted each early-stage lesion and a reference healthy enamel region. Photoacoustic (PA) signals were generated in the tooth using a 532-nm pulsed laser and the light-induced broadband ultrasound signal was detected at the surface of the tooth with an optical path-stabilized Michelson interferometer operating at 532 nm. The measured time-domain signal was spatially resolved and back-projected to form 2D and 3D maps of the lesion using k-wave reconstruction methods. Experimental data collected from areas of healthy and diseased enamel indicate that the lesion generated a larger PA response compared to healthy enamel. The PA-signal amplitude alone was able to detect a lesion on the surface of the tooth. However, time- reversal reconstructions of the PA scans also quantitatively depicted the depth of the lesion. 3D PA reconstruction of the diseased tooth indicated a sub-surface lesion at a depth of 0.6 mm, in addition to the surface lesion. These results suggest that our AOPAI system is well suited for rapid clinical assessment of early-stage dental caries. An overview of the AOPAI system, fine-resolution PA and histology results of diseased and healthy teeth will be presented.

AB - Dental caries remain one of the most common oral diseases in the world. Current detection methods, such as dental explorer and X-ray radiography, suffer from poor sensitivity and specificity at the earliest (and reversible) stages of the disease because of the small size (< 100 microns) of early-stage lesions. We have developed a fine-resolution (480 nm), ultra-broadband (1 GHz), all-optical photoacoustic imaging (AOPAI) system to image and detect early stages of tooth decay. This AOPAI system provides a non-contact, non-invasive and non-ionizing means of detecting early-stage dental caries. Ex-vivo teeth exhibiting early-stage, white-spot lesions were imaged using AOPAI. Experimental scans targeted each early-stage lesion and a reference healthy enamel region. Photoacoustic (PA) signals were generated in the tooth using a 532-nm pulsed laser and the light-induced broadband ultrasound signal was detected at the surface of the tooth with an optical path-stabilized Michelson interferometer operating at 532 nm. The measured time-domain signal was spatially resolved and back-projected to form 2D and 3D maps of the lesion using k-wave reconstruction methods. Experimental data collected from areas of healthy and diseased enamel indicate that the lesion generated a larger PA response compared to healthy enamel. The PA-signal amplitude alone was able to detect a lesion on the surface of the tooth. However, time- reversal reconstructions of the PA scans also quantitatively depicted the depth of the lesion. 3D PA reconstruction of the diseased tooth indicated a sub-surface lesion at a depth of 0.6 mm, in addition to the surface lesion. These results suggest that our AOPAI system is well suited for rapid clinical assessment of early-stage dental caries. An overview of the AOPAI system, fine-resolution PA and histology results of diseased and healthy teeth will be presented.

KW - Photoacoustic microscopy

KW - interferometric detection

KW - early-stage dental caries

KW - lesion detection

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DO - 10.1117/12.2079765

M3 - Conference contribution

SN - 9781628413960

VL - 9306

T3 - Proceedings of SPIE

BT - Lasers in Dentistry XXI

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PB - Society of Photo-Optical Instrumentation Engineers

ER -

Sampathkumar A, Hughes DA, Longbottom C, Kirk KJ. All-optical photoacoustic imaging and detection of early-stage dental caries. In Rechmann P, Fried D, editors, Lasers in Dentistry XXI. Vol. 9306. Society of Photo-Optical Instrumentation Engineers. 2015. 93060E. (Proceedings of SPIE). https://doi.org/10.1117/12.2079765