Photoacoustic imaging of occlusal incipient caries in the visible and near-infrared range
- Author:
Evair Josino da SILVA
1
;
Erica Muniz de MIRANDA
;
Cláudia Cristina Brainer de OLIVEIRA MOTA
;
Avishek DAS
;
Anderson Stevens LEÔNIDAS GOMES
Author Information
- Publication Type:Original Article
- From:Imaging Science in Dentistry 2021;51(2):107-115
- CountryRepublic of Korea
- Language:English
-
Abstract:
Purpose:This study aimed to demonstrate the presence of dental caries through a photoacoustic imaging system with visible and near-infrared wavelengths, highlighting the differences between the 2 spectral regions. The depth at which carious tissue could be detected was also verified.
Materials and Methods:Fifteen permanent molars were selected and classified as being sound or having incipient or advanced caries by visual inspection, radiography, and optical coherence tomography analysis prior to photoacoustic scanning. A photoacoustic imaging system operating with a nanosecond pulsed laser as the light excitation source at either 532 nm or 1064 nm and an acoustic transducer at 5 MHz was developed, characterized, and used. En-face and lateral (depth) photoacoustic signals were detected.
Results:The results confirmed the potential of the photoacoustic method to detect caries. At both wavelengths, photoacoustic imaging effectively detected incipient and advanced caries. The reconstructed photoacoustic images confirmed that a higher intensity of the photoacoustic signal could be observed in regions with lesions, while sound surfaces showed much less photoacoustic signal. Photoacoustic signals at depths up to 4 mm at both 532 nm and 1064 nm were measured.
Conclusion:The results presented here are promising and corroborate that photoacoustic imaging can be applied as a diagnostic tool in caries research. New studies should focus on developing a clinical model of photoacoustic imaging applications in dentistry, including soft tissues. The use of inexpensive light-emitting diodes together with a miniaturized detector will make photoacoustic imaging systems more flexible, user-friendly, and technologically viable.
