Photoacoustic Imaging System based on Diode Laser and Condenser Microphone for Characterization of Dental Anatomy

Abstract

The feasibility of a diode laser and condenser microphone-based photoacoustic imaging system for dental anatomy characterization has been investigated. The sample of this study was human teeth illuminated by a diode laser with a wavelength of 532 nm. The laser and detector were fixed in a static position while the sample was moved in the X-Y direction. A laser diode illuminated the sample at 17-20 kHz frequencies combined with 30%, 35%, 40%, 45%, 50%, and 55% of the duty cycles to investigate optimal laser irradiation for dental anatomy imaging. The acoustic intensity was measured ten times to investigate the characterization of dental anatomical structure, i.e., enamel, dentin, and pulp. The sample was then scanned using the system to determine the characterization of the dental structure in the photoacoustic image. The results of this study reveal that the optimal frequency and duty cycle of laser exposure to produce the photoacoustic image of the sample are 19 kHz and 50%, respectively. The maximum acoustic intensities of enamel, dentin and pulp are -71,8 dB, -70,8 dB, -70,5 dB, respectively. Whereas the minimum acoustic intensities of enamel, dentin and pulp are -72,0 dB, -70,9 dB, -70,6 dB respectively. In this study, a photoacoustic imaging system based on a diode laser and a condenser microphone can generate photoacoustic images of dental anatomical structures. The optical absorption of pulp is stronger than the dentin and enamel layer. Hence the pulp area emits the highest acoustic intensity and emerges as a red area in the photoacoustic image.

Photoacoustic Imaging for Periodontal Disease Examination

“…28 This technique can image soft tissue and does not utilize ionizing radiation. 12,20,29 The anatomical area and extension of periodontal tissue inflammation can be determined based on acoustic intensity acquired from PA imaging.…”

“…This imaging technique can be used to obtain structural, functional, molecular, and kinetic information from various tissues and has been developed for clinical applications, including breast cancer, dermatological, vascular, carotid artery, musculoskeletal, gastrointestinal, adipose, dental and other tissue imaging. 8,11,12 PAI is a non-invasive and low-cost imaging technique and does not produce ionizing radiation. 13 A laser is commonly used as its electromagnetic source.…”

Recent development of photoacoustic imaging in dentistry: A review on studies over the last decade

“…Most studies focus on the ex-vivo application of PAI for the detection of tooth decay ( Arabpou et al, 2019 , Cheng et al, 2016 , El-Sharkawy and El Sherif, 2012 , Khosroshahi and Valizadeh, 2020 , Koyama et al, 2018 , Li and Dewhurst, 2016 , Periyasamy et al, 2018 , Rao et al, 2011 , Sampathkumar et al, 2014 , da Silva et al, 2021 , Tasmara et al, 2023 , Yamada et al, 2016 ). In general, clinical studies of PAI in dentistry assess the pocket depth of periodontal tissues from humans ( Fu, Khazaeinezhad et al, 2022 , Fu, Ling et al, 2022 , Fu et al, 2021 , Lin et al, 2017 , Moore et al, 2018 , Moore et al, 2022 , Mozaffarzadeh et al, 2021 ), and ex-vivo investigations employ samples from human teeth ( Alifkalaila et al, 2021 , Arabpou et al, 2019 , Cheng et al, 2016 , Dias et al, 2018 , El-Sharkawy and El Sherif, 2012 , Khosroshahi and Valizadeh, 2020 , Koyama et al, 2018 , Lee et al, 2017 , Li and Dewhurst, 2016 , Periyasamy et al, 2018 , Rao et al, 2011 , Sampathkumar et al, 2014 , da Silva et al, 2021 , Yamada et al, 2016 ), animal model for mimicking periodontal diseases ( Sari et al, 2022 ), and oral soft tissues from rats ( Widyaningrum et al, 2018 , Widyaningrum et al, 2020 ). PAI was also discovered to be useful in the investigation of dental implants and oral biofilms ( Dias et al, 2018 , Lee et al, 2017 ).…”

“…The PAI system's components and imaging method must still be developed. Alifkalaila et al (2021) PAI for the characterization of dental anatomy. 532 nm diode laser.…”

Photoacoustic imaging of hidden dental caries using visible–light diode laser

“…The results of this study are consistent with previous studies employing a PAI system to examine dental caries. 22,29 This research is still limited to ex vivo study and further researches are needed to compare the photoacoustic imaging with other modalities for hidden caries detection.…”