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

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. © 2021. All Rights Reserved.