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

BACKGROUND: Hidden caries is a type of tooth decay that is difficult to identify through visual diagnosis because teeth with hidden caries appear normal on the tooth surface but are damaged underneath. METHODS: A photoacoustic imaging system based on visible light using a diode laser with a wavelength of 532 nm was developed to detect hidden caries in teeth. RESULTS: The results indicate that the average of acoustic intensity level for healthy teeth is −74.2 ± 0.1 dB, and the average of acoustic intensity range for teeth with hidden caries is −81.2 ± 0.5 dB. The intensity level for the caries area varies depending on the severity of caries. CONCLUSION: Based on the acoustic intensity level measured by the interaction of teeth with laser light, the photoacoustic imaging system in the study can accurately detect the presence of hidden caries and recognize the difference between caries teeth and healthy teeth. This research can be developed into a prototype of a simple device that makes it easy to operate in dental practice.