Detection of incipient carious lesions formed on human teeth in vitro using ultraviolet laser

Objective: A 325-nm ultraviolet (UV) laser was tested for effectiveness in the detection of incipient carious lesions on teeth. Background Data: The combination of early detection with new intervention methods and caries management will be the preferred dentistry of the future. Methods: Carious lesions from extracted teeth or from demineralized teeth were irradiated by UV laser, and the fluorescence spectrum was measured. The peak ratio between two peak intensities in the spectrum was determined. Results: Fluorescence peak intensity of approximately 425 nm was gradually decreased as carious lesions formed, whereas the change 625 nm was less significant. The peak ratio change between peak intensities of approximately 425 and at 625 nm was observed after 30 min of demineralization. Morphological changes were barely observable in this range. Conclusions: A 325-nm UV laser showed high efficacy in the detection of incipient carious lesions. By evaluating peak ratio, the incipient carious lesions could be detected.