Optical diagnosis of dentin caries lesions using quantitative light-induced fluorescence technology

The precise diagnosis of dental caries and determination of their severity are very important when planning for treatment. Low diagnostic power of traditional methods such as radiographic and visual-tactile examinations could increase in the ambiguity of clinical decision about some borderline lesions. The aim of this study was to identify the extent of dentin lesions by using Qraypen (AIOBIO, Seoul, Korea), a device that utilizes QLF technology, at the dentin level through representative 2 cases in this study. In the first case of chronic and deep dentin caries, the fluorescence loss and strong red fluorescence were still detected from the lesions when observed by Qraypen after removing the suspicious lesions using conventional methods. It was possible to gradually remove red fluorescent area until it reached an almost invisible state. In addition, from the second case of acute and secondary caries, it was difficult to detect the crack using conventional diagnostic methods. Based on the result of the Qraypen examination, we could verify the presence of the crack and its severity which had progressed into the pulp as a distinct red fluorescence. In conclusion, the QLF technology could be applied not only to detect dentin caries but also to provide evidences for determining extent of caries removal non-invasively and objectively.