Dental College : Various oral mucosal diseases such as oral potentially malignant disorders(OPMD)and squamous cell carcinoma (SCC)may develop in the oral cavity and are difficult to differentiate. Optical instruments are not invasive and can be repeatedly used. Since 2010, we have used optical instruments effectively to improve diagnosis and treatment. In this study, we conducted subjective and objective evaluations using optical instruments for distinguishing between leukoplakia and SCC.Eighty-two patients diagnosed with SCC and leukoplakia at the Department of Oral and Maxillofacial Surgery, Tokyo Dental College, between April 2017 and March 2018 were selected and evaluated using optical instruments. Also, an oral cancer screening model that used AI(AI oral cancer screening system：AIOS)was prepared and its effectiveness was evaluated.In the subjective evaluation by optical instruments, Fluorescence Visualization Loss(FVL)was confirmed in all SCC cases. In the objective evaluation, SCC was lower than leukoplakia in luminance(SCC 52.6 vs Leukoplakia 74.5cd/m 2 ) . In the coefficient of variation of luminance, SCC was higher than leukoplakia in luminance(SCC 0.22 vs Leukoplakia 0.12) . Regarding luminance ra-

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Oral cancer screening is important for early detection and early treatment, which help improve survival rates. Biopsy is invasive and painful, while fluorescence visualization using optical instruments is non-invasive, convenient, and provides results in real time, and examinations can be repeated. The purpose of this study was to determine the usefulness of optical instruments in oral screening. A total of 314 patients who were examined using optical instruments at Tokyo Dental College between 2014 and 2018 were enrolled in this study. Fluorescence visualization images were analyzed using subjective and objective evaluations. Subjective evaluation for detecting oral cancer offered 98.0% sensitivity and 43.2% specificity. Regarding the objective evaluations for detecting oral cancer, sensitivity and specificity were 61.9% and 62.7% for mean luminance, 90.3% and 55.7% for luminance ratio, 56.5% and 67.7% for standard deviation of luminance, and 72.5% and 85.4% for coefficient of variation of luminance. Fluorescence visualization with subjective and objective evaluation using optical instruments is useful for oral cancer screening.

Background/Aim: Oral cancer screening is important for early detection and early treatment, which help improve survival rates. Biopsy is invasive and painful, while fluorescence visualization is non-invasive, convenient, and realtime, and examinations can be repeated using optical instruments. The purpose of this study was to clarify the usefulness of an optical instrument in oral screening. Patients and Methods: A total of 201 patients, who were examined using an optical instrument in our Department between 2017 and 2018, were enrolled in this study. Fluorescence visualization images were analyzed using subjective and objective evaluations. Results: Subjective evaluations for detecting oral cancer and oral epithelial dysplasia offered 83.3% sensitivity and 75.7% specificity. Regarding the objective evaluations for detecting oral cancer and oral epithelial dysplasia, sensitivity and specificity were 47.4% and 72.4% for luminance value, 94.7% and 79.6% for luminance ratio, and 100.0% and 68.0% coefficient of variation. Conclusion: Fluorescence visualization using optical instruments is useful for oral cancer screening.

Fluorescence visualization devices (FVs) are useful for detecting malignant lesions because of their simple and noninvasive application. However, their quantitative application has been challenging. This study aimed to quantitatively and statistically evaluate the change in fluorescence intensity (FI) during the progression from normal epithelium to squamous cell carcinoma using a reproducible animal tongue carcinogenesis model. To establish this model, rats were treated with 50 ppm 4-Nitroquinoline 1-oxide (4NQO) in their drinking water for 10, 15, and 20 weeks. After 4NQO administration, each rat tongue was evaluated by gross observation, histology, and FI measurements. Fluorescence images were captured by FV, and ImageJ was used to measure FI, which was analyzed quantitatively and statistically. The establishment of a reproducible tumor progression model was confirmed, showing precancerous lesions (low-grade dysplasia [LGD]), early cancers (high-grade dysplasia/carcinoma in situ [HGD/CIS]), and advanced cancers (Cancer). This carcinogenesis model was quantitatively evaluated by FI. The FI of LGD stage was 54.6, which was highest intensity of all groups. Subsequently, the HGD/CIS and Cancer stages showed decreased FI (HGD/CIS: 46.1, Cancer: 49.1) and manifested as dark spots. This result indicates that FI had more variation and a wider range with increasing tumor progression. We demonstrated that FI migration and an uneven distribution are consistent with tumor progression. Since each step of tumor progression occurs reproducibly in this animal model, statistical evaluation was possible. In addition, tumor progression can be monitored by this new FI analysis method in humans.