Clinical Applications and Diagnostic Performance of Adjunctive Light-Based Optical Technologies in Oral Potentially Malignant Disorders and Squamous Cell Carcinoma: A Systematic Review

<b>Background:</b> Oral squamous cell carcinoma often develops from oral potentially malignant disorders and is frequently diagnosed at an advanced stage. Conventional oral examination is limited by moderate sensitivity, observer variability, and poor discrimination between benign and dysplastic lesions. Adjunctive light-based screening technologies have been introduced, but their diagnostic value remains uncertain. <b>Methods:</b> This systematic review followed PRISMA 2020 guidelines and was registered in PROSPERO. MEDLINE (PubMed), Embase, Scopus, and the Cochrane Database were searched through December 2025. Studies assessing adjunctive light-based screening technologies for detecting oral potentially malignant disorders or squamous cell carcinoma were included. Histopathology served as the reference standard. Diagnostic accuracy outcomes were extracted, and risk of bias was assessed using Cochrane-based criteria. <b>Results:</b> Eleven studies were included. Autofluorescence imaging showed consistently high sensitivity but low and variable specificity. Chemiluminescence demonstrated similar or lower sensitivity with poor specificity. False-positive results were frequent, particularly in inflammatory or benign lesions. Marked heterogeneity across studies limited quantitative synthesis. <b>Conclusions:</b> Adjunctive light-based technologies can increase detection sensitivity when used with conventional oral examination but lack sufficient specificity for standalone use. Histopathological confirmation remains mandatory. Standardized, multicenter diagnostic accuracy studies are needed to clarify their clinical role.