Background: Oral biofilms are a major etiological factor in dental caries, periodontal disease, peri-implantitis, and endodontic infections. Increasing antimicrobial resistance and the limitations of conventional therapies have intensified interest in antimicrobial photodynamic therapy (aPDT). Hypericin, a natural photosensitizer derived from Hypericum perforatum, demonstrates potent reactive oxygen species generation and broad antimicrobial activity; however, its dental applications remain insufficiently synthesized. Objective: To systematically evaluate the antimicrobial efficacy, treatment parameters, safety, and clinical potential of hypericin-mediated aPDT against oral biofilms and infections in dentistry. Methods: This systematic review was conducted according to PRISMA 2020 and registered in PROSPERO CRD42024617727. Electronic searches of PubMed/MEDLINE, Embase, Scopus, and the Cochrane Library (January 2010 to December 2025) were performed. Studies assessing hypericin-mediated aPDT in oral or dental contexts were included. Methodological quality was evaluated using a predefined nine-domain risk-of-bias tool. Results: Eleven studies met the inclusion criteria. Hypericin-mediated aPDT demonstrated strong antimicrobial effects, achieving up to 99% planktonic inactivation and significant biofilm reduction across bacterial and fungal species. Activity was particularly pronounced against Gram-positive organisms, including Staphylococcus aureus and Enterococcus faecalis. However, efficacy against mature biofilms was variable and often dependent on formulation and irradiation parameters. Most studies showed moderate methodological quality, with frequent deficiencies in reporting light calibration and dosimetry. Advanced delivery systems, including liposomal and nanoparticle formulations, improved photodynamic performance. Conclusions: Hypericin-mediated aPDT shows promising antimicrobial activity against oral pathogens and biofilms, with favorable selectivity and safety profiles. Nevertheless, the evidence remains predominantly preclinical and heterogeneous. Standardized protocols and well-designed clinical trials are required before routine dental implementation can be recommended.

Background: 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. Methods: 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. Results: 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. Conclusions: 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.