Applications of Second Near-Infrared (NIR-II) Theranostic Agents in Dentistry

Oral diseases such as dental caries, periodontitis, and oral cancer remain significant global health challenges due to their high prevalence and potential for severe complications. Conventional diagnostic and therapeutic methods face limitations including insufficient tissue penetration, low spatial resolution, radiation risks, and the emergence of antibiotic resistance. Near-infrared II (NIR-II, 1000-1700 nm) theranostic agents offer deep tissue penetration, high-resolution imaging, and low tissue autofluorescence, enabling precise diagnosis, and targeted treatment integration. This review summarizes the design and development of various NIR-II platforms, including fluorescent probes, photothermal and photodynamic agents, and multifunctional nanomaterials. Key applications in dentistry include early caries detection, guidance for root canal therapy, monitoring of periodontal inflammation, dental implant evaluation, and oral cancer diagnosis and therapy. NIR-II agents enhance antimicrobial efficacy via photothermal and photodynamic effects, promote tissue regeneration, and reduce systemic side effects. Despite promising advances, challenges such as biosafety concerns, limited retention in the dynamic oral environment, and difficulties in imaging mineralized dental tissues remain. Strategies including biodegradable and biomimetic materials, stimuli-responsive delivery systems, and standardized clinical protocols are critical to overcoming these barriers. Looking forward, interdisciplinary collaboration and technological innovation are expected to accelerate clinical translation of NIR-II theranostics, driving a paradigm shift toward precision, minimally invasive dentistry. This emerging approach holds great potential to improve oral health outcomes by enabling safer, more effective, and personalized dental care.