The potential role of nanozymes applied in stomatology

Oral diseases are frequently associated with bacterial biofilm infection, a vicious cycle of "oxidative stress-inflammation", and hard/soft tissue defects. Within the dynamically changing oral microenvironment, conventional therapeutic strategies struggle to simultaneously achieve multiple functions including oxidative stress alleviation, anti-inflammation and tissue repair. Nanozymes are functional nanomaterials with multi-enzyme catalytic activities, such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). Nanozymes can scavenge reactive oxygen species (ROS) to interrupt the vicious cycle of oxidative stress-inflammation. Meanwhile, nanozymes can also catalyze the generation of ROS to exert antibacterial or anti-tumour effects. Multifunctional composite materials constructed based on nanozymes bring new opportunities for the treatment of oral diseases. This review systematically summarizes the main categories and catalytic mechanisms of commonly used nanozymes in stomatology, including metal-based, metal-organic framework (MOF)-based, nonmetallic, and single-atom nanozymes. It further elaborates their multi-therapeutic effects in periodontal disease, dental caries, pulpitis, peri-implantitis, oral and maxillofacial tumours, bacterial detection and other oral disorders, covering antioxidation, antibacterial activity, bacterial identification, anti-tumour activity, immunomodulation and tissue regeneration. This article also outlines the bottlenecks restricting the clinical translation of nanozymes and prospects the directions for future nanozyme design and optimization, aiming to provide references for basic research and clinical translation of nanozymes in stomatology.