Recent advances in oral adhesives: fabrication, properties, and applications

The oral cavity presents a unique set of challenges for wound healing and drug delivery due to its persistently moist conditions, dynamic mechanical forces, complex microbiota, and high enzymatic activity. Conventional topical formulations such as powders, ointments, and mouthwashes are often limited by poor retention, low bioavailability, and limited functional versatility. In recent years, significant advances have been made in the design and functionalization of biomedical oral tissue adhesives. Their development has evolved from serving primarily as passive physical barriers to increasingly sophisticated systems capable of multifunctional integration, environmental responsiveness, and controlled drug release. This review systematically examines current adhesive dosage forms, including injectable hydrogels, sprayable adhesives, microneedle patches, bioactive patches, and emerging designs such as Janus adhesive patches and stimulus-responsive patches. It critically analyzes the design strategies, material composition, adhesion mechanisms, clinical applicability, and performance trade-offs of each type. Furthermore, it offers perspectives on future directions, with a focus on bioactive integration and clinical translation.