Water-Responsive Materials: Properties, Designs, and Emerging Applications in Oral Healthcare

Water-responsive materials represent a class of stimuli-responsive "smart" materials that have become a focal point of recent research in recent years. Their unique ability to undergo reversible shape changes in response to water or humidity makes them highly versatile for various applications. Inspired by natural phenomena such as the hygroscopic movements of plant fibers and the supercontraction of spider silk, these materials exhibit excellent shape adaptability, phase transition, and wet tissue adhesion capabilities. Their ability to thrive in the aqueous environment, where saliva and gingival crevicular fluid provide a dynamic medium, makes them particularly promising for applications in oral medicine. This review, drawing on literature primarily from the past decade, comprehensively discusses the mechanisms, building blocks, and current advancements in water-responsive materials, with a focus on their potential in oral drug delivery, tissue engineering, and wound management. Key applications include alveolar bone regeneration, chronic wound healing, periodontitis treatment, and hemostatic dressings, where their shape adaptability, biocompatibility, and biodegradability address critical clinical challenges. Despite their potential, the application of water-responsive materials in oral medicine remains underexplored, highlighting the need for further research to optimize their design and functionality. By integrating insights from recent studies, this review aims to provide a foundation for the development of next-generation water-responsive materials tailored to meet the unique demands of oral healthcare.