This book comprehensively addresses clinical applications aimed at the protection and treatment of oral and dental health. It covers fundamental principles in maintaining oral health in geriatric individuals, detailing age-associated changes in oral and dental tissues, nutrition, salivary gland function, mucosal alterations, and the impact of periodontal diseases. Emphasis is placed on the significance of preventive dentistry and challenges faced by the elderly in accessing dental services. Furthermore, the content examines oral mouthwashes, highlighting the roles of chemotherapeutic agents such as chlorhexidine, hydrogen peroxide, cetylpyridinium chloride and natural phytotherapeutic agents like propolis in oral health. The phytotherapeutic agents’ anticariogenic properties are discussed with respect to their antimicrobial, anti-inflammatory, and remineralization effects against cariogenic bacteria like Streptococcus mutans based on scientific literature. Finally, the book provides detailed descriptions of in vitro methods for measuring dentin permeability, including hydraulic conductance devices, scanning electron microscopy (SEM), environmental SEM, confocal microscopy, focused ion beam SEM (FIB-SEM), and scanning electrochemical microscopy (SECM). These advanced techniques contribute significantly to understanding dentin hypersensitivity and evaluating desensitizing agents, serving as valuable tools for both clinical practice and research. The book serves as an essential resource for academicians, dental practitioners, and students in the field of oral health.