Saliva, an easily accessible biofluid, offers a non-invasive window into both oral and systemic health through its diverse molecular cargo. This conceptual diagnostic science article develops a unified model that positions saliva as a central medium for the early detection of oral diseases such as dental caries, periodontitis, and oral squamous cell carcinoma, as well as systemic conditions, including viral infections and certain malignancies. The model integrates the biological composition of saliva—encompassing proteins, metabolites, microbial communities, and nucleic acids—with advanced biomarker detection mechanisms and interpretive frameworks. Recent advances in proteomics, genomics, and metabolomics demonstrate that disease-specific alterations in salivary profiles precede clinical manifestations, enabling proactive screening. The proposed conceptual pathway progresses sequentially from salivary secretion and sample acquisition through technological detection, algorithmic signal interpretation, and clinical application. By conceptualizing these interconnected domains, the model eliminates reliance on invasive procedures while enhancing patient compliance and diagnostic equity. Challenges related to standardization and biomarker validation are addressed conceptually, with emphasis on the translational potential of point-of-care platforms. This framework underscores saliva’s capacity to bridge oral and systemic medicine, fostering earlier intervention and improved outcomes across health domains.
