During 1932–1938, Oral Medicine centers on deciphering the causes and progression of dental caries, integrating causal mechanisms, risk factors, and population-based prevention into research and practice. Fluoride chemistry and fluorosis emerge as core directions, linking enamel and dentin mineral content to fluoride exposure and preventive implications, while histologic analyses of enamel, dentin, pulp, and osseous tissues tie tissue pathology to diagnosis and therapy. The period also integrates neural regulation of dentoalveolar tissues and craniofacial growth patterns to inform prosthetic and orthodontic care, reflecting a holistic approach to the dentoalveolar complex. Historical Significance: The era's work on the cause and nature of dental caries reframes caries as a disease process with natural history, guiding preventive research and early cariology development. Foundational fluorosis studies and fluoride-related caries resistance shape early policy debates and fluoride use in public health. Tissue-level investigations into enamel, dentin, pulp, and fluorosis-induced changes anchor diagnostic and therapeutic paradigms, while the interplay of growth and morphogenesis studies informs clinical approaches in prosthodontics and orthodontics. Together, these contributions cemented a unified, biology-grounded paradigm for Oral Medicine that persisted into later decades.