Fluoride in Dental Caries Prevention and Treatment: Mechanisms, Clinical Evidence, and Public Health Perspectives

Background: Dental caries remains one of the most prevalent chronic diseases worldwide. Fluoride has long been recognized as a cornerstone of caries prevention through enamel remineralization, inhibition of demineralization, and antibacterial activity. However, controversies persist regarding systemic exposure, potential health risks, and ethical debates over community water fluoridation. Previous reviews often focused on isolated interventions, whereas a critical synthesis of mechanisms, clinical efficacy, safety, and public health perspectives is still lacking. Methods: This narrative review synthesized peer-reviewed publications from 2000 to 2025 retrieved from PubMed, Scopus, Web of Science, and leading dental journals. Emphasis was placed on randomized controlled trials, systematic reviews, meta-analyses, and major policy documents. Evidence was thematically appraised across mechanisms of action, clinical applications, comparative efficacy, safety, and sociocultural considerations. Results: Fluoride consistently shows preventive and therapeutic benefits across multiple delivery forms, including toothpaste, varnishes, mouthrinses, supplements, and silver diamine fluoride, with particular advantages for high-risk groups such as children, orthodontic patients, and older adults. Nonetheless, study heterogeneity, variations in protocols, and concerns regarding fluorosis and possible neurodevelopmental effects highlight persistent uncertainties. Comparative analyses reveal trade-offs between efficacy and acceptance, for example, the high caries-arrest rate of silver diamine fluoride compared with its esthetic drawback. Emerging alternatives such as nano-hydroxyapatite, fluoride-containing bioactive glass, and probiotic-based approaches are promising but currently supported by limited clinical data. Conclusions: Fluoride remains central to caries prevention, yet its optimal use requires balancing benefits against risks, addressing cultural and socioeconomic barriers, and tailoring strategies to individual and community contexts. This narrative synthesis underscores the need for well-designed multicenter randomized controlled trials, longitudinal studies to refine safe exposure thresholds, evaluations of novel biomaterials and delivery systems, and the incorporation of patient-reported outcomes to guide future evidence-based policies and clinical practices.