38% Silver Diamine Fluoride in Caries Management: Chemical, Histological, and Clinical Perspectives

Abstract

Dental caries remains a pervasive global public health challenge, disproportionately affecting pediatric, geriatric, and medically compromised populations. Traditional restorative paradigms, while effective, often present financial, behavioral, and biological burdens that limit their universal application. Over the past several decades, 38% Silver Diamine Fluoride (SDF) has re-emerged as a highly effective, non-invasive chemotherapeutic agent capable of arresting active dental caries and mitigating dentin hypersensitivity. This comprehensive review elucidates the multifaceted mechanisms of action underlying SDF therapy, synthesizing recent chemical, microbiological, histological, and clinical evidence. Chemically, SDF reacts with human dental hydroxyapatite to yield silver chloride and calcium fluoride, which subsequently transform into fluorohydroxyapatite. This increases the mineral density of the tooth structure and enhances its resistance to subsequent acid challenges. Concurrently, the silver ions exert potent, sustained antimicrobial activity against cariogenic biofilms by disrupting bacterial cell walls, inhibiting key metabolic enzymes, interfering with DNA replication, and establishing a persistent biocidal reservoir known as the "zombie effect." Histologically, SDF facilitates the occlusion of exposed dentin tubules, safeguarding vital dental pulp and stimulating the formation of tertiary reactionary dentin without inducing irreversible pulpal inflammation when applied appropriately. Clinically, robust evidence demonstrates that periodic SDF applications achieve high caries arrest rates in both primary coronal surfaces and root surfaces of community-dwelling older adults. Despite challenges related to the characteristic black staining of arrested lesions and associated aesthetic concerns, its ease of application, cost-effectiveness, and minimal discomfort render it a pivotal tool for public health initiatives and specialized protocols, such as those tailored for underserved populations. This article provides a definitive exploration of the chemical kinetics, structural transformations, microstructural interactions, and clinical parameters necessary to optimize SDF protocols in contemporary dentistry.