Human Enamel Formation: A Scoping Review for Oral Health Professionals

Background: Tooth enamel is the hardest and most highly mineralized tissue in the human body. It serves as a protective barrier against chemical, mechanical, and microbial challenges. Despite its durability, enamel remains vulnerable to developmental and posteruptive defects such as fluorosis, hypomineralization, and amelogenesis imperfecta (AI). For oral health professionals, a clear understanding of the biological and molecular mechanisms underlying enamel formation is essential for advancing preventive and therapeutic strategies in clinical practice. This review synthesizes current knowledge on enamel formation, with emphasis on its cellular, molecular, and structural determinants, and discusses clinically relevant disruptions as well as emerging biomimetic approaches. Methods: This scoping review was conducted according to the PRISMA-ScR guidelines. A systematic literature search of the mechanisms of enamel formation was performed via Embase and Medline. Titles and abstracts were screened independently by three authors. Studies that primarily addressed enamel defects were excluded from the systematic synthesis; however, these studies were retained for narrative discussion. Following the screening process, 92 publications met the inclusion criteria and were incorporated into the thematic synthesis. Results: Enamel formation is a complex, multistage process involving epithelial-mesenchymal interactions and the sequential activity of ameloblasts during presecretory, secretory, transition, and maturation stages. Key mechanisms include the secretion of enamel matrix proteins (e.g., amelogenin, ameloblastin, and enamelin), proteolytic processing by enzymes such as MMP20 and KLK4, and controlled ion transport, leading to hydroxyapatite crystal growth and organization into rod and interrod structures. The structural arrangement endows enamel with exceptional mechanical resistance. Narrative sections address "What can go wrong?", summarizing genetic, epigenetic, and environmental causes of fluorosis, hypomineralization, and amelogenesis imperfecta, and other developmental defects, whereas "What can we learn from nature?" highlights biomimetic strategies. Conclusions: Human enamel formation is a highly coordinated biomineralization process regulated at the cellular, structural, and molecular levels. Disruptions in these processes underlie major enamel pathologies. Integrating mechanistic insights from natural enamel development with emerging biomimetic technologies offers promising avenues for prevention, diagnosis, and treatment in dentistry. This review provides oral health professionals with a biologically grounded framework to guide evidence-based management of enamel-related conditions.