dentinen

Dentin, also called dentine, is the calcified tissue that forms the bulk of a tooth. It lies beneath the enamel of the crown and the cementum of the root, surrounding and protecting the dental pulp. Dentin provides rigidity and acts as a scaffold for both enamel and root structures.

Dentin is composed of about 70% inorganic mineral content, primarily hydroxyapatite, with around 20% organic matrix (predominantly type I collagen and non-collagenous proteins) and about 10% water. Its microstructure features dentinal tubules, microscopic channels that extend from the pulp to the outer dentin surface. Odontoblasts line the pulp-dentin border and continue to form dentin throughout life, depositing predentin that mineralizes into dentin. Peritubular dentin surrounds the tubules, while intertubular dentin lies between them.

Dentin develops in stages. Primary dentin forms during tooth development before eruption, providing most of the tooth’s shape and strength. After eruption, secondary dentin forms gradually as a lifelong process, reducing the size of the pulp chamber. Tertiary dentin is produced in response to stimuli such as caries, attrition, or trauma and can be reparative or sclerotic. Sclerotic dentin occurs when tubules become mineralized and less permeable, often with aging.

Dentin is more resilient than enamel but permeable to fluids through the tubules, which can convey stimuli to nerves in the pulp. This permeability underlies dentin hypersensitivity and is a focus in restorative dentistry. Clinically, dentin is involved in caries progression, bonding procedures, and remineralization strategies using fluoride and other agents.