dentins

Dentin, also called dentine, is a mineralized connective tissue that makes up the bulk of a tooth, lying beneath the enamel and surrounding the dental pulp. It provides a rigid, resilient scaffold that supports enamel and transmits sensory stimuli from the exterior to the pulp.

Dentin consists of about 70% inorganic hydroxyapatite, 20% organic matrix (primarily collagen type I), and 10% water. It contains dentinal tubules, microscopic channels that extend from the pulp to the dentinoenamel junction, with odontoblastic processes in the tubules surrounded by peritubular dentin. Intertubular dentin forms the main body between the tubules.

Dentinogenesis begins when odontoblasts secrete predentin, which mineralizes to become dentin. Primary dentin forms during tooth development before eruption; secondary dentin forms gradually after eruption; tertiary dentin (reparative or reactive) forms in response to local injury or stimuli.

Dentin is more mineralized than bone but less than enamel, and is relatively elastic. Its tubules allow fluid movement, which can convey stimuli leading to dentin hypersensitivity. The permeability also influences bonding during restorative procedures, and clinicians must manage exposed dentin after caries removal or trauma.

Dentin has no vasculature or nerves of its own; nourishment and sensory input come from the dental pulp. Remineralization and desensitization strategies, such as fluoride or dentin bonding agents, can modify tubule permeability and sensitivity.