Dentinal tubules and hydroxyapatite (None)

Dentinal tubules and hydroxyapatite constitute the primary structural and functional unit of the tooth's dentin layer. Hydroxyapatite is a crystalline calcium phosphate mineral that provides hardness and mineral density to the tooth, while dentinal tubules are microscopic channels that house odontoblastic processes and fluid, connecting the dental pulp to the enamel-dentin junction (NIH, 2023). In clinical dentistry, this complex is a major therapeutic target for treating dentin hypersensitivity and dental caries. When enamel is lost or gingiva recedes, exposed tubules allow external stimuli to cause fluid shifts that trigger pain via the hydrodynamic mechanism (StatPearls, 2023). Drugs and dental materials interact with this target by either occluding the tubule orifices to prevent fluid movement or by promoting the deposition of new hydroxyapatite crystals to remineralize the tooth surface. Common agents include stannous fluoride, which forms a protective layer, and bioactive glasses like NovaMin that release calcium and phosphate ions to facilitate mineral growth (PubMed, 2022).

Other names

Dentin-pulp complexCalcium hydroxyapatiteDentinal canaliculiTooth mineral matrix

Therapeutic agents target this complex through two primary mechanisms: physical occlusion of the dentinal tubules to block fluid movement (hydrodynamic theory) and chemical remineralization of the hydroxyapatite matrix to restore structural integrity. Potassium-based agents also act by depolarizing intradental nerves to reduce sensitivity.