Dental enamel and dentinal tubules

Dental enamel is the highly mineralized, acellular outer layer of the tooth crown, composed primarily of hydroxyapatite crystals arranged in a complex prismatic structure (StatPearls, 2023). Its primary biological function is to provide a durable, protective shield for the sensitive internal components of the tooth against mechanical wear, thermal changes, and bacterial acid attack. Beneath the enamel lies the dentin, which contains thousands of microscopic dentinal tubules that extend from the dental pulp to the enamel-dentin junction (PubMed, 2021). When enamel is lost through erosion or attrition, or when gingival recession occurs, these tubules become exposed to the oral environment. According to the hydrodynamic theory, this exposure allows external stimuli to trigger fluid movement within the tubules, which activates pulpal nerve fibers and results in dentin hypersensitivity (NIH, 2022). Pharmacological treatments target these structures by either promoting the remineralization of the enamel matrix using fluoride ions or by physically occluding the exposed tubule orifices with agents like calcium sodium phosphosilicate or arginine to block sensory transmission (Journal of Dentistry, 2019).

Other names

Tooth enamelEnamelumDentinal canaliculiExposed dentinHydroxyapatite matrix

Therapeutic agents act by physically occluding exposed dentinal tubules to block fluid movement and sensory transmission, promoting the remineralization of the hydroxyapatite matrix through ion exchange (e.g., forming acid-resistant fluorapatite), or by using potassium ions to depolarize and desensitize pulpal nerve endings.