Enamel hydroxyapatite mineral matrix (HAP) (HAP)

Enamel hydroxyapatite mineral matrix is the hardest substance in the human body and serves as the primary structural component of tooth enamel (StatPearls, 2023). It is composed of crystalline calcium phosphate, specifically hydroxyapatite [Ca10(PO4)6(OH)2], arranged in a complex hierarchical structure of rods and inter-rod substance (PubChem CID 14781). The biological function of this matrix is to provide a durable, wear-resistant surface for chewing while protecting the underlying dentin and dental pulp from chemical, thermal, and bacterial insults (NIH, 2022). In the context of disease, the dissolution of this mineral matrix by organic acids produced by plaque bacteria leads to dental caries, while exposure to dietary acids causes dental erosion (StatPearls, 2023). Therapeutic agents like fluoride target this matrix by promoting the formation of fluorapatite, which has a lower solubility product and greater resistance to acid-induced demineralization (Journal of Dental Research, 2018). Additionally, biomimetic materials such as nano-hydroxyapatite are used to directly remineralize and repair the enamel surface by filling microporosities and restoring mineral density (Journal of Nanobiotechnology, 2019).

Other names

HydroxyapatiteHydroxylapatiteCalcium hydroxyapatiteDental enamel mineralCrystalline calcium phosphateCalcium phosphate tribasic

Fluoride ions substitute for hydroxyl groups in the hydroxyapatite lattice to form fluorapatite, which is more resistant to acid dissolution; additionally, remineralizing agents provide a source of calcium and phosphate to restore the mineral matrix (NIH, 2022; Journal of Dental Research, 2018).