Hydroxyapatite (in demineralized dental enamel) (HA (hydroxyapatite))

Hydroxyapatite is the main mineral component of tooth enamel, consisting of crystalline calcium phosphate (Ca₁₀(PO₄)₆(OH)₂), which comprises roughly 95–98% of enamel by weight. Demineralized enamel hydroxyapatite refers to hydroxyapatite whose crystalline structure has been partially dissolved by exposure to acid, leading to loss of calcium and phosphate ions which weakens the enamel and increases susceptibility to dental caries. While not a receptor or protein, demineralized enamel hydroxyapatite is the substrate targeted by remineralizing agents such as fluoride and synthetic hydroxyapatite, which help restore mineral content and improve enamel resistance to acid. Hydroxyapatite is highly biocompatible, and synthetic forms are used in dentistry to aid in mineral repair, reduce sensitivity, and prevent caries.

Other names

Enamel hydroxyapatitedental hydroxyapatitebiological hydroxyapatitecarbonated hydroxyapatite

Not applicable as a canonical target; however, topical agents act by remineralizing hydroxyapatite crystals or substituting ions (e.g., fluoride converts hydroxyapatite to fluorapatite for acid resistance)