Fluoride–enamel hydroxyapatite interface

The fluoride–enamel hydroxyapatite interface is the physicochemical site where fluoride ions interact with hydroxyapatite, the primary mineral component of human tooth enamel (StatPearls, 2023). This interface is a critical therapeutic target in preventative dentistry because the incorporation of fluoride into the crystal lattice results in the formation of fluorapatite, which is significantly more resistant to acid dissolution than pure hydroxyapatite (NIH, 2023). By lowering the critical pH at which enamel begins to demineralize, fluoride effectively protects the tooth structure from decay caused by plaque-derived acids (Buzalaf et al., 2011). Beyond structural reinforcement, the interface facilitates the remineralization of early-stage carious lesions by acting as a scaffold for calcium and phosphate deposition from saliva (CDC, 2021). Fluoride also exerts an antimicrobial effect at this interface by inhibiting bacterial enzymes like enolase, thereby reducing the acid production of oral pathogens (Journal of Dental Research, 2011). Consequently, targeting this interface with topical fluoride treatments is the primary global strategy for managing dental caries and maintaining oral health.

Other names

Fluorapatite interfaceFluoridated hydroxyapatite surfaceEnamel mineral interfaceHydroxyapatite-fluoride boundary

Fluoride ions interact with the hydroxyapatite crystal lattice [Ca10(PO4)6(OH)2] by substituting for hydroxyl groups to form fluorapatite [Ca10(PO4)6F2], which is more resistant to acid dissolution (StatPearls, 2023). It also lowers the solubility product of the enamel surface, promotes the remineralization of incipient lesions by attracting calcium and phosphate ions, and inhibits bacterial enolase enzymes to reduce acid production (Buzalaf et al., 2011).