Hydroxyapatite (Enamel and dentin mineral matrix) (HAP)

Hydroxyapatite is the primary inorganic constituent of human teeth, comprising approximately 96% of dental enamel and 70% of dentin by weight (NIH: PMC4252862). It is a crystalline form of calcium phosphate that provides the essential hardness and structural integrity required for mastication and the protection of the underlying dental pulp (StatPearls: NBK537271). In the oral cavity, this mineral matrix exists in a dynamic equilibrium of demineralization and remineralization, which is heavily influenced by salivary pH and bacterial activity (PubMed: 31857308). When the pH drops below a critical threshold, the mineral dissolves, leading to conditions such as dental caries and acid erosion (NIH: PMC6356944). Therapeutic strategies targeting the hydroxyapatite matrix focus on enhancing its chemical stability, such as through the incorporation of fluoride to form acid-resistant fluorapatite (StatPearls: NBK544272). Additionally, the application of biomimetic materials like nano-hydroxyapatite can repair surface defects and restore mineral density (PubMed: 31857308). These interventions are also critical for managing dentin hypersensitivity by occluding exposed dentinal tubules and blocking external stimuli from reaching the nerve (NIH: PMC3927677).

Other names

Calcium hydroxyapatiteCarbonated hydroxyapatiteDental mineralBio-apatiteDental hydroxyapatite

The primary mechanisms include the promotion of remineralization through ion exchange, such as the substitution of hydroxyl groups with fluoride to form acid-resistant fluorapatite (StatPearls: NBK544272). Additionally, drugs target the matrix by physically occluding exposed dentinal tubules to treat hypersensitivity and by providing a scaffold for biomimetic mineral growth to restore enamel and dentin integrity (PubMed: 31857308, NIH: PMC3927677).