Dentin is primarily composed of inorganic hydroxyapatite, organic matter (mainly collagen), and water.
Detailed Composition of Dentin
Dentin's chemical composition can be broken down into the following components:
-
Inorganic Component (Approximately 70% by weight):
- Hydroxyapatite: The main inorganic component is hydroxyapatite, a crystalline form of calcium phosphate. Its chemical formula is Ca10(PO4)6(OH)2. This provides dentin with its hardness and rigidity.
-
Organic Component (Approximately 20% by weight):
- Collagen: Primarily Type I collagen constitutes the major organic matrix. This collagen provides the framework upon which hydroxyapatite crystals are deposited.
- Non-Collagenous Proteins: Various other proteins, including proteoglycans, glycoproteins (like dentin sialoprotein and dentin phosphoprotein), and growth factors, are present in smaller quantities and play essential roles in dentin formation and mineralization.
-
Water (Approximately 10% by weight):
- Water is present within the dentinal tubules and the organic matrix, contributing to the overall structure and function of dentin.
Table Summarizing Dentin Composition
| Component | Percentage (by weight) |
|---|---|
| Inorganic (Hydroxyapatite) | ~70% |
| Organic (Collagen, etc.) | ~20% |
| Water | ~10% |
In summary, dentin's composition reflects a highly organized arrangement of mineral and organic components, resulting in a tissue that is both hard and slightly elastic, providing support for the enamel.
