The main substance in dentin is hydroxyapatite, a mineral form of calcium phosphate.
Dentin, the tissue that makes up the bulk of a tooth, is a complex material composed of both inorganic and organic components. While it contains collagen and other organic materials, the inorganic component, primarily hydroxyapatite, constitutes the largest portion by weight. This mineral gives dentin its characteristic hardness and resistance.
Hydroxyapatite is a crystalline calcium phosphate that closely resembles the mineral found in bone and enamel. It's chemical formula is Ca10(PO4)6(OH)2. In dentin, hydroxyapatite crystals are smaller and less perfect compared to enamel, making dentin slightly softer and more susceptible to acid attack and dental caries (cavities).
Here's a breakdown of the approximate composition of dentin:
- Hydroxyapatite: Approximately 70% by weight
- Collagen (primarily Type I): Approximately 20% by weight
- Water: Approximately 10% by weight
- Other organic materials: (Non-collagenous proteins, lipids, etc.) present in smaller quantities.
Therefore, while collagen plays a crucial role in the structure and elasticity of dentin, hydroxyapatite is undeniably the main and most abundant substance, giving it its mineralized character.
