Dentine

Dentine is the main supporting structure of the tooth and is the second hardest tissue in the body after enamel. It is 70% mineral and acellular, as hydroxyapatite crystals, and 30% organic as water, collagen and mucopolysaccharide. The main structure is the dentinal tubule, which extends from the external surface to the pulp. There are approximately 30,000 - 40,000 tubules per square millimetre, which can transmit pain to the pulp if the dentine is exposed.

Dentine Types

• Primary dentine forms before tooth eruption.
• Secondary dentine forms after eruption, as the tooth develops with age. It develops from the odontoblasts living within the pulp and is laid down in layers within the pulp cavity.
• Reparative or tertiary dentine forms as a result of trauma to the odontoblasts; this can be thermal, chemical, bacterial or mechanical. Tertiary dentine has few tubules and is darker in colour and very dense in structure.