Dental Terms
Dental Terms
Dentin in North York
Dentin, also known as dentine, is a vital component of teeth found in various animals, including humans. It constitutes the majority of a tooth's structure and plays a critical role in tooth function. Dentin is distinct from enamel and bone, possessing unique characteristics that make it essential for tooth health and sensitivity.
Key features of dentin include:
- Composition: Dentin is primarily composed of apatite crystals, which contain calcium and phosphate. This mineralized tissue is harder than bone but softer than enamel.
- Odontoblasts: Dentin is not a static material; it contains living cells known as odontoblasts. These specialized cells line the pulp cavity within the tooth. In the case of sharks and rays, they also exist in toothlike scales. Odontoblasts extend long projections into the dentin, enclosed within tiny tubules.
- Sensitivity: The odontoblastic extensions within the dentinal tubules play a crucial role in transmitting sensitivity to stimuli such as pain, pressure, and temperature. These sensations are conveyed to and from the nerve in the pulp chamber, allowing the tooth to respond to external factors.
- Secondary Dentin: Throughout life, secondary dentin is continuously produced. It is a less organized form of tubular dentin and serves as a patching material in areas where cavities have started, where enamel has worn away, or within the pulp chamber as part of the natural aging process.
In nonmammalian vertebrates, such as reptiles and fish, enamel is absent. Instead, the tooth crown is covered by a substance called vitrodentin, which is related to dentin but harder than dentin while still softer than enamel.
Some animals, like flounder and cod, have vasodentin, a type of dentin that lacks tubules and receives nourishment directly from capillaries. Although it is more efficient in terms of nutrition, vasodentin is softer and less resistant to diseases compared to tubular dentin. The toothlike scales found in sharks and related fish are also referred to as dentin.
