Which dentin type is formed after major damage such as pulpal exposure?

Which dentin type is formed after major damage such as pulpal exposure?

• A. Primary dentin
• B. Secondary dentin
• C. Tertiary dentin (reparative dentin)
• D. Sclerotic dentin

Answer: (C)

When dentin forms after tooth development, it does so as primary dentin and then continues as secondary dentin after eruption. However, in response to major damage like pulpal exposure, the pulp reacts by laying down a special, irregular type of dentin known as tertiary dentin, or reparative dentin. This dentin acts as a protective barrier to seal the pulp. It forms when the original odontoblasts are damaged or die, and new odontoblast-like cells differentiate from pulp stem cells to deposit dentin with a different, more irregular tubule pattern. If the stimulus is milder and the original odontoblasts survive, reactionary dentin is produced by the same cells and tends to be more organized than reparative dentin but still different from the normal primary dentin. Sclerotic dentin, in contrast, results from aging or mild stimuli and involves mineral deposits within tubules rather than a response to major injury.

When dentin forms after tooth development, it does so as primary dentin and then continues as secondary dentin after eruption. However, in response to major damage like pulpal exposure, the pulp reacts by laying down a special, irregular type of dentin known as tertiary dentin, or reparative dentin. This dentin acts as a protective barrier to seal the pulp. It forms when the original odontoblasts are damaged or die, and new odontoblast-like cells differentiate from pulp stem cells to deposit dentin with a different, more irregular tubule pattern. If the stimulus is milder and the original odontoblasts survive, reactionary dentin is produced by the same cells and tends to be more organized than reparative dentin but still different from the normal primary dentin. Sclerotic dentin, in contrast, results from aging or mild stimuli and involves mineral deposits within tubules rather than a response to major injury.