Which term describes the phenomenon when serum displacement through tubules stimulates odontoblasts and nerves?

• A. Pulpal hypersensitivity
• B. Pulpal inflammation
• C. Dentinogenesis
• D. Reparative dentin formation

Answer: (A)

The main idea is the hydrodynamic theory of dentin hypersensitivity. When dentinal fluid moves inside the tubules—such as serum displaced by a stimulus—it exerts a mechanical force on the odontoblasts and the nearby nerve endings in the pulp. That mechanical stimulus triggers nerve firing, producing the sharp, transient pain we describe as pulpal (or dentin) hypersensitivity. So the phenomenon described fits this pain response caused by fluid movement in dentin.

Other options describe different processes: inflammation involves immune mediators and infection, dentinogenesis is the formation of new dentin, and reparative dentin formation is the deposition of tertiary dentin in response to injury. They don’t capture the immediate neural response to hydrodynamic fluid flow.