The positive or negative displacement of serum fluid through exposed tubules (with enamel removal) affects odontoblasts and pulpal nerve ending called

• A. Pulpal inflammation
• B. Pulpal hypersensitivity
• C. Dentinogenesis
• D. Dental erosion

Answer: (B)

Movement of dentinal fluid within exposed tubules drives the sensation of pain in dentin hypersensitivity. When enamel is lost and dentin is exposed, stimuli cause positive or negative displacement of serum-like fluid in the tubules. This fluid movement deforms the odontoblastic processes and activates the nerve endings in the pulp, producing a sharp, short pain typical of hypersensitivity. The other terms describe different processes: pulpal inflammation involves inflammatory mediators, dentinogenesis is dentin formation, and dental erosion refers to chemical wear of enamel and dentin, not the nerve-pulp response to tubule fluid movement.