Resin-containing Ca(OH)2 stimulates formation of which type of dentin?

• A. primary dentin
• B. dead tract dentin
• C. sclerotic dentin
• D. reparative dentin

Answer: (D)

When the pulp is irritated by a resin-containing calcium hydroxide material, the pulp responds by forming reparative dentin, a type of tertiary dentin. If odontoblasts are damaged, pulp stem cells differentiate into odontoblast-like cells and lay down dentin matrix at the pulp–dentin border, creating a dentin bridge that helps protect the pulp. This is the tissue's specialized defense to injury or irritation from the material.

Primary dentin is the dentin that forms during tooth development and isn’t produced as a response to irritation. Dead tract dentin consists of empty tubules after odontoblasts have died and is not newly formed tissue. Sclerotic dentin is a change associated with aging, where tubules become occluded with mineral, not a product of a pulpal healing response to a caustic material.