Which description best characterizes odontoclasts attached to dentin surfaces?

• A. Multinucleated odontoclast with clear attachment zone and ruffled border
• B. Mononucleated osteoclast-like cell
• C. Ameloblast-like cell
• D. Fibroblast

Answer: (A)

Odontoclasts are multinucleated cells that resorb dentin by attaching directly to the mineralized surface. When they contact dentin, they form a resorption lacuna with a clear attachment zone that seals the cell to the dentin, and they develop a ruffled border facing the dentin. The ruffled border increases surface area and houses the enzymes and proton pumps needed to dissolve mineral and organic matrix, enabling effective resorption. This combination—multinucleated fusion, a tight attachment zone, and a ruffled border—is what characterizes odontoclasts on dentin. The other descriptions don’t fit: a single-nucleus cell doesn’t match the multinucleated nature; an ameloblast-like cell is involved in enamel formation; a fibroblast is a general connective tissue cell not specialized for dentin resorption.