During eruption, which tissue remodeling occurs to facilitate tooth movement?

• A. PDL
• B. Enamel
• C. Dentin
• D. Pulp

Answer: (A)

Movement of the tooth during eruption is made possible by remodeling of the periodontal ligament and the surrounding alveolar bone. The periodontal ligament is a dynamic connective tissue that connects cementum to the bone and contains cells that remodel tissue—osteoclasts resorb bone on the direction of movement and osteoblasts lay down new bone behind the advancing tooth. The fibers of the PDL reorganize to accommodate the new position, allowing the tooth to move through the jawbone without damage. Enamel, dentin, and pulp don’t drive this eruptive mobility; enamel is mineralized and stable, dentin and pulp don’t remodel in a way that facilitates eruption.