Which periodontal ligament process is associated with continuous incisor eruption in rats?

• A. PDL remodeling
• B. PDL calcification
• C. PDL inflammation
• D. PDL resorption only

Answer: (A)

Continuous eruption of rat incisors depends on how the periodontal ligament can remodel as the tooth moves through the jaw. In rodents, these incisors grow throughout life and wear at the tips, so the tooth must advance coronally while staying attached. The PDL remodels by reorganizing its collagen fibers and coordinating bone turnover around the tooth: bone resorption occurs where the tooth pushes against the socket and new bone forms where space is needed, allowing gradual eruption. If the PDL were to calcify, stiffen, or simply resorb without coordinated remodeling, the tooth wouldn’t move properly or maintain attachment. Inflammation would disrupt normal function rather than drive normal eruption. So remodeling of the PDL best explains continuous incisor eruption in rats.