Which structure is associated with delayed eruption of permanent teeth?

Ankylosis is a condition where a tooth becomes fused to the bone, preventing normal eruption. When a tooth is ankylosed, the periodontal ligament is compromised or absent, which normally facilitates the tooth's movement through the bone during the eruption process. As a result, the affected permanent tooth can become trapped in the bone and fails to erupt at the expected time, leading to a delay in the normal dental development sequence.

In contrast, while factors such as root resorption, overcrowding, and jaw alignment can influence the eruption pattern, they do not directly lead to the immobilization of the tooth. Root resorption typically pertains to the roots of deciduous teeth, possibly allowing permanent teeth to come in eventually. Overcrowding can indeed cause eruption delays but generally involves displacement rather than complete fusion. Jaw alignment issues may also affect the position of teeth but do not create a solid bond preventing eruption like ankylosis does. Therefore, ankylosis stands out as the primary condition associated with delayed eruption of permanent teeth.