If the periodontal ligament is lost, what can happen to the tooth?

When the periodontal ligament is lost, the tooth can become ankylosed within the socket. The periodontal ligament is crucial for maintaining the tooth's position in the alveolar bone and for providing support during activities such as chewing. When integrity of this ligament is compromised, typically due to periodontal disease or trauma, the tooth may lose its ability to properly connect to the surrounding bone.

Ankylosis occurs when the tooth root becomes fused directly to the alveolar bone, which leads to a rigid anchoring of the tooth within the socket rather than the normal, flexible attachment. This fusion limits the tooth's mobility and alters its response to forces applied during functional activities, such as biting and chewing. Because of this direct connection, the tooth may exhibit changes in sensory input as well as become more difficult to extract in the future.

This is the relevant consequence of losing the periodontal ligament among the choices provided, illustrating how critical this ligament's integrity is to dental health and tooth stability.