In a tooth that is not in use, the periodontal ligament will appear to be:

In a tooth that is not in use, the periodontal ligament typically appears narrow. This phenomenon occurs due to the reduced mechanical stress and stimulation that the ligament normally experiences during activities like chewing or biting. The periodontal ligament is responsible for connecting the cementum of the tooth root to the alveolar bone, and it is sensitive to the forces applied to the tooth.

When a tooth is not used, the lack of functional pressure leads to a decrease in the fluid and cellular components within the ligament. Consequently, the overall width of the ligament decreases, resulting in a narrower appearance on radiographs. This is a physiological response where the body conserves resources by reducing the size of structures that are not actively functioning, and it reflects the adaptability of the periodontal tissues to changes in load and activity.

The other choices, such as wide, inflamed, or atrophied, do not accurately describe the state of the periodontal ligament in an unused tooth. A wide ligament would suggest considerable stress, inflamed ligament indicates a pathological condition, and atrophied could imply significant damage or chronic disuse over a longer period, none of which align with the short-term scenario of a tooth not being utilized.