Which feature is indicative of primary trauma from occlusion in periodontal disease?

The choice that indicates primary trauma from occlusion in periodontal disease is vertical interseptal bone loss. In periodontal pathology, vertical bone loss typically occurs as a result of trauma from occlusion, which can lead to localized resorption of bone around teeth. This type of bone loss is often seen when teeth experience excessive occlusal forces due to misalignment, high restorations, or other occlusal discrepancies.

Unlike horizontal bone loss, which may be more associated with plaque-induced periodontal disease, vertical bone loss signifies that the occlusion may be contributing to the breakdown of periodontal support structures. The characteristic appearance of vertical bone loss on radiographs further supports this diagnosis, showing a more angular pattern of bone loss around the roots of teeth compared to the more uniform loss seen with other forms of periodontal disease.

The other options relate to different aspects of periodontal disease but do not specifically signify trauma related to occlusion. Horizontal interseptal bone loss typically arises from chronic inflammation, gingival inflammation with increased fluid flow could indicate active periodontal disease, and generalized narrowing of the periodontal ligament usually points towards other issues such as periodontal inflammation rather than occlusal trauma alone.