What clinical sign is indicative of advanced periodontal disease?

Pocket formation around teeth is a significant clinical sign of advanced periodontal disease. In this condition, as the disease progresses, the supporting structures of the teeth, including the gums, become compromised. This leads to the formation of periodontal pockets, which are spaces that develop between the teeth and the gums as a result of the loss of attachment of the periodontal ligaments and bone. The depth and presence of these pockets are indicators of the severity of periodontal disease and can help in assessing the overall periodontal health of a patient.

Other signs may exist, such as swelling of the gums, halitosis (bad breath), and tooth discoloration, but pocket formation is unique in its association with the loss of attachment and is closely linked to the severity of periodontal disease. In contrast, swelling might happen in earlier stages or as a response to inflammation, halitosis could arise from various oral hygiene issues, and tooth discoloration may not necessarily indicate periodontal disease specifically. Hence, pocket formation is the most definitive indicator of advanced periodontal disease.