At what probing depth is periodontal disease typically indicated?

Periodontal disease is typically indicated at probing depths greater than 3 mm because this depth signifies a loss of attachment, which is a key indicator of periodontal disease progression. The probing depth reflects the health of the periodontal tissues; deeper measurements suggest the presence of periodontal pockets, which develop as periodontal tissues are affected by inflammation and destruction. Specifically, when probing depths exceed 3 mm, it is often associated with both clinical attachment loss and the presence of disease, indicating that there may be a significant alteration in the supporting structures of the tooth.

In contrast, probing depths less than 3 mm are generally considered to be within the normal range for healthy periodontal tissues, suggesting a lack of disease. Probing depths of 1-3 mm typically indicate a healthy attachment level, while a depth of 4 mm or greater reinforces the need for further diagnosis and intervention, but the critical threshold for establishing a diagnosis of periodontal disease is above 3 mm.