Stage 4 periodontal disease is defined by what level of attachment loss?

• A. 0-10%
• B. 10-25%
• C. >50%
• D. 25-50%

Answer: (C)

Stage 4 periodontal disease represents severe destruction of the periodontal support, indicated by attachment loss greater than 50% of the tooth’s root. Attachment loss is the loss of the connective tissue attachment from the cementoenamel junction to the base of the pocket, reflecting erosion of the gingiva, periodontal ligament, cementum, and supporting bone. Clinically this shows up as marked tooth mobility, drift or extrusion, possible furcation involvement on multi-rooted teeth, and substantial bone loss on radiographs. Prognosis is poor and treatment often requires extraction or extensive rehabilitation. That’s why the defining level for stage 4 is >50% attachment loss.