Patient with Class II mobility on tooth #28, 9 mm probing depth, pain on biting, suppuration, bleeding, swollen gingiva, heavy plaque. Diagnosis:

Correct answer: A. Periodontal abscess

• A. Correct. The combination of deep probing depth, mobility, suppuration, pain on biting, and heavy plaque/bleeding is classic for a periodontal abscess originating from a pre-existing periodontal pocket.
• B. A periapical (endodontic) abscess would typically not show this degree of deep periodontal probing depth associated with the pulpal source; it's centered at the apex.
• C. Pericoronitis involves inflammation around a partially erupted tooth (commonly third molars), not this presentation pattern centered on an existing periodontal pocket.
• D. A gingival abscess is typically a more localized, superficial process not associated with deep probing depths or mobility.