A patient presents with oral pain described as appearing to 'relieve' on biting down, then hurting again when the pressure is released. The tooth has prior RCT, a sinus tract from the furcation, and radiolucency in the furcation area. The most likely diagnosis is:

Correct answer: D. Cracked tooth/vertical root fracture

• A. Chronic periodontal abscess follows the PDL pocket — it does not typically cause pain relief on biting.
• B. Periapical abscess from failed RCT would show apical radiolucency and no pain relief on biting.
• C. External cervical resorption appears at the cervical region and typically does not cause the 'relief-on-biting' symptom.
• D. Correct. Pain relief on biting followed by pain on release ('cracker' test) is the hallmark of a cracked tooth or vertical root fracture. Combined with a furcation sinus tract and furcation radiolucency on a root canal-treated tooth, vertical root fracture is the confirmed diagnosis.