A 20-year-old presents with severe pain on chewing in the lower molar region. There is no caries, oral hygiene is good, and the radiograph is unchanged. A bridge was cemented three days ago. What is the diagnosis?

Correct answer: A. Acute apical periodontitis

• A. CORRECT. ACUTE APICAL PERIODONTITIS from occlusal TRAUMA. A restoration cemented in hyperocclusion delivers repeated excessive force through the tooth to the periodontal ligament, which becomes inflamed. The signature is pain that is well localised and specifically provoked by BITING and PERCUSSION, in a tooth that is otherwise sound. Radiographs are typically NORMAL early on, because it takes weeks for periapical bone change to become radiographically apparent. Treatment is simple: identify and relieve the premature contact with articulating paper in centric and excursions.
• B. Pulp necrosis gives no response to vitality testing and, once apical pathology develops, an apical radiolucency. The recent bridge and normal radiograph point to a mechanical, not pulpal, aetiology.
• C. Irreversible pulpitis produces SPONTANEOUS, lingering, often poorly localised throbbing pain, frequently worse when lying down and often referred to another arch. The stem describes pain only on function.
• D. Reversible pulpitis produces a sharp pain provoked by COLD or sweet that stops as soon as the stimulus is removed. It is not primarily a biting pain.

Note: Check occlusion on EVERY newly cemented restoration in maximum intercuspation AND in lateral and protrusive excursions. Persistent post-cementation biting pain after occlusal adjustment should raise the possibility of cracked tooth syndrome or a cemented-over pre-existing pulpal problem.