A patient has sensitivity on tooth #30 that hits hard against the opposing tooth. Percussion is positive. The patient has NO history of bruxism and NO recession. Which is LEAST likely to cause the sensitivity?

Correct answer: C. Bruxism

• A. ❌ Super-eruption (over-eruption without opposing tooth contact below) causing the tooth to 'hit hard' IS a plausible cause.
• B. ❌ Cracked tooth syndrome could cause sensitivity with percussion — it IS plausible.
• C. ✅ Correct (LEAST likely). The case EXPLICITLY STATES the patient has no history of bruxism. Therefore, bruxism is excluded by the case history — it is the LEAST likely cause.
• D. ❌ Apical pathology from occlusal trauma is a likely cause given percussion sensitivity — this IS plausible.