Oral Surgery · single question
Which nerve is at highest risk of injury during extraction of a mandibular third molar when the apex is in close proximity to the inferior alveolar canal?
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Correct answer: B. Inferior alveolar nerve
The inferior alveolar nerve (IAN) is the nerve most at risk during mandibular third molar extraction when the tooth's roots are in close contact with or wrap around the inferior alveolar canal. This can result in paresthesia or permanent numbness of the lower lip, chin, and teeth. The lingual nerve is also at risk (especially during retraction or lingual split technique), but the IAN is the primary concern when radiographic proximity to the canal is noted.
- A. ❌ The lingual nerve is at risk during soft-tissue retraction (lingual split technique) but not specifically from root-canal proximity seen on radiograph.
- B. ✅ CORRECT – The IAN is most at risk when roots of the lower third molar are closely associated with the inferior alveolar canal on radiograph.
- C. ❌ The facial nerve is not in the operative field for mandibular third molar extraction.
- D. ❌ The long buccal nerve supplies buccal soft tissue and is not at risk from third molar roots near the canal.