Oral and Maxillofacial Surgery
The OMS section tests surgical judgment rather than memorized procedures: when to operate, how infection and trauma behave anatomically, and how to protect the airway and inferior alveolar nerve. Questions often present a radiograph description, a swelling, or a trauma scenario and ask for the next safest step.
Core rules
- Odontogenic infection follows fascial planes. Floor-of-mouth elevation, tongue displacement, and bilateral submandibular swelling suggest Ludwig angina, an airway emergency requiring urgent drainage and airway control.
- Trismus and dysphagia are red flags for submasseteric, pterygomandibular, or lateral pharyngeal spread, not just 'a big toothache.'
- Third molars are assessed by angulation (Winter) and depth/ramus relationship (Pell-Gregory). Proximity to the inferior alveolar canal on panoramic imaging is an indication for CBCT, not a diagnosis of injury.
- Trauma follows ATLS: airway, bleeding, cervical spine, then fracture diagnosis. Le Fort I is mobile maxilla above the apices; II is pyramidal; III is craniofacial separation.
- MRONJ is staged clinically and radiographically; conservative management dominates unless symptoms progress.
Worked example
A 26-year-old has a horizontally impacted mandibular third molar, Pell-Gregory II B, with roots overlapping the canal on panoramic film. The correct plan is CBCT to map the canal, consent that includes temporary or permanent neurosensory deficit, and consideration of coronectomy if the roots are intimately associated. You do not extract on the basis of the panoramic image alone.
Traps
- Missing lingual space involvement because swelling looks submandibular.
- Treating every asymptomatic impacted third molar as urgent surgery.
- Confusing Le Fort levels or ordering CT before airway assessment.
- Forgetting anticoagulant and bisphosphonate history.