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Progressive Trismus Investigation — ORE Part 1 MCQ

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HardOral MedicineProgressive Trismus InvestigationORE Part 1

A 60-year-old woman presents with progressive difficulty opening her mouth over several months. She has no pain. Maximum interincisal opening is 22 mm. There is no history of trauma, infection or previous surgery, and she does not chew betel nut. Examination shows bilateral woody-hard restriction of mandibular opening. Following referral for specialist assessment, which investigation is most appropriate?

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Correct answer: B — Cross-sectional imaging of the jaws and TMJs

The answer is B. Progressive limitation of mouth opening is not an age-related finding and requires specialist investigation. The painless, bilateral, firm restriction raises concern for structural or fibrotic pathology rather than uncomplicated pain-related temporomandibular disorder. Cross-sectional imaging is required to assess the TMJs and adjacent bony structures; CT is particularly useful if ankylosis or coronoid hyperplasia is suspected, while MRI assesses intra-articular soft tissues. An OPG alone is insufficient because it may miss coronoid pathology and does not adequately assess the joint. Rheumatoid factor alone neither evaluates mechanical causes nor excludes connective-tissue disease. Reassurance would fail to investigate progressive trismus. Masseter biopsy is invasive and is not an appropriate first investigation before imaging and specialist assessment.

Reference: Scottish Dental Clinical Effectiveness Programme. Oral Health Assessment and Review, section 4.1 Assessment of the Head and Neck, May 2012. https://www.sdcep.org.uk/media/sy2ldxp2/sdcep-ohar-version-1-0.pdf