Clinical Diagnosis of Oral and Maxillofacial Disease
The clinical reasoning frame
Clinical diagnosis questions reward a disciplined sequence: history, extraoral examination, intraoral examination, then targeted special tests. Know the vocabulary that separates symptom (patient-reported) from sign (clinician-observed), and primary from secondary lesions. Candidates must be fluent in describing lesions by size, shape, color, surface texture, border, base, and consistency, and in the standard terms: macule, papule, plaque, nodule, vesicle, bulla, pustule, ulcer, erosion, fissure, and petechia.
History that changes the answer
Duration, progression, recurrence, and provocation are high-yield. Ask about tobacco, alcohol, areca nut, medications, and systemic disease. Painless, indurated, non-healing ulceration is the classic red flag for malignancy; painful, recurrent, prodromal tingling vesicles suggest herpes simplex. Bilateral or recurrent parotid swelling provoked by meals points to obstructive sialadenitis; xerostomia with parotid enlargement suggests Sjögren syndrome.
Special tests
Know when to use aspiration, incisional versus excisional biopsy, exfoliative cytology, vital staining, pulp testing, transillumination, and imaging. A common trap: choosing excisional biopsy for a suspected malignancy. Incisional biopsy is preferred for large or suspicious lesions; excisional biopsy suits small, benign, well-circumscribed lesions. Another trap: treating a pigmented lesion with observation when the history describes recent change, irregular border, or satellite lesions.
Worked rule of thumb
For any ulcer, run the DIMS check: Duration over two weeks, Induration on palpation, Margins that are rolled or everted, and Size increasing. Any positive feature triggers biopsy referral rather than topical therapy.
Traps to expect
Questions often present a lesion that looks inflammatory but has a systemic cause (e.g., recurrent aphthae in Crohn disease), or a red herring of a recent dental procedure. Read the whole stem before selecting; the discriminating detail is usually the last clause.