MJDF Cheat Sheet 2026

The 30 highest-yield MJDF facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which investigation is the gold standard for diagnosing oral potentially malignant disorders (OPMDs)? → Incisional biopsy with histological examination (grading of dysplasia)
2. What systemic disease is associated with multiple periapical radiolucencies without obvious dental causes? → Multiple myeloma
3. A patient presents with irreversible pulpitis. Which of the following best describes the appropriate clinical management? → Perform pulp extirpation (root canal treatment initiation) or extraction
4. How many cusps does a mandibular first molar typically have? → Five (three buccal, two lingual)
5. Which cells are responsible for enamel formation? → Ameloblasts
6. Which impression material records the finest surface detail? → Addition silicone (polyvinylsiloxane, PVS)
7. The normal values for overjet and overbite in Class I occlusion are approximately: → Overjet 2–4 mm, Overbite 2–4 mm
8. What is the most common site for oral cancer in the UK? → Lateral border of the tongue
9. Which antibiotic is specifically contraindicated in children under 12 due to dental staining? → Tetracycline and doxycycline
10. What is the primary function of the periodontal ligament (PDL)? → Suspend the tooth in the alveolus, transmit occlusal forces, and provide sensory feedback
11. Which group of patients requires special caution when administering adrenaline-containing local anaesthetic? → Patients taking non-selective beta-blockers (risk of hypertensive crisis)
12. What is the normal ANB angle in a balanced skeletal relationship as measured on a lateral cephalogram? → 2–4°
13. What is the mechanism of action of NSAIDs in dental pain management? → Inhibit COX-1 and COX-2, reducing prostaglandin synthesis at the site of inflammation
14. Which force type is considered optimal for efficient orthodontic tooth movement with minimal tissue damage? → Light continuous force
15. Which of the following clinical features is most characteristic of a true Skeletal Class III malocclusion? → A concave facial profile and a Class III incisor relationship.
16. What is the most common oral manifestation of HIV infection? → Pseudomembranous candidiasis (oral thrush) and linear gingival erythema
17. Ghost images on a panoramic radiograph are caused by: → The contra-lateral X-ray beam creating a mirror image of structures on the opposite side
18. What radiographic sign is associated with external root resorption? → Blunting or irregular shortening of the root apex on periapical radiograph
19. What structural feature of cementum allows the PDL fibres to attach to the root? → Sharpey's fibres embedded in cementum during deposition
20. What is the recurrence rate of an odontogenic keratocyst compared to a dentigerous cyst? → OKC has a high recurrence rate (25–60%); dentigerous cyst rarely recurs after enucleation
21. Which topical anaesthetic is most commonly used before intraoral injections in UK dental practice? → Benzocaine or lidocaine (EMLA-type gel) applied for 1–2 minutes before injection
22. What is the nerve supply to the maxillary premolars? → Posterior and middle superior alveolar nerves (branches of V2)
23. What is the biological mechanism by which dentine hypersensitivity is explained by the hydrodynamic theory? → Fluid movement in dentinal tubules triggers mechanoreceptors at the pulp-dentine boundary
24. What is the most common type of bone pathology found on routine dental radiographs in adults over 50? → Condensing osteitis (focal sclerosing osteomyelitis)
25. The radiation protection principle 'ALARP' stands for: → As Low As Reasonably Practicable
26. Sjögren's syndrome is a systemic autoimmune condition affecting exocrine glands. What is the PRIMARY oral manifestation? → Xerostomia (dry mouth) due to destruction of salivary gland tissue
27. Why does local anaesthesia work less effectively in infected tissue? → Acidic pH in infected tissue increases ionisation of LA, reducing membrane penetration
28. What does the Bolton analysis assess in orthodontic treatment planning? → Tooth size discrepancy between the upper and lower dental arches
29. In the context of vital pulp therapy in a mature permanent tooth, which material is currently preferred for direct pulp capping? → Calcium silicate-based materials (e.g., MTA or Biodentine)
30. What is the primary mineralisation sequence of permanent teeth in humans? → First molars → incisors → canines → premolars → second molars → third molars