The disease processes themselves: how caries progresses through enamel and dentine to the pulp, how periodontal disease destroys supporting structures, and which risk factors raise suspicion of something more serious. Expect questions that give you symptoms and ask you to place them on a progression.
What oral disease covers in the Knowledge Test
- Caries from early demineralisation through to pulpal involvement and abscess
- Gingivitis, periodontitis and the signs that separate them
- Plaque, calculus and biofilm
- Oral cancer risk factors and the features that warrant referral
- How disease presents differently at different stages
Where candidates lose marks
Assuming no pain means no disease. Caries can reach dentine silently.
Treating bleeding gums as normal rather than as a sign requiring action.
Missing that tobacco and alcohol together carry more weight than either alone.
How caries progresses
Questions in this area usually give you a symptom and ask you to place it on the progression. The sequence runs enamel demineralisation, enamel caries, dentine caries, pulpitis, pulp necrosis, then periapical infection or abscess. Pain is an unreliable guide: a lesion can reach dentine with no symptoms at all.
| Symptom | Likely stage |
|---|---|
| Sensitivity to sweet, no cavity visible | Early enamel demineralisation |
| Sharp pain to cold, settles quickly | Dentine involvement, pulp not inflamed |
| Lingering pain after the stimulus goes | Irreversible pulpitis |
| Pain on biting, tender to touch, swelling | Periapical infection |
| No pain at all, visible cavitation | Can still be advanced — pain is not a reliable guide |
Periodontal disease
Gingivitis is inflammation confined to the gingivae and is reversible. Periodontitis involves loss of attachment and supporting bone, and that loss is not reversible. Bleeding on probing is the sign candidates most often dismiss as normal — in an exam it is never normal.
Oral cancer risk
Tobacco and alcohol are the major modifiable risk factors, and together their effect is greater than either alone. A persistent lesion of more than three weeks in a patient with that history warrants urgent referral. Questions here test whether you weigh a genuine risk factor above an incidental detail such as a recent change of toothpaste.
Worked examples
Real questions from our bank, with the reasoning. No sign-in needed.
A patient reports sharp pain to cold that stops as soon as the stimulus is removed, with no spontaneous pain. What is most likely?
- APulp necrosis
- BDentine caries without pulpal involvementCorrect
- CPeriapical abscess
- DEnamel caries only
Why: Sharp pain that stops with the stimulus indicates dentine involvement without inflammation of the pulp. Lingering pain would suggest irreversible pulpitis.
Both free mocks draw from this topic in the same proportion as the real paper — 65 questions in 90 minutes, with an explanation for every answer and a per-topic breakdown at the end.
Start a free mock examOral disease questions, answered
Can caries reach dentine without causing pain?
Yes. Progression can be slow enough that the pulp is not yet involved, so a patient may have no symptoms while a lesion is well established. Absence of pain does not mean absence of disease.
What is the difference between gingivitis and periodontitis?
Gingivitis is inflammation of the gingivae with no loss of attachment, and it is reversible with improved plaque control. Periodontitis involves irreversible loss of periodontal attachment and alveolar bone.
How long should a mouth ulcer last before referral?
A lesion persisting beyond three weeks warrants referral, particularly where risk factors such as tobacco or heavy alcohol use are present.
Which risk factors matter most for oral cancer?
Tobacco use and heavy alcohol consumption, and their combination carries more risk than either individually. Other factors include HPV and, for lip cancer, sun exposure.
Is bleeding when brushing normal?
No. It is a sign of gingival inflammation and should be investigated rather than accepted, however common patients believe it to be.
The other nine topics
Independent study material, not affiliated with or endorsed by NEBDN. Always check the official NEBDN website for the current syllabus. NEBDN does not publish a pass mark for the Knowledge Test.