The preventive side, where dental nurses often lead. Questions cover fluoride, the role of sugar frequency rather than quantity, and how to give advice a patient will actually follow.
What prevention covers in the Knowledge Test
- How fluoride works and who benefits
- Sugar frequency and the acid attack cycle
- Toothbrushing technique and interdental cleaning
- Erosion, and why brushing straight after acid is poor advice
- Smoking cessation and alcohol advice
- Delivering oral hygiene instruction effectively
Where candidates lose marks
Focusing on how much sugar rather than how often — frequency drives caries risk.
Recommending immediate brushing after acidic drinks.
Treating fluoride as only relevant to children.
Fluoride, by age
Delivering Better Oral Health is the national toolkit this advice comes from, and its recommendations are specific about amount as well as concentration. The amount on the brush is as examinable as the strength of the paste.
| Age | Amount | Fluoride concentration |
|---|---|---|
| Under 3 | A smear | No less than 1,000 ppm |
| 3 to 6 | A pea-sized amount | No less than 1,000 ppm |
| 0 to 6, giving concern | Smear or pea by age | 1,350–1,500 ppm |
| 7 and over | Normal amount | 1,350–1,500 ppm |
Frequency, not quantity
The single most misunderstood point in this topic. Caries risk is driven by how often sugar is consumed rather than how much, because each exposure starts an acid attack that takes time to recover from. A patient sipping a sugary drink through the afternoon is at higher risk than one who has the same amount with a meal. Questions are frequently built on exactly this distinction.
Erosion and the timing of brushing
After acidic food or drink the enamel surface is temporarily softened, so brushing immediately can increase wear. The advice is to rinse with water and delay brushing. 'Brush harder straight afterwards' is a distractor that appears often and is always wrong.
Giving advice that lands
Oral health education is part of a dental nurse's role, and questions test method as well as content: explain clearly, invite questions, check understanding, and agree something achievable. Handing over a leaflet is not oral health education.
Worked examples
Real questions from our bank, with the reasoning. No sign-in needed.
A patient says they brush immediately after fizzy drinks to protect their teeth. What is the best advice?
- AKeep doing it, but brush harder
- BRinse with water and delay brushingCorrect
- CStop brushing on days they drink fizzy drinks
- DUse mouthwash instead of brushing
Why: Acid softens the enamel surface temporarily. Rinsing and delaying avoids brushing away softened enamel, without abandoning normal brushing.
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 examPrevention questions, answered
How much toothpaste should a child under three use?
A smear, with a paste of no less than 1,000 ppm fluoride. Children aged three to six should use a pea-sized amount. Where a child aged 0–6 gives concern, Delivering Better Oral Health recommends 1,350–1,500 ppm.
Is it the amount of sugar or how often that matters?
Frequency. Each exposure triggers an acid attack, so repeated small amounts through the day cause more damage than the same quantity taken at once with a meal.
Should you brush straight after an acidic drink?
No. The enamel surface is temporarily softened, so immediate brushing can increase wear. Rinse with water and delay brushing.
Do adults benefit from fluoride?
Yes. Fluoride is not only for children — it helps at every age, and adults with dry mouth, exposed root surfaces or high caries risk may benefit particularly.
Should you rinse after brushing?
No — spit, don't rinse. Rinsing washes away the fluoride that would otherwise stay in contact with the teeth.
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.