Dental caries, often called tooth decay or cavities, can begin in childhood and can affect comfort, eating, sleep and daily life. WHO describes oral diseases as largely preventable, yet they remain common and access to prevention and treatment is unequal.
The helpful message is that decay is a process, not a sudden event. Understanding how plaque, free sugars and fluoride affect that process makes the prevention advice easier to follow.
How does dental caries develop?
WHO explains that dental caries occurs when microbial plaque on the tooth surface converts free sugars in foods and drinks into acids. Over time, those acids break down the tooth. Continued exposure to high amounts of free sugars, inadequate fluoride and insufficient removal of plaque through brushing can lead to caries, pain, tooth loss and infection.
A visible hole is therefore a later sign of an ongoing process. A dental examination can identify the condition and determine what care is appropriate. An article or photograph cannot show how deep a lesion is or whether the tooth’s inner tissues are involved.
What does WHO mean by free sugars?
Free sugars include sugars added to foods and drinks by a manufacturer, cook or consumer. They also include sugars naturally present in honey, syrups, fruit juices and fruit-juice concentrates. This definition is broader than sweets alone.
Looking at the whole pattern can be more useful than concentrating on one product. Sweet drinks, juice, sweetened milk products, biscuits, desserts and other packaged foods may contribute. Ingredient lists and nutrition labels can help families identify added sugars, although labels vary by country.
Why does frequency matter?
WHO’s explanation links sugar exposure with repeated acid production by plaque. A pattern of frequent sugary food or drink can therefore create repeated opportunities for acid to affect teeth. Water as the main drink and meals and snacks that are lower in free sugars support prevention.
This does not require labelling food as morally good or bad. The aim is a sustainable eating pattern that reduces free sugars while maintaining adequate nutrition. Families with feeding difficulties, restricted diets or growth concerns should seek individualized advice rather than remove foods without a suitable alternative.
Gradual, practical changes across the usual weekly pattern can still be meaningful. The prevention goal is lower exposure over time, not a perfect menu at every meal.
What role does fluoride play?
WHO includes adequate exposure to fluoride among the core measures for preventing dental caries. It recommends twice-daily brushing with fluoride toothpaste containing 1000–1500 parts per million fluoride.
Use an age-appropriate amount and supervise brushing according to local dental guidance, especially while a child is learning not to swallow toothpaste. Product labels and national recommendations can differ, so a dentist can advise on the appropriate toothpaste and amount for an individual child.
How should brushing be approached?
Brushing removes plaque and places fluoride on the teeth. Twice-daily brushing works best as a regular routine rather than an occasional response to visible staining or pain. Young children usually need an adult to perform or closely supervise effective brushing.
A calm routine, a consistent time and a position in which the adult can see the teeth may make brushing easier. If sensory, behavioural or physical needs make oral care difficult, a dental professional can help adapt the approach.
Why does WHO recommend water as the main drink?
WHO lists drinking water instead of beverages containing free sugars as a preventive measure. Water avoids repeated sugar exposure and supports hydration. Whether local drinking water contains fluoride depends on the area and should not be assumed.
Whole fruit and fruit juice are not identical in WHO’s definition: sugars naturally present in fruit juice count as free sugars. This distinction can help families understand why a drink described as natural may still contribute to sugar exposure.
What symptoms may require dental assessment?
Tooth pain, sensitivity, a visible hole, swelling, difficulty eating or changes in a tooth deserve dental assessment. Pain can interfere with sleep and school, and infection may spread. Facial swelling, rapidly increasing swelling, difficulty breathing or swallowing, marked illness or inability to drink requires urgent medical or dental evaluation.
Absence of pain does not prove that teeth are healthy. Preventive dental visits allow advice and early treatment before a problem becomes more difficult to manage. The appropriate visit schedule depends on the child’s needs and local services.
Why are inequalities part of the issue?
WHO reports that oral diseases disproportionately affect socially disadvantaged people and that prevention and treatment are often costly or unavailable. Food environments, access to fluoride, transport, service availability and household resources all influence oral health.
Recognizing these factors avoids blaming a child or caregiver. Practical support, affordable preventive services and population policies that reduce free-sugar consumption all contribute to better outcomes.
A practical prevention routine
- Make water the usual drink.
- Limit the amount and frequency of foods and drinks high in free sugars.
- Brush twice daily with fluoride toothpaste in the WHO-stated 1000–1500 ppm range, following age-appropriate local advice.
- Help or supervise until the child can brush effectively.
- Arrange dental assessment for symptoms and use preventive care when available.
These measures reduce risk but cannot guarantee that decay will never occur. Teeth, health conditions, medicines, diet and access to care vary. A dentist can turn general prevention principles into an individual plan.
References
- World Health Organization. Oral health. Source reviewed 4 October 2026.