Dental disease in children is extraordinarily common and extraordinarily preventable. Tooth decay – the breakdown of tooth structure by acids produced by bacteria feeding on sugar – affects 1 in 4 five-year-olds in England. It is the most common reason for hospital admissions under general anaesthetic in children aged 5-9 in England. And it is almost entirely avoidable with a relatively small number of consistent behaviours.
Understanding how teeth develop, when to expect what, how to care for them from the earliest months, and when a dentist visit matters gives parents the information they need to make a genuine difference to their child's oral health.
Healthbooq (healthbooq.com) covers child health including dental care and oral development.
Teething and Primary Tooth Development
Primary teeth (milk teeth) begin forming in the gum before birth. Eruption – the teeth breaking through the gum – typically begins at around 6 months, with the lower central incisors usually appearing first. The full complement of 20 primary teeth (8 incisors, 4 canines, 8 molars) is usually complete by around age 2.5-3.
Teething is variable: some babies teeth with minimal disturbance; others are noticeably unsettled, dribbly, and inclined to gnaw on everything for days before each tooth. High fever and significant illness should not be attributed to teething – they warrant clinical assessment. Rubbing the gum, chilled (not frozen) teething rings, and sugar-free teething gel (available over the counter) are the main approaches for discomfort.
Permanent Teeth and the Mixed Dentition Phase
Permanent teeth begin erupting from around age 6. The first permanent tooth to erupt is typically the first permanent molar – a large tooth emerging behind the last primary molar, with nothing to replace (it is an addition, not a replacement). This is sometimes missed by parents who assume all permanent teeth follow primary teeth in position; the first molar has no primary predecessor and is thus easy to overlook.
By age 12-13, most primary teeth have been replaced, leaving 28 permanent teeth. The four wisdom teeth may erupt between 17-25, if at all.
The Most Important Dental Care Habits
Twice-daily toothbrushing with fluoride toothpaste is the foundation of dental disease prevention. NHS guidance:
For children under 3: use a smear of toothpaste containing at least 1,000 ppm (parts per million) of fluoride.
For children aged 3-6: use a pea-sized amount of toothpaste containing at least 1,000 ppm fluoride.
For children aged 7 and above: use a pea-sized amount containing 1,350-1,500 ppm fluoride (standard adult toothpaste strength).
Spit, don't rinse: after brushing, the child should spit out excess toothpaste but not rinse with water. Rinsing removes the fluoride that would otherwise remain in contact with tooth enamel and significantly reduces the protective effect.
Brushing should be done for 2 minutes, twice daily. Parents should brush (or supervise) until the child is at least 7-8 years old and able to do a thorough job independently.
Sugar and Dental Decay
Tooth decay results from acid attack: bacteria in the mouth (particularly Streptococcus mutans) ferment sugar and produce acid, which demineralises tooth enamel. The frequency of sugar exposure matters more than the total quantity: each sugar intake generates approximately 20-30 minutes of acid attack. A child who sips diluted juice throughout the day is giving their teeth far more acid exposure than one who drinks juice only with meals.
Free sugars (those added to food and drink, plus fruit juices and smoothies) should be limited to mealtimes rather than snacks and drinks between meals. The NHS recommends no more than 30g of free sugars per day for children aged 7-10 (approximately 7 teaspoons), and less for younger children.
Sugary drinks in bottles or sippy cups at bedtime or during sleep are particularly harmful because saliva flow is reduced during sleep, reducing the natural buffering and remineralisation that occurs during the day.
Fluoride Varnish
Fluoride varnish, applied to teeth by a dental professional, significantly reduces decay rates in children. In England, NICE guidance recommends fluoride varnish every 6 months for all children from age 3, and for high-risk children from when the first tooth appears. It is applied in a few minutes at a dental visit.
NHS Dental Care
NHS dental care is free for all children under 18 in England (and full-time students under 19). The NHS recommends children first visit the dentist as soon as their first tooth appears. Early dental visits familiarise children with the environment and allow early identification of risk factors. Dental anxiety is common in older children and adults and is largely a consequence of negative early experiences; positive early visits prevent this.
Key Takeaways
Children begin teething from around 6 months, with the full set of 20 primary (milk) teeth usually complete by age 3. The first permanent molar typically erupts around age 6, before most parents expect it. Tooth decay (dental caries) is the most common chronic disease of childhood in the UK, affecting around 1 in 4 five-year-olds. It is almost entirely preventable with twice-daily fluoride toothpaste, limiting sugar frequency, and regular dental attendance. The NHS recommends that children see a dentist as soon as their first tooth appears, and NHS dental care is free for all children under 18 in England. Fluoride varnish applied by a dental professional from age 3 (or earlier in high-risk children) significantly reduces decay rates.
