Tooth decay affects more children than asthma and hay fever combined — yet the habits that prevent it are straightforward, and they begin long before the school years. Starting early gives your child's teeth the best possible foundation.
Starting oral care from the very first tooth
Most first teeth appear around 6 months of age, though anywhere between 2 and 15 months is within the typical range for a baby's first tooth. Even before any teeth appear, it helps to wipe your baby's gums with a clean, damp washcloth or gauze pad after each feeding. This removes residual milk sugars and bacteria, and gets your baby comfortable with the sensation of something in their mouth — which makes the transition to a toothbrush much easier.
Once that first tooth arrives, start brushing straightaway — there is no need to wait until more teeth come in. Use a soft, small-headed toothbrush designed for infants. The earlier you begin, the more naturally it becomes part of your child's daily rhythm.
How cavities form — and how to interrupt the process
Cavities do not appear suddenly. They develop through a gradual process: bacteria in the mouth — particularly a type called Streptococcus mutans — convert sugars from food and drink into acids. Each time this happens, oral pH drops below 5.5 and the acid begins to dissolve tooth enamel, a process called demineralization. With repeated acid exposures over time, enamel breaks down and a cavity forms.
The encouraging part is that this process can be interrupted early. At the initial 'white spot' stage — before a cavity has fully formed — fluoride can actually rebuild enamel and make it more resistant to future acid attack. Once a cavity has progressed further, it requires dental treatment, which is why catching things early matters.
One important detail about transmission: the bacteria that cause cavities can pass from caregivers to infants through shared spoons, tasting food with the same utensil, or cleaning a pacifier by putting it in your own mouth. Caregivers with active decay can take extra care to avoid sharing saliva with young children — never dip a pacifier in honey or sugar either, and note that honey carries a risk of infant botulism in babies under 12 months.
Brushing technique and the right amount of fluoride by age
Fluoride is the single most effective tool for preventing cavities at home. Both the AAP and NHS agree on the amounts, and they are smaller than most parents expect.
- Under 3 years: a smear — roughly the size of a grain of rice — of fluoride toothpaste with at least 1,000 ppm fluoride, twice daily.
- Ages 3 to 6: a pea-sized amount of toothpaste, still at least 1,000 ppm fluoride.
- Ages 7 and over: a pea-sized amount of toothpaste with 1,350 to 1,500 ppm fluoride.
Brush for approximately 2 minutes, twice a day. The most important session is before bed — once you have brushed at night, nothing else should touch the teeth. After brushing, children should spit out the excess toothpaste but not rinse with water: rinsing washes away the protective fluoride film left on the enamel.
Children need a parent or caregiver to assist with — or at minimum supervise — brushing until around age 10, when most children can reliably manage the technique and duration on their own. Younger children simply do not yet have the fine motor coordination to brush effectively by themselves.
Sugar, snacking frequency, and the bedtime bottle
How often your child is exposed to sugar matters as much as how much sugar they consume in total. Each time sugar reaches the mouth, bacteria produce acids for about 20 minutes. A child who snacks on something sweet every hour is exposed to near-continuous acid attack. Keeping sugary foods and drinks to mealtimes — rather than spreading them across the day — significantly reduces the number of acid episodes.
WHO recommends that free sugars make up less than 10% of a child's total daily energy intake, with further benefit below 5%. For children under 2, WHO advises no sugar-sweetened beverages at all. The AAP recommends no fruit juice before 12 months of age, and limited amounts thereafter — whole fruit is always a better choice than juice, because the fibre slows sugar release and the liquid does not pool around teeth.
The bedtime bottle deserves particular attention. Putting a baby or toddler to sleep with a bottle containing milk, formula, or juice bathes the teeth in sugar for hours while the child's saliva production is low and natural rinsing is reduced. This pattern is one of the most common causes of severe early childhood decay, sometimes called 'baby bottle tooth decay.' If a bottle at bedtime feels necessary, water is the only appropriate option. The AAP also recommends transitioning from a bottle to an open cup by 12 months.
- Keep sweets and sweet drinks to mealtimes, not throughout the day.
- Sticky foods such as raisins and gummy candies cling to teeth and pose a higher risk than foods that clear the mouth quickly.
- Between meals, water is the best drink for teeth.
- Never dip a pacifier in honey, sugar, or any sweetened substance.
- Avoid offering fruit juice before 12 months; keep volumes small after that.
Why baby teeth matter even though they fall out
It is a common and understandable thought: if baby teeth will fall out eventually, does it really matter if they decay? The answer is yes — and for several reasons that extend well beyond the baby years.
Baby teeth support chewing and nutrition during the years when children are growing fastest. They also play a direct role in speech development: teeth help produce sounds including 's', 'th', 'f', and 'v', and children who lose front teeth early can develop speech patterns that are harder to correct later. Baby teeth also act as natural space-holders for the adult teeth developing beneath the gum. When a baby tooth is lost early due to decay, adjacent teeth can drift into the gap, reducing the space available for the incoming permanent tooth and increasing the likelihood of crowding, misalignment, or the need for orthodontic treatment later on.
Beyond structure and speech, untreated cavities in baby teeth cause pain and infection that can interrupt sleep and eating, lead to missed school days, and affect a child's general wellbeing. Research also shows that decay in baby teeth increases the likelihood of decay in adult teeth.
The first dental visit: timing and what to expect
The AAP and the American Academy of Pediatric Dentistry jointly recommend that every child establish a dental home by age 1. In practical terms, this means the first dental visit should happen when the first tooth appears, or by your child's first birthday — whichever comes first. NHS guidance aligns with this: taking your child to the dentist when their first milk teeth appear, or before they turn 12 months, gives them time to become familiar with the environment before any treatment is ever needed.
The first visit is not about finding problems — it is primarily a brief check of the teeth and gums, a conversation about feeding habits and fluoride, and the start of a relationship with a dentist while everything is going well. Starting early also helps children grow comfortable with the dentist before any treatment is ever needed.
Your child's pediatrician can also apply fluoride varnish at well-child visits, starting at 6 months and continuing every 6 months until age 5 (or every 3 months for children with higher cavity risk). Fluoride varnish reduces cavities in baby teeth by approximately one-third. From age 6 or 7, once the back molars have come in, dental sealants become an option: sealants applied to the grooves of back teeth prevent up to 80% of cavities in those teeth over 2 years, and children without sealants have nearly 3 times as many first-molar cavities as those with them.
A daily oral care routine by age
Birth to first tooth
Wipe gums with a clean, damp cloth after each feed. No toothpaste needed yet.
First tooth to age 3
Brush twice daily with a grain-of-rice smear of fluoride toothpaste (at least 1,000 ppm). Spit — do not rinse. Parent does the brushing. Book the first dental visit by 12 months.
Ages 3 to 6
Increase to a pea-sized amount of toothpaste. Brush morning and before bed for 2 minutes each time. Parent assists and checks. Ask the dentist about fluoride varnish (twice yearly or more often if recommended).
Ages 7 to 10
Children can begin brushing independently with supervision. Use toothpaste with 1,350 to 1,500 ppm fluoride. Ask the dentist about sealants for newly erupted back molars. Continue twice-daily brushing and regular dental visits.
Age 10 and beyond
Most children can brush reliably without supervision by this point. Continue twice daily for 2 minutes, spit without rinsing, and maintain regular dental check-ups — typically every 6 to 12 months as recommended by your dentist.