The first sign is easy to miss: a faint, chalky white band along the gum edge of the top front teeth, usually noticed while lifting a toddler's lip to brush. That band is softened enamel, and at this stage it can often be stopped from turning into a hole. Dentists call the condition early childhood caries. The older name, baby bottle tooth decay, points to its most common trigger, which is milk, formula or juice sitting on the teeth for long stretches, especially during sleep.
Sleep is when teeth are least protected
Bacteria in dental plaque turn the sugars in drinks into acid, and that acid draws minerals out of enamel. Saliva normally washes the sugars away and helps the enamel recover. During sleep, saliva flow slows right down. A bottle of milk or juice taken to bed leaves liquid pooled around the upper front teeth for hours with little to clear it, so the acid has a long, uninterrupted window.
The lower front teeth are often spared at first because the tongue covers them during sucking. That is why the pattern, decay on the top front teeth with the bottom ones looking fine, is so typical.
Sleep is not the only risk. A bottle or sipper cup carried around all day and sipped constantly keeps the teeth under repeated acid attack. Both how often and how much sugar reaches the teeth matter.
How decay progresses if nothing changes
The white chalky band is the early stage. Over weeks to months, the softened area can turn yellow or brown and the surface can break down into a cavity. In advanced cases the front teeth may wear down to brown stumps, and infection can lead to pain, swelling or a gum boil. Back teeth often become involved as well.
Children rarely complain early on. Some signs that decay may be hurting include refusing cold drinks, chewing only on one side, or waking more often at night.
The earlier the stage, the more options there are. White areas without a break in the surface can often be stabilised with fluoride varnish, better cleaning and changes to feeding at sleep time. Once a cavity has formed, the tooth usually needs a filling, a crown or occasionally removal. Very young children with extensive decay sometimes need treatment under general anaesthetic in hospital.
Habits that help prevent it
Bedtime is where small changes make the biggest difference. If your child needs a bottle to settle once teeth are through, filling it with plain water removes most of the risk. Milk can still be part of the bedtime routine, given before teeth are cleaned rather than in bed.
Start cleaning as soon as the first tooth appears, using a soft cloth or a small soft brush. Current Australian guidance (ADA, teeth.org.au) is no toothpaste before 18 months unless a dentist advises it, then a smear of low-fluoride children's toothpaste from 18 months to 6 years, and a pea-sized amount of standard fluoride toothpaste from 6. Our guide to cleaning baby and toddler teeth shows the technique, and the fluoride guide explains why it helps.
Introduce a cup from around six months and aim to move off bottles by about 12 months. Babies and toddlers do not need juice or cordial. Water is the best drink between feeds, and tap water in most Australian cities contains fluoride.
Never dip a dummy in honey, jam or anything sweet. Our article on dummies and teeth covers other dummy questions.
Breastfeeding and decay
Breastfeeding has many benefits. A systematic review (Tham and colleagues, Acta Paediatrica, 2015) found that breastfeeding up to 12 months was linked with less decay, not more. Breastfeeding beyond 12 months, especially frequent or overnight feeds, was linked with more decay, although the studies could not fully separate this from other sugars in the diet and cleaning habits. Cleaning the teeth well before bed and watching for white lines is a reasonable approach. Our breastfeeding and dental care article goes into more detail.
Baby teeth do need care, even though they fall out
The back baby teeth stay in the mouth until around ten to twelve years of age. Decay in them can cause pain, infection and trouble eating and sleeping, and early loss can let neighbouring teeth drift into the space meant for the adult teeth. A child who has decay in baby teeth is also more likely to develop decay in adult teeth later on.
Questions we are often asked
When should my child first see a dentist?
When the first tooth appears or by the first birthday. The visit is short and focuses on looking at the teeth and talking through feeding and cleaning. Our first visit guide explains what to expect.
Is it too late if I have been giving a bottle at night?
No. Swapping to water and cleaning the teeth before bed can help from the day you start. Ask your dentist or OHT to check for early white areas.
Does teething cause these white marks?
Teething does not cause decay, although sore gums can make brushing harder for a while. See our article on teething for comfort tips.
If you have noticed white lines or brown spots on your child's front teeth, our dentists and oral health therapists can take a look and help you plan the next steps. Eligible children may be covered under the Child Dental Benefits Schedule, and you can see our current offers.
This article is general information and not a substitute for an individual dental assessment.
