A child's back baby molars usually stay in the mouth until somewhere between 10 and 12 years of age. A cavity found in a four-year-old may therefore have six or more years to grow, hurt and become infected. That is why most decay in baby teeth needs some form of management, although that does not always mean a drill and a filling.
Six years is a long time for a cavity
Parents are often surprised by how long baby teeth last. The front ones are usually lost between about 6 and 8, but the molars and canines hang on until the end of primary school. Our guide to when baby teeth fall out has the usual order.
Enamel on baby teeth is thinner than on adult teeth, and the nerve sits closer to the surface. A cavity can move from a small dark spot to the nerve in months rather than years, particularly in a child who snacks often or goes to bed with milk or juice.
What untreated decay can lead to
The first sign is often nothing at all. Later comes sensitivity to sweet or cold food, then a toothache that wakes a child at night or makes them chew on one side. If bacteria reach the nerve, an infection can form at the root, sometimes showing as a pimple on the gum, swelling of the face or a fever. Our article on dental abscesses in children explains the warning signs.
Infection also matters for the next set of teeth. Each adult tooth develops directly under the roots of the baby tooth it replaces, and a long-standing infection there can leave the adult tooth with a patch of weak or discoloured enamel. If a baby molar has to be removed early, the teeth on either side can drift into the space and block the way for the adult tooth.
Decay in baby teeth is also a strong signal that the adult teeth are at risk, because the same bacteria, diet and habits carry on. In Australia's most recent national child oral health study (2012 to 2014), about one in three children aged 5 to 6 had already experienced decay in their baby teeth.
Treatment does not always mean a drill
Children's dentistry has moved towards the least invasive option that will work for that tooth. The choice depends on the size and position of the cavity, whether it is active, how long until the tooth is due to fall out, and how much a young child can manage in the chair.
Stopping early decay
Chalky white spots and some shallow cavities can be halted with better brushing, high-fluoride varnish and changes to diet. A painted liquid called silver diamine fluoride can arrest some cavities without drilling, though it stains the decayed area black, so it suits back teeth and very young or anxious children better than front teeth.
Filling or covering the tooth
Small and medium cavities are usually cleaned and filled with tooth-coloured material. Larger cavities in molars often do better under a preformed stainless steel crown, which covers the whole tooth and tends to last until the tooth is lost naturally. In some cases these crowns can be fitted without numbing or drilling. Our article on a child's first filling walks parents through the appointment.
When the nerve is involved
If decay has reached the nerve, a baby tooth pulp treatment may save it. If the tooth is too badly broken down or infected, removal may be the kinder choice, sometimes followed by a space maintainer to hold the gap for the adult tooth.
When watching is a reasonable choice
Not every cavity needs active treatment. A dentist may suggest monitoring when a tooth is loose or only months from falling out, when a cavity has become hard and inactive, or when the child is pain-free and the risk of waiting is low. Monitoring is an active plan with review dates, photos or X-rays where helpful, and clear signs that would change the decision.
Stopping the next cavity
Fixing one cavity does little if the cause continues. Brush twice a day with a fluoride toothpaste in the amount suited to your child's age, and help with brushing until about 7 or 8, when most children can manage it well alone. Our guide on toothpaste amounts for children sets this out by age. Keep sweet foods and drinks to mealtimes, give water between meals, and avoid bottles or sippy cups of milk or juice in bed. Fissure sealants can protect new adult molars when they come through.
What parents ask about baby tooth fillings
Will my child need an injection?
Sometimes, for deeper fillings or pulp treatment. Many small cavities, silver diamine fluoride and some preformed crowns need no numbing. The dentist or OHT explains what is planned beforehand so you can prepare your child.
Can treatment be done if my child is very anxious?
Often, with short visits, a gentle pace and the least invasive option. If a lot of treatment is needed in a young child, referral to a registered paediatric dentist, sometimes with treatment under general anaesthetic in hospital, may be discussed.
Book a check for your child
Our oral health therapists Sabrina Tran and Jennifer Nguyen see children for check-ups and prevention, and eligible children are bulk billed under the Child Dental Benefits Schedule. See our current deals page for other options.
This article is general information and is not a substitute for personal dental advice for your child.
