Tooth decay in children is one of the most common childhood health problems, and it is largely preventable. Baby teeth matter: they let a child eat, speak and sleep comfortably, and they hold the space for the adult teeth. This guide explains what causes decay in children’s teeth, the early signs and how to prevent it.
What causes tooth decay in children?
Decay happens when bacteria in plaque turn sugar into acid, and the acid dissolves the tooth surface. The more often teeth are exposed to sugar, the more damage is done. Common causes in children are:
- frequent sugary snacks and drinks, including juice, cordial, soft drink and flavoured milk
- going to bed with a bottle of milk, formula or juice
- grazing through the day, which leaves no time for teeth to recover between meals
- teeth that are not brushed twice a day, or are brushed without help
- not enough fluoride
Early signs of decay in children’s teeth
- white, chalky patches near the gum line, often on the upper front teeth
- brown or black spots or holes
- sensitivity or pain when eating or drinking
- a child avoiding chewing on one side
- swelling or a pimple on the gum, or a child woken by toothache
White patches are the earliest stage and can sometimes be reversed. Brown spots and holes need treatment.
How to prevent tooth decay in children
- Start cleaning as soon as the first tooth appears, using a soft cloth or a small soft toothbrush.
- From 18 months to 6 years, use a pea-sized amount of low-fluoride children’s toothpaste. From 6 years, use standard fluoride toothpaste.
- Brush twice a day. Children need an adult to help until about age 8.
- Offer water as the main drink. Keep sweet drinks and snacks for mealtimes.
- Do not put a baby to bed with a bottle.
- Ask about fissure sealants and fluoride treatment for extra protection.
When should my child first see a dentist?
A first visit when the first tooth appears, or by about 12 months of age, is a common recommendation. Regular check-ups after that let us find early decay while it is still simple to manage. See your child’s first dental visit.
How is decay in baby teeth treated?
Treatment depends on how far the decay has gone. Early patches may be managed with fluoride and changes at home. Cavities are usually treated with a filling. A badly decayed or infected baby tooth may need to be removed. Leaving decay untreated can cause pain and infection and can affect the adult tooth developing underneath.
Is dental care for children covered?
Eligible children aged 2 to 17 can receive up to $1,158 in basic dental services over two calendar years under the Child Dental Benefits Schedule. We bulk bill eligible children. See our Child Dental Benefit Scheme page.
FAQs
Do baby teeth really need fillings if they fall out anyway?
Often, yes. Some baby molars stay until age 11 or 12, and an untreated cavity can cause pain and infection long before the tooth is due to fall out.
Is tooth decay in children the parent’s fault?
Decay has many causes, including diet, enamel quality and how much fluoride a child gets. What matters is finding it early and changing what you can.
Children’s dentistry in Penrith
To book a check-up for your child, contact Penrith Dental Care or call (02) 4733 1197. Read more on our kids dentist page.
Source: Healthdirect Australia, Tooth decay (last reviewed February 2025). This article is general information only and does not replace an assessment with a registered dental practitioner.
Looking for more dental health tips? Browse all articles on the Penrith Dental Care blog, or meet the Penrith Dental Care team. Have a question? See our dental FAQ.
Reviewed by Mina Gibryal, Penrith Dental Care, October 2026. This article is general information and does not replace advice from your own dental practitioner.