Tooth decay (also referred to as dental caries) isn't only the most common type of oral disease – it's also one of the most prevalent diseases in Australia. Over 90% of adults have experienced tooth decay at some time in their lives - for many, this may have started in childhood.[1]

Tooth decay is caused by bacteria in the mouth that feed on sugars contained in food and drink. These bacteria convert sugars into acids that can damage the outer layer of the teeth (the enamel). Over time, this can cause teeth to weaken and form cavities.[4] Want to know more about how sugar can affect your dental health? 

Children may be more prone to tooth decay than adults, possibly because they often consume more free sugars than any other age group.[1] That's why it's important that parents and kids know how to spot the signs that tooth decay may be present and how to lower risks by looking after their teeth.


Test your knowledge of tooth decay with this quick quiz.

1. How many children have experienced tooth decay?

How many Australian children under 10 years old have experienced tooth decay in their primary (baby) teeth?

A. Over 20%

B. Over 30%

C. Over 40%

Answer: C

According to the most recent National Child Oral Health Study (NCOHS), which surveyed almost 25,000 children across Australia, 41.7% of children had experienced dental caries in their primary teeth by the age of 10.[1]

Almost a quarter of young teenagers (23.5%) experienced decay in their permanent teeth by the age of 14.[1]

2. Can tooth decay affect babies?

“Tooth decay isn’t a risk for babies if they aren’t eating solid foods yet.”

1. True

2. False

Answer: False

Even if your child only consumes milk or formula, their developing teeth are still vulnerable to bacteria, plaque and decay. Their protective enamel layer tends to be thinner and softer than an adult’s, sometimes making it more prone to damage.[4]

Allowing milk to stay in prolonged contact with a child's teeth can encourage bacteria. That's why you should clean your child's mouth after feeding and avoid putting them to bed with a bottle.[4]

You should start to brush your child's teeth as soon as they appear, using a wet cloth or small children's toothbrush. You can start to use low-fluoride children's toothpaste from 18 months.[4]

3. What are possible visible signs of tooth decay?

Signs of tooth decay can sometimes be seen by lifting the lip and checking your child's teeth.[2] Which of the following may indicate that decay is present?

A. White bands on the teeth close to the the gum

B. Yellow or brown bands close to the gum

C. Brown or black teeth

D. White spots or flecks on the teeth

Answer: A, B & C

White bands close to the gum line can be an early sign of tooth decay. Yellow or brown bands can indicate that the disease is progressing, and darkened or discoloured teeth suggest advanced tooth decay.[4]

All of these are a cause for concern and you should arrange a check-up with your child's dentist.[4]

White spots or flecks on the teeth may be caused by exposure to too much fluoride while the teeth were developing (fluorosis), or they could be a side-effect of an infection or medication. You should still check with your child's dentist to be sure.[5]

4. What are possible non-visible signs of tooth decay?

Beyond the visible signs, what other symptoms your child is experiencing could indicate that dental caries is present?

A. Toothache

B. Teeth feeling more sensitive to temperature

C. Teeth feeling more sensitive to pressure

D. Bad breath

Answer: All are possible signs of tooth decay or other oral health issue.[1]

Toothache, sensitivity, bad breath and discoloured teeth are common symptoms of a number of oral health problems. You should make an appointment with your child's dentist as soon as possible to get a professional diagnosis and discuss treatments.[1]

5. What is the leading cause of tooth decay?

Which of the following are responsible for the most sugar consumed by Australian children in a typical week?

A. Sugary snacks

B. Soft drinks

C. Fruit juices

D. Cordials

Answer: B & C, although all are contributors.[6]

A survey of children aged 6-13 found that almost two-thirds (62.3%) drink fruit juice and more than half (57.8%) drink soft drinks in a typical week. 32.4% also drink cordials or frozen drinks.[6]

Most fizzy drinks are high in sugar, which increases the risk of tooth decay. These drinks are also highly acidic (including sugar-free varieties), which can erode the surfaces of teeth and make them easier to damage. Fruit juice can also be high in sugar and acids, sometimes containing as much as soft drinks.[7]

The best tooth-friendly drinks are plain water (especially fluoridated tap water) and plain milk. Fresh fruit and raw vegetables are the best alternatives to sugary snacks.[7]

6. Can tooth decay be prevented?

A. No, tooth decay is inevitable.

B. Potentially, with the right steps.

Answer: B

The good news for parents and kids is that there are steps you can take to lower the risk of tooth decay. While it's not possible to get rid of bacteria completely, you can reduce the build-up of plaque on the teeth by helping your child maintain good oral hygiene.[4]

Parents should brush their child's teeth and gums twice a day until they're old enough to control the brush by themselves, usually around 8 years. Only a pea-sized amount of low-fluoride children's toothpaste should be used from around 18 months to 6 years. After this time, they should start to use regular fluoride toothpaste.[4]

Your child's dentist may also recommend preventive treatments such as fissure sealants to lower their risk of tooth decay. Sealants may be applied to primary or permanent teeth to seal pits and fissures that can trap food and bacteria. They can also make teeth surfaces smoother and easier to brush.[3]

Kids’ oral hygiene is important, but so are professional check-ups

There are ways to help your child lower their risk of oral health problems at home, but early signs of tooth decay and other problems may be undetectable or easy to miss.

That’s why it’s still important for your child to visit a dental professional regularly. Usually, children should have their first dental check-up by the age of two.[8] Learn more about kids’ dental or get in touch with your nearest Bupa Dental clinic.



[1] Australian Health Policy Collaboration and Australian Dental Association. Australia's Oral Health Tracker - Technical Paper [Online] 2018 [Accessed June 2018] Available from:

[2] SA Health. Lift the Lip screening [Online] 2010 [Accessed June 2018] Available from:

[3] Australian Institute of Health and Welfare. Oral health and dental care in Australia: key facts and figures 2015 [Online] 2016 [Accessed June 2018] Available from:

[4] Better Health Channel. Tooth decay - young children [Online] 2015 [Accessed June 2018] Available from:

[5] Better Health Channel. Dental care - fluoride [Online] 2012 [Accessed June 2018] Available from:

[6] Roy Morgan. Roy Morgan Young Australians Survey, July 2015-June 2016 [Online] 2017 [Accessed June 2018] Available from:

[7] NHS UK. Sweets, fizzy drinks and bottles [Online] 2015 [Accessed June 2018] Available from:

[8] Better Health Channel. Dental checks for young children. [Online] n.d. [Accessed August 2018] Available from: