signs of tooth decay

Tooth decay is one of the most common diseases in Australia. It affects people of all ages, but young children are at the highest risk.

The most recent National Child Oral Health Study found that 42% of children aged 5–10 had already experienced decay in their baby teeth, which are thinner and softer than permanent teeth, so more easily worn down by bacteria in plaque. Almost a quarter (24%) of children aged 6–14 had also experienced tooth decay in their adult teeth.

If it's not treated early, tooth decay can cause permanent damage to teeth or even tooth loss in severe cases. Even though baby teeth will fall out eventually, early tooth loss can affect a child's ability to eat or speak normally and may cause problems with their adult teeth coming through.

You can help your kids to avoid this by taking steps to protect their teeth and knowing how to spot the signs of tooth decay if it's already present. Here are 5 common symptoms of tooth decay and what to do next.

1. Bands on the teeth

One sign that tooth decay may be present is a discoloured band or spot on the tooth, close to where it meets the gum.

A dull white band can indicate a build-up of plaque that may cause decay if it's not removed.

A darker yellow, brown or black band or other discolouration can be a sign that decay is already present.

2. Darkened tooth

If a whole tooth has turned dark yellow, brown or black, this indicates that decay has already progressed to a more advanced stage. The tooth will likely need to be repaired by a dentist.

3. Hole in the tooth

Some molars (chewing teeth) may naturally have small pits and grooves, but larger cavities are a sign of damage, either from decay or injuries. Cavities can increase the risk of dental disease and infections, so they should be treated by a dentist.

Not all holes in teeth are visible. Children and adults should have regular check-ups with a dentist who can inspect all surfaces of their teeth.

4. Toothache or sensitivity

There can be many reasons why teeth feel painful or sensitive, but it's always a good idea to see a dentist for a diagnosis.

If your child's teeth hurt when they eat, or feel sensitive when they have something hot, cold or sweet, this might be a sign of tooth decay or a tooth infection.

5. Pimple or swelling of the gum

If a tooth infection isn't treated, it can sometimes form an abscess under the tooth. This can be very painful and may show up as a pimple on the gum or a swelling in the gum or face.

Without treatment, an abscess can lead to tooth loss and other serious infections, so you should see a dentist immediately if you're concerned.

Are chalky teeth a sign of decay?

White or tan spots on kids' teeth (especially the molars) are not caused by tooth decay, but if your child has these 'chalky' teeth, they could be more prone to decay. That's because these teeth didn't fully harden during development, so can be damaged more easily.

Your child's dentist may discuss treatments for strengthening their teeth against decay, such as fissure sealants.

What if my child has tooth decay?

If you've spotted any of these symptoms on your child's teeth, you should make an appointment with a children's dentist. They'll examine your child's mouth and may discuss appropriate treatments to reverse decay, restore a tooth or protect their teeth against further decay.

Depending on how advanced tooth decay is, these treatments may include:

  • White filling – removing the decayed part of the tooth and filling the cavity with a composite material, usually glass ionomer cement for children's teeth
  • Bonding – sealing minor pits in a tooth to restore its integrity and keep out bacteria
  • Root canal therapy – if decay has reached the centre of the tooth, root canal treatment may be recommended to remove the infected tissue and replace it with a synthetic material
  • Tooth extraction – dentists will always try to save a tooth, but if it's too badly decayed, extraction may be the only option to prevent decay from spreading

Your dentist will explain what each treatment involves so you can decide if it's the right choice for your child.

Ways to prevent tooth decay

Tooth decay is usually preventable, but only when you understand what causes it and how to lower your child's risks.

Tooth decay is caused by bacteria that gather on the teeth to form plaque, a sticky layer that hardens into calculus if it's not removed. When you consume sugar and starch, these bacteria feed on it and release acids. This wears down the enamel surface of teeth over time, forming cavities.

The 3 main steps to preventing tooth decay are:

  • Improving your oral hygiene to reduce plaque
  • Improving your diet to avoid feeding bacteria
  • Having regular check-ups with your dentist

1. Good oral hygiene

Children and adults should brush their teeth twice a day, taking two minutes each session.

Children can start to use standard fluoride toothpaste around 6 years of age. From 18 months to 6 years, you should use low-fluoride children's toothpaste to avoid fluorosis. Babies' teeth should be gently cleaned with water or a wet cloth.

It's also recommended that parents floss their children's teeth as soon as they grow teeth close together.

2. Healthy diet

Cutting down on sugary snacks and drinks (including soft drinks, fruit juice and cordials) will avoid feeding the bacteria that cause tooth decay.

Water is the healthiest drink, as it keeps the mouth hydrated and washes away bacteria and leftover food. Milk provides calcium, as do other dairy products and other food sources, which helps to build stronger teeth and bones.

A balanced diet from all food groups will support kids' oral health and general health and wellbeing.

3. Regular dental visits

Visiting the dentist for a check-up and teeth cleaning is important for kids and adults of all ages. Children should see the dentist for the first time by their first birthday or 6 months after getting their first tooth.

Regular check-ups with a dentist or oral health therapist make it more likely that problems such as tooth decay will be spotted early, when they're easier to fix and before they cause serious damage. You can also ask your dentist for advice to make sure you're giving your children's teeth the care they deserve.

Talk to a family dentist in Noosa

Is it time for your kids' check-up, or are you worried about their teeth? Contact our friendly team at Tewantin Dental Centre to find out how we can help.

Call (07) 5447 1361 or book an appointment with our children's dentists today.


Do LG & Spencer AJ (Editors) 2016. Oral health of Australian children: the National Child Oral Health Study 2012–14. Adelaide: University of Adelaide Press.

Better Health Channel. Tooth decay - young children [Online] 2019 [Accessed January 2020] Available from:

Better Health Channel. Tooth decay [Online] 2018 [Accessed January 2020] Available from: