What is tooth decay?

Tooth decay is caused by plaque. Plaque is a layer of bacteria (germs) that sticks on your teeth. The germs come from your saliva.

The plaque bacteria change sugar that is in food and drinks into acid. The acid can slowly damage your teeth. You can see tooth decay when a cavity (hole) forms in your tooth. Sometimes a white spot on your tooth can be an early sign of decay.

Tooth decay can affect people of all ages, even very young children.

In Australia, 1 in 3 adults over the age of 15 years has tooth decay that's not treated.

Some children also have tooth decay. About 1 in 3 children under the age of 5 years have tooth decay in their baby teeth.

What are the symptoms of tooth decay?

If you have tooth decay, you may have:

• toothache
• tooth sensitivity — it hurts when you have hot or cold food or drinks
• brown, black or white stains on your tooth surface
• pain when you bite or chew
• red and swollen gums near the decayed tooth

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What causes tooth decay?

Tooth decay starts when the acid from plaque attacks your tooth enamel. Your tooth enamel is the outside layer of the tooth (Image 1).

Lots of acid attacks break down the enamel layer (Image 2). This happens over time.

Tooth decay often starts with a white spot in your tooth enamel. You can usually see the white spot if it's near your gumline. You will not see it if the white spot is in the grooves of your teeth.

If this early decay is not treated, it can become a cavity or hole.

The decay or hole can get deeper into your tooth over time. It can cause a toothache or an abscess (Image 4).

In the later stages of decay, your tooth will look yellow-brown or black.

How does my diet affect my teeth?

Sugar is one of the main reasons that people get tooth decay.

You are more likely to have tooth decay if you:

• eat a lot of sugary foods
• have lots of snacks during the day
• do not clean your teeth regularly
• have a dry mouth — less saliva than you need
• smoke
• do not have regular dental check-ups

When should I see my dentist or dental professional?

Early tooth decay has no symptoms. You should visit your dental professional regularly. Your dental professional will check your teeth for tooth decay.

Many dental health experts recommend that you have a check-up with your dental professional every 6 months.

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How is tooth decay diagnosed?

Your dentist will examine your teeth and ask if you have any symptoms. They may also do an x-ray.

How is tooth decay treated?

Early treatment can stop or even cure tooth decay.

Tooth decay that has not made a hole or cavity can be treated by a dental professional. They will put fluoride paste or varnish on your teeth. You also need to take preventive steps such as:

• regularly brushing your teeth with a fluoride toothpaste
• improving your diet

This will stop the early decay from becoming a cavity or hole.

You might need a filling to restore your tooth structure.

Can tooth decay be prevented?

You can help protect and care for the health of your teeth and gums. The Australian Dental Association recommends:

• Brushing your teeth 2 times a day using a fluoride toothpaste.
• Cleaning between your teeth using dental floss or interdental brushes every day.
• Eating a healthy diet that is low in added sugar.
• Having regular dental check-ups.

Fluoride is important to help prevent tooth decay. Choose a toothpaste that contains fluoride. After brushing:

• spit out any left over toothpaste
• do not rinse your mouth with water

This allows a layer of toothpaste to stay on the surface of your teeth. It will give your teeth protection for a longer time.

Most Australian tap water has fluoride added. This helps protect and strengthen teeth.

It's also a good idea not to have too many sweet foods and sugary drinks in your diet. If you do have sugary food and drinks, it's best to have them with meals.

Your dental professional may recommend that you have a sealant (special layer) put on your teeth. This sealant is put on the grooves in healthy teeth. It can be hard to clean the grooves on your teeth properly. The sealant helps to prevent tooth decay in teeth with lots of grooves.

How can I prevent tooth decay in my child?

Children's teeth have softer and thinner enamel. Their teeth decay more easily than adult teeth.

If you have young children, you can care for their teeth by:

• cleaning their teeth 2 times a day
• avoiding sugary drinks, such as fizzy drinks, cordial and fruit juice
• avoiding sweet food

What are the complications of tooth decay

If tooth decay is not treated, it can cause:

• pain
• tooth abscess
• swelling or pus around a tooth
• damage or broken teeth
• chewing problems

If you lose a tooth, the rest of your teeth may move into the space left by the tooth.

In children, tooth decay can affect their:

• development
• nutrition
• speech
• jaw development

Resources and support

You can find out more about dental care on Healthdirect's teeth cleaning page.

You can read more about how to care for your teeth at Teeth.org.au.

Information in other languages can be found at the SA Dental website.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.