Does Sugar Really Rot Your Teeth?

does sugar really rot teethTooth decay is the most common dental problem in Australia, affecting more than 90% of people in their lives, and the most common chronic disease affecting children. While teeth can decay for many reasons, the leading culprit is sugar added to food and drink.

Even if you've already tried to cut down on sugar in your diet, you and your family could still be consuming more than you realise, thanks to the presence of 'hidden' sugars – those that go under other names, but are just as bad for your teeth and gums.

This Dental Health Week (3 to 9 August 2020), the Australian Dental Association (ADA) and dentists across Australia are helping to raise awareness of these hidden dangers lurking in the grocery aisles to help people of all ages avoid tooth decay. Find out what you need to know or book a check-up with a Sydney CDB dentist.

How common is tooth decay?

Tooth decay (dental caries) can affect people of all ages, but children and teenagers are at the highest risk – both because their developing teeth are softer and thinner than adult teeth, making them more easily damaged, and because they consume the most sugar.

According to the most recent data from Australia's Oral Health Tracker:

  • 34.3% of young children aged 5 to 6 have experienced decay in their primary (baby) teeth
  • 23.5% of children and teens aged 6 to 14 have experienced decay in their permanent (adult) teeth

What's more, many kids and adults have tooth decay that isn't treated:

  • 27.1% of children aged 5 to 10 have untreated decay in their primary teeth
  • 10.9% of children aged 6 to 14 have untreated decay in their permanent teeth
  • 32.1% of teens and adults aged 15+ have untreated tooth decay

Without treatment, tooth decay can spread to other teeth or lead to more serious problems, including gum disease and even losing teeth. Tooth decay is the leading cause of tooth loss for young people.

How much sugar is healthy?

There are two main categories of sugar – natural sugars, such as those found in fruit, milk and natural yoghurt, and added (or 'free') sugars in processed food and drink. Natural sugars are healthy in moderation, but if they're released through juicing or blending they become free sugars, which are more damaging to teeth.

Having some sugar in your diet can provide energy, but most of us have more than necessary, which can cause problems. The World Health Organization (WHO) recommends a daily average of 24 grams or 6 teaspoons of free sugar in food and drink, which varies by age and gender.

The WHO also found that tooth decay is more likely to be present in people who consume more free sugar than recommended. The average Australian has 14 teaspoons of free sugar per day, which is well over the recommendation.

According to Australia's Oral Health Tracker, over 70% of children and teenagers have too much free sugar in their diet, which is largely thanks to their taste for soft drinks, fruit juices and sugary snacks. Adults are less likely to overindulge, but almost half (47.8%) still consume more free sugar than is recommended for health.

How does sugar cause tooth decay?

Sugar doesn't directly cause tooth decay. What happens is that when you eat or drink something containing sugar or other carbohydrates, bacteria on your teeth also consume it. This gives the bacteria the energy to multiply and spread, and they release acids as a waste product. These acids weaken and slowly dissolve the surface of teeth over time, which can eventually form cavities.

Most of this activity happens within 20 minutes of consuming sugar. Drinking water helps to rinse sugar off your teeth and your saliva can neutralise some of the acid, but by that time some of the damage may be done. Naturally, the more sugar you consume, the more there is to feed bacteria and the more acid gets released.

Each time you eat or drink something with sugar, the process starts again. That's why snacking between meals and frequent sips of sugary drinks can cause more damage than having drinks and snacks alongside meals.

Some more important things to know:

  • Many drinks that are high in sugar – such as soft drinks, fruit juices and sports drinks – are also high in acidity. This further erodes the teeth and can make them decay faster, so these should be avoided.
  • Foods that stick to the teeth – such as sticky lollies and dried fruit – expose your teeth to sugar for longer, which also accelerates decay.
  • If you smoke, drink alcohol or take medications that cause a dry mouth, this can also increase the rate of decay by reducing saliva, so acids on your teeth won't be neutralised as easily.

What are the stages of tooth decay?

You might notice tooth decay in the early stages as white spots on teeth, close to the gum line. Improving your oral hygiene at home or visiting a dental clinic to have plaque removed and fluoride applied can usually stop or reverse tooth decay at this stage, before any permanent damage is done. If tooth enamel has started to dissolve, minerals in saliva and fluoride could help to repair it.

If tooth decay continues, spots on the teeth may darken and the enamel will continue to be weakened until cavities (holes) form in one or more teeth. This exposes the softer dentine layer under the enamel, which can cause toothache or sensitivity when you eat or drink something hot, cold or sweet.

More severe tooth decay may expose the interior of the tooth, infecting the soft tissues of the dental pulp or forming a dental abscess below the tooth. These can be extremely painful and need professional care as soon as possible. A badly decayed tooth may turn brown or black and you could risk losing the tooth without treatment.

How to prevent or reverse tooth decay

Tooth decay is a preventable disease if you maintain good oral hygiene. Improving your oral hygiene habits could also help to reverse existing decay in its early stages, combined with treatments from your dentist.

To maintain good oral hygiene:

  • Brush your teeth at least twice a day
  • Use fluoride toothpaste
  • Floss between your teeth once a day
  • Drink plenty of water (especially tap water containing fluoride)
  • Eat a well-balanced diet
  • Cut down on sugar in food and drink
  • When you do have sugar, sip water to rinse your mouth and swallow quickly
  • Avoid snacking and drinking sugary or acidic drinks between meals
  • Chew sugar-free gum to stimulate saliva flow and help neutralise acids
  • Keep up with your scheduled dental check-ups, so your dentist can remove plaque and spot the
  • signs of tooth decay and other problems before they become more serious

Ways to cut down on sugar

If you want to stay within your daily intake targets, you need to know what to look for on nutrition labels when you're shopping in the supermarket or online.

The ADA recommends choosing products with 10g sugar or less per 100g (the lower, the better). Checking sugar content per 100g is a more useful comparison than per serving, as serving sizes can vary between products.

More useful things to know:

  • 4g of sugar = 1 teaspoon
  • 'No added sugar' is not the same thing as 'sugar free'
  • Learn to spot hidden sugars: nectars, syrups, fruit juice, dextrose, fructose, glucose, sucrose and many other names
  • The earlier an ingredient is listed, the more it contains

When to see a dentist

If you're worried that you or your child might have tooth decay, you should make an appointment to see a dentist if:

  • you have a toothache that lasts more than a few days
  • your tooth hurts when you bite down
  • your tooth feels more sensitive to temperature
  • there are white, brown or black marks on your teeth

Tooth decay can sometimes happen without any obvious symptoms. Having regular check-ups with a dentist makes it more likely that they'll spot tooth decay in its early stages before it causes permanent damage.

During your appointment, your dentist will examine your teeth and gums and recommend any treatments they think could help. Depending on how far tooth decay has advanced, these may include:

  • Dental hygiene treatments – professional cleaning and scaling from a dental hygienist to remove plaque from your teeth and apply fluoride to help protect and rebuild enamel.
  • White fillings – if you have a cavity or other tooth damage, your dentist may be able to seal it and restore your tooth using a tooth-coloured filling or a dental crown.
  • Root canal therapy – if decay has reached the centre of your tooth, your dentist may recommend a root canal treatment. This involves removing the infected tissue and sealing the tooth with a crown or filling.
  • Extractions – only as a last resort to protect your other teeth and prevent decay from spreading if a tooth has been too badly damaged to repair.

Your dentist will explain the pros and cons of treatment options and answer any questions you have so you can make informed decisions about your oral health.

Do you need a dentist in Sydney CBD?

If you want to talk to a dentist about your teeth or it's time for your check-up, get in touch to make an appointment at our George Street dental clinic at a time that's convenient for you.

Call our Sydney dentists on (02) 9232 3900 or book online.


Australian Health Policy Collaboration and Australian Dental Association. Australia's Oral Health Tracker [Online] 2018-20 [Accessed July 2020] Available from:

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

Healthdirect. Tooth decay [Online] 2019 [Accessed July 2020] Available from:

Moynihan, P. J., Kelly, S. A. M. 2013. "Effect on Caries of Restricting Sugars Intake: Systematic Review to Inform WHO Guidelines." Journal of Dental Research. URL: