Having healthy teeth and gums plays an important part in your overall health and well being.

Advice and information

We understand the importance of good dental hygiene and so have provided some information and tips to help keep your teeth and gums in good shape. The advice given here is not a substitute for seeking advice from and regularly visiting your dental health practitioner.

What Causes Tooth Decay?

All food and beverages contain fermentable carbohydrates (sugars and starches) that have the potential to cause tooth decay.

Tooth decay (sometimes called dental caries or cavities) is caused by the interaction of bacteria that are naturally present in the mouth with carbohydrates from food and beverages. These tiny organisms form a sticky, colourless, soft film on the teeth called 'plaque'. During the day, plaque builds up naturally on clean teeth, even when there is no food in the mouth.

When we consume foods that contain fermentable carbohydrates (sugars and starches), the bacteria break down the carbohydrates to create acid. Over time, the acid dissolves the minerals in the hard outer layer of the tooth. This is called 'de-mineralisation' and can lead to tooth decay.

However, there are natural repair processes at work in our mouths, which help reduce the extent of decay. Our saliva plays an important role as it helps remove food particles from the mouth and helps neutralise the acids that have been produced by plaque bacteria. It also provides calcium and phosphate to help the teeth re-mineralise (returning the minerals back to the tooth).

Tooth decay is likely to occur when there is more de-mineralisation than re-mineralisation over a period of time. This may happen in the presence of carbohydrates when teeth are not cleaned. It can also happen when foods and drinks containing carbohydrates are consumed frequently, without allowing enough time between consumption of food and drink for re-mineralisation to occur. It can also happen when there is less saliva in the mouth, such as when we are asleep at night. Good oral hygiene during the day and before going to bed at night is therefore important. Saliva also contains low levels of fluoride from toothpaste (and water in areas where fluoride is added), which helps protect teeth from decay.

Oral hygiene and fluoride

Good oral hygiene is vital in the prevention of tooth decay. This involves:

  • Keep your teeth and gums clean by brushing twice daily, particularly before going to bed, with fluoride toothpaste, and by regular flossing.
  • Consider limiting your consumption of foods and drinks that contain fermentable carbohydrates, or that are acidic, to meal times.
  • It is recommended that you wait at least 30 minutes before brushing your teeth and after consuming food or beverages other than water to allow for remineralisation.
  • Schedule regular dental check-ups.

International studies show that fluoride is an extremely effective way of reducing tooth decay. It helps slow down de-mineralisation of the tooth enamel, encourages re-mineralisation and increases the hardness of the tooth enamel, making it less vulnerable to acid. Recent studies show that fluoride can help reverse the very early stages of enamel breakdown at the beginning of the decay process.

In some areas of New Zealand, fluoride is added to municipal water. This is also an effective method of ensuring a regular supply of fluoride to the mouth.

Food and tooth decay

Advances in dental research show that all sources of fermentable carbohydrates, including the sugars found in juices, soft drinks, breads, cakes and sweets, can contribute to the risk of tooth decay.

Sugars and starches (fermentable carbohydrates) are converted to acid by the bacteria in the mouth, and it is this acid that causes tooth decay (cavities). Food & beverages that clear quickly from the mouth have less opportunity to cause decay because bacteria in the mouth have less time to produce acid and cause de-mineralisation. Encouraging saliva production can help neutralise the acid, and a good way to do this is to chew sugar-free chewing gum. Cheese can also help to neutralise acid, so eating some at the end of a meal can help protect teeth against decay. Rinsing the mouth with water after a meal, drink or snack may also help.

Food frequency

Every time we consume any food or drink that contains fermentable carbohydrates the decay-causing bacteria go to work and start to produce acid, leading to de-mineralisation.

This continues for about 20-30 minutes after consuming a food or beverage, or longer if food particles are trapped between the teeth.

Saliva then works to help neutralise the acid and encourage re-mineralisation. But there is evidence to suggest that if there is only a short time before eating or drinking again, the tooth enamel does not have the chance to re-mineralise completely.

Tooth erosion

Tooth erosion is the loss of the hard enamel that covers our teeth. Chemical processes cause this, usually with acids, but unlike tooth decay, bacteria are not involved.

Erosion can be caused by the frequent consumption of acidic foods and drinks such as sparkling drinks, fruit and fruit juices.

Some people are more susceptible, especially when their teeth are frequently exposed to acidic foods and drinks. Sports men and women may be at risk if they constantly sip sport drinks.

As with tooth decay, saliva plays an important role as it helps neutralise the acid and helps with re-mineralisation. After consuming acidic foods or drinks, chewing sugar-free gum, eating cheese or rinsing your mouth with water can also help to protect against tooth erosion by stimulating the production of saliva and removing the residual acid.

Tooth friendly tips:

  • Keep your teeth and gums clean by brushing twice daily with fluoride toothpaste particularly before going to bed and by regular flossing.
  • Rinse your mouth with water, after eating or drinking.
  • Limit the amount of time that foods with fermentable carbohydrates are in your mouth, especially chewy or sticky foods.
  • Eat a wide variety of nutritious foods
  • Limit the exposure of your teeth to food acids by using a straw when drinking sparkling beverages or other acidic beverages such as orange juice and apple juice.
  • Visit your dentist regularly for check-ups.

Special advice for babies and young children

  • Do not give babies or small children sweetened drinks or fruit juice in their feeding bottle. If you do give small children sweetened drinks or fruit juice, give it to them in a cup and try watering it down.
  • Never put babies and young children to bed with a bottle containing sweetened drinks, including fruit juice, milk or formula.
  • Take your baby to the dentist or local children's dental clinic as soon as their first teeth emerge to get advice on caring for their teeth.
  • Parents or older siblings can help younger children get into the habit of brushing their teeth twice a day by making it fun.


  1. Australian Dental Association website, www.ada.org.au
  2. Dietitians Association of Australia website, www.daa.asn.au