Having healthy teeth and gums plays an important part in your overall health and wellbeing.
The advice given here is not a substitute for seeking advice from and regularly visiting your dental health practitioner.
What Causes 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 foods 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 eat foods that contain 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 ‘demineralisation’ 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 remineralise (returning the minerals back to the tooth). Tooth decay is likely to occur when there is more demineralisation than remineralisation 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 remineralisation 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 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 (1) brushing with fluoride toothpaste twice daily, particularly before bed as your mouth produces less saliva when you are asleep, (2) regular flossing to remove plaque both from the flat surfaces of the teeth and from between the teeth and (3) regular dental check-ups.
International studies show that fluoride is an extremely effective way of reducing tooth decay. It helps slow down demineralisation of the tooth surface, encourages remineralisation 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 many areas of Australia, 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 common sugars, including those in juices, soft drinks, breads, cakes and sweets, can contribute to the risk of tooth decay.
Sugars and starches (sometimes called “fermentable carbohydrates”) are converted to acid by the bacteria in the mouth, and it is this acid that causes tooth decay (cavities). Food that clears quickly from the mouth has less opportunity to cause decay because bacteria in the mouth have less time to produce acid and cause demineralisation. Encouraging saliva production can help neutralise the acidic, 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 demineralisation.
This continues for about 20-30 minutes after the snack, or longer if food particles are trapped between the teeth.
Saliva then works to help neutralise the acid and encourage remineralisation. 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 remineralise completely.
