I have read about extrinsic and intrinsic sugars. What is the difference between them and how do they affect my dental health?

You're not the only one who is confused about different types of sugars and their potential to cause tooth decay.

Some scientists divide sugars into "intrinsic" and "extrinsic" sugars. Intrinsic sugars are those present naturally within the cellular structure of food, these sugars are mainly found in fruits and vegetables. Extrinsic sugars are those which are free in food or added to it. Extrinsic sugars are further divided into milk sugars (lactose) and non-milk extrinsic sugars, that is honey and added sugars.

Studies show that dental plaque bacteria can ferment both intrinsic and extrinsic sugars to acids. The acid produced dissolves the enamel of the teeth. All carbohydrate-containing foods (intrinsic and extrinsic sugars and starches) have the potential to contribute to tooth decay.

Each time we nibble a food or sip a drink containing carbohydrates (intrinsic or extrinsic sugars or starch), any decay-causing bacteria present on the teeth start to produce acid and demineralisation commences. This continues for 20 to 30 minutes after eating or drinking, longer if food debris gets trapped between the teeth or remains in the mouth. Between periods of eating and drinking saliva works to neutralise the acids and assist in the process of remineralisation (rebuilding teeth).

If food or drink is taken too frequently the tooth enamel does not have a chance to remineralise completely and caries can start to occur. This is why nibbling or sipping continuously throughout the day should be discouraged. The best advice is to limit the consumption of food and drink containing carbohydrates to no more than 6 occasions per day and ensure teeth are brushed with fluoride toothpaste twice a day.

A healthy, enjoyable diet coupled with good oral hygiene is the best way to protect teeth and promote overall good health. In addition we recommend you to use a fluoridated toothpaste. Fluoride aids the natural remineralisation of the teeth.