Dental caries, also known as tooth decay or a cavity, is a disease where a bacterial process damages the tooth, producing cavities (holes in the teeth).  Two groups of bacteria are responsible for starting tooth decay: Streptococcus mutans and Lactobacillus.  If left untreated, the decay can lead to pain, tooth loss, infection, and in severe cases, death.

The way dental decay appears is highly varied; however, the risk factors and stages of development are similar. In the early stages, it may appear as a small chalky area that may eventually develop into a large cavity. This is usually due to the enamel layer collapsing as the softer decayed dentine layer is unable to support it. Sometimes caries may be directly visible, however other methods of detection such as radiographs are used to assess in between teeth and the extent of tooth destruction.

Tooth decay is caused by specific types of acid-producing bacteria that cause damage in the presence of carbohydrates such as sucrose, fructose, and glucose.  The mineral content of teeth is sensitive to increases in acidity.   A tooth (which is primarily mineral in content) is in a continuous state of movement of demineralization and remineralization between the tooth and surrounding saliva. When the pH at the surface of the tooth drops below 5.5, demineralization proceeds faster than remineralization (meaning that there is a net loss of mineral structure on the tooth’s surface). This results in the start of decay.  Very early stages of demineralization can be arrested by the use of topical fluoride varnishes. “The best form of defense is prevention, which involves a good dental hygiene regime at home and a balanced healthy diet; also seeing your dentist and hygienist regularly to help prevent decay and to get the best advice,” says Dr Rashid of Time Dental, Farnham.