Dental caries refers to a condition where the structure of a tooth is damaged. The damage starts from the enamel at the surface and gradually spreads into the inner structures of the tooth.

A. Why does a tooth become decayed?
The tooth surfaces are normally covered with dental plaque. Every time food or drinks are consumed, the bacteria in the dental plaque will metabolise the sugars in your food to produce acids, which will cause the loss of minerals from tooth surfaces. Although saliva can neutralize the acids and slow down the standardize process, it takes a long period of time to do so. If we eat and drink frequently, the acid cannot be adequately neutralise by the saliva, and the continuous demineralization will eventually result in formation of Dental Caries.

B. Symptoms and treatment of Dental Caries

Early Dental Caries:
The early stage of dental caries occurs in the enamel of a tooth. Early Dental Caries is usually painless and the tooth surface seems intact when examined by the naked eye. Caries at the adjacent tooth surfaces are even more difficult to be detected, and they often need to be confirmed by X-ray.

Treatment:
The early caries lesions can be repaired by highly concentrated topical fluoride applied by dentist.

Dental Caries spreads into dentine:
A cavity appears on the tooth, and pain is felt when eating.

Dental Caries spreads into pulp:
At this stage, the caries lesion is very obvious and causes severe pain. The pulp tissues are infected by the bacteria and may become necrotic. The bacteria may even spread from the pulp to the surrounding periodontal tissues via the apex of the tooth, cause inflammation and lead to the formation of abscess.

C. People who are more prone to having dental Caries

People with dry mouth
Seniors tend to have dry mouth because their salivary glands have degenerated over the years. Chances of having dental caries increase because there isn't enough saliva to neutralize the acid produced by dental plaque. Some of them also take anti-hypertensive and anti-depressant drugs which will cause dryness in the mouth.

People receiving Radiotherapy
Amount of salivary production will significantly decrease for those who had received radiotherapy in the head and neck area. Therefore, chances of having dental caries will greatly increase because there isn't enough saliva to neutralize the acid produced by dental plaque after they eat and drink.

Pregnant women
Dietary habits of pregnant women may change and they tend to prefer sweet and sour food. The frequency of meals may also increase during pregnancy, which results in a higher risk of getting dental caries.

D. Consequences of dental caries

• The cavity emits unpleasant odour and causes bad breath. This directly affects the normal social life.
• Dental caries may lead to persistent pain, which affects one's appetite, studies, work, sleep, or even general health.
• When there is severe dental caries, the bacteria may spread from the pulp to the surrounding periodontal tissues via the apex of the tooth, cause inflammation and lead to the formation of dental abscess.
• If a tooth is severely damaged that even pulp treatment cannot be done, an extraction is necessary. After the extraction, the neighbouring teeth will shift toward the empty space and cause bad alignment of teeth.
• If the teeth which support a denture had been extracted due to dental caries, a new denture has to be made.

E. Methods to prevent Dental Caries

• Keep a good dietary habit
  Every time when we eat or drink, demineralization occurs at the surface of our teeth and creates a chance for getting dental caries. The more often we eat or drink, the greater the chances for us to have dental caries. Therefore, having regular meals three times a day with sufficient amount of food during each meal will reduce the frequency of meals we have, and thus reduce the chance of getting dental caries. Avoid snacking in between meals. If you feel hungry in between meals, you may snack once. When you feel thirsty, just drink plain water to quench thirst.
  
• Brush your teeth with fluoride toothpaste in the morning and before bed at night
  Fluoride strengthens the teeth by increasing their resistance to acid attack. Fluoride also facilitates mineral to re-enter the teeth (remineralization) and helps repair early caries lesions. Therefore, you should brush twice daily with fluoride toothpaste.
  
• Have annual regular dental check-up
  Have regular dental check-up at least once a year so that early dental caries can be diagnosed at an early stage. Preventive dental treatments such as fissure sealants can be applied when appropriate.