Dental caries is a very common problem. Bacteria normally reside in the mouth. They, however, mix with the proteins present in the saliva (spit) to form plaque and attach to the hard enamel surface of the tooth. The bacteria feed on food sugars and starches and produce an acid. This acid eats into the tooth enamel damaging the tooth. What are the symptoms? Initially there may be no symptoms while the enamel is being eaten away. Later, tooth sensitivity may be noticed. There may be discomfort while eating sweet foods and hot or cold drinks or foods. If the cavity becomes very large or a tooth abscess develops which may be accompanied by pain, swelling or fever. This is why it is important to have frequent dental check ups. If it hurts, it is already too late. How is it diagnosed? A dentist may identify the areas of decay quite early. Sometimes dental X-rays may be advised.