Dental decay or dental cavity is basically a hole in the tooth. Dental decay often goes unnoticed until the tooth starts to feel sensitive to hot, cold or sweet, and sometimes gives a strong throbbing toothache which means the decay has reached and damaged the nerve.
Tooth decay is usually caused by bacterial plaque buildup on teeth over time. Foods high in carbohydrates, such as sugary foods and drinks, feed the bacteria in our mouth to produce more acid. This acid is what breaks down the surface of our teeth, causing holes in teeth that are known as cavities. Once our teeth are damaged, the plaque and bacteria can reach the soft dentine and eventually reach the nerve, causing serious toothache. In short, a mixture of a poor diet and poor dental hygiene causes tooth decay.