The Tooth decay is destruction of tooth structure and can affect both the enamel and the dentin layer of the tooth.

The tooth decay occurs when foods containing carbohydrates (sugars and starches) such as breads, cereals, milk, soda, fruits, cakes, or candy are left on the teeth. Bacteria that live in the mouth digest these foods, turning them into acids. The bacteria, acid, food debris, and saliva combine to form plaque, which clings to the teeth. The acids in plaque dissolve the enamel surface of the teeth, creating holes in the teeth called cavities, or caries

To prevent tooth decay and to stop tooth decay :

• Brush your teeth at least twice a day with a fluoride-containing toothpaste. Preferably, brush after each meal and especially before going to bed.
• Clean between your teeth daily with dental floss or interdental cleaners, such as the Oral-B Interdental Brush, Reach Stim-U-Dent, or Sulcabrush.
• Eat nutritious and balanced meals and limit snacks. Avoid carbohydrates such as candy, pretzels and chips, which can remain on the tooth surface. If sticky foods are eaten, brush your teeth soon afterwards.
• Check with your dentist about use of supplemental fluoride, which strengthens your teeth.
• Ask your dentist about dental sealants (a plastic protective coating) applied to the chewing surfaces of your back teeth (molars) to protect them from decay.
• Drink fluoridated water. At least a pint of fluoridated water each day is needed to protect children from tooth decay.
• Visit your dentist regularly for professional cleanings and oral examination.

Researchers are developing new means to prevent tooth decay. One study found that a chewing gum that contains the sweetener xylitol temporarily retarded the growth of bacteria that cause tooth decay. In addition, several materials that slowly release fluoride over time, which will help prevent further decay, are being explored. These materials would be placed between teeth or in pits and fissures of teeth. Toothpastes and mouth rinses that can reverse and "heal" early cavities are also being studied.