Tooth decay is a common disorder, second only to the common cold. It usually occurs in children and young adults, but can affect any person. Tooth decay is a common cause of tooth loss in younger people.
Bacteria are normally found in your mouth. These bacteria change foods -- especially sugar and starch -- into acids. Bacteria, acid, food pieces, and saliva combine in the mouth to form a sticky substance called plaque. Plaque adheres to the teeth. It is most common on the back molars, just above the gum line on all teeth, and at the edges of fillings.
Plaque that is not removed from the teeth turns into a substance called tartar or calculus. Plaque and tartar irritate the gums, resulting in gingivitis and periodontitis.
Plaque begins to build up on teeth within 20 minutes after eating. If it is not removed, tooth decay will begin.
The acids in plaque damage the enamel covering your teeth, and create holes in the tooth (cavities). Cavities usually do not hurt, unless they grow very large and affect nerves or cause a tooth fracture. An untreated cavity can lead to a tooth abscess. Untreated tooth decay also destroys the inside of the tooth (pulp), which will require more extensive treatment, or worse case removal of the tooth.
Carbohydrates (sugars and starches) increase the risk of tooth decay. Sticky foods are more harmful than non-sticky foods because they remain on the teeth. Frequent snacking increases the time that acids are in contact with the surface of the tooth.