What is tooth decay?

Bacteria destruction: Decay is usually caused due to plaque build up on or between your teeth, then the bacteria metabolize the sugars you eat and their byproduct is acid which eats into the outer layer of the enamel. After enough destruction the process enters the softer dentine below the enamel. Now you have a cavity.

Cavities: Tooth decay are holes or structural damage in the teeth. The bacteria in your mouth cause changes to sugar and starch to form acid which along with other things forms plaque that sticks to the teeth. The acids in the plaque cause damage to the enamel of the tooth and cause tooth decay.

No short answer: Tooth decay is a breakdown in the structure of a tooth that is cause by bacteria breaking down food material and releasing acids as a by product.

Bacterial action: Tooth decay is a breakdown in the structure of a tooth that is cause by bacteria breaking down food material and releasing acids when they metabolize the food. Sugars are the worst culprits.

Decalcification...: Tooth decay exists when there is decalcification of tooth structure through the enamel surface into the second layer, the dentin. This decalcification is caused by acid erosion. Bacteria in the mouth convert dietary sugars into acids to cause this decalcification. With good dental hygiene, eating habits, and with prevention with daily Fluoride and xylitol this decay can be best managed.

Bacterial infection: Tooth decay or caries, are caused by a combination of factors, including bacteria in your mouth, frequent snacking, sipping sugary drinks, and not cleaning your teeth well.

Decay: Tooth decay is demineralization of tooth structure due to acid by products of bacterial metabolism of sugar in the mouth

Decay: Decay is caused by bacteria which are naturally occurring in your mouth. When the bacteria are fed sugar, either simple like sweets or complex like bread or sugar, they produce acid which eats into the tooth.