It usually occurs in children and young adults but can affect any person. It is the most important cause of tooth loss in younger people.
Bacteria are normally present in the mouth.
Bacteria, acid, food debris, and saliva combine in the mouth to form a sticky substance called plaque that adheres to the teeth. It is most prominent on the grooved chewing surfaces of back molars, just above the gum line on all teeth, and at the edges of fillings. Plaque and calculus irritate the gums, resulting in gingivitis . Acids begin to dissolve tooth enamel within 20 minutes after eating, the time when most bacterial activity occurs. Untreated tooth decay can result in death of the internal structures of the tooth with eventual loss of the tooth.