Tooth decay requires the simultaneous presence of three factors: plaque bacteria, sugar, and a vulnerable tooth surface. Although several microorganisms found in the mouth can cause tooth decay, the primary disease agent appears to be Streptococcus mutans. The simple sugars used by the bacteria are glucose, sucrose, and lactose. They are converted primarily into lactic acid. When this acid builds up on an unprotected tooth surface, it dissolves the minerals in the enamel, creating holes and weak spots (cavities). As the decay spreads inward into the middle layer (the dentin), the tooth becomes more sensitive to temperature and touch. When the decay reaches the center of the tooth (the pulp), the resulting inflammation (pulpitis) produces a toothache.
Tooth Decay Definition
Tooth decay, which is also called dental cavities or dental caries, is the destruction of the outer surface (enamel) of a tooth.
Tooth decay results from the action of bacteria that live in plaque. Plaque is a sticky, whitish film formed by a protein in saliva (mucin) and sugary substances in the mouth. The plaque bacteria sticking to tooth enamel uses the sugar and starch from food particles in the mouth to produce acid, which destroys the tooth's enamel.