Tooth decay is the breakdown of the tooth enamel, the hard outer surface of a tooth. It is caused by bacteria feasting on sugary or starchy foods, such as candy, bread, milk, fruit, and soda, and producing acids. Bacteria, acid, food debris, and saliva combined, form a sticky substance called plaque. If the plaque is not removed by regular brushing, flossing, and professional cleanings, the acids begin to eat away at the enamel, creating holes called cavities. Tooth grinding can also compromise your child’s tooth enamel, increasing the risk of tooth decay.