The statistics are staggering: According to the Centers for Disease Control and Prevention (CDC), over four million children are affected by tooth decay nationwide, a jump of over 600,000 additional preschoolers over the course of a decade. Senior citizens, those with diets high in carbohydrates and people who live in areas without a fluoridated water supply are also likely candidates for cavities. Have you ever had a cavity? Do you think you know what caused it?