Cavities, also called dental caries or tooth decay, are extremely common in children. They can develop in baby teeth or permanent teeth when bacteria in the mouth combines with the sugar from food, starting a process that eats away at the tooth's outer layer. Cavities are often preventable with proper oral hygiene, a balanced diet, and regular visits to the dentist. This article discusses the causes of cavities in kids, treatment options, and tips for cavity prevention.