Tooth decay, also known as dental caries or cavities, is a common dental problem characterized by the destruction of tooth structure by acids produced by bacteria in dental plaque. It begins with the demineralization of enamel, leading to the formation of small holes or cavities in the teeth. Factors contributing to tooth decay include poor oral hygiene, frequent consumption of sugary or acidic foods and drinks, and inadequate exposure to fluoride. Prevention strategies for tooth decay include practicing good oral hygiene, maintaining a healthy diet, and receiving fluoride treatments as recommended by a dentist.