Cavities and tooth decay refer to the same condition. Cavities are a professional medical term, also known as tooth decay or dental caries, which is a bacterial disease causing damage to the teeth due to various factors. It is generally caused by frequent consumption of sugar or lack of oral care for vitamins. In the early stage, the symptoms of the disease are not obvious, and there might be only minor color changes on the surface of the tooth. However, as time goes on, the decay of the tooth worsens, gradually leading to the formation of cavities. If the disease continues to develop, it could also lead to pulpitis and periapical periodontitis, thus it's crucial to treat cavities at an early stage.