Cavities are a type of destructive dental hard tissue disease caused by bacterial infections and are also a chronic progressive infectious disease. Cavities can only improve through early and effective intervention and treatment; otherwise, the condition may develop further, leading to pulpitis or apical periodontitis. Severe cases can also cause systemic symptoms such as space infections, and some may lead to bacteremia or sepsis. In the early stages of development, cavities have no clinical symptoms. At this stage, filling the cavity is painless. If the decay progresses to reach or approach the dental nerve, filling the cavity can then cause widespread pain. If it reaches the dental nerve, it cannot be directly filled in one go; it requires dental treatment for improvement.