Filling relatively shallow cavities is generally painless, while filling deeper cavities can be painful. The location of the cavity is relatively shallow, the degree of caries is not serious, filling the cavity will be prepared, and the prepared material will be fastened on the cavity, the process is relatively simple, basically no pain symptoms. The location of the cavity is deeper and closer to the pulp, during the filling process machinery, cold water, etc. will stimulate the dentin, in the mechanical stimulation, cold water stimulation will trigger pain. If the cavity is decayed to the nerve of the tooth may also need root canal treatment, the tooth will also be more sensitive, the pain is stronger. The patient will need to be injected with anesthetic during the filling treatment. It is recommended to go to a regular hospital stomatology department in time after discovering the existence of cavities in the teeth.