It is normal to feel bloated after a filling, due to the reaction of the nerve of the tooth caused by the expansion of the material. Temporary discomfort, such as tooth swelling, may occur after a dental filling. This is due to the swelling of the filling material after filling, the nerve of the tooth is compressed and a transient reaction occurs. This usually disappears after 24 hours and there is no significant discomfort. If the tooth swells for a long time after filling, it may be a symptom of deeper caries, and the material stimulates the nerve of the tooth, so you need to consult a doctor in time. Therefore, the feeling of swelling after filling is due to the reaction of the filling material pressing on the nerve, which can disappear automatically after 24 hours, and the prolonged swelling may be the inflammation of the nerve, which needs to go to the dentist for medical treatment in time.