After filling the tooth half a year and start to hurt again may be secondary to caries, pulpitis, apical periodontitis of the tooth. The main treatments are filling treatment and root canal treatment. 1. Filling treatment: It may be secondary caries around the filling after six months of filling, if the pulp is not yet involved, the decayed tissues can be removed and then filled again. 2. Root canal treatment: If you have endodontitis or apical periodontitis, you need root canal treatment to clean up the inflamed pulp tissue and then fill the filling. It is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.