The tooth usually doesn’t hurt, but it hurts when you eat, most likely due to the following three reasons: First, the tooth is split, the most typical symptom of splitting is that it hurts especially when you bite something. The most typical symptom of a split tooth is that it hurts especially when you bite something. And after a long time, an abscess will appear next to the split. Second, the teeth have allergy, if the patient often eats too hard food, the enamel on the surface of the teeth is worn out, the dentin is exposed, there will be dentin allergy, eating too cool, too hot food will appear stimulation pain. Thirdly, if the tooth has deep cavity, there will be food embedding pain, then the patient can still save the dental nerve as long as he goes to the hospital for filling treatment in time. Patients have pain, which proves that the dental nerve is still good so far, so patients must go to the hospital for filling in time.