Sudden toothache may be caused by the following reasons: First, pulpitis attack, if the patient has a deep cavity in the mouth, without timely filling, it is likely that the acute attack of pulpitis occurs when the resistance is weak. If a patient has a wisdom tooth blockage in the mouth and it is not removed in time, it is likely that the inflammation of the wisdom tooth will occur in case of cold or fever, and the wisdom tooth is also prone to repeated inflammation and toothache during the menstrual period of women. If the patient eats something hard, the tooth is afraid to bite again, there is a painful feeling when biting, or even an abscess appears on the mucosa, which proves that the root of the tooth may be damaged and fracture occurs.