The common medical name for tooth decay is caries, and teeth are extracted only when they are so badly decayed that they have no value for retention. If not extracted in time, it may cause diseases such as periapical periodontitis, bacteremia in severe cases, and headache as well as affecting the occlusal relationship of the teeth. 1. Periodontitis and other diseases: If caries is not extracted in time, the broken tooth will easily cause pulpal infection and enter the apical tissues, which will cause periapical periodontitis, alveolar abscess, apical cyst and other diseases, which will cause tooth pain, loosening, redness, swelling, pus and other symptoms. 2. Bacteremia: If the damaged tooth remains in the mouth for a long time, when the infection is serious, the metabolites of bacteria may enter the bloodstream and cause bacteremia, with symptoms such as fever, hypothermia, dizziness, vomiting, and rapid heart rate. 3. Headache: If tooth decay is not extracted in time, the damaged tooth can stimulate the patient to have a toothache, and at the same time, the pain can radiate to the head and face, causing headache. 4. Affecting the occlusal relationship of the teeth: tooth decay can cause pain, and patients are often unable to chew food or close their teeth properly, and if they are not extracted for a long time, the occlusal relationship of the teeth may be affected. It is recommended to consult the stomatology department of regular hospitals in time, and actively treat under the guidance of doctors.