A toothache that you don’t know which tooth hurts is usually the result of causes such as pulpitis and periapical inflammation. You can go to the hospital to choose visual examination, hot and cold examination and imaging examination for detection. 1. Visual examination: You can go to the hospital and under the doctor’s professional guidance, check whether there are any caries, cracks or wedge-shaped defects in the teeth, as well as whether there are any deformed central cusps. 2. Hot and cold diagnosis: Use hot and cold stimuli to line up the response of the teeth, if which tooth is more sensitive, it means which is the tooth that causes pain. 3. Imaging: In the case of adjacent cavities or root fracture, where it is impossible to observe the inside of the gums, imaging can be chosen to assist in the diagnosis of which tooth is causing the pain. When a toothache occurs but it is not clear which tooth is causing the pain, it is recommended that the patient go to the hospital for examination and diagnosis in a timely manner, and under the guidance of the doctor for treatment.