Many people think that toothache can’t be filled and can’t be treated until it doesn’t hurt anymore. Sometimes the doctor fills our tooth because of the pain of tooth decay, but the painful tooth swells up. If we know some reasons of pain, it is extremely useful for us to receive treatment and cooperate with treatment. In fact, there are many kinds of tooth pains, some are decay pain, some are pulpitis pain, and some are periapical tooth pain. The symptoms of different diseases are different, but often people feel mainly pain. For example, some have occasional pain, some have pain from eating hot or cold, and some have pain from biting up against the teeth. All of the above symptoms are to be treated. A good doctor will definitely try to preserve your pulp activity during treatment, but due to the special structural characteristics of the tooth, which is a closed chamber cavity with a solid outer wall, when some people develop severe edema in the pulp after treatment, often this effort will not be successful and there will be pain or apical swelling, so the treatment to preserve the living pulp is at the risk of failure. However, the sensation and prognosis of a retained living pulp tooth is different from that of a dead pulp tooth, and such a risk should still be taken. In the root canal treatment, when the physician seals and disinfects the infected root canal, the effect of the treatment drug on the root tip will sometimes cause painful reactions, and the theoretical practice is to repeatedly change the medication until the bacteria culture is completely free of bacteria before filling the filling, often it takes several times just to change the medication and follow-up, which costs money, not counting time. But in our country, there are few doctors, many patients, patients into the hospital is difficult to achieve the situation, doctors often rely on experience and sealing time to determine whether to give patients fill. Sometimes the medication will still produce some pain and even swelling in some severe reactions to the apical effect, but most will improve with general antibacterial and anti-inflammatory treatment. If the patient is in pain, the patch should be removed and the medication should be sealed and replenished when the pain is all gone. For patients with periapical inflammation (painful biting with swelling), the pulp should first be opened to alleviate the painful symptoms through drainage, and then treated according to the procedures of root canal therapy after the swelling and pain have completely disappeared. It should be noted that since the root canals of such patients are infected, the treatment response may also be much greater.