Toothache caused by tooth decay is usually a symptom of pulpitis caused by tooth decay. Most of the reasons for tooth decay are due to the bacteria invading the hard tissue of the tooth and causing the decay of the hard tissue of the tooth. In the early stage of decay, the main cause is the change of color and texture of the tooth, there is no obvious pain at this time, and the treatment measures are relatively simple at this time, the decayed part should be removed by turbo drill, and then the filling material should be filled up. Once the pain is caused, it means that the caries has reached the deeper part, then the problem cannot be solved by simply repairing the caries, we must remove the caries and open the pulp directly to drain out the inflammation in the pulp, then the pain will be relieved immediately. Then the pulp is extracted and the pulp cavity is filled by root canal treatment. Finally, a crown restoration is applied to protect the entire tooth, so that it can continue to serve the masticatory function of the mouth for a longer period of time.