Tooth decay is not painful and root canal treatment is not necessary in most cases. Tooth decay that is not painful is considered to be in a relatively early stage. In this case, the cavity is mainly in the superficial part of the tooth, but not in the deeper part of the dentin, and it does not cause neuropathic pain. In this case, we can go to the stomatology department and apply the power system of stomatology to remove the decayed part of the tooth, prepare the corresponding cavity shape and fill the cavity with filling material, but there is a special case. However, there is a special case that the pulp of the tooth is already necrotic, then the cavity will not be painful even if it is deeper, if the tooth is found to be darker, it is still necessary to carry out root canal treatment and then crown restoration treatment to protect the cavity.