It is theoretically impossible for an apical abscess to heal itself, when the amount of inflammatory irritants in the periapical tissue at the time of formation of an apical abscess is already large enough and long enough in duration. Infringement of the periapical tissue through the apical foramen or the lateral parapapexy triggers a local immune response, leading to non-self-repairing destruction of the periapical tissue. At this point, without intervention by external therapeutic means, the scope of inflammation may further expand to cause more serious diseases, such as cellulitis, interstitial infections, apical abscesses of maxillary teeth, and possibly maxillary sinusitis by breaking through the mucosa of the maxillary sinus floor. The treatment of periapical abscesses mainly takes the form of root canal therapy, but one should not be optimistic that the periapical abscesses will be cured after root canal therapy is performed, but regular X-rays should be taken one month, three months, six months, one year and two years after root canal therapy to check whether the apical inflammation has been absorbed in comparison with the X-rays taken during the previous initial consultation. If the apical lesion does not shrink after the observation period of two years, then surgical treatment such as apical surgery is required.