Apical periodontitis is classified into acute apical periodontitis and chronic apical periodontitis. The primary goal in acute apical periodontitis is to alleviate pain, while chronic apical periodontitis requires root canal treatment. In cases of acute apical periodontitis, it is necessary to open the pulp chamber and extract the root pulp to facilitate drainage through the root canal. Additionally, if an acute apical abscess extends to the subperiosteal or submucosal areas, incision and drainage of the abscess should be performed simultaneously. Once the acute symptoms of apical periodontitis are controlled, root canal treatment is required, typically involving around four sessions. The treatment of periodontitis follows a specific sequence, generally divided into four stages: 1. The first stage is the initial therapy, which primarily includes oral hygiene education, teaching patients proper brushing techniques, extracting teeth with poor prognosis and no retention value, performing scaling, root planing, and root surface debridement. 2. The second stage is periodontal surgery, which is considered approximately two months after the completion of the initial therapy if periodontal pockets deeper than 5 millimeters persist and bleeding upon probing is still present. 3. The third stage involves restorative treatment and stabilization of loose teeth. 4. The fourth stage, known as the maintenance phase or supportive periodontal therapy, focuses on encouraging patients to attend follow-up visits and addressing any issues that arise during these visits.