Gum abscesses caused by tooth decay in children are often due to inflammation of the periapical region, which requires corresponding treatment such as root canal treatment or incision and drainage. Periapical inflammation. Children’s teeth have large apical holes, so if tooth decay is left untreated, the inflammation can easily spread to the root tip. It causes gum abscess, which is often caused by pulpitis developing into periapical abscess and periapical inflammation breaking through the periosteum to reach the submucosa. Clinically, for this situation, generally for abscess incision and drainage after root canal treatment to remove the infected pulp, at the same time can follow the doctor’s instructions with the antibiotic drug amoxicillin anti-inflammatory. Children’s tooth decay caused by gum abscess, it is recommended to go to the hospital to check the oral cavity and X-ray after targeted treatment.