Before orthodontic treatment for periodontitis, ultrasonic scaling and subgingival scraping must be completed to remove calculus, plaque bad restorations and other irritants and restore the gums to a healthy state. If necessary, deeper periodontal pockets need to be removed and periodontal surgery such as guided tissue regeneration and bone grafting is optional. After 3-6 months of postoperative inflammation control, orthodontic treatment will be performed. By aligning crowded and misaligned teeth, correcting deep overlap and deep coverage of anterior teeth, closing the adjacent gap of teeth, establishing good upper and lower bite relationship and removing bad habits, the development of periodontitis can be controlled and periodontal tissues can be restored to health with good treatment results.