Periapical periodontitis in all-ceramic teeth should be treated by taking apical radiographs to determine the lesion and the area of inflammation. If X-rays show secondary caries in the crown of the abutment tooth, the presence of hypodense shadows in the apical region, and the formation of fistulae or sinus tracts in the apical region, theoretically, the original old crown should be removed and then the jaw of the tooth should be abraded to perform endodontic re-treatment, and after controlling inflammation, the pulp is removed, the root canals are prepared, disinfected, and filled, and then the pulp-opening foramen is closed. The all-ceramic crown is then remade and cemented. If it is found that the abutment tooth shows root fracture accompanied by periapical infection, it is necessary to extract the all-ceramic tooth before restoration.