Combined the elaboration on periodontic- endodontic lesion in the textbook Periodontics with the deficiencies existed in the clinical and teaching work and demonstrated the understanding on the type of the combined periodontic- endodontic lesion, and suggested the viewpoint of no sub- type of combined periodontic- endodontic lesion Only regard the type of pulp disease that induced by periodontal disease as genuine combined periodontic- endodontic lesion.
