Abstract: Objective: To evaluate the clinical effect of a patient with malocclusion, accompanied by chronic severe periodontitis, who was treated with an invisible appliance without brackets. Diagnosis and Treatment: The patient had chronic severe periodontitis complicated by pathologic anterior displaced incisors, deep bite, and deep overjet. After a clear diagnosis and informed consent, the patient underwent a complete periodontal treatment, and was treated with orthodontic treatment by invisible appliance without brackets. Post-treatment lingual fixed retention wires and clear retainers were maintained. Regular periodontal maintenance was performed during the orthodontic treatment. Results: After the patient’s combined periodontal-orthodontic treatment, the deep bite and deep overjet reached a normal level, a good cusp-molar relationship was established, and the occlusal force line was improved. The periodontal condition did not undergo significant aggravation during orthodontic treatment. The results of orthodontic treatment were stable at 2-year follow-up. Conclusions: Bracketless invisible orthodontic appliances have certain therapeutic effect on secondary malocclusion in severe periodontitis.

Key words: periodontitis, periodontitis complicated by pathologic anterior displaced incisors, periodontal-orthodontic combined treatment, treatment by invisible appliance without brackets, skeletal classⅢ high angle malocclusion;