Main Instructor Hsin-Yi Lo
Department / Institution Division of Orthodontics, Veteran General Hospital, Taichung
Classification Case report
「Case」: A 19 year-old female presented Skeletal Class II relationship (ANB:10 o ) with maxilla prognathism (SNA:94 o ), Class II molar relationship with increased LAFH, anterior large overjet (overjet: 7 mm) and convex facial profile with weak chin. The patient underwent four bi-cuspids extraction and space closure under maximum anchorage. Two TADs were placed at bilateral infrazygomatic crests for anchorage reinforcement and upper posterior teeth intrusion. Two TADs were placed at buccal shelf for vertical control. The other two anterior TADs were placed for root-torque control. After 4-year non-surgical orthodontic treatment, improved facial esthetic and functional results were obtained at the end of the treatment.
「Discussion & Summary」: The etiology of skeletal class II malocclusion could be maxillary prognathism, mandibular retrognagia, or a combination of both. The maxilla protrusion with large intermaxillary A-P discrepancy is the indication of surgical therapy. However, with the development of TADs, Class II camouflage treatment can be an alternative while a powerful anchorage system is available. In this case, the patient had a class II malocclusion due to maxillary prognathism. Therefore, after TADs application on bilateral IZCs, we achieved anterior tooth retraction under maximum anchorage while upper subapical screw is contributed for vertical control. Moreover, the IZCs TADs were used to intrude upper molar , while the TADs on bilateral buccal shelf were placed to prevent lower molar from extrusion during space closure. As a result of upper molar intrusion and vertical control of lower molar, the mandible rotated counterclockwise with the ANB decreased and increased chin projection.
Dental Class II Malocclusion with Severe Intermaxillary Basal Bone Discrepency: A Case Report