하악골이 후하방으로 회전된 성장기 골격성 II급 부정교합 환자의 교정치료

Orthodontic Treatment of a Growing Skeletal Class II Malocclusion Patient with a Downward and Backward Rotated Mandible

An 8-year and 4-month-old adolescent boy showed a skeletal Class II pattern, maxillary protrusion, posteriorly rotated chin, and respiratory problem. He also showed a retrusive soft-tissue chin with mentalis muscle hyperactivity when lips were sealed which indicated a vertical excess of the lower anterior facial height and backward rotation of the mandible. The orthodontic goals were to improve facial esthetics and achieve favorable occlusal relationships by applying the counterclockwise directional force and improving the respiratory function. Bioblock was applied to expand the maxillary arch and myofunctional therapy and adenotonsillectomy were performed to improve the nasorespiratory function and tongue posture. After eruption of all permanent teeth, four first premolars were extracted and high-pull J hook headgear, transpalatal arch, and elastic chains were applied to achieve an intrusion of the maxillary incisors and retraction of the incisors. Consequently, functional occlusion and esthetic facial appearance were obtained with a proper directional force and favorable mandibular growth.