Skeletal Class II Prognathic Mandibular Case Report

Through Twin-Block appliance + maxillary expansion and auxiliary muscle function training, the early treatment of adolescent cases with mandibular functional retraction and severe deep overbite and deep overjet of anterior teeth was carried out. A 9-year-old male patient presented with lip exposure, incomplete lip closure, maxillary protrusion, severe labial inclination of upper anterior teeth, narrow upper dental arch, functional mandibular retraction, severe deep overbite and deep overjet of anterior teeth, accompanied by bad habits of biting lower lip and mouth breathing. Early correction was performed by Twin-Block appliance + maxillary expansion, and lip muscle function training was assisted, and perioral tape was used to break the oral breathing habit. The treatment period was 19 months. The patient 's anterior teeth were retracted, the upper dental arch was widened, the sagittal position relationship between the upper and lower jaws was coordinated, the anterior tooth coverage was normal, the facial shape was significantly improved, and the habit of biting the lower lip and mouth breathing was also successfully broken. Although excessive adduction of anterior teeth improves deep overjet, it is also necessary to be alert to the risk of possible mandibular growth inhibition, and to dynamically adjust the plan through regular follow-up and growth assessment. Coordinating the dynamic balance of perioral muscles is conducive to the normal adjustment of teeth and jaw position. Appropriate early treatment of children can greatly reduce the difficulty of stage II correction.