Modified Activators' Effects On Skeletal Class II In Mixed Dentition

This study aimed to explore the application effect of modified activator in the treatment of skeletal class II malocclusion in mixed dentition, and to analyze its correction effect on teeth, jaw and temporomandibular joint ( TMJ ), so as to provide basis for clinical promotion. 20 patients with skeletal class II malocclusion (overjet > 6mm, ∠ ANB > 5 ° ) in mixed dentition were included. The patients were treated with modified activator for 12 months on average. Cephalometric analysis and CBCT were utilized to compare changes in occlusion, jaw, and the morphological change of TMJ before and after treatment. After treatment, the patient's occlusal relationship, soft tissue profile and sagittal relationships between maxillary and mandible were greatly improved. At the same time, the difference of cephalometric indicator∠ANB significantly decrease(from 7.47±1.76° to 3.93±0.55°). Besides, the width of condyle, posterior joint space and articular fossa increased significantly (p < 0.05), and the shape of condylar posterior slope was improved without osseous abnormality. The modified activator can effectively realize the mandibular advancement and improve occlusal function of skeletal class II malocclusion in mixed dentition, stimulate the adaptive growth of condyle. Meanwhile, it has high clinical safety, which is worthy of clinical popularization and application.