RESUMO
Objective: To study the effective initiating time of the maxillary protraction therapy for the children with skeletal classⅢ malocclusion. Methods: 20 cases with class Ⅲ malocclusion were divided into 2 groups: older group (9～ 12 years old) and younger group(5～8 years old), and treated with maxillary protraction. Before and after treatment cephalometric radiographs were taken and analyzed. Results: Good effects were found in both groups. The treatment in the younger patients showed the advantages of shorter treatment period, more skeletal changes, less dental changes and less side effects. Conclusion: Earlier maxillary protraction is more beneficial to the children with Angle Ⅲ malocclusion.
RESUMO
Objective:To study the feasibility of rapid tooth movement by periodontal ligament distraction osteogenesis. Method: Periodontal ligament distraction osteogenesis technology was applied on the experimental side; traditional orthodontic tooth movement technology on the control side in 8 dogs. The treatment was countinued for 14 days. Tooth movement and alveolar bone remodeling were studied by in vivo measuring,roentgenogram, histology and immunohistochemistry 2,3,6 and 10 weeks after treatment respectively. Results:2 weeks after application of treatment tooth movement(mm) with periodontal ligament distraction osteogenesis and that with traditional orthodontic method was 3.49?0.57 and 1.06?0.32 (P0.05) respectively. Active osteogenesis was obsered on the tension loaded side, BMP expression on the experimental tension-loaded side was stronger than that in the control side (P