Estimate The Curative Effect Of Using The Modified Forsus Appliance Treat The Class â…¡ Mandibular Retrusion And Analyze The Temporomandibular Joint Changes On Magnetic Resonance Imagin

Objiective:To compare the lateral profiles、bone changes and temporomandibular joint changes on the magnetic resonance images befoe and after the treatment of Class II mandibular retrusion by using modified Forsus appliance,to investigate the lateral looks、bone changes curative effect and the growth reconstruction of temporomandibular joint.Methods:After straight arch wire techniques neat row of teeth flat list,30children with mandibular retrusion were selected and treated with modified Forsus appliance.Cephalometric radiographs and Magnetic resonance images were taken and analyzed at pre-treatment and post-treatment. Cephalometric radiographs were analyzed with Pancherz analysis. Magnetic resonance images were analyzed with Kurita analysis. The statistical software SPSS13.0was chosen to analyse.Students t-test was used to determine if there were significant differences between pre-treatment and post-treatment.Results:After5～7months of therapy, mean6.2moths, mandibular advanced and mandibular retrusion profiles were obviously improved. The sign of B was advanced obviously,SNB increased by (3.5±1.5)°(P<0.05), ANB decreased by (2.1±0.8)°(P<0.05),and both had significant difference.A-OLP decreased by (0.3±1.2) mm, B-OLP increased by (2.7±2.9) mm,the later had significant difference. The overjet was decreased by (5.0±2.8)mm, and the molar relationship was corrected to Class Ⅰ.The signs of condylar multiplication were observed at the posterior-superior border. The relationship between condylar and fossa (TC/TP)and the relationship between disc and fossa(TD/TP) had significance difference between pre-treatment and post-treatment (p<0.05);But the relationship between disc and condylar (TD/TC) had no significance difference between pre-tr eatment and post-treatment (p>0.05)Conclusion:During modified Forsus appliance combined with straight wire appliance treat Class II mandibular retrusion the mandibular advanced and mandibular retrusion profiles were obviously improved,can effectively stimulate the mandibular growth,balance the maxillary and mandibular relationship,obviously change the patients’lateral profiles,adjust the molar relationship.The modified Forsus appliance could also sitimulate the mandibular growt,condylar and disc produced adaptive reconstruction and the relative positon of condylar-fossa-disc could keep coordination.