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Objective: to alternate teething severe bone before dental anti teeth together patients with an appliance in front of traction therapy before and after the X line lateral piece line cephalometric measurements of the same time occlusal and soft tissue side Maung conduct evaluation, and further analysis patients with severe bone anterior teeth crossbite protraction bone and dental changes before and after treatment, to develop a reasonable, feasible plan of correction to provide important reference for orthodontic treatment. Subjects and Methods: Select an aggregate of 20 patients with severe bone anterior teeth mixed dentition crossbite as research subjects (-6. Lt; ANB lt; -4 °), the mixed dentition light to moderate bone anterior teeth crossbite patients 20 cases as the control group (-4 ° lt; ANB lt; 0 °), each group of men and women of the 10 patients, aged 7-12 years, with an average of 8.7 ± 1.4 years. All patients showed a concave anterior teeth crossbite molars was mesial relationship, anti covering 2-6mm jaw can not turn back, the upper and lower dental arch apparent width not tune may be associated with mild mandibular prognathism is not associated with The excessive growth of the jaw, the mouth of pathological change, no other craniofacial anomalies, generally in good condition, normal growth and development, there was no history of orthodontic treatment. None of the patients arch expansion, using protraction correction only. Before and after treatment cephalometric lateral radiographs were taken, the traditional cephalometric reference system for measurement and analysis of digital X-ray before and after treatment cephalometric piece, and Pancherz skull. 21 measure of hard tissue, soft tissue measure 6. SPSS13.0 statistical package for statistical analysis of the measured data, using a paired t-test statistics measuring changes before and after treatment. The result: the end of the protraction, the two groups of patients were established shallow cover (?) Covering the relationship between molar relationship and skeletal class Ⅲ face significantly improve the appearance of patients and parents contralateral satisfactory. Course of 4-6 months, median treatment duration of 5.3 ± 1.3 months. The two groups of patients before and after treatment were statistically measure of hard tissue SNA, ANB, ANS-Me, N-Me, U1-SN, U1-NA (°), L1-MP, SN-MP, Wits change significance, the measure of all soft tissue changes also have significant differences; addition, the severe group U1-NA distance from the L1-NB angle, L1-NB also has a significant change before and after treatment of U1-L1. 2 the difference between the measurement results of the two groups of patients with head Movies comparison shows that the hard tissue measure ANS-Me, the U1-SN, U1-NA (°) (mm) U1-NA, L1-MP, L1-NB (°) L1-NB (mm), SN-MP, Wits changes, severe group mild to moderate group is more pronounced; soft tissue measure upper lip sudden, the angle of the face, upper lip - aesthetic, lower lip - aesthetic changes, severe group lighter moderate group is more pronounced. Conclusion: 1. Severe bone anterior teeth crossbite mixed dentition together patients with maxillary protraction forward, clockwise rotation of the mandible, the sagittal jaw up and down to the position change is evident, there are significant differences before and after treatment with mild severe group showed no significant difference. . Mixed dentition severe bone anterior crossbite occlusion patients protraction approached teeth lip dumping obvious, the lower incisors obvious lingual inclination, lighter moderate group changes significantly, and there are significant differences. 3. Mixed dentition severe in patients with bone anterior crossbite occlusion protraction, bony changes (26%) was significantly less than the bony changes of mild to moderate group (42%). 4. Protraction treatment of severe mixed dentition patients with bone anterior crossbite occlusion, cephalometric and bone reshaping there were significant changes, the effect of early treatment.
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