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VERTICAL CHANGES OF HIGHANGLE PATIENTS FOLLOWING TOOTH-EXTRACTION TREAMENT

Objective To evaluate changes of vertical craniofacial construction in high-angle patients after tooth-extraction treatment. Methods Forty high-angle teenagers(MP-SN≥38 °) were recruited in this study,four premolars were extracted in half of them,the others were treated without extraction.Cephalometric radiographs taken before and after treatment were traced and measured.Student's t-test was used. Results Compared with that before treatment,U6-PP,N-Me,ANSMe and L6-MP increased significantly in both extraction and non-extraction group after treatment(t=3.14-16.22,P0.05,0.01).A significant difference was noted in Y-axis,L6-MP between two groups after treatment(t=2.59-2.93,P0.05). Conclusion Extraction of premolar cannot change the mandibular plane angle and the growth direction of mandibular,but can increase the molar height.