Abstract: Abstract: Objective To evaluate the clinical efficiency of segmental invisible technique with mini-implant for en-masse retraction of maxillary anterior teeth on the aspect of vertical and torque in the treatment of bimaxillary protrusion. Methods Twelve subjects with upper dental alveolar bone protrusion were selected for this study. Arch-dimension variables were evaluated by cephalometric and dental models before and after orthodontic retraction. All data were analyzed by SPSS20. 0 software. Results For vertical control,U1E-PP was decreased by 0.78mm, U1AP-PP was decreased by 0.29mm,while U1CR-PP was showed no significant difference(P > 0.05). For sagittal control,all the anterior teeth were showed a decreased torque with canine displayed uprighting. Conclusion Segmental invisible technique with mini-implant is efficient in the vertical and torque control of anterior teeth in the treatment of bimaxillary protrusion,and provide an invisible effect meanwhile.

Key words: mini-implant, invisible orthodontic therapy, maxillary anterior teeth retraction