Abstract: Objective: To evaluate the efficiency of distance and angular of tooth movements in adults treated with clear aligners by superimposing the digital modes．Methods: Thrity two Class I adults with 4 first premolar extraction were included in this study，and each patient was treated with Invisalign G6 system. Initially, predicted treatment and actual treatment digital models were celected, imported into 3D Slicer software, superimposed the modes, and compared the predicted and actual changes of distances and angles of upper and lower incisors and canines. Results: Actual changes of distance of all the incisors and canines were much less than predicted changes of distance. The predicted changes of torque angles of upper and lower incisors, and axial inclinations of upper and lower canines were much less than the actual ones. Actual changes of other torque angle, axial inclination and rotation angle were much less than predicted changes. Conclusions: In the adults treated with clear aligners after extraction, actual distances of three-dimensional movements of upper and lower anterior teeth are not enough, the incisors become more lingually incined, and the canines become more distally incined.

Key words: [Key words] Invisible?orthodontic?treatment, adult patient with extraction, efficiency of tooth movement