Abstract: Objective　To explore dentoskeletal changes and factors that correlated with vertical control effect in extraction cases treated with clear aligner appliances and miniscrews. Methods　Thirty-two patients (mean age, 27.1±4.3 years), who were extracted 4 premolars followed by Invisalign treatement with upper miniscrews for retraction of anterior teeth, were retrospectively selected. Cone-beam computed tomography (CBCT) images were taken before and after treatment. Treatment changes in the position of the anterior and posterior teeth, menton, mandibular plane angle (MP-SN), occlusal plane angle (OP-SN) and lower face height (ANS-Me) were measured on the CBCT and cephalometric radiographs generated from CBCT and counted using paired-comparison test. The correlations of significant variables with mandibular plane angle were evaluated using correlation analysis. Results　After treatment, the upper incisors showed significant retraction (6.76±1.75) mm and intrusion (1.57±1.54) mm, and the lower incisors were also significantly retracted (5.56±1.37) mm and intruded (2.94±1.15) mm. The mean vertical change in upper molars was a (1.21±0.79) mm intrusion, while a (0.36±0.92) mm extrusion in lower. Regarding the anteroposterior (AP) dimension, there was a significantly mesial movement in both upper (1.65±1.21 mm) and lower (1.30±0.84 mm) molars. The mean changes in mandibular plane angle was a 1.10°±0.99° of counterclockwise rotation with a anterosuperior movement in menton and a decrease in lower face height, whereas the occlusal plane angle was clockwise rotated. The changes above were all statistically significant (P＜0.05). The changes of mandibular plane angle was significantly correlated with the vertical position of lower molars (r=0.731，P＜0.01), upper molars (r=-0.485，P＜0.01) and upper incisors (r=-0.380, P＜0.05), the AP position of lower incisors (r=0.405，P＜0.05), and the changes of OP-SN angle (r=0.437，P＜0.05). Conclusion　Except retracted upper anterior teeth, extraction cases treated with Invisalign and upper miniscrews appear to have a relatively good vertical control with a decreased mandibular plane angle, which might be associated with the vertical position of upper and lower molars, vertical position of upper incisors, and the AP position of lower incisors.

Key words: orthodontics, corrective, orthodontic anchorage procedures, tooth extraction, cone-beam computed tomography, clear aligner, vertical changes, miniscrews