This two-center retrospective study evaluated the surgical accuracy and one-year stability of the anterior maxillary segment after three-piece segmented Le Fort I osteotomy for anterior open bite correction using a validated voxel-based three-dimensional assessment protocol. Patients treated between January 2016 and December 2021 were included. The anterior maxillary segment was assessed in three translational (left/right, anterior/posterior, intrusion/extrusion) and three rotational (roll, pitch, yaw) dimensions by comparing the virtual surgical plan with the early postoperative position and the early postoperative position with the one-year follow-up. Anterior open bite relapse was defined as a negative overbite, or an overbite of 0 mm without incisal contact, at one-year follow-up. Thirty-five patients (mean age 23 years; 54% female) were included. Mean absolute translational inaccuracy ranged from 0.98 to 1.39 mm and rotational inaccuracy from 1.63° to 4.41°, with the pitch dimension being most difficult to achieve and to stabilize. Anterior open bite relapse occurred in six patients (17%) and was associated with the magnitude of preoperative negative overbite, which was also the strongest predictor of postoperative overbite in exploratory regression analysis. Compared with non-relapsed patients, relapsed patients showed significantly greater extrusive and counter-clockwise pitch deviation from the virtual plan. Differences in postoperative stability between these groups were not statistically significant. Segmented Le Fort I osteotomy provided generally accurate and stable repositioning of the anterior maxillary segment, although vertical and pitch control remain clinically relevant challenges in anterior open bite correction.