OBJECTIVES: To quantify longitudinal bone changes in the maxilla after secondary alveolar bone grafting (SABG) in patients with unilateral cleft lip and/or cleft palate (CL/P), and to describe the maxillary dimensions before and after SABG in all orthogonal planes using a Cone Beam Computed Tomography (CBCT)-based methodology. METHODS: Ethical approval was obtained to retrospectively analyze CBCT scans of children treated for unilateral alveolar clefts. Inclusion criteria encompassed individuals who underwent SABG before the eruption of the cleft-side permanent lateral incisor or, if absent, the permanent ca-nine, and had both preoperative and postoperative CBCT scans. A total of seven measurements of maxillary dimensions in all orthogonal planes, as well as in panoramic reconstruction, were conducted in the CBCT images. The normality of the data was confirmed with the Shapiro-Wilk test. A paired t-test was applied to assess significant differences between the preoperative and postoperative measurements (p <
0.05). The impact of age, gender, and their interrelation was evaluated by two-way ANOVA (p <
0.05). RESULTS: A total of 47 patients, comprising 32 males and 15 females, were selected based on the specified criteria. Notably, we observed a significant increase in sagittal, vertical, and transverse dimensions between the preoperative scans and those taken one year postoperatively (p <
0.05), irrespective of the patients' ages and genders. When considering gender, data indicated that male patients exhibited wider transverse dimensions in both the preoperative and postoperative measurements. CONCLUSIONS: This study introduced a CBCT-based method to quantitatively assess maxillary changes in unilateral CL/P patients after SABG. The approach demonstrated continuous dimensional changes in all orthogonal planes. In addition, it described the maxillae dimensions in all planes. Future research can utilize this method for precise measurement of maxillary alterations and dimensions.