PURPOSE: This study aimed to evaluate the trabecular bone changes after alveolar bone grafting in unilateral cleft lip and palate (UCLP) patients using a computer-aided diagnosis (CAD) system. MATERIALS AND METHODS: The occlusal radiographs taken from 50 UCLP patients were surveyed retrospectively. The images were categorized as: 50 images in group 0 (before bone grafting), 33 images in group 1 (one month after bone grafting), 24 images in group 2 (2-4 months after bone grafting), 15 images in group 3 (5-7 months after bone grafting), and 21 images in group 4 (8 or more months after bone grafting). Each image was grouped as either "non-cleft side" or "cleft side". The CAD system was used five times for each side to calculate the pixel area based on the mathematical morphology. Significant differences were found using a Wilcoxon signed ranks test or paired samples t test. RESULTS: The pixel area showed a significant difference between the "non-cleft side" and "cleft side" in group 0 (404.27+/-103.72/117.73+/-92.25; p=0.00), group 1 (434.29+/-86.70/388.31+/-109.51; p=0.01), and group 4 (430.98+/-98.11/366.71+/-154.59; p=0.02). No significant differences were found in group 2 (423.57+/-98.12/383.47+/-135.88; p=0.06) or group 3 (433.02+/-116.07/384.16+/-146.55; p=0.19). CONCLUSION: Based on the design of this study, alveolar bone grafting was similar to normal bone within 2-7 months postoperatively.