Abstract : The alveolar ridge undergoes both horizontal and vertical resorption following tooth extraction, accompanied by alterations in the structure and composition of the overlying soft tissues. These changes compromise the optimal three-dimensional implant placement and necessitate bone augmentation procedures in such scenarios. The aim of this study was to compare the dimensional changes after horizontal alveolar ridge augmentation for the anterior maxilla, using split-block bone graft and cortico-cancellous bone block. This randomized controlled trial compared two types of bone blocks for alveolar ridge augmentation: split-bone blocks and cortico-cancellous bone blocks. Both types of grafts were harvested from the mandibular symphysis of 20 patients, who were randomly allocated to either group. Cone-beam computed tomography (CBCT) was used to measure the horizontal ridge width before and 6 months after the surgery. Before augmentation, there was no significant difference in the mean alveolar ridge width between the two groups (P = 0.415). However, after the surgery and at 6 months post-operatively, the mean alveolar ridge width was significantly higher in the split-bone block group than in the cortico-cancellous block group (P = 0.035 and P = 0.013, respectively). Within the limitations of our study, we found that the split-block bone graft is more effective than the cortico-cancellous bone block for horizontal ridge augmentation, as it achieved higher ridge width after 6 months of follow-up.