This clinical study was designed to investigate the clinical behavior and assess the volumetric dimensional changes of a cancellous heterologous bone graft, when used to treat anterior maxilla bone defects, in comparison to cortical-cancellous autogenous bone blocks. Seven patients presenting with bone atrophy of the anterior maxilla area received two block grafts in a split mouth design: an autogenous bone block collected from the ascending ramus and an equine-derived bone block. Cone beam computed tomography (CBCT) scans were recorded before the graft surgery (T0), 15 days (T1) and 6 months after the grafting surgery (T2). Bone and graft volume were analyzed using the SimPlant Crystal Pro® software. No complications were observed and all implants could be placed into the planned positions. Equine-derived bone blocks showed a significant smaller volume reduction than autogenous ones (9.2±1.6% vs.14.6±1.2%, respectively, p<0.05). Preliminary results of this clinical study suggest that heterologous bone blocks might be used as a valid alternative to autogenous, intra-orally collected, bone block grafts to obtain sufficient bone volume for the reconstruction and rehabilitation of the atrophic anterior maxilla.