This study aims to evaluate the clinical outcomes of using demineralized, freeze-dried allogeneic bone blocks (DFDABB) combined with the periosteal vertical mattress suture (PVMS) technique for the reconstruction of severe horizontal alveolar bone deficiencies in the maxilla. In continuous horizontal maxillary defects cases, bone augmentation was performed using DFDABB and deproteinized bovine bone matrix (DBBM) filling the interstice. Subsequently, a resorbable collagen membrane was carefully placed over the graft surface, and both the membrane and bone graft were firmly secured using the PVMS technique. Linear changes were assessed through superimposed cone-beam computerized tomography scans obtained before the operation and after a healing period of 6-10 months. A total of 7 female patients with 10 bone blocks and 13 implants were included in this study. One of the wounds was slightly ruptured postoperatively without infection, and all implants showed successful osseointegration. The average alveolar ridge width at a point 5 mm below the crest was 4.52 ± 2.03 mm before bone graft and 9.79 ± 1.57 mm after implantation with an average increase of 5.26 ± 1.97 mm. Similarly, at a point 10 mm below the crest, the pregraft alveolar ridge width measured 7.23 ± 3.60 mm, and postimplantation, it expanded to 11.81 ± 2.90 mm, showing an average gain of 4.58 ± 2.01 mm. This case series demonstrates the successful application of DFDABB combined with the PVMS technique to achieve adequate bone width for implantation at severe continuous horizontal bone deficiency of the maxilla. DFDABB with the PVMS technique resulted in superior horizontal bone gain during maxillary bone augmentation with horizontal continuity deficiency. However, further studies are necessary to validate these findings.