Purpose: To evaluate the efficacy of vertical guided bone regeneration (GBR) in the mandible using a nonresorbable membrane and a bone graft combination of autogenous bone chips and high-temperature processed (HTP) xenograft via CT scans and micro-CT analysis. Materials and Methods: Patients underwent vertical ridge augmentation procedures prior to implant placement. The surgical procedure included flap elevation and placement of a bone graft comprising a 1:1 combination of autogenous posterior mandible–derived bone chips and HTP xenograft graft particles covered with a dense polytetrafluoroethylene (d-PTFE) membrane trimmed to suit the 3D shape of the bone defect. This was fastened securely with titanium (Ti) screws and pins as well as a layer of native collagen membrane. Postoperative complications and ridge measurements were assessed. Before bone augmentation and implant placement, the bone parameters were obtained from CT scans. Biopsy samples were. harvested during implantation and were examined via micro-CT. Results: All 13 study procedures were successful without any complications. The results revealed average vertical and horizontal bone gains of 3.35 mm and 5.15 mm, respectively. A total of 33 implants were successfully placed in the augmented areas, without the need for further bone augmentation. Micro-CT analysis revealed 48% bone, 15% filler material, and 37% noncalcified tissue in the augmented region compared to 65% bone, 3% filler material, and 32% noncalcified tissue in the pristine bone. Conclusions: A mixture of autogenous bone and HTP xenograft, covered with a d-PTFE membrane and a layer of native collagen membrane, was effective for vertical GBR.