Augmentation of alveolar ridge defects is a technique-sensitive procedure in dental implantology. Depending on the size of the defect, it may be necessary to use autogenous bone blocks. However, patients may be against these blocks as these procedures are surgically invasive. Case report: This report describes the restoration of a partially edentulous mandible, which suffered a major bone defect from the right canine to the third molar site after multiple implant losses. The use of a CAD/CAM allogeneic cancellous bone block from a living donor bone was planned for the reconstruction of the alveolar ridge at the defected site. A CBCT scan was taken and the virtual planning of the bone augmentation and placement of four implants was performed. The milled bone block was fixed for augmentation and the implants were placed using a CBCT-generated surgical guide. After osseointegration, a CAD/CAM-fabricated screw-retained metal-ceramic implant fixed partial denture with angulated screw channels was delivered. Results: The use of CAD/CAM-milled, allogeneic bone block resulted in a time-efficient and simplified reconstruction of the defect because no donor site was used, and the fit of the block on the native bone was uneventful and fast. At the 1-year follow-up, an average peri-implant vertical soft tissue decrease of 1 mm on buccal and 0.3 mm on lingual sites was observed and the peri-implant tissues were healthy. Conclusions: The long-term success of this CAD/CAM cancellous bone block needs to be evaluated in well-designed clinical studies.