Various techniques have been proposed to regenerate deficient ridges after tooth removal, including guided bone regeneration, block grafting, distraction osteogenesis, and ridge splitting. However, these procedures are technique-sensitive and often present complications which prevent reconstruction of the deficient ridge and implant placement. In an atrophic anterior or posterior maxilla, these techniques often fail to produce satisfactory long-term outcomes due to the poor bone quality, pneumatization of the maxillary sinus, and the highly cosmetic patient demands. The customized alveolar ridge-splitting (CARS) technique was introduced to improve outcomes and minimize the risk of complications. The synergistic combination of this technique with another augmentation procedure-including lateral window sinus augmentation and guided bone regeneration-allows implant placement into ridges with deficient bone volume both vertically and horizontally. This study presents two case reports that were successfully treated with the CARS technique and additional augmentation techniques to treat severely atrophic ridges in the anterior and posterior maxilla.