Rehabilitation of the atrophic alveolar ridge is often problematic. Bone augmentation surgery may be hindered by a lack of surfaces from which blood vessels can spread during the initial stages of bone regeneration. If heterologous biomaterials are used as an alternative to autologous bone grafts, the standard delivery formats-blocks or granules-both have significant limitations. The present study was designed to evaluate the effectiveness of an alternative material, a flexible equine bone sheet, for vertical ridge augmentation. Forty-nine implants were placed in 18 patients whose vertically atrophic maxillary or mandibular ridges were simultaneously augmented with flexible cortical bone sheets derived from equine femurs. After 4 months, the ridge volume for all patients was completely restored, all implants had successfully osseointegrated, and definitive prostheses were placed. These parameters remained unchanged throughout 3 years of follow-up.