This report presents a histologic assessment of guided bone regeneration for dehiscence defects treated with bovine bone mineral or a combination of autogenous and synthetic bone. The samples were obtained from an autopsy specimen donated by a patient, which is a rare opportunity to evaluate longterm results of guided bone regeneration and osseointegration. The values for bone-to-implant contact were similar in both sites. The augmentation with bovine bone mineral demonstrated bone reconstruction after 1 year, whereas the augmentation with autogenous and synthetic bone failed to maintain the augmented volume, eventually leading to mucosal recession after 5.5 years.