The anterior maxillary osteoplasty restores adequate bone to the edentulous Class IV ridge prior to placement of endosseous implants. The aim of this retrospective study was to compare the long-term survival of implants placed into the particulate bone of an anterior alveolar osteoplasty to those placed into a 'block' onlay bone graft. Of 85 patients with Class IV 'knife-edge' alveolar ridges, 50 received interpositional particulate bone via an alveolar osteoplasty and 35 received an onlay cortico-cancellous graft. A total of 386 implants were placed as a secondary procedure and followed postoperatively (mean 6 years; 39 failures). There was improved cumulative survival of implants placed into the particulate bone of an osteoplasty compared to the block bone of an onlay graft. Implants supporting a fixed superstructure had a longer cumulative survival than those supporting a removable appliance. There was no statistical difference between implants placed into male and female bone, or between those in edentulous and partially dentate jaws. Within a partially dentate jaw there was a statistically significant increase in cumulative survival for implants within osteoplasty inlay bone compared to onlay bone grafts. Anterior osteoplasty is the surgical treatment of choice for augmentation of the resorbed Class IV alveolar ridge prior to placement of osseo-integrated implants.