The purpose of this study was to evaluate treatment of resorbed posterior mandibles with interpositional bone grafts (the "sandwich" technique) and implant-supported prostheses. Six consecutive patients with resorbed posterior mandibles (seven sites) were treated by the sandwich osteotomy technique with an interpositional bone graft harvested from the iliac crest. Vertical bone height was measured before surgery and 3 to 4 months later, prior to implant placement, on computed tomography scans to evaluate the augmentation obtained. In all the treated sites it was possible to place implants. None of the 21 implants placed failed, and minimal bone resorption was present 14 to 16 months after the prosthetic loading. If confirmed by long-term follow-up studies and more cases, these findings suggest that interpositional bone grafting in the posterior mandible could be a viable alternative to other surgical techniques.