This randomized prospective study evaluated the clinical benefits of using a corticocancellous mixture of freeze-dried bone allograft alone or in combination (1:1) with particulated autogenous bone for horizontal ridge augmentation and subsequent implant placement. Twenty-four patients with atrophic ridges received lateral ridge augmentations with particulate grafts placed around tenting screws and covered with a fixed acellular dermal matrix membrane. Thirty-three standard-diameter implants were successfully placed in 21 patients after a 24-week graft healing period. Three patients experienced early postoperative infections following the grafting procedure (12.5% of sites). At reentry, the allograft alone group showed similar average horizontal ridge width gains (3.33 ± 0.83 mm) to the combination group (3.09 ± 0.63 mm; P = .44). The mean graft resorption between baseline and reentry averaged 13.89%.