Four partially edentulous patients received particulate autogenous bone and platelet-rich plasma (PRP) in one sinus and particulate autogenous bone alone in the contralateral sinus. After 6 months of healing, two or three Osseotite implants were inserted, and an additional Osseotite mini-implant was placed into the graft through the lateral wall of the sinus. At abutment connection, the mini-implants were retrieved for histologic examination. Despite similar clinical and radiographic healing patterns, a higher bone-to-implant contact rate was observed on the implants placed in bone and PRP than on those placed in bone only (46.75% ± 13.6% versus 20.5% ± 5.57%, respectively).