Platelet-rich plasma is an autologous product that is derived from whole blood through the process of gradient density centrifugation. The proposed value of this product in dental implantology and in bone augmentation procedures lies in the ability to incorporate high concentrations of the growth factors PDGF, TGF-ß1, TGF-ß2, and IGF, as well as fibrin, into the graft mixture. Research has shown an increased bone maturation rate and improved bone density when this product, or its recombinant growth factors, is added to small bony defects or to larger defects that use autogenous bone as the grafting material. This study tested the efficacy of platelet-rich plasma in three bilateral sinus graft cases with grafts of anorganic bovine bone that contained minimal or no autogenous bone. Histomorphometric analysis indicated that the addition of platelet-rich plasma to the grafts did not make a significant difference either in vital bone production or in interfacial bone contact on the test implants.