Sinus floor augmentation with simultaneous placement of dental implants using a combination of deproteinized bone xenografts and recombinant human osteogenic protein-1 - A histometric study in miniature pigs

Maxillary sinus floor augmentation with autogenous bone has become a widely accepted procedure in implant dentistry. The use of osteoconductive bone s ubstitutes in this indication is controversial, since their use can lead to a prolonged healing time, inhomogenous ossification, foreign body reaction , migration of particles and low bone-implant contact (BIC). The purpose of this study was to examine whether the combination of an osteoinductive pro tein (recombinant human osteogenic protein-1 (rhOP-1 = bone morphogenetic p rotein-7) with natural bovine bone mineral (BioOss(R)) would improve ossifi cation and the bone-implant contact (BIC) in a sinus floor augmentation wit h simultaneous placement of implants. In this study, the maxillary sinus fl oors in 5 miniature pigs were augmented with 3 mi BioOss(R) containing 420 mu g rhOP-1 on the test side and 3 mi BioOss(R) alone on the control side. At the time of augmentation a titanium implant (ITI(R)) was inserted from a laterocaudal direction. After 6 months of healing the sites of augmentatio n were removed and examined in non-decalcified sections by microradiography , fluorescence microscopy of sequentially labelled specimens and by histome try. On both sides, significant amounts of newly-formed bone were observed. However, on the test sites, the percentage of BIC in the augmented area wa s 80.0% versus 38.6% on control sites. It can be concluded that the applica tion of bone morphogenetic proteins caused a more rapid and enhanced osseoi ntegration of simultaneously placed implants when compared to the bone subs titute alone. Therefore recombinant human osteogenic protein-1 delivered by natural bone mineral has the potential to become a clinical alternative fo r autogenous bone grafts in sinus floor augmentation.