This study evaluated the effects of osteogenic protein 1 (OP-1) placed in a gap around uncoated and hydroxyapatite (HA)-coated implants. Unloaded cylindrical titanium alloy implants were inserted in the femoral condyles of 16 skeletally mature dogs surrounded by a 3-mm gap. The gap around the implants was filled with 325 microg OP-1 in 130 mg bovine collagen type I as carrier (OP-1 device) or collagen carrier alone or left empty. All groups were tested with both HA-coated and uncoated implants, and the animals were sacrificed after 6 weeks. Implant fixation was determined by push-out test. Bone ongrowth and bone formation were evaluated by quantitative histomorphometry. OP-1 device enhanced mechanical fixation of uncoated and HA-coated implants, resulting in a higher shear strength than implants with collagen matrix and control implants. Bone ingrowth and bone formation in the gap were also stimulated 3-fold for OP-1 groups when compared with empty controls, but no difference was found between OP-1 groups and collagen matrix groups. This study suggests that the OP-1 device placed in a gap around uncoated and HA-coated implants is capable of enhancing mechanical fixation and periimplant bone formation. The collagen carrier alone also enhanced bone ongrowth and fixation significantly.
View details for Web of Science ID 000086458900011
View details for PubMedID 10794230