Existing Bone-Derived Bone Morphogenetic Protein-2 Initiates Contact Osteogenesis on the Surface of a Titanium Implant

The dental implant relies on osseointegration and the response of bone to the implant surface. This process comprises bidirectional bone formation, including bone deposition on the implant surface toward the existing bone (contact osteogenesis) and vice versa (distance osteogenesis). It is unclear whether these processes are independent or whether contact osteogenesis is initiated by other factors. Therefore, this study aimed to identify the initiator of contact osteogenesis. We hypothesized that contact osteogenesis does not occur when it is physically isolated from distance osteogenesis, which would imply that some factors from the wounded bone normally promote contact osteogenesis. Using a rabbit tibial implant model, we tested the effects of human recombinant bone morphogenetic protein-2 (BMP-2) and plasma-rich plasma, which are possible initiators from bone and blood, respectively. Titanium implants with BMP-2 showed a better bone-to-implant contact (BIC) ratio. We concluded that BMP-2 initiated contact osteogenesis on the surface of titanium implants.