Contact Osteogenesis: In this the osteogenic cells attach to the implant surface and the new (de novo) bone is formed on the implant surface first. The developing bone matrix can directly interlock within the surface morphology. The implant surface has to become colonized by bone cells before bone matrix formation can begin. Contact Osteogenesis is the desired tissue response leading to firm osseointegration. It results in bone apposition to the implant surface.