Endosseous dental implants include an at least partly, externally-threadedbody portion, an internal cavity or shaft with an opening to the cavity orshaft at the top surface of the implant, and, in the internal cavity or shaft,a threaded portion, and a two part interlock chamber contiguous to saidthreaded portion including multi-lobed surfaces in a first part, and aplurality of lobes, slots or grooves in a second part..