Immediate loading of dental implants can significantly decrease treatment time and thus increase patient acceptance. However, there is still a need to investigate whether an implant in which primary stability is achieved can be immediately loaded without the formation of connective fibrous tissue at the interface. Three transitional implants were placed in an edentulous mandible: two implants loaded immediately and one left unloaded. All transitional implants were retrieved after a period of 12 weeks to perform qualitative and quantitative analysis of the peri-implant tissue and bone-implant interface. Bone biopsy specimens containing the transitional implant were analyzed using microcomputed tomography (micro-CT). Subsequently, the same samples were analyzed using standard undecalcified histology. Micro-CT analysis showed that bone tissue was slightly detached from the surface of the loaded implant. Histology demonstrated the presence of a soft tissue layer inside the socket. Morphometric values of total bone volume, bone-implant contact, and bone connectivity were higher for the unloaded implant, which appeared to be covered by an almost continuous layer of bone. Micro-CT evaluation of some morphometric parameters and histologic results pertaining to small-diameter transitional implants showed that uncontrolled loading may produce untoward effects on peri-implant bone healing.