The formation of the mucosal adhesion was studied in a dog model. One‐piece implant devices were placed in the edentulous mandible of dogs, and healing was monitored using light microscopic examination of biopsies sampled at different intervals during a 3‐month period. In the initial phase of the wound between the implant and cut connective tissue, a fibrin clot/coagulum formed that was infiltrated with mainly neutrophils and limited amounts of macrophages. The number of inflammatory cells subsequently subsided, and the wound surface became characterized by its dense layer of fibroblasts that appeared to be in intimate contact with the implant surface. In the 2nd to 3rd week of healing, the density of fibroblasts was reduced, the amount of collagen and matrix components increased, and epithelial cells, extending from the oral epithelium, had started to occupy marginal parts of the connective tissue wound. Collagen fibers in the previous wound area became organized in bundles after about 4 weeks. After 6 to 8 weeks the mucosal adhesion appeared mature, and the interface zone at tissue–implant was comprised of a combined epithelial and connective tissue adhesion to the implant surface. Since the build‐up of the soft tissue adhesion did not change much after the first month, it is suggested that a homeostasis had been reached at this interval.