Early healing of implants placed into fresh extraction sockets: an experimental study in the beagle dog. III: soft tissue findings.

AIM To describe histologically the early phases of soft tissue healing to implants placed into fresh extraction sockets. MATERIALS AND METHODS In 16 beagle dogs, 64 3.25-mm-wide cylindrical screw implants were inserted into the distal sockets of the third and fourth lower premolars using a one-stage trans-mucosal healing protocol. Biopsies were then taken at 1, 2, 4 and 8 weeks and prepared for histological examination. RESULTS One-week specimens showed a junctional epithelium and an underlying loose connective tissue rich in inflammatory cells. At 2 weeks, signs of epithelial proliferation and a more organized connective tissue were observed. At 4 and 8 weeks, inflammation was absent; the epithelium appeared mature and in close contact with the surface of the healing abutment or the implant. The connective tissue was dense in an area close to the implant surface and the fibres were aligned parallel to the implant surface. The soft tissue dimensions at 8 weeks were approximately 5 mm, including about 3-3.5 mm of epithelium and 1-1.5 mm of connective tissue. CONCLUSION Soft tissue healing to implants placed in fresh extraction sockets may result in a longer epithelial interface than implants placed in a healed ridge.