An experimental study on the features of peri-implant epithelium: immunohistochemical and electron-microscopic observations.

The purpose of this study was to investigate the immunohistochemical and the ultrastructural features of the implant circumference epithelium of the beagle dog using various types of antibodies. The peri-implant epithelium was at an acute-angle from the gingival epithelium and was arranged in parallel to the implant surface. With immunohistochemical staining, the peri-implant epithelium was strongly positive for KL-1, and weakly positive for CK4, CK8 and CK19. These positive reactions for keratins and also for PCNA and BM-1 were similar to those seen in the oral mucosa. In the peri-implant epithelium, a plentitude of microvilli were observed at the periphery of cells at the implant sites, and bacteria were observed between the implant and the peri-implant epithelium without the formation of half desmosomes. There were many lipid-like vacuoles or lysosome-like granules. The intercellular space was wider than the junctional epithelium, and random migrations of large numbers of neutrophils could be seen. Taken together, the peri-implant epithelium is similar to that seen in the oral mucosa, and it is structurally different from the junctional epithelium.