The microbiota associated with oral endosteal sapphire ceramic implants was studied using cultural methods. Samples were taken from both implant and control (tooth) sites, and comparisons were made between healthy and diseased and between implant and control sites. Diseased sites harbored a microbiota with a large number and proportion of Gram-negative anaerobic rods, black-pigmented Bacteroides, and surface translocating bacteria. Healthy sites in the same patients had smaller amounts of bacteria dominated by facultative Gram-positive cocci and rods. The microbiota in diseased and healthy implant and control sites was very similar. It is suggested that peri-implant tissues behave very similarly to periodontal tissues and that peri-implantitis lesions should be considered as site-specific infections harboring a high number of periodontal pathogens, mainly Gram-negative anaerobic rods. Schlagwörter: dental implants, peri-implantitis, periodontal pathogens