Osseointegration is becoming increasingly routine in the rehabilitation of partially or fully edentulous patients. However, the surrounding tissues may be subject to inflammatory conditions similar to periodontal disease and so require maintenance. This article discusses the background, aetiology, diagnosis of peri-implant diseases, and the maintenance, care and treatment of peri-implant infection in osseointegrated implants. Three case studies are presented to illustrate points in the care of implants.