BACKGROUND: Little is known regarding the histologic hard and soft tissue changes that occur in chronic periimplantitis situations in humans. It is critical to gain an understanding of all aspects of periimplantitis to develop appropriate therapeutic approaches. METHODS: An 83-year-old African American man presented with a fractured implant affected by severe, chronic periimplantitis and surrounded by keratinized gingiva. A trephine biopsy of the implant and surrounding tissues was analyzed histologically. RESULTS: Histological analysis of the periimplantitis specimen revealed significant inflammatory infiltrate consisting predominantly of lymphocytes and plasma cells. In addition, epithelial migration and bone loss to the apical vent were noted. CONCLUSION: This case report documents a single case of periimplantitis that was left untreated for 7 years. The presence of significant keratinized tissue and a smooth surface implant failed to prevent fibrous encapsulation of the implant.