Peri-Implantitis and Concomitant Perigraftitis of an Implant Placed in a Site That Had Alveolar Ridge Preservation Three Decades Earlier: A Case Report With Human Histology.

Introduction: Although alveolar ridge preservation may minimize alveolar ridge shrinkage following tooth extraction, there is a paucity of data on the effects of alveolar ridge preservation on implant-related outcomes. The purpose of this manuscript is to report on peri-implantitis of an implant placed at a site that had alveolar ridge preservation three decades earlier, and the subsequent dislodgement of an approximately 1-cm grafted bone specimen during degranulation 4 months after implant reversal.

Case Presentation: A 58-year-old male had #18 removed and the extraction socket grafted in the 1980s. In 2016, an implant was placed at #18 and restored with a screw-retained restoration. It developed mobility and was removed in 2017; the explantation site was not grafted. In 2018, another implant was placed at #18 and restored in 2019 with a screw-retained restoration. At the 1-year follow-up, the implant had developed peri-implantitis. Consequently, it was reversed without flap elevation. Four months later, infection remained. A buccal mucoperiosteal flap was reflected. Implant threads remained visible in the grafted bone. During degranulation, an approximately 1-cm grafted bone specimen dislodged from the mandible. Microscopy of the specimen shows numerous synthetic graft particulates surrounded by vital bone, with a mixed acute and chronic inflammatory infiltrate on its periphery.

Conclusion(s): Within the limitation of this case report, absence of bone resorption due to impaired/altered bone metabolism of the grafted bone likely allowed bacteria to reach and infect the grafted bone via the implant fixture during development and progression of peri-implantitis.