Features of peri-implantitis associated with luting cement extrusion: a histopathologic report in humans

Objective: To describe and illustrate the histologic characteristics of luting cement-induced peri-implantitis in the posterior maxilla of a 56-year-old man. Case presentation: A dental implant inserted 6 years previously in the maxillary left first premolar region revealed pus and swelling. A periapical radiograph showed severe bone loss around the dental implant, and the presence of surrounding residual particles of luting cement. The implant was removed with its adjacent tissues. The harvested implant was fixed in formaldehyde solution (formalin). A 4-mm fragment of soft tissue and a 6-mm fragment of bone were cut from the implant specimen and submitted for routine processing of hematoxylin-eosin (h&e) slides for histologic analysis. The implant specimen was processed and embedded in glycol methacrylate resin and ground to a thickness of 50 µm for histologic examination. Results: The microscopic examination of the h&e slides showed connective tissue with an inflammatory infiltrate composed of histiocytes, lymphocytes, and plasma cells. There was a fragment of viable bone integrated with the bone graft material. The bone showed evidence of active resorption by osteoclasts in Howship lacunae. The implant sections showed trabecular bone with lamellar structure in the apical portion. Foreign body, compatible with luting cement, was present in the coronal portion, adjacent to the threads of the implant, as well as osteoclasts in Howship lacunae. Conclusion: This report, documenting a case of peri-implantitis associated with excess cement extrusion, revealed that that the bone loss was associated with an inflammatory infiltrate. Additional studies focusing on the histopathologic characteristics of peri-implantitis could help to increase the knowledge of peri-implant disease to shed light on prevention and treatment. Keywords: excess cement extrusion, histology, peri-implantitis