Abstract

ObjectiveTo characterize the distribution of macrophages, neutrophils, NK cells, and blood vessels in peri-implantitis compared to healthy aged gingiva samples.Materials and MethodsThis observational study included eight gingival samples from peri-implantitis and eight from periodontally healthy individuals. By immunofluorescence were identified neutrophils, NK cells, macrophages, and their pro-inflammatory or pro-healing phenotypes, and blood vessels. Two ROIs were designated as zone 1, connective tissue closest to the epithelium and zone 2, connective tissue over 200 microns from the rete ridges. Immune cells and vascular structures were quantified and characterized according to their distribution in both zones.ResultsTwo peri-implantitis zones were characterized by unique macrophage phenotypes and blood vessel architecture. Blood vessels were larger in zone 2 in peri-implantitis. A greater number of NK cells and macrophages were found in peri-implantitis compared to healthy aged samples. A higher presence of pro-inflammatory macrophages was found in zone 1 compared to zone 2. A similar proportion of pro-inflammatory and pro-healing macrophages were found in zone 2.ConclusionA specific distribution for pro-inflammatory macrophages and vascular architecture is observed in peri-implantitis. TNF-alpha colocalizes with macrophages in the connective tissue near rete ridges. NK cells are more abundant in peri-implantitis than in healthy samples.